桩单位体积承载力问题探讨

STUDY ON BEARING CAPACITY PER VOLUME OF BORED-CAST-PLACE PILES

根据现场试验和弹塑性有限元数值模拟,对不同灌注桩单位体积承载力问题进行了比较研究,主要包括直径不同的直桩间、直桩和楔形桩间、楔形角不同的楔形桩间、直桩和扩底桩间、扩底直径不同的扩底桩间的单位体积承载力的比较。结果表明,桩的承载力高,其单位体积承载力并不一定也高;楔形桩和扩底桩的单位体积承载力相对较好;短而粗的楔形桩的单位体积承载力比长而直的楔形桩的更好;扩底桩的扩底直径、直桩的直径除特殊情况外,不宜过大;在桩型确定好后,选择合理的桩尺寸是必要的;进行桩端注浆、使桩进入较好的持力层、清除存渣等可提高桩的单位体积承载力。

Based on field tests and elastic-plastic FEM, the paper has a comparative study on the bearing capacity per volume of bored-cast-place piles. The comparative study include equal-diameter pile and equal-diameter pile, equaldiameter pile and tapered pile, tapered pile and tapered pile, equal-diameter pile and belled pile, belled pile and belled pile. The results show that the bearing capacity per volume of pile is not all higher when its bearing capacity is higher. The bearing capacity per volume of tapered pile and belled pile are comparatively better. The bearing capacity per volume of short and thick tapered pile is better than long and slender tapered pile＇s. Expect for especial circumstance, the belled diameter of belled pile and the diameter of equal-diameter pile should not be big excessively. The rational selection of geometry＂ dimension of pile is essential after the type of pile is confirmed. The measures of pouring slurry in pile end, making pile puncture into better bearing layer, cleaning out sediment of hole bottom can improve the bearing capacity per volume of a pile.