筒桩复合地基固结性状三维有限元分析

3D FEM Analysis of Consolidation Behavior of Tubular Pile Composite Foundation

考虑了桩、土、土工格栅之间的相互作用及地基土体固结的影响,采用三维有限元方法研究了路堤荷载作用下,打穿软土层和未打穿软土层的固结特性、沉降特性和应力分布特性,并对桩长、桩间距等影响因素进行的分析。研究表明:应使桩长穿透软土可压缩层,以满足控制地基最大沉降量的要求;格栅最大拉应力分布于盖板边缘处,随着地基固结时间的增加,格栅拉应力逐渐增大;随桩间距的增加,复合地基桩端处超静孔压的消散速率变小,桩与桩间土的沉降加大;随着桩长的增加,下卧土层超静孔压消散速率明显加快;临界桩长范围内,桩长对地基沉降起控制作用。

With consideration of pile-soil-geogrid interaction and soil consolidation, the consolidation, settlement and stress distribution properties on penetrated and partially penetrated soft soil were studied with FEM under the road embankment loading.Moreover, the influencing factors such as pile length and pile space, ere.were discussed.The result shows that （1） to meet the requirements of control the largest settlement, the pile length should be designed to penetrate the soft compression layer; （2） The largest tensile stress of geogrid occurs at the edge of cover board, with increase of ground consolidation, the tensile stress increases gradually; （3） with increase of pile spacing, the dissipation rate of excess pore water pressure at pile tip decreases, and the settlement of pile and soil between piles increases; （4） with increase of pile length, the dissipation rate of excess pore water pressure at weak soil layers speeds up obviously; （5） at range of critical length of pile, pile length makes controlling effect on settlement of ground.