黄土基坑典型区域不同含水率土体强度与变形特性研究  

Study on soil strength and deformation characteristics with different moisture content in typical areas of loess foundation pits

作　　者：钟华 官宸慧 刘路路 ZHONG Hua;GUAN Chenhui;LIU Luu(Guangxi Road and Bridge Engineering Group Co.Ltd.,Nanning 530200,China;School of Civil Engineering,Wuhan University,Wuhan 430072,China;State Key Laboratory of Deep Geotechnical Mechanics and Underwater Engineering,China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]广西路桥工程集团有限公司,广西南宁530200 [2]武汉大学土木建筑工程学院,湖北武汉430072 [3]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116

出　　处：《南京工业大学学报（自然科学版）》2024年第2期205-215,共11页Journal of Nanjing Tech University(Natural Science Edition)

基　　金：国家自然科学基金(42302320)。

摘　　要：为了研究黄土地区基坑稳定性受含水率与应力路径影响的规律,针对基坑3个典型区域施工时土体实际受力情况,考虑黄土在不同含水率下强度差异明显的特性,选取具有代表性含水率的黄土进行3种应力路径下的加载、卸载试验,并进行对比研究。对比3类应力-应变曲线的偏应力峰值发现,黄土抵抗加载的能力>抵抗轴向卸载的能力>抵抗侧向卸载的能力;对比强度指标得出,含水率在26%及以上时,试样强度大幅下降,并且两者为指数函数关系;饱和试样的孔压在卸载前期为负值,采用Logistic函数得到的孔压与轴向应变的关系可以反映该现象;3种应力路径下的应力-应变关系进行归一化处理后均符合双曲线关系,根据该关系可得初始切线模量的经验公式,进而推导出变形模量。试验结果得出的规律和参数取值可为黄土地区基坑建设提供参考。The study examined the impact of moisture content and stress path on the stability of foundation pits in loess areas with the focus on the soil stress conditions during construction in three typical pit areas.Considering the significant strength differences in loess at different moisture levels,loess samples with representative moisture contents were selected for loading and unloading tests under three stress paths for comparative analysis.The results showed that by comparing the deviatoric stress peaks of three different stress-strain curves,it was found that loess demonstrated greater capacity to resist loading than axial unloading,and more so than lateral unloading.According to the strength indices,when the moisture content was 26%or above,the strength of the samples decreased significantly,exhibiting an exponential relationship.The pore pressure of saturated samples was negative at the early unloading stage,a phenomenon depicted by the Logistic function relationship between pore pressure and axial strain.The stress-strain relationships for the three stress paths conformed to a hyperbolic relationship after normalization.From it,an empirical formula for the initial tangent modulus could be obtained,and then the deformation modulus could be derived.The insights and parameters obtained from the test results could provide references for foundation pit construction in loess areas.

关 键 词：黄土基坑 含水率 土体强度 孔隙水压力 变形模量 

分 类 号：TU444[建筑科学—岩土工程]