为研究格栅套筒加筋碎石桩复合地基的变形特性及沉降计算方法,开展加筋碎石桩复合地基承载变形机理分析.将复合地基划分为加筋段、非加筋段和下卧层三部分:基于空间问题的胡克定律和分层总和法思路,考虑加筋段桩土存在相对滑移但不出现塑性区,采用桩体单元并利用分层迭代法予以计算;由于非加筋段桩土竖向和径向变形协调,引入桩土单元体模型予以分析;下卧层沉降量则通过分层总和法计算,从而推导出格栅套筒加筋碎石桩复合地基沉降计算公式.工程实例分析结果表明,上述沉降计算方法所得结果与实测值较接近,且克服了现有分析方法所得结果偏于危险的缺陷,具有较好的合理性与可行性.%An analysis of the bearing and deformation mechanism of a composite foundation reinforced with geogrid-encased stone columns is presented in order to obtain its bearing characteristic and settlement calculation method. The composite foundation is divided into three parts:the reinforced section, the unreinforced section, and the underlying stratum. Based on the Hooke' s law of space problem and layer summation method, the settlement of the reinforced section is calculated with the layered iteration method in view of the relative slip displacement between the pile and soil of the reinforced section without a plastic zone. The compatibility of vertical and radial deformation of the unreinforced section is analyzed based on the pile-soil element model. The settlement of the underlying stratum is calculated by the layer summation method. Therefore, the calculation formula can be derived for a composite foundation reinforced with geogrid-encased stone columns. The results of engineering examples show that the settlement result obtained from this method is close to the measured one. Furthermore, the method is more feasible and can be applied in engineering practice, whereas the results calculated with other available methods are more dangerous.
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