A study of land subsidence in the subway shield tunnel excavation in soil strata in Wuhan
【摘要】 为分析隧道盾构开挖引起的地表沉降规律,本文以武汉地铁三号线为工程背景,采用现场监测和数值模拟计算相结合的方法,综合分析了土质地层盾构开挖时隧道的纵向、横向地表沉降特征,探讨了不同注浆半径条件下地表沉降变化规律,结果表明:数值计算结果与现场监测数据相吻合;开挖过程中盾首上方地表沉降迅速,盾构穿过后沉降减缓,注浆后回弹,最终趋于平稳;隧道拱顶沉降值最大,平均沉降值约40 mm,离隧道轴线越远沉降值越小,形成沉陷槽,沉陷槽宽度约30 m;注浆半径越大,沉降值越小,施工时可根据技术要求和经济条件选择最优注浆半径。
【Abstract】 In order to analyzes the characteristics of ground settlement caused by shield tunnel excavation,based on the engineering background of the Wuhan Metro line 3,this paper adopts the method of combining field monitoring and numerical simulation,compares and analyzes the law of surface subsidence in vertical and horizontal directions with shield excavation and discussed the rule of surface subsidence under the different conditions of different radius of grouting. The results indicate that the numerical calculation is in accordance with the field monitoring data. In the process of excavating,the settling velocity of ground above the front of shield is rapid. After the sedimentation of tunnel shield,the speed slows down. The surface rebounds after grouting,then the surface is in a constant state. The sedimentation number of the tunnel vault remains the biggest,and the average sedimentation number is about 40 mm. The farther the tunnel vault stays away from the tunnel axis,the smaller the sedimentation number reaches. Then the subsidence trough is formed,with a width remaining about 30 m. The smaller the radius of grouting is,the bigger the sedimentation number achieves. The optimal radius of grouting is chosen during the construction on the basis of technical requirements and economic conditions.
【Key words】 metro tunnel； numerical simulation； grouting range； surface subsidence；
- 【文献出处】 水文地质工程地质 ,Hydrogeology & Engineering Geology , 编辑部邮箱 ,2015年01期