多元复合地基是一种新型的复合地基技术.推导出瞬时加荷条件下多元不排水长短桩复合地基桩间土的固结方程,基于双层地基一维固结理论建立了相应的固结解析解.通过与有限元解的比较验证了解析解的正确性.利用建立的固结解析解进行参数分析,研究了多元不排水桩长短桩复合地基的固结特性.计算结果表明,多元不排水长短桩复合地基的固结速率随长桩压缩模量和置换率的增加而增大.短桩压缩模量和置换的变化对复合地基固结速率的影响很小.短桩较短时,短桩长度的变化对复合地基固结速率几乎没有影响,短桩较长时,复合地基固结速率随短桩长度的增加而增大.此外,多元不排水长短桩复合地基的固结速率随短桩以下土体压缩模量的增加而增大.“,”The impervious multi-long-short piles-reinforced ground is a new type of composite ground technology. The equations governing the consolidation of the surrounding soils within the composite ground are derived under instantaneous load. The analytical solutions are then developed for the consolidation of the composite ground based on the one-dimensional consolidation theory of a double-layer ground. The comparison of the consolidation rates from the proposed analytical solution with the FEM is made to verify the correctness and accuracy of the proposed analytical solutions. Parametric study is conducted to investigate the consolidation behavior of this new type of composite ground using the proposed analytical solutions. The results show that the consolidation rate of the composite ground with impervious multi-long-short piles increases with the increase of the area replacement ratio and the constrained modulus of the long piles. The area replacement ratio and the constrained modulus of the short piles have insignificant influences on the consolidation rate of the composite ground. When the short piles have shorter lengths, the variation of the length of the short piles has little influences on the consolidation rate of the composite ground. The consolidation rate increases with the increase of the length of the short piles when the short piles are long enough. Furthermore, it increases with the increase of the constrained modulus of the soil bellow the tip of the short piles.