考虑嵌固段桩前土体弹塑性变形的锚索微型桩群计算模型研究  

Study on Calculation Model of Anchor Cable Micro Pile Group Considering Elastoplastic Deformation of Soil in Front of Embedded Pile

作　　者：朱彦鹏[1,2] 成栋 杨奎斌 刘东瑞 ZHU Yanpeng;CHENG Dong;YANG Kuibin;LIU Dongrui(Western Eng.Research Center of Disaster Mitigation in Civil Eng.of Ministry of Education,Lanzhou Univ.of Technol.,Lanzhou 730050,China;Key Lab.of Disaster Prevention and Mitigation in Civil Eng.of Gansu Province,Lanzhou Univ.of Technol.,Lanzhou 730050,China;School of Civil Eng.and Architecture,Shaanxi Univ.of Technol.,Hanzhong 723001,China)

机构地区：[1]兰州理工大学西部土木工程防灾减灾教育部工程研究中心,甘肃兰州730050 [2]兰州理工大学甘肃省土木工程防灾减灾重点实验室,甘肃兰州730050 [3]陕西理工大学土木工程与建筑学院,陕西汉中723001

出　　处：《工程科学与技术》2024年第5期190-202,共13页Advanced Engineering Sciences

基　　金：国家自然科学基金面上项目(51978321);甘肃省科技重大专项(23ZDFA007);教育部高端人才和创新团队支持计划项目(IRT_17R51)。

摘　　要：锚索微型桩群在中小型边坡治理及边坡紧急抢险工程中的应用越来越广泛,但现有的计算模型对嵌固段桩前土体塑性变形及桩侧土体受力变形连续性考虑较少。针对这一问题,首先根据锚索微型桩群加固土质边坡的特点,以潜在滑裂面位置为分界线,将微型桩群分为受荷段与嵌固段进行分析。对于受荷段,将桩间土简化为水平土弹簧,有效考虑桩间土力的传递作用;对于嵌固段,采用理想弹塑性p-y曲线分析桩-土相互作用。其次,将冠梁处预应力锚索简化为弹性支座,将其作用力转移至后排桩桩顶,再由桩顶冠梁重分配至各排桩桩顶处,从而达到对桩顶位移的约束作用。最后,以帕斯捷尔纳克(Pasternak)双参数地基梁法为基础,建立考虑嵌固段桩前土体弹塑性变形及桩侧土体受力变形连续性的锚索微型桩群有限差分计算模型,并迭代求解得到该结构的水平位移与内力。利用该计算模型分别对微型桩群与锚索微型桩群加固土质边坡进行算例计算,与试验、数值模拟结果对比分析,验证该模型的合理性,并探讨土体剪切刚度、锚索束及桩径对该锚索微型桩群水平位移与内力的影响。研究表明:嵌固段桩前土体塑性变形及桩侧土体受力变形连续性对微型桩的水平位移与内力有较大影响;随着锚索束的增加,桩身最大正弯矩及水平位移均不断减小,可通过增设锚索束达到控制桩身变形与内力的目的。Anchor cable micro-pile groups are increasingly utilized in small and medium-sized slope treatment and slope emergency rescue engineering.However,existing calculation models rarely consider the plastic deformation of the soil in front of the embedded section of the pile and the continuity of the deformation of the soil on the side of the pile.To address this issue,the characteristics of the anchor cable micro-pile group in strengthening soil slopes are examined,and the micro-pile group is divided into a loaded section and an embedded section based on the location of the potential sliding surface.For the loaded section,the soil between piles is simplified as a horizontal soil spring,which effectively accounts for the transfer of soil force between piles.For the embedded section,the ideal elastic-plastic p-y curve is employed to analyze the interaction between the pile and the soil.The prestressed anchor cable at the crown beam is simplified as an elastic support.Its force is transferred to the pile top of the back row of piles and then redistributed to the pile tops of each row of piles by the crown beam.This arrangement achieves the constraint effect on pile top displacement.Finally,based on the Pasternak two-parameter foundation beam method,a calculation model for the anchor cable micro-pile group is established,considering the elastoplastic deformation of soil in front of the embedded pile and the continuity of soil deformation around the pile.The finite difference method is utilized to solve the calculation model,and the horizontal displacement and internal forces of the structure are obtained.The calculation model is utilized to evaluate examples of soil slope reinforcement with micro-pile groups and anchor cable micro-pile groups,respectively.The study results are compared to both experimental and numerical simulation ones to verify the model's rationality.The effects of soil shear stiffness,the number of anchor cables,and pile diameter on the horizontal displacement and internal forces of the micro-pile gro

关 键 词：边坡 微型桩 锚索 内力与变形 理想弹塑性p-y曲线 

分 类 号：TU443[建筑科学—岩土工程]