Undrained shear strength of soft clays from push cone penetration test

Géotechnique ◽  
2001 ◽  
Vol 51 (2) ◽  
pp. 167-168 ◽  
Author(s):  
C. Mesri
Keyword(s):  
Shear Strength ◽  
Cone Penetration Test ◽  
Undrained Shear Strength ◽  
Penetration Test ◽  
Cone Penetration ◽  
Soft Clays ◽  
Undrained Shear

scholarly journals Cone Penetration Test in Stiff Over Soft Clay in Centrifuge Test

2019 ◽  
Author(s):  
Qiang Xie ◽  
Yuxia Hu ◽  
Mark Cassidy ◽  
Alireza Salehi
Keyword(s):  
Shear Strength ◽  
Layer Thickness ◽  
Soft Clay ◽  
Undrained Shear Strength ◽  
Centrifuge Test ◽  
Clay Layer ◽  
Penetration Test ◽  
Cone Penetration ◽  
Cone Resistance ◽  
Undrained Shear

Abstract This paper describes a numerical study on soil characterization of stiff over soft clays in centrifuge test using cone penetration test (CPT), especially when the top stiff layer is thin relative to the centrifuge cone size. An extensive parametric study was conducted using large deformation finite element (LDFE) analysis, with the cone penetrating continuously from the soil surface. The LDFE model has been validated against existing physical test data with very good agreement. Since the bottom soft clay was normally thick enough to fully mobilise the ultimate cone resistance, its undrained shear strength can be interpreted by the existing approach for cone deep penetration in a uniform clay layer. Thus, the challenge was to interpret the strength of the top stiff layer, where the layer thickness was not thick enough to fully mobilise its ultimate resistance. Both top layer thickness ratios (to the cone diameter) and layer strength ratios were considered in the parametric study. Based on the results from LDFE analyses, the interpretation formula of the undrained shear strength in the top stiff layer was proposed as a set of new bearing factors. The proposed cone bearing factor was a function of the ratio of the measured peak cone resistance in the top layer to the stable/ultimate cone resistance in the bottom layer and the ratio between the top layer thickness to the cone diameter. The formula can be used directly when the top layer thickness was known based on the sample preparation. However, the layer interface can be identified based on the study here, if the top layer thickness was not certain. A design flow chart was provided for interpretations of top clay layer strength and top layer thickness based on the cone resistance profile obtained from CPT test.

Interpretation of cone penetration tests. Part I: Sand

1983 ◽  
Vol 20 (4) ◽  
pp. 718-733 ◽  
Author(s):  
P. K. Robertson ◽  
R. G. Campanella
Keyword(s):  
Shear Strength ◽  
Pore Pressure ◽  
Cone Penetration Test ◽  
Deformation Characteristics ◽  
Penetration Test ◽  
Cone Penetration ◽  
Stress History ◽  
Penetration Testing ◽  
Cone Penetration Testing ◽  
Recent Developments

Significant advances have been made in recent years in research, development, interpretation, and application of cone penetration testing. The addition of pore pressure measurements during cone penetration testing has added a new dimension to the interpretation of geotechnical parameters.The cone penetration test induces complex changes in stresses and strains around the cone tip. No one has yet developed a comprehensive theoretical solution to this problem. Hence, the cone penetration test provides indices which can be correlated to soil behaviour. Therefore, the interpretation of cone penetration data is made with empirical correlations to obtain required geotechnical parameters.This paper discusses the significant recent developments in cone penetration testing and presents a summarized work guide for practicing engineers for interpretation for soil classification, and parameters for drained conditions during the test such as relative density, drained shear strength, and deformation characteristics of sand. Factors that influence the interpretation are discussed and guidelines provided. The companion paper, Part II: Clay, considers undrained conditions during the test and summarizes recent developments to interpret parameters for clay soils, such as undrained shear strength, deformation characteristics of clay, stress history, consolidation characteristics, permeability, and pore pressure. The advantages and use of the piezometer cone are discussed as a separate topic in Part II: Clay. The authors' personal experiences and current recommendations are included. Keywords: static cone penetration testing, in situ, interpretation, shear strength, modulus, density, stress history, pore pressures.

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