M113EXQ Earthwork Engineering Laboratory Interpretation And Design Report

Question:

You will use laboratory measurements to create an ‘Interpretive Laboratory reporting’ according to the guidelines set out in Appendix A.

Note the page limits. Extra pages are not considered for marking.

Please use Font size 11 single spacing.

Also, you will complete a “Geotechnical Report” following the guidelines set out in Appendix B. This report will include the interpretation of laboratory data contained in the “Interpretive Laboratory Report”.

Note the page limits. Extra pages are not considered for marking.

Font size 11 is the best. Single spacing is acceptable.

Answer:

This report documents subsurface geological conditions, provides analysis of the expected site conditions for the project and then gives a recommendation as to design and construction criteria for roadway sections.

This report provides a geotechnical baseline which can be used for evaluating the scope and existence of altered site conditions.

The report can be used by project designers, bidders and construction personnel as well contractors.

Description of the project

This project is designed to widen an existing road for vehicle pullout maintenance.

On the south bond there will be RW1-RW3 retaining walls, and on the north bond there will be RW4 retaining wall. All of these will be in compliance with Highways England Standards.

The table below shows the proposed retaining wall designs.

No.

Limits approximative

Wall Height (ft.

Notes

Line “AL1”.

756+26 – 756+91

The spread footing will only be formed using the existing embankment fill slope of 2:1.

The new approach wall fill will maintain a height of 0.6 meters, even though the wall will measure 1.8 meters in height.

The slope of the finish will be minimum 1.2 meters from the edge of horizontal footing closest to wall.

“AL1” Line

756+06 – 760+38

The existing slope of 2:2 of the embankment fill is used for the foundation of the spread footing. Partly on the existing embankment and partially on the new one.

An adjacent bench will be constructed of 0.6 to 1.25 meters.

“AL1 Line”

762+48 – 763+26

The existing slope of 2:2 of the embankment fill is used for the foundation of the spread footing. Partly on the existing embankment and partially on the new one.

An adjacent bench will be constructed of 0.6 to 1.25 meters.

Line “AL1”

778+60 – 779+50

The existing slope of 2:2 of the embankment fill is used for the foundation of the spread footing. Partly on the existing embankment and partially on the new one.

An adjacent bench will be constructed of a level height of 0.6 to 1.25 meters.

Taber Drilling was hired by the group to drill three borings in order to determine the subsurface conditions. These bores were located within existing asphalted shoulder areas, which are close to the proposed walls.

They took soil samples at different times using a 3.0-inch O.D.

Modified California sampler, and a 2-inch O.D.

These samples were driven into an electric hammer that weighed approximately 140 pounds. The hammer fell at 30 inches per blow.

Bulk composite samples were also taken from the topmost 0.46 to 1.25 meters of the borings.

Taber Drilling refilled the borings with concrete grout when the drilling was complete (Craig 2014 p. 369).

Conditions of the Subsurface Soil

A pavement section is located on the south bond of a road. It is composed of 3 to 5-inch hot mix asphalt concrete, laid over a 5-inch aggregate base.

This layer extends from 0.6 to 0.8% meters to the depth below the naturally-existing grade.

A fill is found under the pavement section. This fill is composed of very hard to firm, lean-to-fat clay up to 5 meters below the naturally occurring grade (Olson 2016,p. 615).

A pavement section measuring approximately 8 inches is found on the north bond of road borings. It is composed of hot mix asphalt concrete laid on 5-6.5 inches of aggregate base. The aggregate base is clay sand mixed with gravel. It extends to approximately 0.6909M below the naturally occurring grade.

This pavement section contains a fill of hard, lean-to-fat clay and high density silty soil to an approximate depth of 2.4M beneath the naturally existing Grade.

Groundwater

During the drilling process, there was no groundwater in any of the borings.

The group looked at the groundwater data from nearby dams and wells that was available in the municipal council’s resources (Radon 2017, p. 555).

The information gleaned from these data sources indicated that groundwater levels at this site fluctuated between Ele.

-7.6m to -10.7m which is about 15m below the existing ground surface at the site.

It was however noted that shallow perched water would be found within the soils at the site’s surface during spring and winter.

Field and Laboratory Testing

For soil samples obtained from exploratory borings, the following laboratory tests were conducted:

Test for moisture content and dry densities

Plasticity index test

Triaxial/direct shear tests

In order to determine the relationship between maximum soil dry density and soil moisture content, the Moisture Content and Dry Density Test is used (Sanglerat 2013, page 415).

This result was obtained by a proctor test.

The soil compaction curve, which illustrates the correlation, is useful in determining the maximum water level at which soil can achieve its maximum dry density through compaction.

This test is incontinuous because it cannot determine the dry density directly. The bulk density and the moisture content must be first determined to calculate the dry densities from the formula.

Different soil samples were found compacted at different water levels. The compaction curve, as shown below, was calculated by plotting drydensity against water content (Donaghe 2012).

RW1 Retaining Wall

Highways England Standards information about standards and quality measures indicates that the spread footing of Retaining Wall RW1 would be established within the exiting fill slope at 2:1. There will not be any bench in front.

The wall will still be approximately 0.6 m high, but the fill will retain a height of 0.8 m.

The wall’s horizontal top edge will be minimum 1.2m away from the slope at the finish.

Given the subsurface conditions that I saw in the borings that were done within the same road approach fill fill, I predicted that the spread footing foundation materials would be very stiff to hard and lean to thick clay fill.

Based on the results from the pocket penetometer test (Helwany 2010, page 245), the fill’s compressive strength is unconfined at 0.9m.

This compressive force exceeds the shear strengths that are developed by the properties the granular soil used to design the standard plan for the wall.

The DMRB Volume 5 – Section 3: TA 79/99 amendment No 1 is suitable for Retaining Wall RW1 based upon the minimal retained fill height, the very tough to hard soil conditions and a planned distance of 1.2 m between the footing at expected foundation levels.

Highways England Standards information about standards and quality measures indicates that the existing 2:2 slope of embankment fill will only be used to build the spread footing. This will be partially on the old embankment and partly on the new.

Acton 2013, page 114.

Due to the subsurface conditions in the borings, I expected that the spread footing foundation materials would be made of very stiff to firm lean to fat clay.

With the possibility of a new filled, it is possible to use more conservative standard-plan soil properties to determine the foundation bearing capacity and the lateral capability for footings embedded in the ground. (Hoddinott 2010, P. 189).

It is suggested that the minimum footing embedment in the wall be increased from 0.9 m to the finish grade in front the walls to provide passive resistance/passive wedge.

The top edge of your footing should be placed horizontally at least 1.8m from the finish’s slope face.

The Bearing Resistance of the Spread Footing was assessed using the various methods outlined in Bridge Design Specifications (Editors 2008), p. 258.

These were the methods used in the analysis

Modified bearing capability factor for footing on sloped ground

Soil properties for the standard plan with a friction angle at 34 degrees and a unit weigh of 120 pcf

Consider loading conditions and footing dimensions to accommodate the standard wall heights of 3.6m and 4.8m, respectively, in order to account for any variation in the proposed wall heights

45 is the standard geotechnical resistance coefficient used in strength limit resistance analysis. A geotechnical resistant factor of 1.0 is used for extreme limit cases.

It was discovered that the wall’s bearing strength was greater than the strength and extreme limit loads. This was based on an analysis of Highways England Standards.

Wall Retaining Wall RW4

Highways England Standards has provided information about standards and quality measures. The existing slope of 2:2 of the embankment will be used to build the spread footing. Partly on the existing and the new embankment.

A level bench will be constructed at the wall’s front, measuring between 0.6 and 1.5 m.

To provide the necessary passive resistance/ passive wedge against footing foe faces, it is recommended that the minimum footing embedment be increased to 0.9m below the finish grade in front the walls.

It is important that the top edge (of the footing) is at least 6 ft horizontally from slope face of finish (Craig 2014).

Based on the results from the pocket penetometer test, the compressive strength of fill is unconfined at 0.9 m.

This compressive force exceeds the shear strength which is determined using the properties granular soil used to design the standard plan for the wall.

Highways England Standards can still be used for this analysis, provided that the recommended footing depth and footing distance are taken into account when designing this road.

X (90, 20,), Y(-60,-20).

The above calculations are based on

Mohr’s Circle:X

Estimation and measurement of the wall

Step 1

The number of required blocks to be determined

The length of the wall (in inches) and the length of a block = blocks per course

=4375/11.5= Approximately 380 blocks per race

Step 2

The number of courses to be offered

Number of courses = Height of a wall (in inches)

50 courses for 200/4

As you can see, there is no water in the retaining walls. The calculations will not be subject to surcharge.

Eurcode standards and requirements for soil strength, and other properties will all be met in the calculation.

These calculations are based on the assumption that the retaining walls will be made of mass concrete and that the embankment is 5.0M high.

Table 2

Cl 1.4321

Table 1

Table 3

Table

Case A

1400mm thick

Case B

1400mm thick

Comment

H=5.0m, medium-sized retaining wall that is compact and does not require water pressure.

Soil properties for compact sand

Dense Medium-sized sand with moderate grade:

Assuming sub-angular particles of soils SPT N=20 at a depth (5)

So N,=1.7*20=34 and C=4.8

Design Tan=tan=0.670 oder 0.675

0.75*design tanning=0.364, 0.503

Design

Surcharge of 10kN/m2 for soils that are retained behind the wall

You can try 1400mm thick wall

Active pressure =

TOTAL

Check maximum bearing pressure at CIRIA C516

design 2

45.5kN/m2 sliding force

Unplanned excavation of the wall front without a surcharge

Depth of excavation =10% clear height of at least 5.0M

Sliding force = 35.8 KN/m2

Case A is critical because of the surcharge on both sides. Thus, the wall must be 1400mm thick.

Euro code Standards may require a thinner wall than the traditional CP2 in order to calculate the 10 kN/m2 charge on the rear wall.

P W Ia

263600 KN/m2 OK

231.5 kN/m2>228.9 Okay

45.573.1kN/m OK

P W Ia

220600 kN/m2 Ok

158.4205.6 OK

35.871.3KN/m2 OK

References

Acton, QA 2013. Issues In Engineering Research and Application: 2013 Edition. ScholarlyEditions Sydney.

Aysen A 2009 Problem Solving in Soil Mechanics. CRC Press, New York.

Craig, RF 2014. Craig’s Soil Mechanics Seventh Edition 7th edn CRC Press, Washington.

Donaghe RT 2012 Advanced Triaxial Testing of Soil & Stone, Issue 977, ASTM International New York

Editors, S 2008 – Tailings and Mine Waste 2002: Proceedings at the 9th International Conference. Fort Collins (Colorado), 5th Edn, CRC Press. Colorado.

Fang H-Y 2013, Foundation Engineering Handbook 10th edn Springer Science & Business Media Beijing.

Helwany S 2010, Applied Soil Mechanics using ABAQUS applications, 8th edn John Wiley & Sons New Delhi.

Hoddinott KB 2010 Testing Soil Mixed with Waste or Recycled Materials. Issue 1275. ASTM International, London.

Koseki J 2017, Soil Stress-Strain behavior: Measurement and Modeling: A Collection Papers from the Geotechnical Symposium Rome March 16-17 2006, Springer Science & Business Media Chicago.

Kutter, BL 2014 Triaxial Shear and Torsional Shear Test Results For Sand, 10th edn Naval Facilities Engineering Service Center Salt Lake

Lade PV 2016, Triaxial Testing of Soils. 3rd edn. John Wiley & Sons. Paris.

Landva A 2010, Geotechnics in Waste Fills Theory and Practice, 4th edition, ASTM International London.

Levy SM 2011, Construction Calculations Manual. 5th edn. Elsevier London.

Olson G 2016, Soils & the Environment: A Guide To Soil Surveys And Their Applications, 5th edn Springer Science & Business Media Manchester.

Planas J 2012 Fracture and Size Effects in Concrete and Other Quasibrittle materials, 6th edition, CRC Press Chicago.

Radon, JC 2017, Fracture & Frustration: Elastoplasticity Thin Sheet and Micromechanisms Problems. Elsevier, New York.

Raj, PP 2008. Soil Mechanics and Foundation Engineering. 4th edn. Pearson Education India. Washington.

Reeves GM 2016, Clay Materials Used for Construction, 4th edn. Geological Society of London. London.

Sanglerat G 2013, Physical characteristics of soils, plasticity, settlement calculations, interpretation of in-situ tests, 7th edition, Elsevier Chicago

Teng JG 2015 Buckling of Thin Metal Shells. CRC Press, Manchester.

Trenter, NA 2010 Earthworks: A Guide 2nd edn Thomas Telford Paris

Watson, I 2013, Hydrology: An Environmental Approach. CRC Press, Washington.