引汉济渭工程黄三段输水隧洞围岩变形与压力分析

Analysis on deformation and pressure of surrounding rock of water conveyance tunnel of Huangsan Section for Hanjiang-to-Weihe River Valley Water Diversion Project

以分析深埋长隧洞围岩应力和应变为目标,考虑隧洞施工方式,围岩支护形式等因素,通过数值计算,动态模拟隧洞施工过程,获取了黄三段输水隧洞初期支护后的围岩变形情况以及围岩与衬砌相互作用关系。计算结果显示:采用设计的初期支护形式,可有效控制不良洞段的围岩变形,Ⅳ、Ⅴ类围岩最大收敛变形满足规范设计要求。Ⅳ、Ⅴ类围岩与衬砌间的相互作用力随衬砌浇筑时距掌子面距离的增加而降低,但在距掌子面约4倍洞径后降幅微小。通过对比分析经验方法与数值方法所确定围岩压力成果,确定了衬砌结构设计所需的围岩压力指标,为黄三段输水隧洞设计提供了依据,分析方法可为相似工程提供参考。

In order to analyze the stress and the strain of surrounding rock of deep buried long tunnel,the dynamic simulation of tunnel construction process is calculated considering tunnel construction mode and surrounding rock supporting form. Through the relevant numerical calculation,both the deformation of the surrounding rock and the relationship of the interaction between the surrounding rock and the lining after the initial support of the water conveyance tunnel of Huangsan Section of Hanjiang-to-Weihe River Valley Water Diversion Project are obtained. The calculation result shows that the adoption of the design for the initial support pattern can effectively control the deformation of the surrounding rock within the tunnel section under poor geological condition,and then the maximum convergent deformations of the surrounding rocks of Class IV and Class V can meet the requirement from the relevant design specification. The interactive force between the lining and the surrounding rocks of Class IV and Class V is decreased along with the increase of the distance to the working face during the placement of the lining,but the decreasing amplitude is to be quite small after the distance to the working face being about four times of the tunnel diameter. The surrounding rock pressure index necessary for the design of the lining structure is determined with the result of the surrounding rock pressure obtained through the relevant comparative analysis,empirical method and numerical method,which can provide a basis for the design of the water conveyance tunnel of Huangsan Section,from which the analysis method can provide references for the similar projects as well.