Similarity Solution for the Synchronous Grouting of Shield Tunnel Under the Vertical Non-Axisymmetric Displacement Boundary Condition

Abstract.Similarity solution is investigated for the synchronous grouting of shield tunnel under the vertical non-axisymmetric displacement boundary condition in the paper.The synchronous grouting process of shield tunnel was simplified as the cylindrical expansion problem,which was based on the mechanism between the slurry and stratum of the synchronous grouting.The stress harmonic function on the horizontal and vertical ground surfaces is improved.Based on the virtual image technique,stress function solutions and Boussinesq’s solution,elastic solution under the vertical non-axisymmetric displacement boundary condition on the vertical surface was proposed for synchronous grouting problems of shield tunnel.In addition,the maximum grouting pressure was also obtained to control the vertical displacement of horizontal ground surface.The validity of the proposed approach was proved by the numerical method.It can be known fromthe parameter analysis that larger vertical displacement of the horizontal ground surface was induced by smaller tunnel depth,smaller tunnel excavation radius,shorter limb distance,larger expansion pressure and smaller elastic modulus of soils.

基于平面和深部位移联合监测的滑坡精准勘察

基于某高速公路高边坡滑坡工程,在地质调查、钻探、原位测试等基础上,引入基于平面和深部位移联合监测模式进行精准勘察。通过平面位移监测确定滑坡周界和滑动方向;通过深部测斜确定滑面位置;通过6孔钻探补充查明空间结构特征。根据深部监测指导钻孔取样获取滑带土指标,检算天然和饱和工况下的稳定性系数分别为1.01、0.98;分析监测数据,滑坡滑动规律为连续降雨期间滑动速率增大,停止施工后滑动速率下降,变形速率从后部向前部逐渐减小,属推移式滑坡;提出清方+重力式罩面的综合整治方案。

竖向非轴对称位移边界条件下柱孔收缩问题弹性解析

针对竖向非轴对称位移边界条件下浅埋隧道开挖围岩位移和地表位移计算,基于虚拟镜像技术的源-源法,将竖向地表的剪应力修正为0,并在应力修正之前获得围岩的弹性解。对于柱孔和镜像柱孔联合作用在水平地表边界产生的竖向正应力和剪应力,采用调和函数及相应的应力函数解答进行应力修正,获得第2和第3部分围岩位移解。通过Boussinesq解答和积分思路,将竖向地表边界的水平正应力修正为0。根据线弹性叠加原理,将以上位移进行叠加,得到竖向非轴对称位移边界条件下浅埋隧道开挖围岩位移的最终解。由围岩位移最终解推导出水平和竖向地表边界的地表沉降和侧向位移。通过与数值模拟方法的比较,验证本文理论方法的可靠性。