软土基坑中长短桩支护的数值模拟研究

Numerical Simulation of Both Long and Short Piles in the Deep Excavation in Soft Soils

放坡+等长桩+被动区加固是武汉深厚软土基坑中常采用的支护方法,然而在软土地区按等长桩进行布置会导致支护造价较高。为了降低支护造价,以实际工程为背景,探讨长短桩在基坑支护中的最优配比选型。首先采用ABAQUS有限元和天汉基坑软件对比分析等长桩桩体的受力情况,并将监测数据与软件计算结果相对比,验证有限元软件计算结果的合理性,然后以等长桩有限元模型为基础,在ABAQUS中建立长短桩支护三维模型,分析四种不同配比的长短桩在基坑支护的受力和变形,并选出最优长短桩配比支护方式。研究表明一长一短的桩型配比支护方案相比其它三个方案更可有效支护基坑,为武汉地区类似软土基坑工程支护设计提供参考。

The frequently used deep excavation supporting methods in Wuhan are slope down with open cut,equal length soldier piles and passive zone improvement.However,the utilization of a uniform length of soldier piles in soft soils leads to an excessive construction cost.To reduce the excavation support cost,a case history of different soldier pile length is presented in this paper.The stress-strain relationship in the soldier piles with various lengths are evaluated by using ABAQUS finite element analysis and Tianhan commercial deep excavation software and compared with the excavation supported by the uniform length soldier piles.Both the monitored data and the analytical results are compared to validate the numerical simulation approach.Then,based on the validated uniform length soldier pile excavation supporting model,the three-dimensional model with different length soldier pile excavation support was established by using ABAQUS software.The stress and deformation of four different types of soldier pile lengths are evaluated and the optimized soldier pile length arrangement is obtained through the analysis.Compared with the other model,the one long and one short soldier pile arrangement can effectively provide the excavation support.