Experimental study on performance of GRS bridge abutment with flexible face
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摘要: 基于静载作用下加筋土柔性桥台结构工作性能的试验研究，综合对比分析桥台基础距下部挡墙面板的距离D对柔性桥台结构极限承载力、下部挡墙变形特点、筋材应变和土压力的影响。试验结果表明：当下部加筋挡墙中筋材长度为整体桥台高度时，桥台结构极限承载力随偏移距离D增加呈现先增加后减小趋势，且在D为0.4HL(HL为下部挡墙高度)时达到最大值；加筋柔性桥台整体结构加载至破坏前一级载荷时，桥台基础沉降与台背加筋土顶部沉降均呈近似线性变化，且D/HL为0.4时二者差异沉降最小；挡墙面板顶部的水平位移明显大于中、底部，且挡墙水平位移与挡墙高度比值均小于1%；挡墙中各层筋材应变最大值随D增加而逐渐向远离面板方向发展，且D为0.4HL时台背加筋土和下部挡墙加筋中筋材的应变相差不大，整体柔性桥台结构工作性能达到最佳状态。Abstract: Based on the experimental study on performance of geogrid-reinforced soil (GRS) bridge abutment with flexible face under static load, the effects of offsets distance, D, between abutment foundation and panel of retaining wall on the ultimate bearing capacity of GRS bridge abutment, deformation characteristics, strain of geogrids and earth pressure are comprehensively and comparatively analyzed. The test results show that the ultimate bearing capacity of GRS abutment exhibits a remarkable increase tendency with the increase of D/HL (HL, height of geogrid-reinforced retaining wall) before D/HL=0.4 for GRS retaining wall with the length of geogrids supposed to be equal to the height of GRS abutment, and the maximum ultimate bearing capacity can be obtained when D/HL=0.4, which is followed by a significant decrease while Dis greater than 0.4HL. Before failure happens to GRS abutment, the settlement of abutment foundation and top surface of GRS behind abutment tends to be linear and the differential settlement reaches the lowest level when D/HL=0.4, and the ratios of horizontal deformation of panel to the height of lower wall are less than 1%. Moreover, horizontal deformations at top of lower walls are significantly greater than those in the middle and at the bottom of lower walls. Additionally, the maximum values of strains of geogrids occur and keep to be away from panel with the increase of D/HL, and the strain level of geogrids in the lower wall and upper wall is almost the same as that when D/HL=0.4. Therefore, the optimum performance of GRS bridge abutment can be obtained simultaneously.
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