JRMGE / Vol 16 / Issue 3
Soil disturbance evaluation of soft clay based on stress-normalized small-strain stiffness
Yanguo Zhou, Yu Tian, Junneng Ye, Xuecheng Bian, Yunmin Chen
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a MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Institute of Geotechnical Engineering, Center for Hypergravity Experiment and
Interdisciplinary Research, Zhejiang University, Hangzhou, 310058, China
b Ningbo Rail Transit Group Co., Ltd., Ningbo, 315010, China
2024, 16(3): 990-999. doi:10.1016/j.jrmge.2023.08.019
Received: 2023-01-30 / Revised: 2023-06-27 / Accepted: 2023-08-14 / Available online: 2023-12-03
2024, 16(3): 990-999.
doi:10.1016/j.jrmge.2023.08.019
Received: 2023-01-30
Revised: 2023-06-27
Accepted: 2023-08-14
Available online: 2023-12-03
Soil disturbance includes the change of stress state and the damage of soil structure. The field testing indices reflect the combined effect of both changes and it is difficult to identify the soil structure disturbance directly from these indices. In the present study, the small-strain shear modulus is used to characterize soil structure disturbance by normalizing the effective stress and void ratio based on Hardin equation. The procedure for evaluating soil sampling disturbance in the field and the further disturbance during the subsequent consolidation process in laboratory test is proposed, and then validated by a case study of soft clay ground. Downhole seismic testing in the field, portable piezoelectric bender elements for the drilled sample and bender elements in triaxial apparatus for the consolidated sample were used to monitor the shear wave velocity of the soil from intact to disturbed and even remolded states. It is found that soil sampling disturbance degree by conventional thin-wall sampler is about 30% according to the proposed procedure, which is slightly higher than that from the modified volume compression method proposed by Hong and Onitsuka (1998). And the additional soil disturbance induced by consolidation in laboratory could reach about 50% when the consolidation pressure is far beyond the structural yield stress, and it follows the plastic volumetric strain quite well.
Keywords: Natural clay, Soil sample disturbance, Shear wave velocity, Small-strain shear modulus, Hardin equation
Article Data
Author(s) Information
Yanguo Zhou
Yanguo Zhou is currently full professor in College of Civil Engineering and Architecture, Zhejiang University, China. Prof. Zhou obtained his BSc degree in Civil Engineering in 2001 and his PhD in Geotechnical Engineering in 2007, both from Zhejiang University, China. Then he became a faculty member of Department of Civil Engineering, Zhejiang University, since 2007. He worked as visiting associate researcher in Department of Civil and Environmental Engineering, University of California, Davis, from 2011 to 2014. He is now the council member of Seismological Society of China, the committee member of the International Society for Soil Mechanics and Geotechnical Engineering TC104 (Physical Modeling) and TC304 (Reliability). His research interests include (1) soil dynamics and geotechnical earthquake engineering with emphasis on soil liquefaction and mitigation; (2) soil testing and foundation engineering with emphasis on soil disturbance; and (3) hypergravity experiment by centrifuge shaking table test. He has been participated in a number of national research projects and consulted several major engineering projects.