高填方膨胀土作用下刚柔复合桩基挡墙结构数值模拟  

Numerical simulation of composite rigid-flexible pile-supported retaining wall under the action of high-filled expansive soil

作　　者：郑俊杰[1] 吕思祺 曹文昭[1] 景丹 ZHENG Jun-jie;LU Si-qi;CAO Wen-zhao;JING Dan(Institute of Geotechnical and Underground Engineering,Huazhong University of Science and Technology,Wuhan,Hubei 430074,China;Shanghai Municipal Engineering Design Institute (Group)Co.,Ltd.,Shanghai 200092,China)

机构地区：[1]华中科技大学岩土与地下工程研究所,湖北武汉430074 [2]上海市政工程设计研究总院(集团)有限公司,上海200092

出　　处：《岩土力学》2019年第1期395-402,共8页Rock and Soil Mechanics

基　　金：国家重点研发计划(No.2016YFC0800200);中国博士后科学基金资助项目(No.2017M612459);华中科技大学自主创新研究基金~~

摘　　要：针对高填方膨胀土路基边坡的治理问题,提出了在膨胀土和挡墙之间设置EPS(聚苯乙烯泡沫)柔性垫层的刚柔复合桩基挡墙结构。采用FLAC^(3D)建立了刚柔复合桩基挡墙结构支护的高填方膨胀土路基数值模型,并基于热-力耦合模型实现了湿度变化后的高填方膨胀土变形模拟,进而对比分析了5种不同工况下刚柔复合桩基挡墙结构的受力变形特性及路面变形,并着重探讨了EPS垫层厚度和刚度对刚柔复合桩基挡墙结构墙背土压力和水平位移的影响。研究结果表明:刚柔复合桩基挡墙结构的墙背土压力、抗滑桩桩身弯矩和剪力、挡土墙和抗滑桩水平位移均明显减小,但路面沉降和水平位移有所增大;EPS垫层弹性模量越小或厚度越大,则EPS垫层压缩量越大,允许膨胀土发生的侧向变形也越大,刚柔复合桩基挡墙结构的受力和变形则越小;柔性EPS垫层减压作用的充分发挥,必须同时满足厚度和弹性模量2个方面的条件,单一采用垫层刚度指标不足以反映EPS垫层的影响。A composite rigid-flexible pile-supported retaining wall(CRF-PSRW) including EPS cushion was proposed aiming for the treatment of high-filled expansive soil subgrade slope. The numerical model of CRF-PSRW used for high-filled expansive soil subgrade was established by FLAC3D. Based on the thermal-mechanical coupling model, the deformation of expansive soil was simulated with the change of humidity. The mechanical and deformation behaviors of CRF-PSRW in five different working conditions were compared and analyzed. The effects of thickness and stiffness of EPS cushion on the earth pressure and horizontal displacement of the CRF-PSRW were further investigated. The results show that the CRF-PSRW can obviously reduce the earth pressure of retaining wall, bending moment and shear force of anti-slide pile, and horizontal displacement of the structure. However, settlement and horizontal displacement of pavement are found to significantly increase. The compression amount of EPS cushion increases with the decrease of elastic modulus or increase of thickness. Then larger lateral deformation of the expansive soil is permitted, leading to reduction of the force and deformation of CRF-PSRW. In order to give full play to the decompression effect of flexible EPS cushion, the conditions of thickness and modulus of elasticity must be satisfied at the same time.The single cushion stiffness index is not enough to reflect the influence of EPS cushion..

关 键 词：刚柔复合桩基挡墙 EPS垫层 膨胀土:数值模拟 

分 类 号：TU473[建筑科学—结构工程]