基于收敛-约束法和ZSI的隧道初期支护时机研究  

Study of Initial Supporting Time of Tunnel Based on Convergence-constraint Principle and Zone State Index

作　　者：张子龙 姜谙男 吴洪涛 焦明伟 ZHANG Zilong;JIANG Annan;WU Hongtao;JIAO Mingwei(School of Transportation Engineering,Dalian Maritime University,Dalian,Liaoning 116026,China;Jilin Provincial Transportation Planning and Design Institute,Changchun,Jilin 130021,China)

机构地区：[1]大连海事大学交通运输工程学院,辽宁大连116026 [2]吉林省交通规划设计研究院,吉林长春130021

出　　处：《公路工程》2020年第4期41-47,73,共8页Highway Engineering

基　　金：国家自然科学基金项目(51678101);中央高校基本科研业务费专项资金项目(3132014326);吉林省交通运输项目(2017ZDGC-4)。

摘　　要：为了解决隧道开挖后初期支护的时机问题,提出了基于收敛约束原理和围岩局部安全评价方法单元状态指标(Zone State Index,ZSI)的初期支护时机确定方法。该方法首先计算得到隧道的围岩特征曲线,结合围岩位移速率先对最佳支护时机对应的围岩应力释放率进行初步判定;然后再利用单元状态指标ZSI对围岩局部稳定性进行确认评价,增加了支护时机选择的正确性。最后以相同变量围岩位移为基础将围岩特征曲线和纵向变形曲线进行耦合分析,建立起应力释放率和掌子面与监测断面间距之间的对应关系,得出以支护与掌子面控制间距为依据的最佳支护时机选择。以甄峰岭2号隧道为例,建立FLAC^3D有限差分数值模型,采用该方法确定了多种工况下隧道合理的支护时机。研究结果表明,围岩特征曲线的形状和斜率受围岩级别和隧道埋深的影响较大;以单元状态指标ZSI与围岩位移速率相印证,可以增加支护时机选择的准确性,为隧道支护时机的选择方法提供了一种新思路;计算所得的支护与掌子面的控制间距对实际工程起到很好的指导作用。In order to research the issue of supporting opportunity of flexible support, a new method is proposed based on the convergence-constraint principle and zone state index. In this method, the ground response curve is calculated firstly, and the supporting opportunity is preliminarily determined by combining with the displacement rate of surrounding rock. Then the stability of surrounding rock is confirmed and evaluated by using ZSI as the basis, which increases the correctness of the former results. Finally, based on the surrounding rock displacement of the same variable, the ground response curve and longitudinal deformation profile are coupled and analyzed, and the corresponding relationship between the stress release rate and the spacing between the tunnel face and the monitoring section is established, so as to calculate the control spacing between the supporting structure and the tunnel face. Taking the engineering example of Zhenfengling No. 2 tunnel as the background, a numerical model is established by using FLAC3D finite difference software, and the reasonable support opportunity of tunnel under various working conditions is determined by this method. The research results show that the shape and slope of the characteristic curve of surrounding rock are greatly influenced by the level of surrounding rock and the buried depth. The accuracy of the choice of support opportunity can be increased by combining with the displacement criterion and the stability criterion of the Zone State Index, which provides a new idea for the selection method of tunnel support opportunity. The calculated control spacing between the supporting structure and the tunnel face plays a good guiding role in the actual engineering.

关 键 词：收敛-约束 隧道 支护时机 单元状态指标 数值模拟 

分 类 号：U45[建筑科学—桥梁与隧道工程]