不同埋深对某水电站隧洞围岩流变稳定性影响

在高埋深下进行隧洞的开挖意味着将克服巨大的构造应力与自重应力,而在进行洞室开挖设计中地应力作用也是不容忽视的。因此,基于卸荷岩体理论和流变理论,依托室内流变试验进行了相关流变参数的反演,结合有限元分析软件ANSYS以及有限差分软件FLAC对比分析了不同埋深下隧洞围岩在加衬砌前后的蠕变变形量、塑性区等。结果表明:随着埋深的增加,隧洞周围的卸荷作用会越来越明显;洞室的开挖卸荷及洞侧围岩的共同作用,使得隧洞在埋深由浅及深的过程中经历了从“压力拱”的出现到消失的过程;当埋深增加时隧洞的水平向位移越来越大,洞侧变形将成为影响隧洞稳定的一个主要控制因素。

Effect of Buried Depth on the Rheological Stability of Surrounding Rock of a Dam Tunnel

Tunnel excavation with large depth will be confronted with huge tectonic stress and self-weight stress,and the geostress cannot be ignored in the design of excavation.According to theoretics of unloading and rheology,in-version of rheological parameters were conducted based on indoor rheological tests,and furthermore,the creep de-formation and plastic zone of surrounding rock at different depths before and after lining were compared and ana-lysed by ANSYS and FLAC.Results reveal that as buried depth increased,the tunnel’s unloading effect became more obvious;a pressure arch occurred and then disappeared under the joint action of unloading and surrounding rock;and the tunnel’s horizontal displacement increased,hence lateral deformation became a controlling factor of tunnel’s stability.