不平衡土压力对整体式桥台-H型钢桩-土体系力学性能影响试验

Experiment on Effect of Unbalanced Earth Pressure on Mechanical Behavior of Soil-abutment-steel H-pile in Integral Abutment Jointless Bridges

为研究不平衡土压力对整体式桥台-H型钢桩-土体系力学性能的影响,在已开展的不平衡土压力下整体式桥台-H型钢桩-土相互作用拟静力试验研究基础上,进一步开展了更大不平衡土压力(台后土表面均布荷载增大了3.81 kPa)下整体式桥台-H型钢桩-土相互作用拟静力试验研究,对比分析了更大不平衡土压力对桩身水平变形、桩侧土压力、应变和弯矩等方面的影响。结果表明:在试验条件下,更大不平衡土压力对桩身水平变形、土抗力、应变和弯矩的分布规律无影响;正向加载时,更大不平衡土压力使得桩身累积变形的位置更深,桩侧最大土抗力和桩身弯矩增大;负向加载时,更大不平衡土压力也使得桩身累积变形的位置更深和弯矩增大;正向加载时,更大不平衡土压力使得累积变形减小,负向加载时则相反;正向加载时LAHP模型的桩侧土抗力、应变和弯矩显著大于负向加载时的,正向加载时的最大桩侧土抗力和弯矩分别为负向加载时的2.2倍和2.1倍。

In order to study on effect of unbalanced earth pressure on mechanical behavior of soil-abutment-steel H-pile in integral abutment jointless bridges(IAJBs),based on soil-abutment-steel H-pile interaction test under unbalanced earth pressure,a reciprocating low-cycle pseudo-static test on soil-abutment-steel H-pile interaction was carried out under larger unbalanced earth pressure(increase the uniform backfill load of 3.81 kPa behind abutment).The study was performed to find the effect of larger unbalanced earth pressure on the horizontal deformations,soil resistance,strain and bending moment of pile.The test results indicate that under the experimental conditions,larger unbalanced earth pressure has no influence on distribution law of horizontal deformations,soil resistance,strain and bending moment.The larger unbalanced earth pressure improves the buried depth of accumulative deformation,soil resistance and bending moment of pile under positive loading.The larger unbalanced earth pressure also improves the buried depth of accumulative deformation and bending moment of pile under negative loading.In addition,the larger unbalanced earth pressure makes the accumulated deformation decrease under positive loading.It makes the accumulated deformation increase under negative loading.The soil resistance,strain and bending moment of the LAHP model under positive loading are significantly larger than those of negative loading.The maximum soil resistance and bending moment of pile in positive loading are 2.2 times and 2.1 times as much as negative loading,respectively.