中文摘要：

分析了加筋碎石桩复合地基的承载机理,探讨了加筋碎石桩复合地基的几种破坏模式。在不同的破坏模式下根据极限平衡理论导出了加筋碎石桩单桩极限承载力计算公式,破坏模式1主要由格栅套筒抗拉强度控制,破坏模式2由加筋段桩体侧摩阻力和非加筋段桩体鼓胀破坏前向上提供的端承力共同控制。实例计算表明,加筋碎石桩的承载力比普通碎石桩的承载力有显著提高,且加筋碎石桩的加筋深度与格栅抗拉强度之间有最优组合,最合理地利用加筋格栅提高碎石桩承载力,最后将加筋碎石桩应用到了高速公路软基处治中。

英文摘要：

The bearing mechanism of composite foundation of geosynthetic-encased stone columns was analyzed,and several kinds of failure mode of the composite foundation were investigated.In different failure modes,according to the limit equilibrium theory,a calculation formula of the ultimate bearing capacity of single geosynthetic-encased stone column was proposed.Failure mode 1 is mainly controlled by the tensile strength of geogrid sleeve,and failure mode 2 is controlled by the pile-lateral friction of geosynthetic-encased stone column and the end bearing capacity of common stone column before the damage of swelling deformation.The example of calculation indicates that the（1） bearing capacity of geosynthetic-encased stone column has significantly improved than that of common stone column;（2） the reinforcing depth of geosynthetic-encased stone column and the tensile strength of geogrid sleeve have a best combination for the most rational using of geogrid to improve the bearing capacity of the stone column.At last,the geosynthetic-encased stone columns were applied to treatment of weak subgrade of expressway.