2种支护模式下土岩双元地层基坑变形影响效应的研究  

Research on the Effect of Foundation Pit Deformation of Soil-rock Binary Stratum under Two Support Modes

作　　者：许杰 刘洋 郑卫琴 徐嘉祥 武科[2] Xu Jie;Liu Yang;Zheng Weiqin;Xu jiaxiang;Wu Ke(The 7th Institute of Geology&Mineral Exploration of Shandong Province,Linyi 276000,China;School of Civil Engineering,Shandong University,Jinan 250061,China)

机构地区：[1]山东省第七地质矿产勘查院,山东临沂276000 [2]山东大学土建与水利学院,山东济南250061

出　　处：《市政技术》2022年第9期122-131,共10页Journal of Municipal Technology

基　　金：山东省重点研发计划(2018GHY115015)。

摘　　要：为探究土岩双元地层的土岩空间分布特征和施工参数对吊脚桩结构和微型钢管桩-锚杆联合支护结构变形规律的作用效应,采用有限元软件ABAQUS,建立了2种支护模式下的三维有限元模型。同时,综合考虑土岩结合面的倾斜角度和锚杆预应力大小等因素,对比分析了2种支护模式下的多种工况。研究结果表明:1)土岩结合面对2种支护结构的变形规律均有重要影响,其倾斜角度可以改变桩身所受到的侧向土压力,当土岩结合面斜向抗滑桩一侧时会增大其侧向土压力,从而导致桩身和土体的水平位移变大,但土岩结合面对岩层及其桩身影响不大;2)吊脚桩支护结构适合下部有一定放坡空间、岩石完整性较好和变形控制要求严格的情况,锚杆预应力在合理的范围内,其增加比例同桩身水平位移的减小比例相近;3)微型钢管桩-锚杆联合支护结构适合对基底空间要求比较严格、岩石完整性较差和变形控制严格的情况,随着微型钢管桩-锚杆的预应力不断增大,其控制微型钢管桩桩身水平位移的效果并不明显,但施加锚杆预应力之后可以进一步将桩身的水平位移控制在更加安全的范围内。In order to explore the effect of soil-rock spatial distribution characteristics and construction parameters of soil-rock binary stratum on the deformation law of the end-suspended pile structure and the micro-steel pile-anchor joint support structure,two support modes were established by ABAQUS finite element software.Comprehensively considering factors of the inclination angle of the soil-rock interface and the prestress of the bolt,various working conditions of the two support modes were compared.The research results show that the soil-rock interface has an important influence on the deformation of the two supporting structures.Its inclination angle can change the lateral earth pressure on the pile side.When the soil-rock interface inclines to the anti-sliding pile side,the lateral earth pressure will increase,and the lateral displacement of the pile body and soil will increase.The soil-rock interface has little effect on the rock layer and the pile body;The supporting structure of the end-suspended pile is suitable for the situation that the lower part has a certain grading space,the rock has good integrity,and the deformation control is strict.The prestress of the bolt is within a reasonable range whose increase proportion is similar to the decrease one of the horizontal displacement of the pile body.The micro steel pipe pile-anchor rod joint support structure is suitable for the situation that the requirements for the base space are relatively strict,the rock has poor integrity,and the deformation control is strict.With the increase of the prestress of the micro steel pipe pile-anchor rod,the effect of the horizontal displacement of the pile body is not obvious.But the horizontal displacement can be further controlled within a safer range after prestressing of the anchor rod.

关 键 词：土岩双元地层 基坑开挖 吊脚桩 微型钢管桩 数值模拟 

分 类 号：TU375[建筑科学—结构工程]