Repeated LWD test to assess the stiffness properties of clayey soil
Repeated LWD test to assess the stiffness properties of clayey soil
Geotechnical failures are often the result of not recognizing or adequately evaluating conditions prior to construction of a pavement system. The dominant geotechnical factor(s) for many pavement distresses is/are the stiffness and/or strength of the subgrade materials (U.S. Department of Transportation, 2006). To investigate further the stiffness properties of geotechnical materials, the current study has been undertaken to evaluate the feasibility of using a new multifunctional light weight deflectometer (LWD) to determine the in-situ dynamic deformation moduli (Evd) of clayey soil under repeated loading. This method is considered simple and a time saving technique to measure the in- situ dynamic properties of geotechnical materials. A sandy silty clay soil has been chosen for testing. At the beginning, the soil was compacted in a test pit, and then, series of in-situ repeated LWD were conducted at different ranges of water contents (namely 16%, 19% and 24%) under various applied stress levels (namely, 24 kPa, 38 kPa and 50 kPa). The test results have showed that increasing the water content decreases the dynamic deformation moduli, similarly, increasing the applied stresses decreases the dynamic deformation moduli as well. The multiple regression analysis has been used to model the dynamic deformation moduli of the tested soil based on the measurements reported from repeated in-situ LWD tests. A strong correlation has been found between the Evd and the water content, degree of saturation and applied axial stresses for the tested soil with high correlation coefficient of 0.99.
Dina Kuttah
18th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE2024)
A - New developments on structural design
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