燕尾式隧道单双线贯通方案数值模拟优化与应用

Numerical Simulation Optimization and Application on Scheme for Dovetail Type Tunnel Connecting Single-line Hole and Double-line Hole

以杭黄项目毛蓬岗隧道为背景,应用FLAC3D有限元软件,对燕尾式隧道单双线贯通方案进行数值模拟.通过分析研究开挖后的应力场、位移场,对拟定方案进行优化并提出建议:隧道开挖时预留变形量可减小至1cm;开挖后对地表沉降影响较小,围岩和中隔墙自身稳定性较好;为了降低爆破动力扰动,一方面左右线隧道加强初期支护使中隔墙处于有利的三向受压状态,另一方面改进爆破方法,减小最大单段起爆药量;同时做好初期支护背后脱空的预控及处理.单双线隧道的顺利贯通,充分验证了理论分析的合理性和可行性,同时可作为类似工程的参考.

Aimed at Maopenggang Tunnel of Hanghuang Project,the numerical simulation is carried out by using the finite element software FLAC3D at dovetail type tunnel.By analyzing and studying the stress field and displacement field after excavation,the optimization of the proposed scheme is carried out and some suggestions are put forward.Firstly,the reserved deformation during tunnel excavation can be reduced to lcm.Secondly,after excavation,the surface settlement is small,and the stability of surrounding rock and partition wall is good.Thirdly,in order to reduce the dynamic disturbance of blasting,the initial support of left and right line tunnel should be strengthened to make the partition wall in a favorable three-way compression state,on the other hand,the maximum blasting charge should be reduced to improve the blasting method.At the same time,the attention should be paid to the pre-control and treatment of the hole behind the initial support.The smooth completion of single-line and double-line tunnels fully verifies the rationality and feasibility of theoretical analysis,which could be used as a reference for similar projects.