Soil shear strength parameters, i.e. cohesion (C) and friction angle (ϕ) are typically determined using laboratory and in situ tests, although some limitations are involved in laboratory tests, such as the need for considering size effects and the use of undisturbed sampling. Cone penetration testing (CPT) has been recognised as a rapid and versatile procedure to provide continuous soil records, particularly in marine environment. In this study, an analytical approach is utilised to calculate drained soil strength parameters using piezocone penetration test (CPTu) records, i.e. qt (corrected point resistance) and fs (sleeve friction) and the results are compared with those obtained from laboratory tests. Current methods for obtaining shear strength parameters using CPT data are based on bearing capacity and cavity expansion theories and are able to estimate only ϕ in sands, and undrained shear strength (Su) in cohesive soils. In this paper, by combining bearing capacity theories and direct shear modes of failure at CPTu tip and sleeve resistances, and considering the pore water pressure at the shoulder of the piezocone (u2), a set of equations is derived. By inputting CPTu data including qt, fs and u2 at a certain depth, soil shear strength parameters can be calculated simultaneously. Finally results obtained from this method are compared with measured soil shear strength parameters, using a data bank consisting of 50 sets of CPTu sounding carried out in marine deposits at various locations around the world. The comparison between predicted and measured C and ϕ values indicates good consistency and low scatter for the results obtain from the proposed method. This demonstrates that the proposed method is able to predict soil shear strength parameters in difficult marine environments with acceptable accuracy.
Drained soil shear strength parameters from CPTu data for marine deposits by analytical model
Ships and Offshore Structures ; 11 , 8 ; 913-925
2016-11-16
13 pages
Article (Journal)
Electronic Resource
English
Drained soil shear strength parameters from CPTu data for marine deposits by analytical model
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