超大沉井基础下沉施工应力与变位分析

Analysis of Stress and Displacement in Sinking Construction of Super Large Open Caisson Foundation

基于常泰长江大桥主墩沉井基础下沉施工,运用有限元分析软件对沉井施工的首次下沉进行了数值模拟。对沉井下沉结束后的应力以及变位进行了分析,结果表明:沉井在下沉完毕后,沉井刃脚截面全面受压,最大压应力出现在刃脚与刃脚相连的隔墙位置上,沉井最外圈井壁应力在隔墙处会发生突变,但应力值整体上从长轴方向圆弧中点到短轴方向直线中点逐渐下降。同时,沉井下沉结束后,沉井位移量由上到下逐渐减小,在隔墙连接处位移量产生突变,而土体的沉降量在隔墙处大于井孔位置,在刃脚部位土体沉降最大。

Based on the sinking construction of caisson foundation of main pier of Changtai Changjiang Bridge,the first sinking of caisson is simulated by finite element analysis software.The stress and displacement of caisson after sinking are analyzed.The results showed that:(1)After the completion of sinking of the caisson,the cross section of the caisson blade foot is under overall compression,and the maximum compressive stress appears on the partition where the blade foot is connected to the blade foot.The shaft wall stress of the outermost ring of the caisson will suddenly change at the partition wall,but the stress value gradually decreases from the circular arc midpoint in the long axis direction to the linear midpoint in the short axis direction on the whole.(2)After the completion of caisson subsidence,the displacement of the caisson gradually decreases from top to bottom,and the displacement of the caisson suddenly changes at the partition connection,while the settlement of the soil at the partition is greater than that at the borehole,and the soil settlement at the edge foot is the largest.