EPS板减载措施在明洞高回填土应用中的数值模拟研究

NUMERICAL SIMULATION STUDY OF THE APPLICATION OF EPS BOARD IN THE OPEN CUT TUNNEL WITH HIGH BACKFILL

以兰渝铁路兰州枢纽工程长寿山隧道二号明洞为工程背景,分别研究了不同回填高度下有无EPS板以及EPS板厚度不同时对明洞结构的减载效果。计算结果表明:EPS板宽度与明洞结构宽度相同时,铺设EPS板对于拱顶减载效果明显;并且在EPS板厚度为30 cm时减载效果最佳,但对于拱腰没有明显减载效果;铺设EPS板时,EPS板中部土体位移与两侧土体位移差明显,上部土体下沉较大,进一步验证了EPS板的减载作用机理;回填土高度在30 m以上时,结构顶部铺设EPS板对于减小拱顶结构的竖向位移效果明显。

Based on the 2th open cut tunnel of Changshoushan of Lanzhou-Chongqing railway,the effect of no EPS board and a few thickness EPS board on open cut tunnel is studied under different thickness backfill. The result indicates that: when the EPS board width and the structure width are the same,the effect of EPS board on the vault is obvious. The effect is best when the EPS board's thickness is 30 cm,but the effect on the hance is unobvious. The vertical displacement deference between middle soil and both side soil is obvious when EPS board is laid,and the vertical displacement of the middle is larger,which proves the principle of the EPS board to reducing the earth pressure further. When the height of backfill is up 30 m,the effect of EPS board on reducing the vertical displacement of the vault is obvious.