基于割线模量的散体材料桩复合地基沉降计算  

Settlement calculation of stone columns-improved composite foundation based on secant modulus

作　　者：李传勋[1] 刘聪 LI Chuanxun;LIU Cong(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang,Jiangsu 212013,China)

机构地区：[1]江苏大学土木工程与力学学院,江苏镇江212013

出　　处：《江苏大学学报（自然科学版）》2024年第4期482-489,共8页Journal of Jiangsu University：Natural Science Edition

基　　金：国家自然科学基金资助项目(42377183)。

摘　　要：基于土体侧限条件下的应力-应变关系曲线均为双曲线的现象,且应用割线模量计算土体的竖向应变更有助于实现程序计算,首先利用土体割线模量与压缩指数和压缩模量的关系,得到桩周土体割线模量的确定方法.在此基础上,基于等应变假设条件得到考虑土体非线性压缩的桩土应力比,并提出改进的应力修正法和复合模量法,以实现散体材料桩复合地基非线性沉降计算.最后结合模型试验和实际工程算例,对2个改进的沉降计算方法开展验证分析.研究结果表明:室内模型试验中,改进的应力修正法和复合模量法的沉降计算值与试验值误差均小于1.00 mm,表明改进的沉降计算方法具有一定的可靠性;实际工程算例中,改进的复合模量法计算值与实测值间误差为8.70%,远小于JGJ 79—2012《建筑地基处理技术规范》中规定的复合模量法误差(55.06%),改进的应力修正法计算值与实测值误差为8.73%,远小于JGJ 79—2012中规定的应力修正法误差(55.11%).对比分析表明,改进的沉降计算方法优于JGJ 79—2012中的复合模量法和应力修正法,且改进方法计算值更接近实测值,说明改进方法具有更好的可靠性和适用性.The stress-strain relationship of soils under confining conditions is hyperbolic.In this case,secant modulus can be adopted to calculate the vertical strain of soils,which is helpful to realize the settlement calculation.The secant modulus of the soil around stone columns was determined according to the relationship between the secant modulus and the compression index and compression modulus.The column-soil stress ratio considering the nonlinear compressibility of soils was proposed based on the assumption of equal strain,and the improved stress correction method and composite modulus method for nonlinear settlement calculation of composite foundations with stone columns were further provided.The two improved methods for the settlement calculation were verified by the model test and actual project.The results show that for the laboratory model test,the differences between the measured results and the calculated results by the improved composite modulus method and modified stress correction method are less than 1.00 mm,which indicates that the improved method for settlement calculation is reliable.For the actual project,the error between the improved composite modulus method and the measured results is 8.70%,which is less than the specified error of 55.06%by the composite modulus method in the JGJ 79—2012.The error between the improved stress correction method and the measured results is 8.73%,which is less than the specified error of 55.11%by the stress correction method in the JGJ 79—2012.The comparative analysis shows that the improved settlement calculation method is better than the composite modulus method and stress correction method in the JGJ 79—2012,and the calculated results by the improved method are closer to the measurement results,which indicates that the improved method has better reliability and applicability.

关 键 词：复合地基 散体材料桩 沉降计算 复合模量法 应力修正法 

分 类 号：TU473.1[建筑科学—结构工程]