Details:

Creators:
Anderson, J. Brian ; Ogunro, Vincent
Anderson, J. Brian ; Ogunro, Vincent Less -
Corporate Creators:
University of North Carolina at Charlotte. Department of Civil and Environmental Engineering
Corporate Contributors:
North Carolina. Dept. of Transportation. Research and Development Unit
Subject/TRT Terms:
[+]
Earth Pressure Earth Pressure--Mathematical Models Mathematical Models Retaining Walls Retaining Walls--Design And Construction--Piedmont (U.S. : Region)--Retaining Walls--Design And Construction Soils--Piedmont (U.S. : Region)
Publication/ Report Number:
FHWA/NC/2006-51
Resource Type:
Tech Report
Geographical Coverage:
North Carolina
Edition:
Final report; July 2004-June 2007.
Corporate Publisher:
North Carolina. Dept. of Transportation
Abstract:
Anecdotal evidence suggests that earth pressure in Piedmont residual soils is typically over estimated. Such estimates of earth pressure impact the design of earth retaining structures used on highway projects. Thus, the development of an appropriate model for estimating earth pressure would result in more rational design of retaining structures in Piedmont residual soils. Accordingly, the objective of this research was to develop an earth pressure model for Piedmont residual soil.

An experimental program to estimate, model, and measure earth pressure in Piedmont residual soils was carried out by the University of North Carolina at Charlotte. This study centered around the instrumentation, construction, and load testing of four sheet pile retaining walls at two sites in the Charlotte Belt and Carolina Slate belt regions of the Piedmont. The scope of work included extensive insitu and laboratory soil testing to estimate soil strength parameters for the residual soils; and numerical models to plan the load testing program and evaluate the results. Results of the load tests showed little or no earth pressure due to Piedmont residual soil. Interpretation of data from the sites using theoretical and numerical methods supports this findings.

Conclusions from this study include: 1) The earth pressure currently used in design of retaining structures in Piedmont soils is greater than earth pressure measured during load tests. Field measurements from the instrumented wall load tests demonstrated that the retained soils exerted little or no pressure on the structure. 2) The Piedmont soils that were tested in this research had significant strength. The average drained friction angle was 28o and the average drained cohesion intercept was above 300 psf. These values were consistent with those found in the literature for similar soils. 3) Based on the soil test results as well as the minimal earth pressure detected during the load tests, the soil strength parameters, φ’and c’ should be used together in Rankine’s earth pressure equation to predict the earth pressure in Piedmont soils. And 4) Triaxial tests provided the most consistent measurement of φ’ and c’. The borehole shear tests also measure φ and c’ but should only be used when triaxial testing is unavailable.


Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:79c6f861442152a20f18f651f6976df33f9fcd207f0982087e9f85e484c6372a
Download URL:
https://rosap.ntl.bts.gov/view/dot/17181/dot_17181_DS1.pdf
File Type:

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