Initial support distance of a non-circular tunnel based on convergence constraint method and integral failure criteria of rock  

基于收敛约束法和岩石整体破坏准则的非圆形隧洞初始支护距离

作　　者：AN Xue-xu HU Zhi-ping SU Yan CAO Shuang-li TAO Lei ZHANG Yong-hui 安学旭;胡志平;苏岩;曹双利;陶磊;张永辉(School of Civil Engineering,Chang’an University,Xi’an 710061,China;Institute of Underground Structure and Engineering,Chang’an University,Xi’an 710061,China;Hanjiang to Weihe River Valley Water Diversion Project Construction Co.,Ltd.,Xi’an 710024,China)

机构地区：[1]School of Civil Engineering,Chang’an University,Xi’an 710061,China [2]Institute of Underground Structure and Engineering,Chang’an University,Xi’an 710061,China [3]Hanjiang to Weihe River Valley Water Diversion Project Construction Co.,Ltd.,Xi’an 710024,China

出　　处：《Journal of Central South University》2022年第11期3732-3744,共13页中南大学学报（英文版）

基　　金：Project(2021JLM-49) supported by Natural Science Basic Research Program of Shaanxi-Joint Fund of Hanjiang to Weihe River Valley Water Diversion Project,China;Project(42077248) supported by the National Natural Science Foundation of China

摘　　要：For deep tunnel projects,selecting an appropriate initial support distance is critical to improving the self-supporting capacity of surrounding rock.In this work,an intuitive method for determining the tunnel’s initial support distance was proposed.First,based on the convergence-confinement method,a three-dimensional analytical model was constructed by combining an analytical solution of a non-circular tunnel with the Tecplot software.Then,according to the integral failure criteria of rock,the failure tendency coefficients of hard surrounding rock were computed and the spatial distribution plots of that were constructed.On this basis,the tunnel’s key failure positions were identified,and the relationship between the failure tendency coefficient at key failure positions and their distances from the working face was established.Finally,the distance from the working face that corresponds to the critical failure tendency coefficient was taken as the optimal support distance.A practical project was used as an example,and a reasonable initial support distance was successfully determined by applying the developed method.Moreover,it is found that the stability of hard surrounding rock decreases rapidly within the range of 1.0D(D is the tunnel diameter)from the working face,and tends to be stable outside the range of 1.0D.在地下隧洞开挖过程中,为了充分发挥围岩的自承能力,掌子面附近初期支护距离的选择至关重要。在这项研究中,提出了一种直观、快速的隧洞初期支护距离的确定方法。首先,基于收敛约束法,将非圆形带衬砌隧洞的解析解与可视化Tecplot软件相结合,构建三维空间力学模型。然后,根据岩石整体破坏准则,计算硬质围岩隧洞的破坏倾向系数,并输出其空间分布图。在此基础上,定义隧洞的关键破坏位置,并建立隧洞关键破坏位置的破坏趋势系数与其距工作面的距离之间的关系。最后,将与临界失效趋势系数对应的工作面距离作为最佳支护距离。以实际工程为例,应用该方法成功地确定了合理的初始支护距离。此外,还发现硬质围岩隧洞的稳定性在距工作面1.0D(D为隧洞断面最大距离)范围内迅速下降,在1.0D范围外趋于稳定。

关 键 词：tunnel engineering convergence confinement method integral failure criteria of rock non-circular tunnel initial supporting distance 

分 类 号：U455.7[建筑科学—桥梁与隧道工程]