穿越公路偏压小净距隧道施工方法探讨

西康高速公路长哨小净距隧道地形复杂特殊，尤其在出口段存在浅埋、偏压现象，且左隧道覆盖层上部为陕西省S102省道，隧道开挖期间，省道正常开通。为研究隧道开挖方式对省道路面沉降及洞室开挖后围岩稳定性的影响，通过建立符合实际地形的三维模型，分别针对上下台阶法、留核心土法、侧壁导坑法3种开挖方法进行了数值模拟，对不同开挖方式隧道不同位置的塑性区、围岩变形及地表沉降进行了分析，提出了符合实际的开挖施工方案，并同实际现场监测数据进行了比较。研究结果表明，采用上下台阶开挖法实现省道下的小净距隧道穿越方式，可保证施工期间省道的正常运行及隧道围岩的稳定性。

study of construction methods for crossing bias smallinterval highway tunnel

Changshao Expressway tunnels with small spacing have complicated and special topographies;especially at the region of outlet,the provincial expressway S102 is only 5 meters over the vault of the left tunnel;and the right tunnel is pressed by an unsymmetrically pressure.In order to study the effects of excavation types on surface settlement and stability of surrounding rockmass,a three-dimensional model which is corresponding to realistic landform is built to simulate distribution of plastic zones,deformatio...