密实砂土地层盾构隧道开挖面失稳离心模型试验研究汤旅军.pdf

3 C/D=0.5 1 2 + C/D=0.5 C/D=1 2 TU41 A 2013 (1984 )E-mail: tljzjdx@126.com Centrifugal model tests on face stability of shield tunnels in dense sand TANG Lü-jun1, 2, CHEN Ren-peng1, 2, YIN Xin-sheng1, 2, KONG Ling-gang1, 2, HUANG Bo1, 2, CHEN Yun-min1, 2 (1. MOE Key Laboratory of Soft Soils and Geoenviromental Engineering, Zhejiang University, Hangzhou 310058, China; 2. Institute of Geotechnical Engineering, Zhejiang University, Hangzhou 310058, China) Abstract: When tunneling in sand using the shield machine, failure of the tunnel face occurs frequently due to the inadequate support pressure. Centrifugal model tests with different overburden-to-diameter ratios (i.e., C/D= 0.5, 1, 2) are performed to study the problem of tunnel face stability in dense sand. During the tunnel face failure, with the increase of the horizontal displacement of the tunnel face, it is found that the support pressure firstly decreases rapidly to the limit support pressure and then increases gradually to the residual support pressure. A “wedge-prism” failure zone occurs in front of the tunnel face after the face failure. For the relatively shallow buried tunnel (e.g. C/D=0.5), the failure zone has extended to the ground surface in the limit state. While for the relatively deep buried tunnel (e.g. C/D=1 and 2), the failure zone is still in the interior of the ground in the limit state. It is also found that the limit support pressure increases