针对土工袋装砂石桩复合路基,通过有限元分析方法研究了路堤长期堆载下袋体包裹长度、土工袋刚度以及置换率对复合路基的性状影响。数值计算结果表明:与普通砂石桩相比,袋装砂石桩复合路基的桩土应力比显著提高,土体沉降变形明显减少,桩身鼓胀变形得到有效限制;在一定范围内增加袋体刚度能有效提升复合路基承载性能;荷载较小时,增加袋体包裹长度对桩土应力比及沉降的影响并不明显,随着路堤高度增加,需全长包裹以减少桩体沉降;增大置换率一方面有利于减少桩体沉降,而另一方面将减少桩体的有效利用率。基于单元体模型,推导了袋装砂石桩的变形和应力的弹性解析解,并通过有限元分析方法对理论解进行验证,得到较好的吻合度。 Aiming at the effect of geotextile bagged sand pile composite foundation, the effect of bag body length, geotextile bag stiffness and displacement rate on the performance of composite subgrade under long-term embankment loading was studied by finite element analysis. The numerical results show that the pile-soil stress ratio of sacked gravel piles composite subgrade significantly increases compared with that of ordinary gravel piles, the settlement of soil subsidence decreases obviously, and the bulge deformation of piles is effectively limited. In a certain range, The rigidity can effectively improve the bearing capacity of the composite subgrade. When the load is small, the effect of increasing the length of the bag body on the stress ratio and settlement is not obvious. With the increase of embankment height, it needs to be wrapped with full length to reduce the pile settlement. On the one hand, it helps to reduce the settlement of the pile while on the other hand it will reduce the effective utilization of the pile. Based on the unit body model, the elastic analytical solutions of the deformation and stress of the bagged sand pile are deduced. The theoretical solution is verified by the finite element analysis method, and the good agreement is obtained.