7/29/2019 Geotechnical Engineering II (CIE-302) (Makeup)[1]

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Reg.No:

(A Constitute College of Manipal University)MANIPAL INSTITUTE OF TECHNOLOGY

VI Semester B.E (Civil Engg.)End Semester Examination - May 2010

GEOTECHNICAL ENGINEERING-II (CIE 302)Time: 3 Hours Max. Marks: 50Note:I. Answer any F1VEjilll questions.2. lvlissing data i(any may he suitahfy assumed and clearly he indicated3. Draw neat sketches wherever necessary.IA. Differentiate between the general shear failure and the local shear failure. Discuss the effectof water tabk on the bearing capacity of the soil. (2.5 marks)IB. How is the selection of a suitable ground improvement technique is made and what are thefactors considered in the selection? (2.5 marks)IC A square footing 2.5m x 2.5m in size is founded at a depth of 1.2 m below the groundsurfaee. rhe load on the footing acts at an angle of 15 to the vertical. The unit weight of the soilis 20kl\; m '. c IOk:--Jm' and 25 . Calculate the net ultimate bcaring capacity of the footing if(a) the water table rises to the base of the footing (b) the water table rises to the ground surfaceand (c) the \\ atcr table is 1.25 m below the base. Use IS: 6403-1981 recommendations.

(5 marks)2 \. Dlfll:rentldle bd\\een disturbed. undisturbed and representative samples. (5 marks)213. rhe locatIOn of ground water table is required to be established in a claye) strata. Water inthe bore hole was bailed out to a depth of 10.35m below ground surface and rise in water wasrecorded at intervals of 24 hours as follows:

hi = 615 cm at 24 hoursh2 52.0 em at 24 hoursh3 47.9 cm at 24 hours

Ddermine the location of ground water table. (5 marks)

3 \. J)emc an exprcssion for Rankinc's active earth pressure in cohesive soil. Also denve andexplain cntlLdl height of unsupported vertical cut. (5 marks)

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3B. A 5m deep canal has side slopes of I: 1. The properties of soil are CII=18kN/m2. 1I=2.e 0.78 and G 2.78. If Taylor's stability numbcr is 0.108. detcrmine the factor of safety withrespect to cohesion when the canal runs full. (5 marks)

4A. Determine the Rankine Passive pressure force per meter length of the retaining wall asshown in FigAA. The water table is at the junction of two layers. Take.y,,=9.81 kN/m3.

(5 marks)48. Enumerate the various methods of soil exploration and mention the circumstances underwhich each is best suited. (5 marks)5A. A machine foundation is subjected to a forced vibration. Vibrating force can be expressed asQ Q(lsintwhere Q(I 66 kN and (J)=52 rad/sec. The weight of the machine with the foundationtogether is 289 kN and spring constant is 89x 104kN/m. Assuming that the foundation behaveslike a mass spring system. determine (i) Natural frequency (ii)Maximum vertical amplitude ofmotion (iii)Critical damping coefficient if damping ratio is 0.27 (iv) Damped natural frequency.

(5 marks)58. In a 9 pile group. the pile diameter is 30 cm and the center to center spacing of the squaregroup is 1.4m. If unconfined compressive strength of the soil is 60 kN/m2. determine whether thefailure would occur with the pile acting individually or as a group? All the piles are 10m long.rake f1 0.9. Also determine the safe load if the factor of safety is 2. (Nc=9) (5 marks)

6\. I.xplain the different methods of rectification of tilts and shifts ofa well foundation?(3 marks)

68. fxplain a Vinro compactionn.\pplications of geosynthetics(,n)uti ng

(4.5 marks)6(', What are the hal.ards due to an earthquake? Discuss in brief only those hazards related togeotechni