暗挖隧道施工对下穿既有铁路路基沉降规律分析

余敦猛

摘要:

为研究暗挖隧道施工对既有铁路路基沉降变形影响，采用有限元法模拟分析隧道开挖不同时期路基纵向和横向沉降规律，路基两侧水平偏差沉降模拟以及不同隧道埋深，不同岩土强度参数对铁路路基沉降的影响。结果表明：隧道开挖对路基沉降差值曲线呈现出明显的正态分布规律；在隧道掌子面与前方将要开挖形成拱顶的地层位置较远时，沉降较缓慢，沉降值也较小；在掌子面到达该拱顶位置时，沉降量将以较大的速率快速上升，拱顶沉降较明显；隧道埋深越大路基沉降最大值越小；导致路基沉降变形的主要岩土强度参数是内摩擦角。

Abstract:

In order to study the impact of tunnel construction on the settlement and deformation of the existing railway subgrade, the finite element method was used to simulate and analyze the longitudinal and lateral settlement laws of the subgrade in different periods of tunnel excavation, the horizontal deviation settlement simulation on both sides of the subgrade, as well as different tunnel depths and different rock and soil strengths. The influence of parameters on the settlement of railway subgrade. The results show that the difference curve of the settlement of the roadbed by the tunnel excavation presents an obvious normal distribution law; when the tunnel face is far from the stratum that will be excavated in front of the arch, the settlement is slower and the settlement value is also smaller. ; When the tunnel face reaches the vault position, the settlement will rise rapidly at a larger rate, and the vault settlement is more obvious; the greater the tunnel depth, the smaller the maximum settlement of the subgrade; the main rock and soil strength that causes the settlement and deformation of the subgrade The parameter is the angle of internal friction.