库岸土质滑坡蠕变作用下悬臂抗滑桩受荷劣化特性研究

Research on Deterioration Characteristics of Cantilever Anti-Slide Pile under Loading of Reservoir Bank Soil Landslide Creep

【目的】研究库岸土质滑坡在库水周期性浸泡作用下对悬臂抗滑桩劣化特性的影响。【方法】采用广义Kelvin蠕变模型描述库岸土质滑坡的蠕变作用,将悬臂抗滑桩假定为Winkle弹性地基梁,研究蠕变作用对抗滑桩内力的不利影响。【结果】得到库岸土质滑坡体蠕变位移场,构建了库岸土质滑坡抗滑桩蠕变内力计算式。以三峡库区桥头北滑坡为实例,分析表明考虑滑坡体蠕变作用后,悬臂抗滑桩在工程竣工后的前30 d内桩体内力增长速率较快,在100 d后趋于平稳;桩顶位移、滑动面处弯矩、剪力与不考虑滑坡体蠕变时相比分别增大了约0.8倍、1.7倍和0.3倍。【结论】在采用抗滑支挡结构治理库岸土质滑坡时应考虑到由库水周期性浸泡引发的滑坡体蠕变作用,特别是蠕变应力对抗滑支挡结构服役性能有明显的劣化效应。

[Purposes]The effects of reservoir bank soil landslides on the deterioration characteristics of cantilever anti-slide piles under the periodic immersion of reservoir water were studied. [Methods]The generalized Kelvin creep model is used to describe the creep effect of the reservoir bank soil landslide, and the cantilever anti-sliding pile is assumed to be a Winkle elastic foundation beam, and the adverse effect of the creep effect against the internal force of the sliding pile is studied. [Findings]The creep displacement field of the reservoir bank soil landslide mass is obtained, and the calculation formula of the creep internal force of the reservoir bank soil landslide anti-slide pile is constructed. Taking the Qiaotou North landslide in the Three Gorges Reservoir area as an example, the analysis shows that after considering the creep effect of the landslide body, the internal force of the cantilever anti-slide pile increases rapidly in the first 30 days after the project is completed, and tends to be stable after the 100 th day. The displacement of the pile top, the bending moment at the sliding surface, and the shear force are increased by about 0.8 times, 1.7 times and 0.3 times, respectively, compared with those without considering the creep of the landslide mass. [Conclusions]The creep effect of the landslide mass caused by the periodic immersion of reservoir water should be considered when using the anti-sliding support structure to control the soil landslide on the reservoir bank, especially the creep stress has obvious deterioration effect on the service performance of the anti-sliding support structure.