高喷插芯组合桩水平承载特性大尺寸模型试验研究

高喷插芯组合桩（简称JPP桩）是一种适用于软土地基的新型组合桩，能有效提高桩的竖向承载力，并取得了相当规模的应用。为了研究其水平承载特性，利用河海大学岩土所自行研制开发的大型模型槽试验进行水平承载桩静载作用下的大尺寸模型试验。通过与普通圆截面灌注桩、加承台JPP桩的水平承载性能的对比，试验表明，JPP桩水平承载力较普通圆截面灌注桩提高了15%，桩身最大弯矩处在桩顶以下大约2 m处，桩侧土压力主要集中在上部2 m范围内土体。同时，试验表明加了承台后，JPP桩的水平承载能力有了大幅度的提高。利用规范推荐的基于m法的灌注桩水平承载力公式，对JPP的水平承载力进行了计算，结果与试验值基本吻合。其结果可以为类似土层下水平受荷JPP桩的设计与研究提供参考。

Large-scale model test analysis of behaviors of jet grouting (JG) soil-cement-pile strengthened pile under lateral load

JG(jet grouting) soil-cement-pile strengthened pile, simply called JPP pile, is a new sort of composite pile used in soft foundation. It may improve the vertical bearing capacity effectively; and it has been practically used in a considerable scale. In order to study the behaviors under lateral load, large-scale model test is carried out, using large test room made by Hohai University. It is shown that the JPP pile could improve horizontal bearing capacity by about 15% compared with bored concrete pile; and the biggest bending moment of JPP pile is located in the place 2 m below the pile tip; and lateral earth pressure is concentrated in the top 2 m soil. Meanwhile, with a cap added, JPP pile has a much higher horizontal bearing capacity. According to the formula for bored concrete pile based on m method, which standard remmends, horizontal bearing capacity of JPP pile has been calculated; and calculation results basically coincide with the experimental results. The results may be useful for the practical engineering and analysis of JPP pile in the similar soil layer.