Low Strain Dynamic Shear Modulus of Cemented Sand from Cone Penetration Test Results

Low strain dynamic shear modulus property is generally used to subclassify soil strata, determine elastic settlements under geotechnical structures, and characterize the dynamic nature of soils. Several methods to interpret the dynamic shear modulus of sands from in situ friction cone test results have been developed. These methods used calibration chamber test data of clean sands. Therefore, these methods are not valid for interpreting the shear modulus of cemented sands. Introduced here is an interpretation method to estimate the shear modulus of cemented sand. Thirty-seven friction cone penetration tests (CPTs) were conducted on artificially cemented sand specimens of relative densities ranging from 45 percent to 85 percent and confining pressures ranging from 100 to 300 kPa in a laboratory stress-strain-controlled calibration chamber. Cementation levels of 1 and 2 percent were used in preparing cemented specimens. Resonant column tests were also conducted on the same sand with identical cementation levels. The CPT and resonant column test data are used in developing an interpretation method that includes semiempirical correlations. Simple interpretation charts are also provided to directly estimate the low strain shear modulus of cemented sand from tip resistance, unconfined compressive strength, and relative density data. Comparisons between predictions of the proposed interpretation method and the present measured shear modulus test data indicate that the interpretation charts have provided reasonable predictions. The comparisons also indicate that the predicted results on clean sands obtained by different researchers are in agreement with each other.