(R-037-2011)

M E M O R A N D U M

TO: Keith Caudill, PE

Project Management Coordinator

Division of Highway Design

FROM: Bart Asher, PE

Geotechnical Branch Manager

Division of Structural Design

BY: Jason Wright

Geotechnical Branch

DATE: August 27, 2012

SUBJECT: Estill County

KY 89 and Dry Ridge Rd. Intersection

FD04 033 0089 015-016

Item # 10-8306.10

Mars # 8123301D

Geotechnical Engineering Roadway Report

An abbreviated geotechnical engineering report is complete for the subject project. The

Geotechnical Branch performed the drilling, sampling and testing. The purpose of the

investigation is to define the soil and subsurface conditions for the roadway. Reduced size

Geotechnical Symbol Sheet, Geotechnical Notes Sheet and Cut and Embankment Stability

Sheets are attached. The CADD input for these sheets is being e-mailed to the Design

Consultant, URS Corporation, as DGN files, for incorporation into the roadway plans.

The Select Rock Quantity Sheet was submitted by the design consultant. Based on these

estimates, the only durable rock that will be encountered during construction will be acidic shale,

which cannot be used as rock roadbed. However, the District has informed the Geotechnical

Branch the subject project and the project located at KY 89 and Tire Shredder Road (item # 10-

8306.20), approximately 0.5 miles away, will be combined and let under one contract. Based on

quantities, received from that project, there is a sufficient quantity of limestone from roadway

excavation for both projects. A separate Geotechnical Roadway Report, titled R-038-2011, will

be issued for the project located at KY 89 and Tire Shredder. If the subject project and the

project located at KY 89 and Tire Shredder Rd (item #10-8306.20) are not let as one project

please contact the Geotechnical Branch so an addendum to this report can be issued to reflect any

changes.

New Albany Shale will be encountered in the cut slopes. New Albany Shale is known to

produce acidic runoff when exposed to air and water causing environmental damage to

vegetation and streams. Remedial measures to treat the acidic drainage from the cut slope and

embankments constructed of the New Albany Shale are required. In an attempt to conform to

EPA requirements regarding to the PH of the surface water runoff, the following remedial

measures are recommended:

EMBANKMENTS- The New Albany Shale shall be encased in the embankments with

a minimum of 2.5 ft (measured perpendicular to the fill slope) of clay soil (classified as CL or

CH) on the outer layer. Typically, the top 4 feet of the embankment is encased. This is done to

Keith Caudill (R-037-2011)

Item # 10-8306.10

08/27/12

Page 2 of 4

control the corrosion of guardrail and/or sign post from the acidic shale. In lieu of encasing the

top 4 feet, the District has determined that wooden guardrail post shall be used. Therefore, it is

recommended that the top 2 feet (from finish grade) of the embankment be encased with clay soil

(classified as CL or CH). The embankment encasement shall be constructed at a maximum of 8-

inch lifts. A minimum 0.5 ft of topsoil should be spread loosely and/or loosely compacted on the

outside of these slopes for vegetation. To prevent erosion adequately vegetate these slopes

immediately after completion. Borrow material may be required to perform the encasing of

the acidic shales.

CUTS- The cut slopes in the New Albany Shale shall be over-excavated a minimum of

4.5 feet and shall be serrated. A minimum of 4 ft (measured perpendicular to the slope) of clay

soil (classified as CL or CH) shall be compacted horizontally on the serrated cut slopes. Compact

this material in maximum 8-inch (loose thickness) lifts. A minimum 0.5-ft of topsoil should be

spread loosely and/or loosely compacted on the outside of these slopes for vegetation. To prevent

erosion adequately vegetate these slopes immediately after completion. Borrow material may

be required to perform the encasing of the acidic shales.

Stability analyses were deemed unnecessary due to the shallow foundation soils that were

encountered during drilling. Slopes can be constructed 2H: 1V or flatter, as determined by the

engineer.

Geotechnical recommendations are as follows:

1) In accordance with Section 206 of the current Standard Specifications, the moisture content of

embankment material shall not vary from the optimum moisture content as determined by KM

64-511 by more than +2 percent or less than -2 percent. This moisture content requirement shall

have equal weight with the density requirement when determining the acceptability of

embankment construction. Refer to the Family of Curves for moisture/density correlation.

2) All soils, whether from roadway or borrow, may require manipulation to obtain proper

moisture content prior to compaction. Direct payment shall not be permitted for rehandling,

hauling, stockpiling, and/or manipulating soils.

3) Excavation of surface ditches and channel changes adjacent to embankment areas shall be

performed prior to the placement of the adjacent embankments. The material excavated for the

channel changes and surface ditches is suitable for embankment construction if dried to proper

moisture content in accordance with Section 206 of the current Standard Specifications.

4) The contractor is responsible for conducting any operations necessary to excavate the cut

areas to the required typical section. These operations shall be incidental to the unit bid price for

roadway excavation or embankment-in-place.

5) Foundation embankment benches shall be placed in accordance with Standard Drawing RGX-

010 at the locations listed below and/or as directed by the Engineer.

MAINLINE

STATIONS 4+25 TO 6+25 RIGHT SIDE

Keith Caudill (R-037-2011)

Item # 10-8306.10

08/27/12

Page 3 of 4

6) Where shale bedrock is encountered at the top of subgrade in the cuts, the roadbed shall be

undercut two (2) feet below the proposed grade and the limits of the roadbed excavation shall be

extended to the ditch lines. The refill shall be constructed as specified in Section 204 of the

Standard Specifications for Road and Bridge Construction, current edition, with limestone from

roadway excavation. For Roadway Excavation projects, the excavation of the shale material

shall be paid at the applicable unit bid price (Common Excavation or Rock Excavation) and the

placement of rock refill shall be incidental. For Embankment-In-Place projects, the placement of

rock refill shall be paid at the unit bid price for Embankment-In-Place and the excavation of the

shale material shall be incidental. For either case, no compensation shall be made for the

incidental portions of this work.

7) The New Albany Shale shall be encased in the embankments with a minimum of 2.5 ft

(measured perpendicular to the fill slope) of clay soil (classified as CL or CH) on the outer layer

and a minimum of 2 ft cover (from finish grade) on top of the embankment. The embankment

encasement shall be constructed in a maximum of 8-inch lifts. A minimum 0.5 ft of topsoil

should be spread loosely and/or loosely compacted on the outside of these slopes for vegetation.

To prevent erosion adequately vegetate these slopes immediately after completion.

8) The cut slopes in the New Albany Shale shall be over-excavated a minimum of 4.5 feet and

shall be serrated. A minimum of 4 ft (measured perpendicular to the slope) of clay soil (classified

as CL or CH) shall be compacted on the serrated cut slopes. Compact this material in maximum

8-inch (loose thickness) lifts. A minimum 0.5 ft of topsoil should be spread loosely and/or

loosely compacted on the outside of these slopes for vegetation. To prevent erosion adequately

vegetate these slopes immediately after completion. See cut stability sheet

9) If borrow material is required for the encasing of the acidic shale, the soil shall be a clay soil

that is classified as a CL or CH.

10) Interceptor ditches with berms shall be installed above all cut slopes in the New Albany

Shale and along the toe of any embankments containing the New Albany Shale that would

receive significant runoff from adjacent areas. This will minimize the volume of runoff requiring

treatment and reduce any erosion of cut faces or soil treatment material.

11) The ditch line through the cut sections shall be lined with Channel Lining Class IV.

Agricultural lime shall be placed over the Channel Lining at approximately 3 lbs/ft2. The

agricultural lime should be added to the ditch line periodically by the district, as needed.

12) Temporary mitigation procedures for neutralizing the acidic runoff from areas containing

New Albany Shale are required during construction of cuts and embankments, as directed by the

engineer. Possible procedures are to direct the runoff from the cuts and embankment containing

exposed New Albany Shale along or through piles of crushed limestone and/or trench drains

backfilled with agricultural crushed limestone. Appropriate erosion control measures (such as silt

checks, silt fences, hay bales, etc.) must be utilized to capture soil fines that would quickly clog

these crushed stone filters. If the embankment encasement is simultaneously constructed with

the embankment the additional mitigation will not be required (for embankment only).

13) Any stockpiling of the New Albany Shale will require controlled drainage, as directed by

the Engineer.

Keith Caudill (R-037-2011)

Item # 10-8306.10

08/27/12

Page 4 of 4

14) The contractor shall follow the applicable regulations regarding the deposal of acidic

materials for any New Albany Shale.

15) The New Albany Shale cannot be left exposed to weather during any seasonal shutdowns.

16) New Albany shale cannot be used to stabilize wet areas.

DESIGN RECOMMENDATIONS . . .

1) The project should be designed for a 2 foot rock roadbed. A CBR design value of 11.0 is

recommended for the rock. The rock shall consist of limestone from roadway excavation. The

placement of this material is incidental to the unit bid price for roadway excavation or

embankment-in-place. Please insert the following note in the pavement design sheets: The rock

roadbed shall consist of limestone from roadway excavation.

2) An average soil shrinkage value of two (2) percent is estimated for this project. This value

should be applied to the formula for calculating the Apparent Shrinkage as outlined in the Design

Manual. The recommended rock swell factor is estimated to be ten (10) percent for material

excavated below the rock disintegration zone (RDZ).

cc: Division of Design (Plan Processing Section)

TEBM for Pavement Design

Division of Construction

TEBM for Project Delivery & Preservation (District)

TEBM for Project Development (District)

URS Corporation

Attachments

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UV89

DRY RIDGE RD

Estill County - KY 89

LegendStations

Project Area

State Roads

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Local Roads

¯Estill County

KY-89Item No. 10-8306.10Mars No. 8123301D

Correct sight distance problemsat Intersection of KY-89 and

Dry Ridge Rd.

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0 500 1,000250 Feet