人工挖孔支盘桩桥梁基础承载性能静载荷试验研究

Experimental Study on Bearing Capacity of Artificial Excavating Squeezed Branch Pile Foundation with Static Load Test

以人工挖孔支盘桩桥梁基础现场静载荷试验为根据,借助埋设在桩身的钢筋应力计以及桩底的土压力盒反映在加载阶段桩身轴力和桩底土压力的变化,研究人工挖孔大直径支盘桩的荷载传递规律和承载能力。分析结果表明:人工挖孔支盘桩Q-S曲线呈缓变型,增强了桩土的共同作用,有效地发挥了土层的承载能力;在工况相同的条件下,相比等直径桩其沉降变形降低,承载力提高;支盘对于荷载的分担有明显的时序性,上部支盘先于下部支盘发挥作用,两支盘间的桩侧阻力有明显降低。

Based on site static load test on artificial excavating squeezed branch pile foundation,the changes of axial force along pile and soil pressure under pile during loading are separately reflected by steel stress meter buried in pile body and soil pressure gauge at the bottom.Then the load transfer law and bearing capacity of artificial excavating large-diameter squeezed branch pile are analyzed.The results show that Q-s Curve of artificial excavating squeezed branch pile trends to change slowly,which strengthens pile-soil interaction and effectively exerts the bearing capacity of soil mass.Under the same condition,the settlement of artificial excavating squeezed branch pile is smaller and bearing capacity is larger compared to those with the same diameter.Branches share loads with time sequence,i.e.,upper branch shares load earlier than lower branch.Pile side resistance between branches is significantly reduced.