不同开挖法对某隧道开挖的围岩稳定性分析

Analysis of the Stability of the Surrounding Rock of a Tunnel Excavation by Different Excavation Methods

为研究不同开挖法对色季拉山隧道开挖的围岩稳定性的影响,对比分析两台阶开挖法、三台阶开挖法和全断面开挖法在开挖过程中围岩的应力变化及变形情况。基于钻孔SJLSZ-1位置处岩石样品的岩性参数,结合隧道相关支护数据,利用Geo-Studio软件中的SIGMA/W模块分别对该隧道不同开挖法开挖进行数值模拟,并分析隧道开挖的稳定性。结果表明:3种方法在开挖过程中以及全部开挖后,掌子面围岩XY位移主要集中在隧道的顶部及仰拱,而最大主应力主要集中在隧道的左拱腰以及右拱腰;对比云图变化及监测点数据,全断面开挖法的XY位移量最小,拱顶24.8 mm,右拱脚28.3 mm;应力变化最小,左拱腰690.303 kPa,右拱腰721.171 kPa;综合数值模拟分析过程中监测点的位移数据以及应力数据发现,全断面开挖法为隧道的最优开挖方法。研究结果可为类似隧道开挖提供参考。

To study the influence of different excavation methods on the stability of the surrounding rock in the Shergyla mountain tunnel excavation,the stress changes and deformation of the surrounding rock during the excavation process were compared and analyzed among two-step excavation method,three-step excavation method and full section excavation method.Based on the lithological parameters of the rock samples at the location of borehole SJLSZ-1 and the relevant tunnel support data,the excavation of the tunnel by different excavation methods was numerically simulated using the SIGMA/W module of Geo-Studio software and the stability of the tunnel excavation was analyzed respectively.The results show that the XY displacement of the surrounding rock at the palm face is mainly concentrated in the top of the tunnel and the elevation arch,while the maximum principal stress is mainly concentrated in the left and right arch waist of the tunnel during the excavation process and after the full excavation of the three methods;comparing the cloud change and monitoring point data,the XY displacement of the full section excavation method is the smallest,24.8 mm at the top of the arch and 28.3 mm at the right arch foot;the stress change is the smallest,690.303 kPa at the left arch waist 690.303 kPa,right arch waist 721.171 kPa;comprehensive numerical simulation analysis of the displacement data and stress data of the monitoring points,found that the full section excavation method is the optimal excavation method for the tunnel.The results could take some reference for similar tunnel excavations.