城市隧道穿越既有支挡结构开挖顺序及加固支挡优化研究

Study on Excavation Sequence and Reinforcement System Optimization of Urban Tunnel Crossing Existing Supporting Structure

为解决城市隧道穿越既有支挡结构出洞开挖顺序问题,以重庆曾家岩嘉陵江大桥工程南侧主线隧道洞口穿越既有支挡结构为依托,通过有限元数值分析,隧道采用顺洞向、逆洞向和先顺后逆3种开挖顺序对既有支挡结构的影响进行研究,并在支挡结构原设计加固方案的基础上提出优化设计。结果表明,隧道采用逆向出洞对既有支挡结构影响最小,原设计加固方案可取消斜撑、外侧地梁和抗滑桩,所得结果可供类似工程参考。

To solve the problems of excavating sequence of urban tunnels crossing existing supporting structures,this paper relies on the tunnel entrance crossing existing supporting structures,which is the southern part of Zengjiayan Jialing River Bridge project in Chongqing,and adopts finite element numerical analysis method to do research into the the influences of three excavating sequences on the existing supporting structure in forward direction,in reverse direction and in both forward and reverse direction respectively.Then,based on the original design reinforcement scheme of the supporting structure,the optimal design is proposed.The results show that the reverse excavating method has the least influence on the existing supporting structure,and the original design can be prompted by eliminating the diagonal bracing,the lateral ground beam and the anti-slide pile.The results obtained can provide a reference for similar projects.