基于FLAC^(3D)的公路隧道塌方段工程处置及其优化

Engineering treatment and optimization of collapse section of highway tunnel based on FLAC^(3D)

以浙江省武义县白阳山隧道为工程背景,采用FLAC^(3D)有限差分法,模拟现阶段采用的预留核心土-上下台阶法开挖下围岩的变形及应力变化规律,并从优化施工方法的角度,综合分析开挖过程中隧道围岩位移及塑性区分布情况,评价不同施工方案对围岩稳定性的影响.结果表明,预留核心土-上下台阶法存在洞身位移变化大的问题;预留核心土-三台阶法控制围岩位移变化效果最好,且围岩塑性区变化范围最小.

Based on the engineering background of Baiyangshan Tunnel in Wuyi County,Zhejiang Province,this paper applied the finite difference method FLAC^(3D)to simulate the deformation and stress variation law of surrounding rock caused by the excavation of reserved core soil and upper and lower steps method,and then from the perspective of optimizing the construction method,comprehensively analyzed the displacement and plastic zone distribution of tunnel surrounding rock during excavation and evaluated the influence on surrounding rock stability of different construction schemes.The results show that the method of reserved core soil and upper and lower steps method has the problem that the displacement of tunnel body varies greatly,while the reserved core soil and three steps method has the best effect to control the displacement change,and the plastic zone extends the smallest change range.