双圆盾构施工对邻近砌体建筑物影响的数值模拟

采用三维MIDAS/GTS软件,考虑建筑物-土体-隧道共同作用,模拟了双圆盾构隧道垂直穿越墙下筏基砌体结构建筑物的工况,研究隧道施工引起的建筑物附加沉降及荷载,考虑隧道水平位置及墙体层数改变的影响。分析结果表明:随着双圆盾构机穿越建筑物,建筑物的沉降量逐渐增大,完全通过以后建筑物沉降趋于稳定并略有回弹;沿隧道掘进方向的建筑物产生短期不均匀沉降,先从零逐渐增大,随后逐渐减小并趋于零;构件第一主应力最大值σ1和墙体最大剪应变均逐渐增大并趋于稳定。随着隧道轴线与建筑物轴线水平距离从零开始增大,建筑物呈现向隧道一侧倾倒的趋势,基础局部倾斜先增大、后减小;在一定范围内,σ1最大值和最大剪应变基本保持不变,超出后逐渐减小,并接近初始值。随着建筑物层数的增加,墙体最大剪应变呈线性增长,对建筑物造成轻微的损害。

NUMERICAL SIMULATION OF THE EFFECT OF DOUBLE-O-TUBE SHIELD TUNNEL CONSTRUCTION ON ADJACENT MASONRY BUILDINGS

Considering the interaction of building-soil-tunnel,the raft foundation masonry structure was vertically crossed by double-O-tube(DOT) shield tunnel,which was simulated by the 3D MIDAS/GTS software.The additional settlement and force of structure caused by tunnel construction were analyzed,and the changes of building’s floor and the axis distance between building and shield tunnel were considered.The results showed that during the passage of the DOT shield tunnel through the building,the settlement of the building increased;the settlement was stable and had a little rebound when shield machine passed the building;the building had short uneven settlement in driving direction,and it increased first from zero then gradually decreased to zero;the maximum first principal stress σ1 and the wall maximum shear strain increased and then was stable.With the increase of axis distance between building and tunnel,the building tended towards to tunnel side,the incline of local foundation increased first and then decreased;the maximal σ1 and the maximal shear strain were all remained unchanged within a certain range,and then gradually decreased gradually and approached to their initial value.With the increase of building’s floor,the maximal shear strain linearly increased,and it would cause minor damage to the building.