EMPIRICAL RELATIONSHIPS OF CPTu RESULTS AND UNDRAINED SHEAR STRENGTH

Akbar Cheshomi

《Journal of GeoEngineering》 13卷2期 (2018/06) Pp. 49-57

https://doi.org/10.6310/jog.201806_13(2).1

摘要

Cone penetration testing (CPTu) and pore pressure measurement have long been used to estimate the undrained shear strength (S_u) of clay, although the evaluation of strength from CPTu results in fine-grained soil is mostly empirical. In fact, for various reasons, in-situ methods such as CPTu and laboratory methods may give different results for S_u for a specific soil. The present study correlated the results of 22 CPTu and 50 uniaxial compression tests conducted on quaternary alluvial clay from southern Iran. Empirical relationships with acceptable coefficients of correlation between Su and CPT parameters were obtained and values of the empirical cone factors N_k, N_(kt), N_(ke), and N_(Δu) are proposed for these clays. A comparison of these values with values proposed in previous studies suggests that the cone factors depend on the type of the reference test used. Although the plasticity and consistency index also affect cone factors, it was not possible to determine an acceptable empirical relationships for these parameters.

關鍵字

CPTu ； undrained shear strength ； empirical cone factors