回填土区深层搅拌桩和高压旋喷桩复合地基的静承载性能

结合实际工程现场静载试验,采用有限元计算方法研究了桩长和桩土模量比对深层搅拌桩和高压旋喷桩复合地基在回填土中的桩体承载特性、荷载传递及复合地基变形特性的影响。结果表明,在回填土区,深层搅拌桩以桩体上部破坏为主,增加桩长不能有效地提高复合地基承载力,增加桩体强度尤其是上部桩体的强度则能够较大地提高复合地基承载力,高压旋喷桩可有效增强回填土地基的承载力。提出的桩体弹性模量取值范围可供设计参考。

Study on Static Bearing Capacity of Composite Foundations with Deep Mixing Pile and High Pressure Rotary Grouting Pile in Backfill Ground

The mechanisms of deep mixing pile and high-pressure rotary grouting pile in backfill ground is analyzed on the basis of in-situ tests under static load.The effects of pile length and the pile-soil modulus ratio on the bearing property of a pile,the translation characteristics of load and the deformation of the deep mixing pile composite foundations and the high pressure rotary grouting pile composite foundations in the backfill ground are studied by the finite element method.It is indicated that,in the backfill ground,deep mixing pile fail mainly on the top,the bearing capacity of composite foundation can't be enhanced effectively by increasing pile length but can be increased largely by increasing the pile strength especially that of the top,the bearing capacity of composite foundation can be enhanced effectively by high pressure rotary grouting pile.The range of pile elastic modulus is proposed for the reference of design.