车辆荷载对基坑支护结构的影响分析

为了研究车辆荷载对基坑支护结构体系的影响,针对常规等效代换土层厚度法未考虑破裂棱体破裂角变化问题,引入改进等效代换土层厚度法,依据库伦土压力理论,计算破裂棱体自重,结合破裂棱体平衡关系式,循环迭代得到破裂角收敛值,根据此破裂角换算得到新的土层厚度。基于地铁车站基坑工程,通过数值模拟,采用常规方法和改进的等效代换土层厚度法研究车辆荷载对基坑支护结构的影响,分别得到支护结构的水平位移曲线。研究表明,破裂角变化会引起代换土层厚度变化,从而影响计算精度;在基坑支护结构设计中,采用改进等效代换土层厚度法来考虑车辆荷载影响是可行的。

Analysis of the Influence of Vehicle Load on Deep Excavation Supporting Structure

In order to analyze the influence of vehicle load on deep excavation supporting structure,the conventional equivalent thickness of soil layer method is introduced,and the problem of the change of rupture angle caused by vehicle loads is addressed,and an improved method is introduced to solve this problem. The deadweight of rupture mass is calculated according to Coulomb' s earth pressure theory.The convergence value of rupture angle is obtained by means of circulative iteration with reference to the equilibrium relation where the rupture mass keeps an equilibrium state,and the thickness of the new soil layer is calculated based on the rupture angle. In the light of the foundation pit of metro station in a city,and the influence of a conventional method and the improved equivalent layer method on supporting structure are compared by simulation,and the curves of horizontal displacements are obtained. The results indicate that the change of rupture angle will cause the change of the equivalent thickness of soil layer,and,as a consequence,the calculation accuracy is affected. It is applicable to employ the improved equivalent thickness of soil layer method to address the influence of vehicle load..