偏压条件下排桩加内支撑支护深基坑受力与变形分析

基坑开挖受周围环境制约较大，需根据具体条件采取不同的支护方式。尤其对于狭长基坑两侧存在偏压的情况，基坑变形以及支护结构受力会存在较大差异。本文以西安科技八路综合管廊深基坑支护工程为研究对象，采用数值模拟与现场监测相结合的方法，对偏压条件下基坑的变形以及支护结构受力变化规律进行了深入的研究分析。研究结果表明：随着基坑开挖，水平位移和竖向位移均呈逐渐增大趋势，锚杆和内支撑对水平位移控制效果明显。桩身内力在锚杆与内支撑位置突变明显，避免了桩身受力过大。由于受右侧已开挖基坑的影响，导致基坑两侧变形有所差异，但位移值相差不大。说明该深基坑支护方案设计合理，支护效果良好，满足偏压条件下对基坑变形控制的要求。研究结果可为类似基坑工程的支护与开挖提供一定的指导。

Stress and deformation analysis of deep foundation pit supported by pile and internal bracing under unsymmetrical loaded

The excavation of foundation pit is greatly restricted by the surrounding environment, and different supporting methods should be adopted according to specific conditions. Especially for the case of bias pressure on both sides of the narrow and long foundation pit, the deformation of the foundation pit and the stress of the supporting structure will be very different. In this paper, taking the utility tunnel deep foundation pit of Keji Eighth Road in Xi-An as an example, the method, combining numerical simulation with field monitoring, were adopted to study and analyze the deformation of foundation pit and the regular of force change of supporting structure. The results shown that: With the excavation of foundation pit, the horizontal and vertical displacement increased gradually. And the control effect of bolt and inner support on horizontal displacement was obvious. The internal force of pile body break obviously in the position of anchor rod and internal support, which avoids the pile body being stressed too much. Due to the influence of the excavated foundation pit on the right, the deformation of both sides of the foundation pit was different, but the displacement value was close. The design of the deep foundation pit supporting scheme was reasonable and the supporting effect was good, which meet the requirement of deformation control of the foundation pit under the condition of unsymmetrical loaded. The results of this study can provide some guidance for similar excavation.