An In Situ Test Method for Evaluating the Coupled Pore Pressure Generation and Nonlinear Shear Modulus Behavior of Liquefiable Soils
An In Situ Test Method for Evaluating the Coupled Pore Pressure Generation and Nonlinear Shear Modulus Behavior of Liquefiable Soils
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评估可液化土的耦合孔隙压力产生和非线性剪切模量行为的原位测试方法
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
E. Rathje
中科院分区：
文献类型：
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作者：
B. Cox;K. Stokoe;E. Rathje
提出了一种评价超孔隙水压力产生与非线性剪切模量行为耦合响应的原位试验方法。该技术是一种主动的、基于应变的方法，可用于直接评估就地土壤的抗液化能力。该试验以类似于地震的方式对原生土壤沉积物进行动态加载为前提，同时使用插入式传感器测量其响应。动态加载通过安装在小车上的大型液压振动筛进行，该振动筛用于在可液化土壤沉积物的仪器部分内产生垂直传播（向下）、水平极化的变振幅横波（svh波）。新开发的推入式传感器由三组件（3D） MEMS加速度计和微型孔隙水压力传感器组成。新的测试方法已用于在地表以下约3至4米的可液化土壤沉积物中进行现场试验。这些试验成功地测量了：(1)超孔隙水压力的产生；(2)原生粉砂沉积物的非线性剪切模量行为与诱导循环剪切应变和加载循环次数的关系。这些成就表明，在准确评估土壤沉积物对地震液化的易感性方面，我们向前迈进了一大步。虽然本文给出了典型的测试结果，但本文主要侧重于新测试方法的设备，现场测试实践和数据分析程序。
An in situ test method for evaluating the coupled response between excess pore water pressure generation and nonlinear shear modulus behavior has been developed. This technique is an active, strain-based method that may be used to directly evaluate the liquefaction resistance of soils in place. The test is based on the premise of dynamically loading a native soil deposit in a manner similar to an earthquake while simultaneously measuring its response with push-in sensors. Dynamic loading is performed via a large, buggy-mounted hydraulic shaker (vibroseis) that is used to generate vertically propagating (downward), horizontally polarized shear waves (Svh-waves) of varying amplitude within an instrumented portion of a liquefiable soil deposit. The newly-developed, push-in sensors consist of a three-component (3D) MEMS accelerometer and a miniature pore water pressure transducer. The new test method has been used to conduct field experiments in liquefiable soil deposits approximately 3 to 4 m below the ground surface. These tests were successful at measuring: (1) excess pore water pressure generation, and (2) nonlinear shear modulus behavior in native silty-sand deposits as a function of induced cyclic shear strain and number of loading cycles. These accomplishments represent a large step forward in the ability to accurately evaluate the susceptibility of a soil deposit to earthquake-induced liquefaction. While typical test results are presented herein, this paper primarily focuses on the equipment, field testing practices, and data analysis procedures for the new test method.