喀斯特地区新型异形灌注桩承载特性与影响因素试验研究

喀斯特地区灌注桩施工常常发生漏浆且造成成桩质量不佳与承载力不足的严重后果.根据喀斯特地区地基连通孔道分布广泛的特点,提出了一种新型灌注桩——布袋桩,并设计基岩模型进行布袋桩成桩试验,探讨布袋桩成桩可行性.在成桩可行的基础上进行8组静载模型试验,研究布袋桩的承载特性与影响因素.试验结果表明:布袋桩成桩质量良好,通过布袋桩...

Experimental Study on Bearing Behavior and Influencing Factors of a Special-shaped Cast-in-place Pile in Karst Area

The leakage of slurry during cast-in-place pile construction in karst area often results in poor quality and insufficient bearing capacity of pile. In view of the wide distribution of connected channels in the karst area, we propose a new type of cast-in-place pile in dendritic shape with bags socketed into the karst caves. We probed into the feasibility of such bag-pile by designing bedrock model for pile-forming test, and on this basis, we further investigated the bearing characteristics and influencing factors of bag-pile via eight groups of static load model tests. Results demonstrated good quality of cast-in-place bag-pile. The ultimate bearing capacity of the proposed bag-pile is about 1.5 times that of ordinary pile of equal diameter, and the settlement of bag-pile is much smaller than that of ordinary pile of equal diameter under the same load conditions. Besides, the axial force of bag-pile body obviously reduced at the upper and lower interfaces of the dendritic structure which enhanced the side friction performance of the pile. Load transfer is of obvious time effect. The bearing capacity of bag-pile is positively correlated with the length, number, and buried depth of the dendritic structure.