关于挡土墙抗倾覆稳定分析的讨论
Overturning stability of retaining walls
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摘要: 对挡土墙抗倾覆稳定传统分析方法存在的主要问题进行讨论, 指出其存在各种问题的主要原因是理论分析的假定前提不合理。假定挡土墙在倾覆临界状态时受到的竖向荷载与实际受力状态一致, 定义倾覆稳定系数为墙土体系所能提供的最大抗倾覆力矩与墙体实际受到的倾覆力矩之比, 据此通过力学分析, 导出挡土墙倾覆稳定系数K0计算公式, 由新公式可知:K0随地基极限承载力的增大而增大, 随垂直荷载的增大而变小, 与偏心距成反比。抗倾覆稳定性与基底的应力状态是密切相关的, 通过对各相关规范的地基承载力验算要求与抗倾覆稳定安全系数的对比研究表明, 只要挡土墙地基承载力满足规范要求, 抗倾覆稳定一定满足, 不必再进行抗倾覆验算。Abstract: The main defect in the traditional overturning stability analysis for retaining walls is discussed. It is pointed out that the main reason is the irrational premise of its theoretical analysis. A more rational overturning coefficient K0 is then derived by assuming that the vertical load on the retaining wall at the limit state is the same as the actual state of loading. The overturning stability coefficient is defined as the maximum anti-overturning moment provided by the retaining wall system divided by the overturning moment from the actual soil load. Using the new definition of overturning coefficient, it is shown that K0 increases with the increase of the ultimate bearing capacity of foundation soil and decreases with the increase of vertical load. It is also inversely proportional to the load eccentricity at the base. The overturning stability of a retaining wall is closely related to the stress state at its base. By comparing the requirements of bearing capacity and overturning stability in China's design codes, as long as the bearing capacity of foundation meets the design requirements, the overturning stability can be guaranteed, and it is not necessary to individually check the overturning stability.