粉质黏土基坑卸荷隆起变形的简化计算方法  

A simplified calculation method for upheaval deformation induced by unloading of silty clay foundation pit

作　　者：崔瑜瑜 吴立鹏 沈兴华 王兴召 秦亚琼 刘杰 卢正[1] 吴磊 CUI Yu-yu;WU Li-peng;SHEN Xing-hua;WANG Xing-zhao;QIN Ya-qiong;LIU Jie;LU Zheng;WU Lei(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Wuhan Municipal Engineering Design&Research Institute Co.,Ltd.,Wuhan,Hubei 430023,China;Hubei Institute of Water Resources Survey and Design,Wuhan,Hubei 430070,China)

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049 [3]武汉市政工程设计研究院有限责任公司,湖北武汉430023 [4]湖北省水利水电规划勘测设计院,湖北武汉430070

出　　处：《岩土力学》2023年第5期1425-1434,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.42077262,No.42077261,No.41672312)。

摘　　要：基坑卸荷隆起变形计算对基坑稳定性分析具有重要意义。基于现有土体压缩-回弹试验数据及多个地区粉质黏土基坑变形数据进行分析,推导出土体回弹模量与卸荷比之间的指数关系,并结合Mindlin应力解与分层总和法,利用两个实际工程案例进行验证对比,提出了一种卸荷条件下基坑隆起变形的简化计算方法。结果表明:简化计算方法仅根据常规土工试验参数(重度、压缩模量等)即可快速对基坑卸荷隆起变形量进行预估,且计算结果与现场实测值较为接近。进一步分析可知,基坑形状相同时,随着基坑面积的线性增大,基坑底部隆起变形会非线性增大;基坑面积相同时,长条形基坑的隆起变形小于正方形基坑。该方法可为粉质黏土地区卸荷条件下的基坑隆起变形预测提供参考。Calculation of unloading-induced upheaval deformation of the foundation pit is of great significance to the stability analysis of the foundation pit.The exponential function between rebound modulus of soil and unloading ratio is deduced based on the existing laboratory test results of the soil compression–rebound test and published results of silty clay foundation pits in different areas.Then,a simplified calculation method for upheaval deformation is proposed by combining the Mindlin's solution and the layer-by-layer summation method.The accuracy of the proposed method is validated using the results of two engineering examples.It is found that by using the simplified calculation method,the upheaval deformation induced by foundation pit unloading can be easily predicted only using soil parameters obtained by conventional geotechnical tests,and the predicted results of this method are close to the measured values.The further analysis shows that when the shape of the foundation pit is the same,the upheaval deformation at the bottom of the foundation pit nonlinearly increases with the linearly increase in the area of the foundation pit;when the area of the foundation pit is the same,the upheaval deformation of the strip foundation pit is smaller than that of the square foundation pit.The proposed method can provide theoretical guidance to the upheaval deformation prediction of the foundation pit in the silty clay area.

关 键 词：基坑 卸荷附加应力 回弹模量 卸荷比 隆起变形 

分 类 号：TU470[建筑科学—结构工程]