【摘要】 以丽江至香格里拉铁路中义隧道为依托,采用数值计算的方法,结合试验段的现场监测资料,对在围岩和初期支护间设置缓冲层控制初期支护变形的效果及不同地应力侧压力系数下缓冲层的合理厚度进行了研究。研究表明:在围岩与初期支护间的边墙段设置合理厚度的高密度泡沫板(EPS)可显著提高初期支护的稳定性,并使初期支护最大水平收敛、拱顶下沉减少10%左右;中义隧道埋深在800 m附近、发生严重大变形的区段,地应力侧压力系数小于0.9时,可不铺设缓冲层;地应力侧压力系数为1.0～1.3、1.3～1.5、1.5～1.7时,缓冲层的合理厚度分别为100 mm、150 mm、200 mm。更多还原

【Abstract】 In order to control the initial support deformation, this paper took Zhongyi tunnel of Lijiang to Shangri-La railway as an example, to analyze the large deformation control effects and reasonable thickness of buffer layer set between surrounding rock and initial support. The research results are as follows. High-density foam board(EPS) with reasonable thickness which set between surrounding rock and initial support can significantly improve the initial support stability, and make the maximum level converge of initial support and vault crown settlement decreased by about 10%. The buffer layer is not necessary in the section of Zhongyi tunnel with severely large deformation where the buried depth is near 800 m, and the lateral pressure coefficient of geostress is less than 0.9. When the lateral pressure coefficient of geostress is 1.0～1.3, 1.3～1.5, 1.5～1.7, the reasonable thickness of buffer layer is 100 mm, 150 mm, 200 mm, respectively.更多还原