坑外偏压荷载作用下既有深基坑支护结构性状分析

针对既有深基坑坑外通常存在临时堆载的情况,依托某建筑物地下室深基坑工程,运用ABAQUS有限元数值建模并结合实测数据,分析了坑外偏压荷载大小、荷载位置及荷载分布宽度对既有深基坑支护结构受力和变形的影响。研究结果表明:坑外偏压荷载大小不同情况下基坑两侧支护结构水平位移和弯矩差异较大,左侧(有荷载侧)桩体的水平位移大于右侧(无荷载侧),并且右侧桩体会发生逆向位移;左侧桩体最大弯矩随着荷载的增大而增加,右侧桩体最大弯矩呈减小的趋势;荷载位置对左侧桩体影响较大,而对右侧桩体影响较小,并且坑外荷载距基坑越远对既有深基坑支护结构影响越小;左侧桩体水平位移和最大弯矩随着荷载分布宽度增加而逐渐增大,而右侧桩体水平位移在减小且其最大弯矩略有增加;在对深基坑进行设计时,需要考虑坑外荷载的影响。

Analysis of Supporting Structure Behavior of Existing Beep Foundation Pit under External Bias Load

Based on the deep foundation pit engineering of a certain building, ABAQUS finite element numerical model was used to analyze the influence of the bias load size, load location and load distribution width on the stress and deformation of the support structure of the existing deep foundation pit. The research results show that the horizontal displacement and bending moment of the supporting structure on both sides of the foundation pit vary greatly under different external bias load. The horizontal displacement of the pile on the left side (with load side) is greater than that on the right side (without load side), and the reverse displacement will occur on the right side; the maximum bending moment of the left pile increases with the increase of pile load, while that of the right pile decreases. The load position has a great influence on the left pile body, while has a small influence on the right pile body. Moreover, the farther the outside load is from the foundation pit, the smaller the influence is on the existing deep foundation pit. The horizontal displacement and maximum bending moment of the pile on the left gradually increase with the increase of load distribution width, while the horizontal displacement of the pile on the right decreases and its maximum bending moment slightly increases. Therefore, the influence of pit load should be considered in the design of deep foundation pit.