不同埋深条件下直墙拱顶巷道破裂的数值试验

为研究不同埋深条件下直墙拱顶巷道围岩破裂形态,采用RFPA2D软件进行了数值模拟试验。通过数值试验发现:不同埋深条件下的巷道围岩均从巷道的拱脚和墙角处最先发生破坏,且沿拱脚斜向下和沿墙角斜向上扩展,最终导致巷道两帮围岩破裂失稳;同时由于深部巷道围岩的荷载较大,破坏裂缝也从巷道两帮扩展到拱顶和底板。通过分析巷道围岩应变数据,发现围岩体内径向拉应变是造成巷道围岩破坏的主要原因。该数值试验结果与有关物理试验结果具有一致性,能进一步丰富深部岩体破裂方面的研究成果,更好地指导深部地下空间的开发和应用工作。

Numerical test on the rupture of straight-wall vault tunnel under different burial depths

In order to study the fracture form of surrounding rock of straight-walled vault tunnel under different burial depths, the numerical simulation tests were carried out by RFPA. The results of numerical test showed that the surrounding rock of tunnel under different burial depths were all destroyed first from the arch foot and the corner of tunnel, then the cracks spread diagonally downwards along arch feet and diagonally upward along the corners of the wall, and eventually the fracture and instability of both side walls of surrounding rock in tunnel occurred; meanwhile, due to the large load of surrounding rock in deep tunnel, the cracks also extended from the both sides of tunnel to the arch top and the bottom floor of tunnel. Through the strain data analysis of surrounding rock, it was found that the radial strain of surrounding rock is the main cause of the fracture of surrounding rock in tunnel. The numerical test results were consistent with the related physical test results, which can further enrich the research results of fracture of deep rock mass and better guide the development and application of deep underground space.