盾构施工参数对土体及单桩的影响  

Effects of Shield Driven Parameters on Surrounding Soils and Single Pile with Finite Element Method

作　　者：王丽[1] 杨文彬[1] 武钰翔 郑刚[2] 

机构地区：[1]大连交通大学土木与安全工程学院,辽宁大连116028 [2]天津大学滨海土木工程结构与安全教育部重点实验室,天津300072

出　　处：《大连交通大学学报》2015年第1期58-63,共6页Journal of Dalian Jiaotong University

基　　金：国家自然科学基金资助项目(51208071)

摘　　要：采用对隧道洞室周边及开挖面的土体施加由盾构机引起的各种荷载的方法模拟盾构施工,通过变化注浆压力及推进力研究盾构施工对周边土体及单桩基础的影响.增加注浆压力是减小盾构推进对周围土体影响的最有效的措施.当注浆压力足够大,推进力、盾尾脱离及浆液硬化对土体的影响程度相同.若使隧道顶点的沉降及隧道底部土体的回弹减小相同的数量,底部注浆孔的压力要大于顶部注浆孔的压力.当推进力大于临界值时,推进力对隧道周边土体的影响明显增加.隧道周边及地表处各点的位移变化主要发生在盾构机通过这些点所在位置时,衬砌生成后,随后的开挖步对其影响很小.桩侧隧道洞室衬砌生成后,随后开挖步施加的注浆压力可以明显减小桩顶沉降,注浆压力越大,桩顶最终沉降越小.推进力对桩顶沉降影响不明显.盾构施工引起的桩顶和桩底的沉降始终相同,即桩整体下沉.桩顶无荷载及桩顶施加工作荷载时,开挖引起的桩顶沉降相同;桩顶施加极限荷载时,开挖引起的桩顶沉降明显增加.Pressures and shearing forces are enforced on the soils to simulate the real reactions between shield driven machine and surrounding soil during tunneling. The effects of shield driven on surrounding soils and single pile are studied with the variations of the thrust force and grouting pressure. The most effective way of reducing the effect of shield driven is increasing the grouting pressure. When the grouting pressure is large e- nough, the effects from thrust force, tail departing and hardening of slurry are similar. In Order to make the same reduction in settlement on the top of tunnel and the rebound at the bottom of tunnel, the grouting pres- sures of the grouting whole at the bottom need to be greater than those on the top. When the＂th＇rust force is lar- ger than the threshold value, the effects of shield driven on the surrounding soils increase apparently. The main variations in displacements in the soils happen when driven machine just passes by, and the effect from the subsequent excavation steps are neglectable on account of the installation of lining. For single pile, the settlements at pile head decrease apparently due to the grouting pressure from the subsequent excavation steps, and the greater the grouting pressure is, the smaller the settlement at pile head. The effect of thrust force on the piles can be neglected. The settlements at pile head and tip are always the same during driven process. The settlements at pile head are identical when the loads applied are smaller than the working load. The settle- ments at pile head increase obviously when the extreme load is enforced.

关 键 词：盾构法 施工参数 注浆压力 推进力 盾尾脱离 

分 类 号：U455.43[建筑科学—桥梁与隧道工程]