岩质倾斜地层下邻近双线隧道的深基坑开挖变形分析

Deformation Analysis of Deep Foundation Pit Excavation of Adjacent Double-track Tunnel in Tilted Stratum

当前岩质深基坑模拟开挖分析中多将地层假定为水平分布,这与实际的岩质边坡岩层分布相悖。为此本文基于某岩质深基坑现场地质勘察资料,建立了符合实际岩层分布,考虑邻近双线隧道的深基坑开挖模型,分析了倾斜岩质地层的初始状态、深基坑开挖变形,以及深基坑开挖对邻近隧道的影响。分析结果表明:倾斜岩质地层下主应力与地层分布保持一致;倾斜地层下邻近隧道开挖产生扭转偏压效应;岩质深基坑支护变形规律与地质构造密切相关;现有抗滑桩+锚索支护下,既有隧道变形微小。分析结果对岩质倾斜地层下的类似工程分析,具有一定的参考意义。

The rock excavation of the deep foundation pit for simulation analysis is often assuming the strata is horizontal distribution, which is inconsistent with the actual distribution of rock slope rock. In this paper, based on the field geological investigation data of a rocky deep foundation pit, a deep foundation pit excavation model in line with the actual rock strata distribution and considering adjacent double-track tunnel is set up. Then the initial state, the deformation of deep foundation pit excavation, and the influence of deep excavation on adjacent tunnel of sloping rock formation are analyzed.The analysis results show that the principal stress of the sloping rock formation is consistent with the distribution of the rock stratum; adjacent tunnel excavation under the tilted strata has reverse bias effect; rock of deep foundation pit deformation is closely related to the geological structure; under the existing anti-slide pile plus anchor cable, the tunnel deformation is small. The result of the analysis has certain reference significance for the similar projects of rock slope.