Stiffness decay characteristics and disturbance effect evaluation of structured clay based on in-situ tests
Stiffness decay characteristics and disturbance effect evaluation of structured clay based on in-situ tests
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基于原位试验的结构粘土刚度衰减特性及扰动效应评价
DOI：
10.1016/j.sandf.2022.101184
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发表时间：
2022-10
影响因子：
3.7
通讯作者：
Xianwei Zhang
中科院分区：
文献类型：
--
作者：
Ran An;Lingwei Kong;Wenzhuo Shi;Xianwei Zhang
沉积粘土的结构以不可忽视的方式影响其力学行为。本文提出了一种基于自钻旁压和地震旁压试验的剪切模量和应变衰减曲线（G-γ曲线）研究原位刚度特性的有效方法。为了评价开挖扰动对结构性粘土的影响，将预钻孔旁压试验的刚度参数与自钻孔旁压试验的结果进行了比较。结果表明，将自钻旁压试验的应变相关切线剪切模量Gt和地震旁压试验的小应变模量G 0进行综合，可以得到完整的原位G-γ曲线。在同一应变尺度下，半对数坐标系下双曲线型的G-γ曲线的同步观测表明，不同深度土体刚度衰减模式具有相似性。Gt和G 0随深度的增加可归因于结构性粘土中固结压力和胶结强度的提高。现场试验测得的G/G 0-γ曲线与Stokoe模型预测的结果基本吻合。开挖扰动削弱了结构性粘土的刚度，如在相同深度下，预钻孔测压数据的Gt显著小于自钻孔测压试验的Gt。定量分析表明，由实测结果计算的扰动度对土层深度的敏感性较低，与土层应变水平呈较强的负相关关系。该研究为基于原位试验预测结构性土的刚度参数提供了一种有效的方法。
The structure of the sedimentary clay influences its mechanical behavior in non-negligible ways. This paper proposes an effective approach for investigating the in-situ stiffness characteristics from shear modulus and strain decay curves (G–γcurves) based on self-boring pressuremeter and seismic dilatometer tests. To evaluate the excavation disturbance effects on the structured clay, the stiffness parameters from pre-bored pressuremeter tests are compared with the results of self-boring pressuremeter tests. The result indicates that the complete in-situG–γcurves can be acquired by integrating the strain-dependent tangent shear modulusGtfrom self-boring pressuremeter tests and the small-strain modulusG0from seismic dilatometer tests. Simultaneous observations of theG–γcurves with hyperbolic shapes in semi-logarithmic coordinates at the same strain scale show the similarity of the stiffness decay mode of the soil at different depths. The increase in the measured values ofGtandG0with depth can be attributed to the improved consolidation pressures and cemented strength in the structured clay. Additionally, the G/G0–γcurves measured by the in-situ tests generally agree well with the results predicted by the Stokoe model. The excavation disturbance weakens the stiffness of the structured clay, as evidenced byGtfrom the pre-bored pressuremeter data being significantly smaller than that from self-boring pressuremeter tests at the same depth. Based on quantitative analysis, the disturbance degree computed from the measured results has a low sensitivity to the soil depth and a strong negative correlation with the strain level of the soil. This study provides an effective method for predicting the stiffness parameters of structured soil based on in-situ tests.
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影响因子：
5.8
作者：
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通讯作者：
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作者：
K. Senetakis;A. Anastasiadis;K. Pitilakis;M. Coop
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DOI：
--
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1995
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