基于Biot固结方程研究地下水位对隧道防水型衬砌的内力影响

Study on the Impact of Underground Water Level on Internal Force of Tunnel Waterproof Lining Based on Biot Consolidation Equation

地下水位是影响隧道防水型衬砌力学行为的一个重要因素。为了研究地下水位变化对防水型衬砌的影响,基于Biot固结方程考虑17种不同地下水位的工况。利用FLAC3D有限差分法数值模拟,采用均匀连续各向同性渗流模型,得到不同工况下隧道衬砌结构的内力。通过分析衬砌在不同水位下产生的内力,总结地下水位变化对隧道防水型衬砌受力的影响规律。计算结果表明:地下水位在大于隧道半径3倍以上的范围,拱顶、拱肩与拱墙的轴力不随地下水位变化;在地下水位变化的时候,拱顶为最不利位置,拱墙为安全位置。

Underground water level is an important factor that affects the mechanical behavior of tunnel waterproof lining. In order to study the effect of underground water level changes on water proof lining, Biot consolidation equation is used to calculate 17 different conditions of underground water level. FLAC3D finite differential method of numerical simulation and homogeneous isotropic seepage model are employed to obtain the internal force of tunnel lining structure under different working conditions. Through the analysis of the internal force of lining under different water level, the law of the influence of underground water level changes on the waterproof tunnel lining stress is then fined. The calculation results show that when the underground water level is more than 3 times greater than the radius of the tunnel, and the axial force on the arch and spandrel arch wall doesn＇t change with the change of the water level; when the ground water level changes, the vault is the most unfavorableposition, while the arch wall is a safe one.