基于改进MSD法的软土深基坑支护侧移规律

软土地层中建造大型深基坑工程时往往面临着较大的风险和挑战,支护结构易发生变形且难以预测.对已有的可动强度设计(mobilizable strength design,MSD)理论进行总结,引入围护结构的弯曲应变能和内支撑的压缩弹性势能,完善基坑变形过程中的能量守恒体系,改进MSD法计算公式,并以济南黄河隧道北岸盾构工作井基坑工程为依托,对软土地层深基坑连续墙的变形进行预测,同时利用有限元分析法进行预测,并将预测结果与现场监测数据进行详细的分析比对,论证改进MSD法+有限元分析法预测体系的可靠性,分析误差来源,提出降低误差的措施,供类似工程参考.

Analysis of Lateral Displacement Law of Deep Foundation Pit Support in Soft Soil Based on Improved MSD Method

The construction of large-scale deep foundation pit in soft soil is often faced with great risks and challenges. The supporting structure is easy to be deformed which is difficult to be predicted. This paper summarized the existing MSD theory, and introduced the bending strain energy of the retaining structure and the compression elastic potential energy of the internal support, also improved the energy conservation system in the process of foundation pit deformation, improved the MSD method calculation formula. Meantime, this paper predicted the deformation of the continuous wall of the deep foundation pit in soft soil layer based on the north bank shield shaft foundation pit project of Jinan Yellow River tunnel, and applied the finite element analysis method for prediction, and compared the prediction results with the field monitoring data in detail. This paper demonstrated the reliability of the improved MSD + FEA prediction system, and analyzed the error sources, and put forward the measures to reduce the error for the reference of similar projects.