武汉地区基坑一般黏性土的力学特性与其物理指标间的相关性研究

摘要

General cohesive soil is common in foundation pits engineering in Wuhan area and the study on its engineering characteristics and the correlation between its physical and mechanical parameters has practical significance.In order to research the physical and mechanical parameters of typical general cohesive soil in foundation pits in Wuhan area,on the basis of 45 foundation pits engineering,this paper objectively analy-zes the engineering characteristics of the general cohesive soil and the correlation between its physical and mechanical parameters by the method of mathematical statistics and regression analysis.The main conclu-sions are as follows:(1 )The static Cone Penetration Test value (PS value)ranges from 0 .8 MPa to 1 .6 MPa and the Standard Penetration Test value (N value)ranges from 3 to 7;(2 )The saturation of soil is relatively high,and so is the plasticity and compressibility,which may produce unfavorable impact on sedi-mentation deformation of foundation pits and high-rise buildings;(3 )In addition,the moisture content,void ratio and liquid limit coefficient of the soil show negative correlation with its cohesion and frictional angle (c and)derived from direct shear test,whereas the compression modulus shows the positive correlation with the two indexes.The study could provide reference for the parameter selection of foundation pits in-vestigation and design in Wuhan area.%一般黏性土作为武汉地区基坑工程中常见土层，对其工程特性与其物理力学参数的相关性研究对提高深基坑支护技术和经济性具有重要的现实意义。为研究武汉地区基坑工程典型一般黏性土的物理力学特性，以武汉地区45个基坑工程为基础，采用数理统计及回归分析方法，分析了武汉地区一般黏性土的工程特性与其物理力学参数间的相关关系。结果表明：武汉地区基坑工程一般黏性土的静力触探指标PS 值变化范围为0．8～1．6 MPa，标准贯入指标N值的变化范围为3～7，土体饱和度较高，可塑及压缩性中等偏高，这将对基坑及高层建筑沉降变形产生不利影响；此外，一般黏性土的含水率、孔隙比、液限系数与直剪试验条件下抗剪强度指标c、值间呈负相关关系，一般黏性土的压缩模量与直剪试验条件下抗剪强度指标c、值间呈正相关关系。该研究结果可为武汉地区基坑工程设计的参数取值提供依据。