热力耦合作用下圆形水工隧洞围岩弹塑性解析解

为研究圆形水工隧洞围岩弹塑性区受力特点，基于Mogi-Coulomb强度准则和弹塑性理论，考虑温度和衬砌结构的影响，推导热力耦合作用下水工隧洞围岩应力、洞壁位移和围岩塑性区半径的解析解。依托新疆某高地温水工隧洞工程进行计算分析，对中间主应力系数、温度、混凝土强度、衬砌厚度和围岩应力分布及塑性区半径间的关系展开参数分析。结果表明：温度变化产生的拉应力会使衬砌结构对围岩支反力减小，围岩塑性区半径和洞壁位移有所增大，隧洞岩体稳定性变差；中间主应力系数b对岩体强度影响较大，b=0.5时围岩塑性区半径明显小于不考虑中间主应力时的塑性区半径；提高混凝土强度和增加衬砌厚度在初始阶段都能明显限制围岩塑性区发展，虽后续效果都不佳，但增大衬砌厚度更能限制围岩塑性区发展。

Elastoplastic analytical solution of surrounding rock of circular hydraulic tunnel under thermal mechanical coupling

In order to study the mechanical characteristics of the elastoplastic zone of the surrounding rock of circular hydraulic tunnel, based on the Mogi-Coulomb(Mogi-Coulomb) strength criterion and the elastoplastic theory, considering the effects of temperature and lining structure, the analytical solutions of surrounding rock stress, wall displacement and surrounding rock plastic zone radius of hydraulic tunnel under thermal mechanical coupling are deduced. Relying on the highland temperature hydraulic tunnel project in Xinjiang, the calculation and analysis are carried out, the relationship between the intermediate principal stress coefficient, temperatures, concrete strength, lining thickness and surrounding rock stress distribution and plastic zone radius is analyzed. The following conclusions are drawn: 1) The tensile stress caused by temperature change will reduce the support reaction of the lining structure to surrounding rock, the radius of plastic zone of surrounding rock and the displacement of tunnel wall will increase, and stability of the surrounding rock will be worse; 2) The intermediate principal stress coefficient has a greater impact on the strength of the surrounding rock. When b=0.5, the radius of the plastic zone of the surrounding rock is obviously smaller than without considering the intermediate principal stress; 3) The improvement of concrete strength and the increase of lining thickness can obviously limit the development of plastic zone of surrounding rock in the initial stage. Although the follow-up effect is not good for limiting the development of plastic zone of surrounding rock, increasing the lining thickness can more restrict the development of plastic zone of surrounding rock.