矩形闭合墙桥梁基础墙-土-承台相互作用研究

矩形闭合地下连续墙基础是一种新型的桥梁基础。通过室内模型试验,对闭合墙基础墙-土-承台相互作用进行系统的研究。试验研究表明:闭合墙基础承台土反力分布的总体特征是承台下土芯的角点处最大,边缘处次之,中心区最小。在一定范围内,承台下土芯截面积越大,承台土反力分布越趋于均匀化。承台对上部墙段的内摩阻力存在"削弱效应",而对下部墙段的内摩阻力则有一定的"增强效应",承台对墙端阻力也有一定的"增强效应"。承台土反力的荷载分担比约为10%～20%,若在闭合墙的竖向承载力计算方法中,不考虑承台的作用,忽略承台土反力,是不合理的。模型试验和分析结果为矩形闭合地下连续墙基础的设计计算提供了重要依据。

Diaphragm wall-soil-cap interaction in rectangular-closed-diaphragm-wall bridge foundations

Rectangular-closed-diaphragm-wall foundation is a new type of bridge foundation. Diaphragm wall-soil-cap interaction was studied through a model test. It was observed that the distribution of soil resistance under the cap is not homogeneous. Soil resistance in the corner under the cap is larger than that in the border, and soil resistance in the center is the smallest. The distribution of soil resistance under the cap will be more uniform, if sectional area of soil core is enlarged to a certain extent. Due to the existence of the cap, there is "weakening effect" in inner shaft resistance of the upper wall segments, and there is "enhancement effect" in the lower wall segments and in the toe resistance. Load shearing percentage of soil resistance under the cap is 10%~20%. It is unreasonable to ignore the effects of the cap and the soil resistance under the cap in bearing capacity calculations.