曲线盾构隧道开挖面被动极限支护力分析  

Analysis of Passive Limited Supporting Force of Curved Shield Tunnel Excavation Face

作　　者：傅鹤林[1] 胡才超 林锐 黄震[1] 张加兵[1] 史越[1] FU He-lin;HU Cai-chao;LIN Rui;HUANG Zhen;ZHANG Jia-bing;SHI Yue(Central South University,Changsha,Hunan 410075,China)

机构地区：[1]中南大学,长沙410075

出　　处：《铁道工程学报》2018年第11期48-54,共7页Journal of Railway Engineering Society

基　　金：国家自然科学基金项目(51578550;51538009;51478473);中南大学研究生自主探索创新项目(2018 zzts666;2018zzts193);长沙市工务局建设项目(SZ201525-ZX11;SZ201525-ZX12)

摘　　要：研究目的:曲线盾构隧道在掘进过程中,开挖面受力极其复杂,稳定性难以控制,容易因千斤顶推力过大而造成前方土体的隆起现象。本文以砂土地层为例,基于筒仓理论和极限平衡法,建立曲线盾构隧道开挖面在前方土体被动破坏条件下的"倒梯台-楔形棱柱体"分析模型,提出开挖面被动破坏极限支护力计算方法,然后通过编程试算和数值模拟验证本文所述模型及计算方法的可靠性与准确性。研究结论:(1)被动极限支护力随埋深和内摩擦角的增加而增大,且增长速率逐渐加快;(2)当线路曲率半径小于200 m且土体内摩擦角大于25'时,被动极限支护力对线路曲率半径非常敏感,当线路曲率半径大于800 m时被动极限支护力与直线隧道几无差别;(3)数值模拟结果显示,数值解与理论解变化趋势一致且相差较小;(4)本研究结果可为类似曲线盾构隧道,尤其是小转弯半径盾构隧道开挖面被动极限支护力的确定提供理论基础。Research purposes:In the construction process of curved shield tunnels,the force of excavation face is extremely complex and the stability is difficult to control,so it is very likely that the thrust of the jack will cause uplift of the soil in front because of passive failure.Taking the sand strata as an example,this paper established a combination model of "inverted ladder-wedge prism"to reveal that the soil in front of the excavation face of curved shield tunnels uplifts up because of passive failure based on the silo theory and limit equilibrium method,and deduced the calculation method of passive limited supporting force for curved tunnels.Then,we confirmed the accuracy and reliability of this model and calculation method through programing and simulating. Research conclusions :(1)The passive limited supporting force increases with the increase of buried depth and internal friction angle,and the growth rate gradually increases.(2)When the radius of the line is less than 200m and the internal friction angle is more than 25 degrees,the passive limited supporting force is very sensitive to the curvature radius,and when the radius is more than 800m,the passive limited supporting force is almost no difference with straight tunnels.(3)The numerical results indicate that the numerical solution is consistent with the theoretical solution and the difference is quite small.(4)The research results can provide theoretical basis for determining the passive limited supporting force in the constructions of similar curved shield tunnels especially small turn radius shield tunnels.

关 键 词：曲线盾构隧道 砂土地层 被动破坏 极限平衡法 筒仓理论 

分 类 号：TU456.3[建筑科学—岩土工程]