采用总荷载不变法的非静水压隧道摄动拓展解  

Extended perturbation solutions of a non-hydrostatic pressure tunnel based on total load invariant method

作　　者：张常光[1,2] 李宗辉 关港辉 孙松 ZHANG Changguang;LI Zonghui;GUAN Ganghui;SUN Song(School of Civil Engineering,Chang′an University,Xi′an 710061,China;State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology),Chengdu 610059,China)

机构地区：[1]长安大学建筑工程学院,西安710061 [2]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都610059

出　　处：《哈尔滨工业大学学报》2023年第6期71-82,共12页Journal of Harbin Institute of Technology

基　　金：地质灾害防治与地质环境保护国家重点实验室开放基金(SKLGP2020K022);长安大学中央高校基本科研业务费专项资金(300102282206)。

摘　　要：为描述实际地应力场下隧道塑性区演化规律和支护设计原则,基于Mohr-Coulomb准则和弹-脆-塑性模型,采用总荷载不变法并引入弹性区应力摄动解,建立了非静水压力下圆形隧道水平轴和竖向轴处的塑性区半径方程,继而利用几何相似原理拓展至其他方位角处,并与文献总荷载不变法(以应力基尔希公式为基础)、Kastner法、复变函数法和实测数据进行对比,结合非关联流动法则推导塑性区位移解析解,探讨侧压力系数与脆性软化对隧道塑性区边界线、塑性区位移分布和围岩特征曲线的影响特性。结果表明:相比文献总荷载不变法和Kastner法,2阶摄动解作为非静水压圆形隧道的弹性区应力表达式更合理,且得到复变函数法的正确性验证;侧压力系数对隧道塑性区边界线的形状和范围均有明显影响,需针对具体方位角选择支护类型和尺寸以调控收敛约束交点处的支护压力与围岩稳定变形;隧道塑性区半径和洞壁位移随围岩峰后强度的降低而显著增加,宜使用弹-脆-塑性模型构建围岩特征曲线。To describe the evolution law of tunnel plastic zone and the principle of support design under in-situ stress field,this paper presented equations of plastic zone radius at horizontal and vertical axes of a circular tunnel under non-hydrostatic pressure with the total load invariant method.The two equations were based on the Mohr-Coulomb criterion and the elastic-brittle-plastic model,and a stress perturbation solution in the elastic zone was introduced.Then,the equations were extended to other azimuth angles according to the geometric similarity principle.The obtained equations of plastic zone radius were compared with the results of the total load invariant method(based on the Kirsch stress formulation),Kastner method,complex variable function method,and measured data.An analytical solution of plastic zone displacement was derived using the non-associated flow law.Finally,parametric studies were performed to investigate the effects of lateral pressure coefficient and brittle softening on the plastic boundary,distribution of plastic zone displacement,and ground response curve.Results showed that the second-order perturbation solution taken as the stress equation in the elastic zone of a nonhydrostatic tunnel was more reasonable than the total load invariant method and the Kastner method,and it was verified against the complex variable function method.Lateral pressure coefficient had an obvious influence on the shape and range of tunnel plastic boundary,so support type and size should be determined for specific azimuth angles to control support pressure and stable rock deformation at the intersection point of convergence-confinement analysis.Plastic zone radius and tunnel wall displacement increased significantly with the decrease in rock postpeak strength,so the elastic-brittle-plastic model was suggested to calculate ground response curve.

关 键 词：隧道工程 非静水压力 总荷载不变法 摄动法 脆性软化 

分 类 号：TU452[建筑科学—岩土工程]