局部超载作用下的支挡结构土压力问题是制约高密度城区发展的常见问题之一。为了探讨局部超载对邻近支挡结构土压力的影响规律,以及现有计算理论的合理性与适用性,通过模型试验针对支挡结构不同位移模式下局部超载对其土压力的影响进行研究,分析支挡结构土压力分布、大小与位移模式的关系,并将试验结果与现有理论计算结果进行对比。研究表明:对于无黏性土,在邻近局部超载影响下,支挡结构的土压力分布形态及大小与各点位置处的位移量有关,随着位移量的增加呈指数函数降低;局部超载对土压力的主要影响范围与规范算法相一致,但规范与现有简化土压力计算法在某些区域范围内存在不适宜性,且不适宜区域与支挡结构的位移模式有关;弹性法土压力计算值能够包络邻近局部超载支挡结构各种位移模式下的土压力,其分布形态与实测值相一致,偏于安全,但在局部超载主要影响范围以外偏大,可进行修正折减。

The earth pressure of retaining structure adjacent to the action of local overload is one of the common problems in the development of high-density urban area. The influence of local overloading on the earth pressure of adjacent retaining structures under different displacement modes was investigated via model test, and the rationality and applicability of existing calculation theories were analyzed. The relations of scale and distribution of earth pressure against displacement mode of retaining structure was acquired, and the test results were compared with the existing theoretical calculation results. Conclusions were obtained as follows: for cohesionless soil, the distribution form and scale of earth pressure of retaining structure under local overload are related to the displacement at each point, declining exponentially with the growth of displacement. The main influence range of local overload on earth pressure obtained by the present method was consistent with that by standard method, but the standard method and the proposed simplified method are not suitable in some areas, which is related to the displacement mode of retaining structure. The earth pressure calculated with elastic method can cover all kinds of displacement modes of the adjacent retaining structure under local overload. Its distribution pattern is consistent with the measured value, which is safe, but can be modified and reduced when it is larger than the main influence range of local overload.