长短桩复合地基沉降计算方法研究

Research on Settlement Calculation of the Long-Short-Pile Composite Foundation

目的研究长短桩复合地基的一种新型的地基处理技术,解决沉降计算方法问题.方法从长短桩复合地基的作用机理入手,针对长短桩复合地基中桩、土、垫层相互作用特点,在剪切位移法的基础上,引入Mylonakis&Gazetas的桩与桩、桩与土相互作用模型,同时考虑垫层作用影响,导出了长短桩复合地基计算时的桩-桩、桩-土以及土-土相互作用柔度系数.结果通过桩-土-垫层体系共同作用的长短桩复合地基沉降计算的新方法及编制相应的计算程序对某工程实例进行分析的结果表明,沉降计算值与实测值吻合较好.结论新的长短桩复合地基沉降计算方法表明此方法计算长短桩复合地基的沉降是可行的,深入探讨长短桩复合地基的沉降计算对于开发和推广其工程应用具有理论和工程意义.

As a new foundation treatment technology, long-short pile composite＇s design theory is still in primary phase, and there are no explicit settlement calculation methods in active codes. So it is necessary to study the working mechanism and the methods of settlement calculation. In this paper, the mechanics of Ion＆short-pile composite foundation are fully discussed. Meanwhile, based on the shear deformation method, the Mylonakis ＆ Gazetas models about mutual action between two piles and the one between pile and soil are introduced. Considering the performance of cushion, the flexible factors of mutual actions are provided. Then the settlement calculation of long-short-pile composite foundation which can consider the mutual actions between pile, soil and cap is deduced, and the correlated program is also developed. Finally, an engineering example is discussed with the method. A comparison shows that calculated results and measured data from a field test pile are in a good agreement, indicating that the presented approach is feasible and applicable in engineering practice.