异形截面全夯式扩底灌注桩竖向承载受力机理研究

Study on mechanism of vertical bearing capacity of fully rammed bottom-enlarged bored pile with irregular section

提出一种异形截面全夯式扩底灌注桩,与直径500mm圆形截面全夯式扩底灌注桩进行对比,异形截面全夯式扩底灌注桩横截面面积可以扩大至圆形截面面积的1.357倍,且施工贯入比较容易,异形截面全夯式扩底灌注桩与圆形截面全夯式扩底灌注桩在同等桩身截面面积的情况下还可增大桩身侧面积,有利于增大摩擦力。对3根内切圆直径为500mm的异形截面全夯式扩底灌注桩进行现场载荷试验并采用ABAQUS软件对其进行分析,得到了异形截面全夯式扩底灌注桩荷载-沉降曲线和桩端土体挤密影响范围。有限元计算结果与现场试验结果基本吻合,验证了异形截面全夯式扩底灌注桩桩端土体挤密范围取值的合理性及数值模拟结果的准确性。

A new fully rammed bottom-enlarged bored pile with irregular section was presented.Comparing with the fully rammed bottom-enlarged bored pile with 500 mm diameter circular section,the cross-sectional area of the fully rammed bottom-enlarged bored pile with irregular section can be expanded to 1.357 times of the circular cross-sectional area,and the construction penetration is relatively easy.Given the same section area of pile body,fully rammed bottom-enlarged bored pile with irregular section can increase the lateral area of pile body,which is beneficial to increase friction when compared with the circular section pile.Three fully rammed bottom-enlarged bored piles with irregular section of 500 mm inner tangential circle diameter were field tested and analyzed by ABAQUS software.The load-displacement curves of fully rammed bottom-enlarged bored piles with irregular section and the influence range of soil compaction at the end of piles were obtained.The results of finite element calculation are basically in agreement with the field test results,which can verify the rationality of the soil compaction range at the end of the irregular-shaped fully rammed bored pile and the accuracy of the numerical simulation results.