素混凝土桩复合地基承载机理的离散元分析

采用二维离散单元法模拟了素混凝土桩复合地基的浅层平板载荷试验。将数值试验结果与现场试验结果对比,以验证离散单元法的适用性,并基于加载过程中地基土体的宏微观响应,分析复合地基的破坏机理。分析结果表明:土体的转动场、应力偏转等变化较大的区域主要集中在直接承载的桩体周边区域,越向外侧所受影响越小;当荷载超过地基极限承载力时,复合地基发生冲切破坏,桩端发生刺入破坏;桩顶荷载、桩侧阻力、桩端阻力、桩土应力比与沉降的变化规律与现场试验结果相似,说明采用离散元法分析素混凝土桩复合地基的承载机理是可行的。

Discrete Element Method Analyses on Bearing Mechanism of Composite Ground Treated by Plain Concrete Piles

The bearing tests on the composite ground treated by plain concrete piles is numerically simulated by the two dimensional Discrete Element Method(DEM).The DEM’s numerical results are compared with that of in-situ results,and the bearing mechanism of the composite foundation is analyzed.The numerical results show that the rotating field of the earth mass and stress field are strongly affected along the pile under the plate,which means that the adjacent pile has great constraint effect on the deformation of the soil between plies.When the load reaches the ultimate bearing capacity,the treated ground develops a punching shear failure and the pile develops a penetration failure.The change laws of pile top load,pile side resistance,pile tip resistance and pile-soil stress ratio with settlement are similar to the in-situ results,which indicates the feasibility of DEM in analysing the bearing mechanism of composite foundation.