【作者】 陈峥； 何平； 张安琪； 王秀英；

【Author】 CHEN Zheng;HE Ping;ZHANG An-qi;WANG Xiu-ying;School of Civil Engineering, Beijing Jiaotong University;

【机构】 北京交通大学土木建筑工程学院；

【摘要】 三南铁路凤咀江隧道位于岩块、碎石杂填土浅埋危险地层中。该文应用三维有限元分析方法,研究隧道在三台阶七步开挖法施工下,开挖进尺分别为0.5 m、1.0 m、1.5 m、2.0 m、2.5 m和3.0 m六种情况隧道掌子面及围岩未支护段的变形破坏规律。研究结果表明:开挖进尺对拱顶沉降变形和边墙水平收敛变形有极大影响;未支护段破坏区域大小与开挖进尺成正相关,而开挖进尺对掌子面破坏区域大小的影响较小;V级围岩隧道施工过程中开挖进尺要控制在1.0m内,并且要采用管棚或小导管超前支护来确保施工的安全;通过掌子面注浆可以提高掌子面的稳定性,增大开挖进尺。更多还原

【Abstract】 Fengjujiang tunnel of Sannan Railway is in the shallow-buried danger geological condition back filled with broken rock blocks. It is excavated by the three-bench seven-step method.The deformations and damage law of the tunnel face and un-supported section are researched by 3D finite element analysis method. Six digging lengths of 0.5 m, 1.0 m, 1.5 m, 2.0 m, 2.5 m and 3.0 m are respectively discussed. The study results indicate that the digging length has a great influence on the settlement of the crown and distortion of tunnel sidewall. The damaged area of the un-supported section is in proportion to the digging length while is of little impact on the tunnel face. The digging length should be limited under 1.0m to the surrounding rock at classes V, and the pipe-roof or small duct should be used to guarantee the safety in construction. The stability of tunnel face and digging length can be increased by the tunnel face grouting.更多还原