Chapter I

INTRODUCTION

Engineering science is the science devoted to the investigation, study and solution of engineering and environmental problems, which may arise as the result of the interaction between geological, and the activities of people, as well as for the prediction of and development of measures for the prevention or remediation of geological hazards.

Engineering geology is thus one of the most interesting and useful subject for the layman and the knowledgeable people alike.It is only the only subject which gives information about the earth.

Studies of geological history reveal periodical occurrence of large-scale catastrophic phenomena like orogeny, eperiogeny, intense volcanic activity and glaciations. These distinguish the beginning or end of geological era, which is relatively calm and flourishing with life. Thus engineering geology is a broad subject, which can only be understood by doing extensive observation in the field-through hills and mountains, valley and gorges and along dense forest and terrains.

The civil engineering structures as are erected on the earth, so the geology of earth i.e. features, properties and behavior of ground are very essential to be studied. The field study will help to be acquainted with the properties of rocks, its chemical alterations and deviations in properties with respect to time, external forces, agents, geological hazards, function of mass movement, debris flow, etc. can be known through our eye in the field trip.

Malekhu area, its panoramic view impressed all of us with its greenery as well as the river flowing there, as if they want to unfold the mystery of Malekhu by striking on different places and exposing boulders, rocks, soil, etc. there.

This Malekhu bearing cool climate and consisting of nearly all geological cases to study proves to be the best place for site visit for the students of Engineering and Geology. As an Engineering student we were there to learn about Malekhu’s wonderful geological diversities and almost all types of the rocks, structures and geological factors like rivers, hills, slopes, sedimentation, etc.

We have chosen this Malekhu area but not other area because Malekhu is the only place where we can unfold the geology of the entire country through the small area here. Also as Malekhu helps us to study the various probable causes of geological failure of civil engineering construction, as we have to study different types of mass movement activities like slope failure, landslides; we chose this Malekhu area. Malekhu consists of geological structures like Benighat Slate, Malekhu Limestone, Robang Formation, their lithology, boundary condition and exposure places. Also the Raduwa formation, Bhaise Dhovan Marble attitudes can be studied there.

Fold, fault, joints, veins, thrust formed during rock formation significances provide a challenging situation not only to the geologist but also we dreaming to be civil engineers.

We thus, the student of engineering geology, the branch of science devoted to the investigation, study and solutions of engineering and environmental problems which may arise as the result of interaction between geology and the works and activities of people, as well as for the prediction and development of measures for the prevention or remediation of geological hazards; are very lucky to be participated on a three day geological trip in Malekhu organized by our college, Kathmandu Engineering College.

OBJECTIVES

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The main objectives of our field visit were: Measurement of dip and strike, Study of bedding, foliation, Handling of compass for documentation of Engineering geological data, Study of mass movement activities, Study of morphology of river channel, Rock identification in the field, Identification of geological units of the Lesser Himalaya and Kathmandu Nappe, Engineering geological studies along the large scale geological discontinuity (The Mahabharata Thrust) and Study different types of rocks.

INSTRUMENTS

The various instruments used in the field study were as follows:

(i) Hammer

A hammer was used to test the hardness of rock in the field. It was performed by striking the tip of hammer and the surface of the rock whose hardness was to be determined.

(ii) Geological Compass

A geological compass was used to measure the attitudes of the geological structures. The compass was mainly used for measuring the bearing of object with respect to north, to measure attitudes of geological structures such as strike and dip of planes, plunge and trend of lines, to measure slope orientation. The commonly used geological compass during the field visit was Clinometer and Brunten Compass. The main operation of geological compass consists of opening the compass carefully, leveling the spirit level and placing the compass on the planer feature to take the measurement.

(iii) Measuring Tape

A measuring tape was used to measure the distances between different discontinuities such as in the outcrop of rock strata.

(iv) Dilute Acid Bottle

An acid bottle was used to test whether the studied sample contained calcite as its main mineral or not. If the sample rock gets reacted with acid then the rock was considered as the calcite containing rock.

Chapter II

STUDY OF MASS MOVEMENT ACTIVITIES AND SOLUTION MEASURES

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Mass Movement

Disintegrated and Fragmented rock materials due to mechanism of weathering processes i.e. mechanical, chemical and biological are called rock wastes. The movement of rock waste down the hill slope is called mass movement. Mass movement is the detachment and down slope transport of soil and rock material under the influence of gravity. The sliding of these materials is due to their position and gravitational forces. But mass movement is accelerated by presence of mainly water. The movement of rock waste depends on the ration of shearing resistance of material to the magnitude of shearing force, which is called factor of safety (Fs).

Here,Fs = (Shearing resistance of Material)/(Magnitude of Shearing Force)

If Fs < 1, mass movement occurs If Fs > 1, stable condition of slope If Fs = 1, equilibrium condition of slope

a) Types of Mass Movements:

In general, mass movement has been classified into main thee types i.e. slope failure, debris flow and landslide.

i) Slope Failure:It is the movement of weathered surface rock/soil layer of steep slope in small dimension and rapid movement. In this there may be absence of slip surface. Steep slopes, loose soil, excavation of rock on downhill side are the main causes of slope failure.

ii) Debris Flow:It is the movement of deposited or eroded sediments along the stream. It is the rapid movement of large amount of viscous soil and boulders either separately or mixed together, and occurs mostly along river valley side.The difference of debris flow, earth flow and mudflow is related to size of particles and amount of water.Debris flow ------------- Earth flow --------------- Mudflow (Increases Water Content)Debris flow ------------- Earth flow --------------- Mudflow (Decreases Size of Particles)In case of debris flow 20-80% of particles are coarser than sand sizes but in case of earth and mudflow more than 80% of particles are mud and sand.

iii) Landslides:It is the movement of large sediment mass of soil and rock material along a slip surface under the influence of gravitational force. It is also the mass movement which has a clear sliding surface with large dimension, occurs in gentle slope and moves slowly and continuously basically due to influence of water and gravity.On the basis of movements and materials, Varnes (1978) classified landslides, which are as follows:

a) Falls:Falls are abrupt movement of the slope material that separates form steep slopes and cliffs. Depending upon the slope materials involved, it may be called rock fall, debris fall and soil or earth fall.

b) Topples:Topples are blocks of rock that tilt forward on a pivot and then separate from the main mass, fall on the slope, and subsequently bounce and roll down the slope. They may be rock topples, debris topples and soil topples.

c) Slides:

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These are movements caused by finite shear failure along one or more rupture surfaces, which are visible or whose presence can be inferred. There are two types of slides:

i) Rotational: This type of slide involves sliding movements on the circular or near circular surface. They generally occur on slopes of homogeneous clay, shale, weathered rocks and soils.

ii) Translational: This type of slide involves non-rotational block slide i.e. mass movements on more or less planar surface. They generally occur on unconsolidated soils, slab of rock and debris.

d) Spread:These failures are caused by liquefaction whereby saturated, loose, cohesion less sediments are transformed into a liquid state. Rapid ground motions, such as those caused by earthquake are responsible for this phenomenon.

e) Flows:Flows are rapid movement of material as a viscous mass where inter-granular movements predominate over shear surface movement. These are debris flow, mudflow, and rock flow depending upon the nature of material involved in movements.

f) Complex failure:There are slides in which failure occurs due to combination of fall, flow, slide, spread, topples, etc. with multiple slip surfaces.

Factors Causing Landslides:There are several factors that directly or indirectly cause slope instability. In stable condition shearing resistance of material is higher than magnitude of shearing force but it is modified by various internal and external factors and so the shearing resistance of material is less than magnitude of shearing force, hence landslide occurs. These external and internal factors, which cause failure, are primary causes of failure and secondary causes of failure. Force of gravity, strength, rock structure (folding, faulting, jointing, foliation, bedding), soil depth, porosity, permeability, rock type and soil type are the primary causes of failure and seismicity, intensity of precipitation, land use, natural slope conditions, rock and soil weathering conditions, presence or absence of gullies, streams and rivers and ground water conditions are the secondary causes of failure.

Preventive Measures For Landslide:

The preventive measures for landslides are construction of retaining structures, piling works for reinforcing ground and anchor works.

1 Retaining Wall: Retaining walls are relatively rigid walls used for supporting the soil mass laterally so that the soil can be retained at different levels on the two sides. According to construction material, following are the types of retaining wall:

Gabion Wall – Made by filling stones in wire net Stone Masonry Wall – Made by stones jointed by cement Concrete Masonry Wall – Made by mixtures of aggregates and cement

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Retaining wall is constructed to resist the thrust due to soil sliding. This method is used to prevent small-scale landslides having small thrust. It is usually applied in combination with other methods since it is very difficult to prevent a landslide with retaining structures only. The flow of ground water is high in the landslide area; therefore, flexible structures such as gabion wall should be adopted as retaining structure.

2 Pile Works: Steel Piles of 200-600 mm are driven through the sliding surface to control landslide movement directly. This work is used in very urgent and important locations.

3 Anchor Works: An anchor is applied to prevent a landslide through the tensile strength of steel wire or steel bar, which anchors the sliding soil mass to the bedrock. One end of the wire is fixed to the bedrock and other end is fastened to a bearing plate on the sliding mass.

Corrective Methods for Maintaining Stability of Landslide:The corrective method includes the reduction of pore water pressure, slope reformation and erosion protection. These methods are applied when landslide occurs in particular place.

1 Reduction of Pore Water Pressure: It can be reduced by improving of surface and sub-surface water drainage. This can be done by constructing surface and sub-surface water drainage system and prevention of water infiltration by application of bioengineering techniques i.e. armoring; surface water should be drained out to prevent infiltration from precipitation into the sliding mass.

2 Slope Reformation: Due to landslide, slope may become steep and unstable. The soil removal after trimming of slope is main function for correction. Sliding force can be reduced through the partial or entire removal of the sliding mass from crown side of the landslide.

3 A Loading Embankment Work: It is made at the top of the landslide to balance the sliding force with the additional loading force. This method is also widely used because of its reliable and immediate effect and sometimes is combined with soils removal work at the head of landslide.

4 Protection From Erosion: Landslides are caused due to the degrading of streambed or toe erosion caused by meandering of stream. In such cases prevention of erosion at toe part of the landslide mass or steam bed is important through the construction of structures like check dams, revetment work, spurs, dike, etc.

Mass movement is the movement of the superficial surface of the land by leaving their original positions abruptly of extremely slowly and starts either a downgrade movement or vertically downward sinking. Mass movement is the most challenging slope process related to the potential energy developed due to the gravitational stress may or may not influence by the pore water pressure. Slope failure, landslides, debris flow and creep are the major mass movement phenomena. As the mechanism of the mass movement differs, the necessary treatments and stabilization measures are also different for each. Also the complex types are also present which make the problem more complex.

b) CASE STUDIES

LOCATION 1

CASE 1 : Jhyaple Khola (Chainage: 15+200)

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In this place, we found that there was certain ground mass movement towards downward direction, which occurred during the monsoon season. So as safety measurements were taken by building the breast walls around the region where the mass movement has occurred. The movement of the rock has occurred in slow but steady condition. During the monsoon season, the rainwater had flown in the area weakening the rocks by flowing inside the cracks and the steep slope further added in the rupture of the hill site. Geological material present there was also of low load bearing capacity due to the presence of the fractured rock. Dynamic load due to the moving vehicles further increased the danger of failure of the site. Due to these problems in the site, some of the consequences followed them such as the traffic interruption during monsoon season, economic loss as we had to rebuild the road or the construction site after the landslide has done the damage. Thus we have to take some preventive measures in order to minimize the consequences as far as possible. For this purpose, first we have to build the breast walls taking in the account of the factor of safety (factor of safety = resisting force/driving force).

The factor of safety in our case should always be greater than 1.5 otherwise other solution measurements has to be taken such as building stabilizing structures which is called stabilization measures such as rock bolt, anchoring in the soil, retaining wall (gabion wall) etc. To stop further mass movement, bamboos were planted at critical places. Even after the building of the stabilizing structures, we also add protection measures such as surface drain, friction angle (slope angle), and vegetation such as herb are planted which is now called bioengineering. Whatever the solution measures are taken it is never 100% appropriate because they won't be able to prevent the movement for long period of time. Further, the self-weight of the gabion wall hampers the equilibrium of the material and the structure. The protection measure is applicable only for the falling material but not for the equilibrium structure.

It includes the mass wasting of hill slopes process in which pre-dominancy of P.E. has been disturbed by shifting the position of mass, the slope failure.

Causing Factors:

1 Slope steepness

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2 Constituent materials with low strength

3 Increase in water pressure during monsoon

4 Uncontrolled flow of surface water

5 Contrasting behavior of clay in slope surface

CASE 2: Jhyaple khola [Chainage: 15+300]

In this site we observed a medium scale failure with the exposure of a scarp which is human induced slope failure. We could observe a winter water stream that had more or less presumed the shape of a small gully. The concentration of the nearby water seepage in this region must have eventually resulted into this failure.

Considering the precaution measure, a toe wall has been constructed about 15 meters from the failure so that debris due to further erosion would not obstruct the highway and get accumulated within the wall. Notable whip holes were also observed in the wall.

LOCATION 2

CASE 3 : Far bank of Mahesh Khola at Juge Khola Bazaar

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In this site we observed a big portion of hill slope by the left of which a small downstream, Juge Khola, was flowing in the south direction and just at the base of the slope another river a bit larger than the earlier, Mahesh Khola, flowed in west direction. The picture clearly showed that the region is an example of fragile geology because within an area of a couple of kms. large number of scarps old and new appeared which indicated the region itself to be quite unstable. Altogether five scarps occurred out of which three of them just above the river were old ones. Sandwiched between the two old scarps was a rather newer slide. At the extreme left corner appeared the other newer slide. Just above these slides, there was the other new slide. There might be presence of slip surface just below the scarps of the system of slides above the Mahesh Khola, which can be determined by the methods, mentioned above. Nearly midway of the site we could observe a gully comprising of Debris. Observing the older scarps we could conclude that in one way the region was gradually getting stabilized due to these failures.

Nearly at the tip of the region we did observe human inhabitance. But the most interesting thing was that just below the region there were some scarps and further erosion if occurs in the same region may lead into human exodus resulting chaotic scenario on the whole. This type of landslide is known to be complex landslide.

LOCATION 3

CASE 4 : Confluence of Belkhu Khola and Trishuli River

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This site consists of a cliff, which is vertical, but this site seems to be stable. This is because exposed soil is of red colour and the soil becomes red when it is exposed for a long period of time. All steep slopes are also not stable. If slope is of 35-60 degree then the slope is unstable. If the slope is more than 60 degree i.e. the slope is vertical, it is stable. Vegetation is also seen along a line in the cliff. This is because of the permeability contrast. Different beds are seen in that cliff. A layer of coarser and finer grain is also seen in the cliff. Water can easily pass through coarser layer but water is not permeable through finer layer. So due to the permeability contrast there is seepage in that layer and due to the presence of moisture in that layer growth of vegetation occurred. The freehand sketch of the field is also attached herewith.Near these site remains of the old bridge is also seen. There is not any sort of failure of cracks in the foundation of the bridge. So failure of the bridge is not the engineering failure. It is due to the absence of enough knowledge about the river behavior. From the surroundings we can see pebbles and boulders at a great height, which shows that river, had reached at that height during some period. So the bridge collapsed because it must have been built below the flood plain. There is presence of human inhabitance along the river banks which is not so safe regarding the potentiality of the river and in the near future it may result into human casualties during the next winter in case if the flow exceeds its current boundary. We should also estimate the debris potentiality of the river while constructing a bridge and we should build it above the flood plain of the river. Thus considering these facts a new bridge has been built in that area quite above the reach of the river even in the high potential time. The picture below explains how the positioning of the old bridge failed.

LOCATION 4

CASE 5 : 4 Km from Gajuri (42 Km. along Prithvi Highway)

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The picture shows the mass movement occurred probably due to the flow of water into the mass from the topside of the mass through cracks. The retaining structure has also suffered some damage. Further possibility of mass movement at this area is prevented by erecting gabion wall, stone masonry wall and a special type of surface drainage system which is called ‘Cascade Drain’ was introduce here. At the very near to the roadside drainage there was a long gabion wall which was playing a great role to prevent the flow of failure mass over the road. At this particular site, there was a small example of Bioengineering to prevent further landslide. s on the roadside by which water entered the road. During the construction phase, the less quality materials were used. There is presence of vegetation on both sides of the mass movement site.

LOCATION 5

CASE 6 : Malekhu Rockslide (Chainage 43+000)

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In above picture, we can clearly see that there are three different planes at the same site. Due to the intersection of these three planes, pieces of rock are sliding down to the roadside. Due to the presence of there intersecting planes, there we can see the broken pieces of rocks have wedge shaped structure. This type of failure is known as wedge failure.

Chapter III

ROCK EXPOSURES AND MEASUREMENTS:

a) Planner features at the rock outcrops

The features preserved in the rock, which are responsible to form the plane surface, are called planner features. Bedding plane in a sedimentary rock is an example of planner features. Bedding plane generally follow the

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deposition plane.

b) Attitudes of the geological Structures

Linear features

Planner features

Orientation of linear features

Trend: The orientation of horizontal projection of the linear feature measured with respect to the north is called Trend.

Plunge: The angle of inclination measured of its own linear feature horizontally is called plunge.

Planner features

Strike: The line of intersection of an incline plane with its own horizontal projection is called strike line and the orientation of the strike line is called Strike with respect to the universal North (bearing of the strike line)

Dip Direction: The orientation of the maximum inclination of a planner surface with reference to universal North (bearing of max. inclination)

Dip amount: The angle of maximum inclination plane with respect to its own horizontal projection.

c) Measurement of the Attitudes of Planner Features at the Rock Outcrops using Geological Compass

Handling of geological compass

A geological compass is an instrument used to measure the attitudes of the geological structures. The compass is mainly used for measuring the bearing of structures with respect to north, to measure attitudes of geological structures such as strike and dip of planar features, plunge and trend of lines and to measure orientation of slope.

The commonly used geological compasses during the field visit are as follows:1. Clinometer compass2. Brunten Compass3. Clark compass4. Digital compass5. Digital geological compass in combination to P.C.

Out of these, the compass used in the field was the Brunten's compass.

Brunten's compass: This compass can be used to measure both the bearing and inclination of the planar structures i.e. it can be used as both compass and clinometer. The compass consists of two parts held together by a screw. One part consists of the mirror and the other part consists of the needle and the spirit levels.

Measurement of the bearing (Dip direction):

The face with the mirror should be placed parallel to the planar surface along its maximum inclination. Then folding the other part, i.e. main part, the main, the main part should be made horizontal by centering the spirit level in it. Then the reading/bearing shown by the needle should be recorded as the dip direction of the planar

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feature.

Measurement of inclination (Dip Angle):

The edge of the compass should be aligned in the direction of maximum slope. Then leveling the bubble in the centre of the tube the angle of the structure was seen which the dip angle is.

Procedures to handle the compass

i) The compass should be opened carefully.

ii) Measurement of the dip direction and dip angle should be done as mentioned above.

iii) The rotation of the compass parts should be done carefully in such a way that the minimum force is applied.

iv) While using the compass for the accurate measurements, the compass should be aligned in the direction of the maximum inclination.

v) The leveling should be done accurately. If necessary the mirror can be used.

vi) For more accurate data, the reading can be taken at two or more places in the same planar features.

Observation in Malekhu Bank(Dip direction and Dip amount of beds and joint sets)

S. N. Dip direction (00 – 3600) Dip amount (00 – 900) Remarks1 1740 850 B2 730 810 B

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3 1690 810 B4 2520 620 J5 1790 850 B6 1680 810 B7 2750 640 J8 1680 810 B9 2690 630 J10 1670 830 B11 1730 810 B12 1710 820 B13 1670 760 B14 1620 810 B15 2750 640 J16 1690 810 B17 1650 810 B18 1670 830 B19 2740 650 J20 2610 660 J

Chapter IV

RIVER CHANNEL MORPHOLOGYRiver is a mass of water that flows along a path high to low gradient carrying different materials and responsible for different geological actions, such as erosion, transportation and deposition of sediments.

a) Types of River Channels

i) Straight River: This type of river follows a straight path. The topography of the area is characterized by steep relief. The gradient of the river path is also high causing flow velocity of water high. Since the energy level of such river is high, the erosion rate is intensely higher than the deposition of the sediments. Deep

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scouring along the river path is higher than the side cutting. Straight rivers are dominantly occurred in the higher Himalayan regions.

ii) Meandering River :This type of river follows a zigzag path. The topography of the area is characterized by moderate

relief. The gradient of the river path is so moderate that the river strikes in one end and returns in the other direction making the zigzag path. The river is wider and flows with lower velocity than that of Straight River. Since the energy level of such river is medium, the erosion rate and the deposition rate of sediments is comparatively equal. The side cutting by the river is higher than the deep scouring along the river path. Meandering rivers are dominantly occurred in the midlands and lesser Himalayan regions.

iii) Braided River: In this type of river, a single river path is diverted into several paths and may converge to single

later. The topography of the area is characterized by low relief. The gradient of the river path is so low and the river area is wider and flows with low velocity. Since the energy level of such river is low, the depositional rate of sediments is intensely higher than the erosion rate. Braided rivers are dominantly occurred in the Terai Region.

b) Landforms Developed By The Rivers:

a) Ox-bow Lake:This type of feature is developed by the meandering river. In meandering river, sometimes the condition becomes such that due to the intense erosion on two striking banks, in one stage the both banks meet each other. Due to such phenomenon, the river follows the straight path leaving the curved stagnant water body, which is known as Ox-bow Lake.

b) Fan:When sediments flow down from high gradient tributaries on the low relief, the sediments gets accumulated forming a fan shaped deposit, which is called fan deposit. Since the deposit is due to water, the fan is known as alluvial fan. If the materials are dominantly composed of large angular fragments, then the deposit is called debris fan.

c) Delta:This feature is common on the confluence of river and sea. Rivers take sediments along with it and on the flat land, the sediments spread. The sediment deposits the Greek letter ‘Delta’, so the deposit is called Delta.

c) River Channel Morphology at the Trishuli-Thopal Confluence

The Trishuli River flows almost East to West. At Thopal-Trishul Confluence there is an island formed due to presence of hard rock, which is in the process of weathering and vegetation. The Thopal Khola flows form N to S and meets the Trishuli towards S-W. The middle terrace had been cultivated. The Trishuli is much wider in comparison to Thopal Khola. There is construction material on the flood plane but of low quality.

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Picture at Location 2 (about 200m towards Dhading Besi)

Chapter V

IDENTIFICATION OF ROCKS IN THE FIELDRock is defined as the naturally forming, hard and compact solid aggregates or assemblage of minerals forming crust of the earth. According to mode of formation and properties they can be classified into three types as follows:

a) Igneous Rock: Those rocks that are formed by the process of magmatism are known as Igneous Rock.Magmatism : The process of rock forming by the cooling and solidification of molten mobile material magma by the crystallization is called magmatism. In this process magma looses its heat gradually on upward movement; it looses heat and becomes crystal by crystallization.

Igneous rocks are formed by random orientation of minerals interlocked with each other. Generally Igneous Rocks are large rocks and can be easily distinguished from other rocks. The most commonly found igneous rock in Nepal is Granite. Granite is the light-colored plutonic igneous rock. In Malekhu, it was found at a distance 3025m south along the stream from the highway. It is used in architectural and massive construction. It is also used in monuments and memorial; as columns and steps in buildings. Volcanic rock is not found in Nepal, as it

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is an intrusive rock.

b) Metamorphic Rock:Those rocks formed from the alternation of pre-existing rocks (sedimentary or igneous) by the process of metamorphism are called metamorphic rocks.Metamorphism: It is the natural process by which the existing rocks are modified into new rocks under the influence of pressure, temperature and chemical reaction.In metamorphic rock there is preferred orientation or directional arrangement of the minerals. This directional arrangement develops the linear or planar features in the rock called cleavage. If the cleavage plane is smooth with no minerals such plane is called slaty cleavage. Other types of cleavages observed in metamorphic rocks are Schistosity and Gneissosity.

c) Sedimentary Rock:Those rocks formed by the process of sedimentation are called sedimentary rocks.Sedimentation: It is process of accumulation, compaction, cementation and consolidation of sediments formed by the weathering of old rocks either Igneous of Metamorphic. Broadly sedimentation includes:

1 Compaction : Decrease in volume by weight of overlaying sediments.2 Lithification : Change of loose sediments into rock.3 Petrification : Matter converted into massive and hard.4 Cementation : Joining of sediments with fine materials.5 Digenesis : Cementation, compaction and finally growth of new minerals.

These rocks are identified in the field by their distinct strata (beddings). But the bedding planes formed in these rocks may be regular or irregular.

d) Major Rock Types of the Field Study Area

Location L1

Limestone:

Limestones are common and abundant

among sedimentary rock. Limestone are typical

non-clastic rocks that are formed either

chemically, due to precipitation of CaCO3 from

surface water or organically due to the

accumulation of hard parts of organism. They

react vigorously with cold and dilute acid. They

are suitable as road metal as construction

material but may not be very durable.

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Location L4

Slate:

Slate is a dense, fine grained,

argillaceous metamorphic rock. It has unique

characteristics of slaty cleavage. It is formed due

to dynamic or regional metamorphism of shale.

By virtue of its cleavage cleavage character, it

splits easily into very thin sheets or slabs of

uniform thickness and considerable size. Slates

usually exhibit uniform color. Generally they are

black or dark grayish black. Slate is very dense

looking and extremely fine grained. Foliation is

clearly visible though the constituent minerals

are fine and unrecognizable. This is the cause of slaty cleavage character. Slates are mainly made up of mica and quartz

and other minerals are biotite, muscovite, talc, chlorite and feldspar. Slate is a bad conductor of electricity. Its softness,

fine grain size and easy workability enable it to be used in the electrical industry as switchboard, bases and various turned

or shaped parts.

Location L5

DOLOMITE:

Dolomite is a carbonate rock of

sedimentary origin and is made up chiefly-

more than 50 percent of the mineral

dolomite which is a double carbonate of

calcium and magnesium with a formula of

CaMg(CO3)2. Ferrous iron is present in

small proportions in some varieties.

Gypsum also makes appearance in some

dolomites. The appearance of dolomite is

exactly with limestone. The appearance of

limestone is in different form, like white in

which dolomite are formed by the

alternation of limestone in which part of

calcium is replaced by magnesium. This process is called dolomitization.

The main property of dolomite is that it reacts with acid in powder form by giving efflorescence. The compositions of

dolomite are SiO2, CaO minerals. The dolomite is of impure limestone & Mg coated. Due to weathering they are found in

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elephant skin color.

LOCATION L6

Bolder of gneiss

It consists of band of light colours and separated by dark colors. Cleavage of foliations of light and dark colors is called Gniessosity. It has more shear strength. The rock so formed is called gneiss. In another bolder of gneiss, there are eye shaped structures called augen and this bolder is called augen gneiss.

LOCATION L7

Rock bolder of granite:

It is a Plutonic rock, crystalline, no glass content, consisting of quartz (20%), K-feldspar (60%), plagioclase (15%), orthoclase. It consists of small pieces of metamorphic rock with sandy color called xenolith formed due to the variation of PTX. Xenolith is the relict of country rock preserved in the intrusive rock. Xenolith has the more strength than the intrusive rock.

Location L8

PHYLLITE:

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It is similar to slate in appearance and

represents slate itself. They absorb

chemicals such as potassium and

change over to micaceous minerals.

Thus, shales recrystalline with mica

and quartz as the predominant

constituents. Under higher grades of

metamorphism, slates successively

give rise to phyllites, schist and

gneisses.

Location L9

QUARTZITE

Quartzite is a typical example of a parametamorphic

rock. It is siliceous in composition and is formed out

of dynamic or thermal or dynamothermal

metamorphism of sandstone. Uniform color

throughout the rock; generally white or pale color but

red, brown, grey, green and other colors may also

occur. Grain sizes are variable; some are fine

grained while others may be coarse grained. Its

structure is Granulose. It is crystalline, dense and

compact. Quartz is essential constituent. Other

minerals which may occur are mica, garnet, feldspar,

pyroxene, chlorite, kyanite, epidote, magnetite, etc. It

is strong, hard, and durable and has a pleasing color. But by virtue of its very high hard minerals, the workability or dressing

becomes very difficult. Quartzite rocks are highly suitable as road metal, concrete aggregates, paving blocks, etc. They are also

useful in the manufacture of silica bricks.

Location L10

SCHIST:

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Schist is very common metamorphic rock and it is

a general name given to all metamorphic rocks

bearing a particular structure called schistose

structure or schistocity. Different schist shows

different color, e.g. mica schist (muscovite) is

silvery in color, biotite schist is black in color,

chlorite schist is dark in color,etc. The minerals

which occur commonly in schist are; hornblende,

sillimatnite, tourmaline, chlorite, muscovite, biotite,

talc, kyanite, quartz, garnet, staurolite, etc. They

are in general considered weak, incompetent,

harmful and undesirable rocks from the civil

engineering point of view.

Location L11

MARBLE

It is a calcareous metamorphic rock formed out of the thermal metamorphism of limestone. Though it is not very hard or strong or

durable, it is most valuable rock occurring in nature. It’s valuable due to its pleasant color, good appearance, easily workable,

charming translucency, and the ability to take brilliant polish.

Pure marble is milky white in color. Fine, medium or coarse grained, but the size is equigranular. Marbles react vigorously with

cold and dilute acids and scratched by hammer. Calcite, Olivine, Garnet, Graphite, Mica, Talc, Pyrite, etc. are the minerals found

in marble.

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Chapter VI

GEOLOGY OF THE STUDY AREA

a) Geology of the Malekhu area

Malekhu area bearing cool climate, neither hot nor cold lies in the latitude between 27o 45’ and 27o

52’ and the longitude between 84o

58’ and 84o 59’. Lying between the Hilly and the Terai region of Nepal in the Mahabharata

range, Malekhu has the altitude of about 400m from the sea level. Thus, to define, it is a part of Dhading District of Bagmati Zone which is 72 km. southwest of the Kathmandu valley accessible from the Prithvi Highway.

Near Malekhu, different rivers are flowing. The lowest altitude is the confluence of Malekhu River flowing from south to north. Thopal and Trishuli rivers are also there which are flowing from north to south and east to west respectively. So far, the highest area of the place has been recorded 1036 m. The region also lies in the range of Mahabharata Thrust, as there is a presence of soft rocks at the lower level and hard rocks while going upstream.

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b) Recognition of geological units in the field

Geological unit is the geological boundary found between two types of different rocks. They are of two types:

1. Inferred boundary -The boundary, which is not exposed or seen by naked eyes.

2. Confirmed boundary -The boundary that is exposed .It is also of two types as follows:

a. Sharp -one type of rock is immediately disappeared and another type of rock is continued soon.

b. Transitional-quantity of one type of rock is increasing and another type of rock is decreasing.

Following geological units were observed in the field:

i) Benighat Slate (bg):

The name is derived from the village “Benghat” at the confluence of Budhi-Gandaki and Trishuli River. This formation consists of grey to black slate. In some places it is highly carbonaceous (graphitic). Also it is calcareous and dolomitic at the lower part. Intercalation of quartz vein 2-4 cm. thick is also observed in some places. The beds are not thicker than 5-7 cm in this formation. This formation is about 500-3000m thick.

Attitude of bedding plane:

Strike : E-W

Dip Direction : S

Dip Amount : 860

Along Thopal Khola and Dhading road:

After 300m from suspension bridge over Trishuli River, calcareous beds of Benighat slate is observed; which is fine-grained yellowish gray in color and highly fractured and jointed.

Attitude of bedding plane:

Strike : N 850 E- S 850 W

Dip Direction : N 50 W

Dip Amount : 750

The difference in attitude in the Benighat slates indicates that these may be fault in this formation.

ii) Malekhu Limestone (ml):

The name was derived from the village “Malekhu” along Prithvi Highway.

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The Malekhu limestone has a transitional contact with Benighat Slate near the suspension bridge along Malekhu Dhading road on right bank of Trishuli River. It is composed of light yellow colored siliceous limestone of fine grained to dense, crystalline and massive. In the middle and top part of this formation, the dolomitic limestone is observed; bounding structure in quartz veins is also observed in limestone, which shows contemporary pressure-temperature conditions. Drag fold at the top of this formation on the left bank of the Malekhu Khola is observed. Weathered rock is blakish in color and fresh exposure is brown in color. The average thickness of this formation is about 800 m.

Along Malekhu Khola towards upstream:

About 400m far from the bridge over the Malekhu Khola, we observe nearly vertical beds of dolomitic limestone of grayish white of elephant skin color.

Attitude of the bedding plane

Strike : N 700 E – S 700 W

Dip Direction : S 200 E

Dip Amount : 750

About 200 m from the previous location along Malekhu Khola towards upstream we observed a fault plane. Left side of the fault plane composed of limestone of whitish yellow color and the right side of the fault plane composed of grayish white phyllitic limestone. The fault plane composed of mylonite bressia. Nearly 200m from the fault plane, there is a transitional contact between Malekhu limestone and Robang formation.

Attitude of the BedStrike : N 700E – S 700 WDip direction : S 200 EDip amount : 900

iii) Robang Formation (rb):

The name is derived from the village “Robang” in Dhading District. Along Malekhu Khola, on the right bank about 500 m from the Prithvi Highway near Malekhu Bazaar contact between dolomitic limestone and dark green phyllite of Robang formation was observed from where; river bends sharply.

Main lithology is phyllite and yellowish quartzite called “Dunga Quartzite” which is highly jointed. Phyllite is gradually replaced by massive yellowish quartzite towards south. Some phyllite beds are black in colour due to graphite. Nearly middle part of the formation, we observed Amphibolites, a metamorphic product of basic intrusive rock-dolerite.

The thickness of this formation is about 200-1000m.

Attitude of the bedding Plane:

Strike : N 550 E – S 550 W

Dip Direction : S 350 E

Dip amount : 500

Attitude of bed at Dunga Quartzite:

N 800 E – S 800 W

S 100E

900

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Along Prithvi Highway Towards Gajuri:About 500m far from the Malekhu Bridge, the contact between Robang Formation and Malekhu Limestone is found which is transitional contact.Attitude of Bedding Plane:Strike : N 80º E – S 80º WDip direction : S 10º EDip amount : 75º

About 100m far from the contact, amphibolite, a metabasic rock is observed which is weathered and is olive and muddy in colour with contact of metabasic rock and quartzite is observed. It may be Dunga Quartzite.Attitude of bedding plane at Dunga Quartzite:Strike : N 85º E – S 85º WDip direction : S 5º EDip amount : 85º

iv) Raduwa formation

The name is derived from the village "Raduwa" in Dhading District. A highly fractured zone of Mahabharat Thrust exposed at right bank of Malekhu Khola; even fine grey to black mylonite is observed. The main rock type of this formation is mica-schist of coarse-crystalline of dark grey colour due to predominant micaceous minerals. It has micro fissures, produces metallic sound when hammered. It has quite low strength and its excavation loss is high.

v) Bhaise Dhovan Marble

The formation is named after the village “Bhainsedovan” on the Tribhuvan highway.The contact between Raduwa Formation and Bhainsedovan Marble is more or less sharp. Well-exposed marble is observed in front of Dharapani. The metamorphic equivalent of limestone is marble, which is dominant lithology of that area and is white in colour, crystalline in texture associated with pyrite mineral. Exposure is highly weathered and reacts well with dilute HCl and the crystal calcite is well developed and parallel laminations are also observed. Folds were observed as secondary structures. It is about 800m thick.

Attitudes of Beds:Strike : N 70º E – S 70º W

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Dip direction : S 20º EDip amount : 70º

Chapter VII

RECOGNITION OF GEOLOGICAL STRUCTURES IN THE FIELD

Due to the distribution of stress generated through various geological processes, different types of deformation of rock or earth’s crust takes place forming different geological structures. These geological structures can be categorized mainly as follows:

a) Fold :

Folds are deformational structure on the rock strata formed due to compressive forces. They are ductile deformation.

Components of Fold:

1 Crest and Trough : Convex and concave portions of wavy undulation.

2 Core : Innermost part of fold.

3 Hinge line : Line running through the point of maximum curvature of fold.

4 Axial Plane : Imaginary plane formed by joining all hinge lines and divides folds as symmetrically as possible.

5 Limb : It is a side of the fold.

6 Axis : Line of intersection of the axial plane and the ground surface.

7 Angle of fold : Acute angle formed by intersection of lines extended from the respective limbs, also

26

known as inter-limb angle.

Identification of Fold:

1 By direct observation: Bending of rock strata can be directly observed in mountain, cliff, quarries, deep cutting and trenches.

2 Repetition of Strata: In regional geological mapping, if there exists repeated strata in the cyclic order, then the presence of fold can be predicted.

3 Attitudes of beds: Opposite dip of the beds also indicate the presence of fold.

Effects of Folding and their Engineering Importance:

Folded rocks are high strained zone, so special consideration must be taken during the construction of infrastructure on them. Some important effects of folding are:

1 For construction of dam foundation on large fold, the flank dipping toward downstream is unfavorable and the one dipping upstream is comparably safer.

2 In case of tunneling, or tunnel passage through syncline, then the stress is exerted more on side than crown, while in anticline condition, tensional fracture may be developed on the crown causing over break. In syncline condition, there is more ground water problem.

3 In synclinal aquifer, the ground water potential is higher but in anticlinal condition, it is adverse.4 In folded area, there is possibility of rupture, due to action of further stress.

b) Fault

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A fault is a failure in rock along which there has been a relative displacement of the two sides parallel to the fracture plane. Fault is result of brittle deformation due to tension and compression. The displacement may vary from a few centimeters to many kilometers depending upon the nature and magnitude of stresses and resistance offered by rocks.Parts of Faults:

Fault Plane : Plane along which relative movement takes places.Hanging Wall : Block which rests above the fault plane.Foot Wall : Block which lies below the fault plane.Slip : The displacement that occurs during the faulting.

Causes of Faulting

1 Application of shearing stresses that causes sliding action.2 Stresses induced due to shrinkage of earth.3 Stresses due to convection current induced due to the heat supplied by the lower hot part of the earth.4 Due to folding of rock strata.5 Brittle nature of rock.

Evidences of Faulting

1 Direct Evidence: Slickensides: These are parallel grooves formed due to frictional sliding on a flat, polished

looking surface. Orientation of the grooves indicates the direction of movement. Fault Breccia: These are angular unconsolidated material consisting of fragments of rocks,

mostly of black color and occur on the either or both sides of the fault plane or may form a zone.

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Fault Gauge: These are fine-grained, unconsolidated material consisting of pulverized rock. This is the most stressed zone.

Abrupt Termination: Abrupt termination of any geological structure also indicates the presence of fault.

2 Indirect Evidence: Repetition and Omission of Strata: If in the regional geological map, there exists repetition

and omission of strata, the presence of fault can be predicted. Physiographic Features: Different physiographic features like topographic variations also

show the presence of faulting. Mineralization: The fault zone is the region of high stress, due to which intense pressure

and temperature occur resulting mineralization of high P/T minerals. If high P/T minerals like Kynite and Sillimanite are frequently shown then the presence of fault can be predicted.

The garnet found in schist of Raduwa Formation in Malekhu Area also indicated that Mahabharat Thrust passes through the area.

c) Joints

Joints are the fractures along which there has been no relative displacement along the fracture plane. Joints are the result of brittle deformation due to tensile or shearing stresses.Terminologies:

1 Master Joint: More prominent continuous joint.2 Joint Set: Group of joints occurring in the same altitude.3 Conjugate Joints: Two perpendicular sets of joints.4 Joint System: Combination of two or more sets of joints.5 Open Joint: Joints in which the blocks have been opened up for small distances in the direction

29

perpendicular to fracture planes.6 Close Joint: Joints in which blocks have no separation.7 Continuous Joint: Joint running up to prominent distance.8 Discontinuous Joint: Joints disappearing at shorter depth.

Field Recognition and Observations of Joints:

Joints were observed at various rock outcrops and exposures. They appeared as planes of failures along which the fractured masses of rocks had no relative displacement.

Engineering significance and considerations:

Joints influence many engineering operations. The selection of site for dams and reservoirs and alignments for highway and tunnels through rocks will require very thorough investigations of joints for arriving at safe and economic designs.

Joints are always to be considered as a source of weakness of the rock and as pathways for the leakage of water through the rock. Both there properties of joints destroy the inherent soundness of the rock to a great extent They bring about great reduction of shearing strength of rocks and if cut slope is made through them there is always a chance of potential failure and immediate failure considering set of joints.

d) Veins

It is the type of intrusion of one mineral in the other one due to which the strength of the rock can either increase or decrease. If there is vein of other weaker mineral in stronger one then its strength will definitely decrease.

Engineering significance

They are significant in the field of engineering as the presence of strong mineral inside a weak one would strengthen the mineral and vice versa. Thus, during the construction, we should not look superficially but should at least excavate up to some depth so as to confirm the presence or absence of such features otherwise there would be danger failure of our structure.

e) Thrust

Low angle (10o-15o) reverse fault is thrust. It is the case in which the hanging wall has actually been moved up relative to the footwall. They are common in folded mountains and originate from the process of adjustment of the rocks imposed to stresses.

f) UNCONFORMITY

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When rocks are formed continuously or regularly one after another without any major break, they are said to be a set of a conformable beds and this phenomenon is called conformity. All beds in a set of conformable sequence possesses same attitude.

On the other hand, when depositional gap or break occurs between the two conformable sequences, it is called unconformity. So, unconformity is a plane of discontinuity that separates two rock sequences, which differ notably in age. Unconformity may be Parallel, Angular or Non-conformity.

g) Engineering Geological significance of Geological Structures:

They are significant structures in case of engineering studies as they signify the strength of the rock. With more thrust the rock strength would definitely be weakened and thus the construction in those areas would be dangerous. Life of any engineering structures constructed over any geological structures is governed by the number and natures of above-mentioned structures. Hence, before the implementation any projects on those particular cases; the detailed study of these structures is must for the better lifespan of the project.

Chapter VIII

ENGINEERING GEOLOGICAL STUDIES OF THE ROCK OUTCROP:

a) Rock Mass :It is a mass of rock interrupted by discontinuities with each constituent discrete block having intact rock properties. Rock masses are heterogeneous because of differing rock types, presence of discontinuities and varying degree of weathering.Intact Rock: It is the term applied to rock containing no discontinuities.

b) Discontinuities: Different forms of discontinuities are bedding planes, foliation, joints, faults and fault zones.

c) Characteristics of Discontinuities in Rock Mass:

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i) Orientation: Orientation of discontinuities is confirmed by measuring attitude of the plane. Discontinuities having same attitude are referred as a set of joints. So, in rock mass there may be one or more set of joints. A set of discontinuity or intersection of discontinuity sets may cause rock instability according to the relation with hill slope. According to the relation between joint sets and hill slopes, there may be plane, wedge or toppling failure in the rock mass.

ii) Spacing: It is the perpendicular distance between the discontinuities planes with its adjacently parallel another discontinuity plane. The spacing of discontinuities effects overall rock mass strength or quality. Even the strongest intact rock is reduced to one of little strength when closely spaced discontinuities encountered. Spacing may be even, random or clustered distribution. Factors effecting spacing of discontinuities may be lithology, tectonic stresses, depth, etc.

iii) Aperture: It is widening distance between two discontinuities. It may be tight or open and the space may be empty, partially filled or completely filled.

iv) Roughness: The surface of discontinuity may be smooth or very rough. The friction angle of rock depends upon the degree of roughness. Higher the degree of roughness, higher will be the frictional angle.

v) Seepage: Water pressure reduces the stability of slope by reducing the resisting force of potential failure surface. In the rainy season, the pore water pressure increases the driving force causing more instability. Based on intensity of water flow, the seepage may be categorized as follows:Dry--------Damp------Wet------Dripping------Flowing

(Increasing in the intensity of water flow)vi) Infilling Materials: They may be clay, slit, sand or coarse fragmental material or mixture of

them, resulting from depositional filling, faulting or wall rock weathering. These materials typically have low shear strength. The presence of infilling material may have a profound influence on the strength of a jointed rock mass.

Chapter IX

ROCK MASS RATING

Depending upon different parameters of the rock mass, the rock mass can be classified as very good rock, good rock, fair rock, poor rock or very poor rock. For this, observations are done in the related site or observation of considered rock mass is done and data (numeric) are collected to analyze the quality of rock and depending upon final total rated value rock is assigned to one type of above mentioned class. This method of determining the rock quality depending upon various parameters is known as Rock Mass Rating.

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Different rating system or classifications are developed and adopted each giving different emphases to various parameters, and it is recommended to use at least two methods at any site during the rating of the rock mass.

Different mass classification systems are as follows:1 Terzaghi’s Rock Mass Classification System2 Rock Quality Designation Index (RQD) --- Deere et al. 19673 Bieniawski’s Geomechanics Classification4 Rock Tunneling Quality Index (Q value) --- Barton et al. 1974

Among these systems, the two most commonly used rock mass classifications are Bieniawski’s RMR and Barton et al’s Q system. Both methods incorporate geological, geometric and design/engineering parameters in arriving at a qualitative value of their rock mass quality. In the field visit, we used Bieniawski’s RMR Classification System.

Bieniawski’s Geomechanics Classification:In 1976, Bieniawski published the details of a rock mass classification called the geomechanics classification and widely known as rock mass rating (RMR) system. From the beginning to 1989, he has made significant modifications in the ratings assigned to the different parameters. In this system, RQD is used as one of the parameters.

Following six parameters are used to classify a rock mass using RMR system:1 Intact Rock Strength2 RQD3 Spacing of Discontinuities4 Orientation of Discontinuities5 Condition of Discontinuities6 Ground Water Condition

In this system, different rating values have been assigned to different parameters according to their weight. In the field, all the parameters are measured and assigned to the respective rating values. Finally, the summation of rating value of all the individual parameters give the final rating value and the rock mass is classified as follows:

Class No. Rating Value Rock QualityI 100-81 Very Good RockII 80-61 Good RockIII 60-41 Fair RockIV 40-21 Poor RockV <21 Very Poor Rock

Different Parameters that were taken in consideration during the field visit are as follows and the copy of Table

(Rock Mass Rating System (After Bieniawski, 1989)) is attached with the report, upon what our rock mass rating

based.

Parameters Included:

(i) Strength of intact rock material(ii) RQD

Rock Quality Designation is the test done as one of the parameter of Rock Mass Rating. In this method the

33

specimen is obtained through the process of drilling. When one-meter length of specimen is drilled out, the length sum of specimen pieces that has intact rock of length more than one meter is summed up and the percentage value is found out. If drilling is expensive but the precision that the work should be done is less then this test is done externally. Now mathematical formulae that give RQD are:

a) If specimen is obtained through drilling (One-meter length)

SUM OF LENGTH OF PIECES HAVING LENGTH>10CMRQD = X 100 %

100 (Total length of core run)

b) If it is done externallyRQD = 115 – 3.3 JV

Where Jv is Joint Volume.This formula is Imperial formula that may give incorrect information sometimes.

(iii) Spacing of Discontinuity(iv) Condition of Discontinuity

1 Persistence2 Separation3 Roughness4 Infilling Materials5 Weathering Condition

(v) Ground Water Condition

Rock Mass Rating in the Field:

S. N. PARAMETERS VALUE RATING

34

1

2

3

4

5

Strength of Intact Rock Material

RQD

Spacing of Discontinuity

Conditions of Discontinuity

a) Persistence

b) Separation

c) Roughness

d) Infilling Material

e) Weathering

Ground Water Condition

150 MPa

46%

12.625 cm.

93.75

4mm

Slightly Rough

Soft Filling (Clay)

Slight Weathered

Completely Dry

TOTAL

12

8

8

6

1

3

2

5

15

60

Result:

The total rating of the rock is found to be 60, so it is 3rd Class Rock (Fair Rock). Its average stand up time is 1 week for 5m. span. Cohesion of this rock mass is 200-300 KPa and friction angle of rock mass is 25o-35o.

Conclusion:

Our field trip to Malekhu thus ended in the third day and we headed back to our college. We were able to gain the knowledge of geological element and their properties as well as features in the geological features in the geological field trip in Malekhu. The objectives of the study were fully met with the co-operation of teachers and

35

students. We were acquainted with the geological structures like fault, fold, joint, etc. that were preserved in the rock during formation of rock or after formation of rock. We studied them, as they are the major factors in construction of roads, dams and tunnels.

During the Malekhu site visit, our main objective was to understand the geology of the entire country through the small area. The tour was also intended to give an insight to the various probable cause of geological failure during any civil engineering construction. Different types of mass movements activities are studied like slope failure, landslides, etc. The main cause of mass movements was found to be steep slope and more slope height. Also pore water pressure was the next important cause of mass movement. The most of them can be cured by constructing retaining walls. Bioengineering methods would be the most important preventive measure. If economically strong other preventive measures like reinforcement, anchoring of slide portion could be done.

On the field trip, we found Malekhu area rich in metamorphic rocks like phyllite, schist, gneiss, slate and quartzite rocks in little extent in comparison to other rocks. The Robang Formation, Raduwa Formation, Bhainsedovan Marble Attitudes were studied by calculating strikes, dip direction and dip amount. We also learnt about the river channel, structures like delta, fan and ox-bow lake formed by them, their types as straight, meandering and braided as categorized by studying morphology of the river. This helped us to know the different location at river channel where erosion and deposition takes place. At the last day we learnt rock mass rating of limestone bed located near Malekhu Old Bridge considering different parameters like strength, discontinuity, ground water condition, etc.

Last but not the least; we learnt many things about geological elements, their characteristics, geological changes, modes of formation of different structures, rocks, etc. from our field trip. We are very grateful to our teachers who gave guidance and our friends for their valuable support during three days field trip in the Malekhu area.

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