太中银铁路土石分界地层隧道施工工艺参数选择和优化

Selection and Optimization of Construction Parameters for Tunnels Embedded in Boundary Region between Soil and Rock on Taiyuan-Zhongwei-Yinchuan Railway Line

土石分界地层隧道的施工,由于其岩体石质较差,风化严重并且还经常夹有泥层或泥砂层,自稳能力差,施工极其困难,安全风险及压力极大,施工方法及工艺参数的选择对施工能否安全顺利进行至关重要。文章结合太中银铁路土石分界地层隧道的施工情况,初步拟定几种相对适合的开挖方法,通过数值模拟计算,分析不同开挖参数对隧道稳定性的影响。根据洞周位移、围岩塑性区分布以及支护结构受力情况,并结合隧道具体的地质条件,分区段确定和优化隧道的施工工艺参数。

In boundary region between soil and rock, ground is of low strength and strongly weathered, mixed with soil or sand layer, unstable, and the safety risk of tunnel construction is obvious. Construction method and technical parameter selection are essential for safety. Considering tunnels constructed in ground boundary region between soil and rock on Taiyuan-Zhongwei-Yinchuan railway, by means of numerical simulation and calculation, this paper analyses the impact of different excavation parameters （excavation by parts, excavation sequence, bench height, bench length） on tunnel stability. Based on tunnel profile displacements, distribution of plastic zones and stresses in support structure as well as geological condition, tunnel construction parameters were optimized.