富水地层盾构施工引起的沉降实测分析

ANALYSIS OF MEASURED SETTLEMENT CAUSED BY SHIELD CONSTRUCTION IN WATER-RICH STRATUM

盾构隧道开挖受地质影响较大,不同地区不同土层开挖会导致其盾构施工引起的地层损失率η和地表沉降槽宽度系数K也不同,导致其施工经验难以完全借鉴。文中以杭州地铁8号线一期SG8-2标中文桥区间风井-桥头堡站盾构区间为工程背景,对该地区的盾构施工引起的实测数据进行分析,得到该地区的地层损失率η和地表沉降槽宽度系数K;并对盾构施工中的盾尾注浆压力采用Plaxis有限元进行建模分析,得到该区域开挖时,符合规范地表沉降控制下的的最优盾尾支护压力,为该地区的盾构施工工程提供参考。

The excavation of shield tunnels is greatly affected by geology situations. The excavation of different soil layers in different regions would cause the formation loss rate η and the width coefficient K of the surface settlement trough caused by shield construction to be different, which makes it difficult to fully learn from its construction experience. Taking Hangzhou Metro Line 8, the first phase of SG8-2 bid: Wenqiao ventilation shaft-Qiaotoubao station shield tunnel section as the engineering case, the measured data caused by the shield construction in the area was analyzed, and the stratum loss rate η and width coefficient K of the surface settlement trough in the area was also obtained. Furthermore, the grouting pressure of the shield tail in the shield construction is modeled and analyzed by using Plaxis software to obtain the optimal shield tail support pressure under the control of the standard ground settlement when the area is excavated, which may provide reference for shield construction projects in the region.