刚性基础下砼芯水泥土桩复合地基沉降计算  

Settlement calculation of composite foundation with concretecored DCM pile under rigid foundation

作　　者：俞建霖[1,2] 徐山岱 杨晓萌 陈张鹏 龚晓南 YU Jianlin;XU Shandai;YANG Xiaomeng;CHEN Zhangpeng;GONG Xiaonan(Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,China;Zhejiang Urban Underground Space Development Engineering Research Center,Hangzhou 310058,China)

机构地区：[1]浙江大学滨海和城市岩土工程研究中心,浙江杭州310058 [2]浙江省城市地下空间开发工程技术研究中心,浙江杭州310058

出　　处：《中南大学学报（自然科学版）》2020年第8期2111-2120,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51978610);浙江省重点研发计划项目(2019C03103)。

摘　　要：为了计算复合地基沉降并研究其相关影响因素,首先,考虑界面相对位移对界面侧摩阻力的影响,获得理想弹塑性荷载传递函数;然后,根据荷载传递法的基本原理,建立砼芯、水泥土桩和桩周土三者各自的平衡微分方程,得到三者相应的应力位移表达式;最后,通过与数值模拟对比验证了该方法的可靠性,分析了上部荷载、含芯率、面积置换率、桩周土和下卧层压缩模量对复合地基沉降量的影响。研究结果表明:刚性基础下砼芯水泥土桩复合地基中砼芯承担了较大部分的上部荷载,水泥土桩次之,桩周土的荷载分担比最小;随着荷载增大,砼芯的荷载分担比逐渐减小,桩周土和水泥土桩的荷载分担比逐渐增加,荷载由砼芯向外逐步传递到水泥土桩与桩周土;随着上部荷载减小,含芯率、面积置换率、桩周土和下卧层压缩模量增加,复合地基沉降量逐步减小,其中含芯率的影响相对较小;除下卧层压缩模量外,各影响因素对桩周土压缩量的影响程度显著大于下卧层土体压缩量的影响程度。In order to calculate the settlement of composite foundation and study the relevant influencing factors,firstly,the influence of the interface relative displacement on the side friction resistance of the interfaces was considered,and the ideal elastic-plastic load transfer function was obtained.Secondly,according to the basic principle of load transfer method,the equilibrium differential equation of the concrete core,cement soil pile and soil around the pile were established respectively,and the corresponding expressions of stress and displacement were obtained.Finally,the reliability of the method was verified by comparing with the results of numerical simulation,and the influence of upper load,core ratio,area displacement ratio,soil around the pile and underlying layer compression modulus on the settlement amount of composite foundation was analyzed.The results show that in concrete-cored DCM pile composite foundation under rigid foundation,the concrete core bears most of the upper load,followed by the cement soil pile,and the load sharing ratio of the soil around the pile is the smallest.With the increase of the load,the load sharing ratio of concrete core decreases gradually,the load sharing ratio of the soil around the pile and the cement soil pile gradually increases,and the load is gradually transferred from concrete core to the cement soil pile and the soil around the pile.With the decrease of the upper load,the core ratio,area replacement ratio,the compression modulus of the soil around the pile and underlying layer increase,and the settlement amount of the composite foundation gradually decreases,among which the influence of the core ration is relatively small.Except for the compression modulus of the underlying layer,the degree of influence of various factors on the compression of soil around the pile is significantly greater than that of the underlying soil.

关 键 词：砼芯水泥土桩 复合地基 荷载传递法 界面相对位移 沉降 

分 类 号：TU43[建筑科学—岩土工程]