基于特征融合的既有隧道上基坑开挖变形量数值模拟

Numerical Simulation of Excavation Deformation of Foundation Pit on Existing Tunnels Based on Feature Fusion

针对隧道上基坑开挖极易引发周围地质失衡、变形的问题,研究基于特征融合的既有隧道上基坑开挖变形量数值模拟。在明确某工程段基础地质条件的基础上,构建基坑数值模型,开展基坑开挖施工模拟,提取变形图三个特征并利用权重融合在一起,确定变形区间,进而分析既有隧道上基坑开挖应力分布情况以及X轴、Y轴和Z轴三个方向的基坑开挖变形量。结果表明:X轴、Y轴和Z轴三个方向均出现不同程度的变形,其中Y轴变形量最大,其次是X轴,最后是Z轴,说明该工程基坑开挖主要对垂直方向的地质结构产生变形影响。X轴、Y轴和Z轴三个方向的变形量均未超过设置的标准,说明该工程基坑开挖并未影响下方既有隧道的安全性和稳定性。

Aiming at the issue of geological imbalance and deformation caused by excavation of foundation pits in tunnels,a numerical simulation of excavation deformation in existing tunnels is studied based on feature fusion.On the basis of clarifying the basic geological conditions of a certain engineering section,a numerical model of the foundation pit is constructed to simulate the excavation construction of the foundation pit.Three characteristics of the deformation map are extracted and fused together using weights to determine the deformation interval.Then the stress distribution of the excavation of the foundation pit on the existing tunnel and the excavation deformation of the foundation pit in the X,Y,and Z directions are analyzed.The results show that there is varying degrees of deformation in the X,Y,and Z directions,with the Y axis having the largest deformation,followed by the X axis and finally the Z axis.This indicates that the excavation of the foundation pit in this project mainly affects the deformation of the geological structure in the vertical direction.The deformation in the X axis,Y axis,and Z axis directions do not exceed the set standards,indicating that the excavation of the foundation pit do not affect the safety and stability of the existing tunnel below.