近距离下穿施工对既有矩形顶管通道的影响分析

Influencing analysis of construction of mining tunnel close crossing underneath the existing rectangular pipe jacking tunnel

以广州地铁二八线14标同福西站矿山通道下穿既有矩形顶管通道施工为背景,采用FLAC3D进行数值模拟,通过对比实测数据与数值模拟结果,分析讨论孔隙水压力与土体变形的关系;结合评价土体扰动程度孔隙水压力变化率指标,分析矿山通道开挖至不同断面时,对顶管通道的扰动变化规律,以及对比分析环形开挖预留核心土法、三台阶法、全断面法开挖矿山通道对矩形顶管通道的扰动效应差别。研究结果表明:环形开挖预留核心土法对顶管通道的扰动影响最小,三台阶法次之,全断面开挖对顶管通道扰动较大。研究结果为本工程提供了较好的方案支持,为相关工程提供参考。

Based on the construction of mining tunnel close crossing underneath the existing rectangular pipe jacking tunnel atTongfu station of No.2 and No.8 extension line of Guangzhou subway（the 14th section） , it was simulated by software FLAC3D. By comparing measured data with numerical simulation results, the relationship between pore water pressure and soil deformation was analyzed. Then combining the pore pressure change ratio index that evaluate degree of soil disturbance analyses disturbance variation of jacking tunnel with excavation to different sections of the mining tunnel, as well as the differences of disturbance effect of rectangular pipe jacking tunnel are analyzed by comparing the reservation core soil excavation method, three step method and full section method of mining tunnel. T have shown that; the influence of ring reservation core soil excavation on pipe jacking tunnel is the smallest, followed by three-step method, and the influence of full section excavation on pipe jacking tunnel is large. The research result provides a better solution support for the project and reference for related projects.