冲刷作用下单桩水平承载特性试验研究及数值模拟

Experment on the lateral load capacity of single piles under scour conditions

为了掌握冲刷前后桩基础水平承载性能的变化规律,通过自行设计加工的水平加载装置,进行了一系列不同冲刷深度下的桩基室内模型试验,获得在不同水平荷载作用下桩头水平位移以及沿桩身的应变,掌握冲刷作用对桩基水平承载性能的影响。在此基础上,采用FLAC3D软件模拟单桩在水平荷载作用下的承载性能,并依据模型试验结果修正数值模型相应参数,获得能考虑冲刷作用影响的单桩计算模型。用该计算模型对冲刷角、桩顶固定方式和不同冲刷深度下单桩的水平承载力性状进行分析,得出如下结论:当冲刷深度小于1.5倍桩径时,水平极限承载力受冲刷影响较小;而当冲刷深度达到大于2倍桩径,小于8倍桩径时,水平极限承载力受冲刷影响较大,下降幅值达到80%;当冲刷深度继续增大,水平极限承载力下降趋于平缓;在一定的冲刷深度下,当冲刷范围变化时,桩基侧向承载力变化不明显;桩头固定有利于减小冲刷对桩基承载力的影响。

The author devised laboratory model experiments under different scour depths. After that, the fi-nite difference software FLAC3 Dis used to simulate the test model, and comparing the results between them,then correct the model parameters according to the model test results. Based on the revised numerical mod-el, the author discuss the scour angel,the pile head fixed method,and scouring forms, put forward someconclusions that are beneficial to practical engineering. When the scour depth is less than 1.5 times pile di-ameter,the lateral load capacity is not likely to be influenced by scour, while the scour depth increase upto 8 times pile diameter,the lateral load capacity decrease 80 % compared to un-scoured conditions. Nu-merical analysis indicates that under a certain scour depth,pile lateral load capacity is not likely to be in-fluenced by scour width,and fixed pile head is beneficial to the lateral bearing property.