压重平台堆载对软土地区基桩承载力的影响

The Influence of Counterweight Platform Load of Foudation Pile Bearing Capacity in Soft Soil Area

以广州南沙某工程为例,通过在软土地区进行超大吨位桩基静载试验,结合桩身内力测试,探讨分析了不同试验支墩处理方式下压重平台堆载对软土地区基桩承载力的影响。通过“换填垫层”处理支墩地基,压重平台堆载过程中桩侧出现负摩阻力,堆载完成后开始测试得到的桩身最大轴力明显大于千斤顶施加的荷载。而采用“支撑桩+桩帽”处理支墩地基,压重平台堆载过程中桩侧未出现负摩阻力,且堆载完成后开始测试得到的桩身轴力呈现自桩顶向下随着深度增加而逐渐变小的合理分布。结果表明,在超厚层软土地区中进行桩基静载试验,宜尽量采用“支撑桩+桩帽”处理支墩地基以减少压重平台堆载对基桩实受承载力的影响。

Combined with pile internal force test,super-tonnage static load test was proceed in soft soil area where a project in Nansha,Guangzhou as an example,which discuss and analyze the effect of bearing capacity of test pile heaped load for different test supports treatment methods.Negative friction resistance appears on the pile side during the process of loading on the counterweight platform by replacing the cushion course processing foundation of supports.The maximum axial force of pile measured during static load test is obviously greater than the load applied by jack.However,the negative friction resistance wasn’t appeared by the process foundation of supports combined braced pile and pile cap.Last but not the least,axial force of pile is decreasing from the top of pile to the bottom resonably after the process of loading.The results show that super-tonnage static load test process in soft soil area,adopt measure that the process foundation of supports combined braced pile and pile cap to reduce the influence of stacked load on pile bearing capacity.