软土地区桩柱式路基力学行为的数值模拟

Numerical simulation of mechanical behavior for pile-column supported subgrade over soft ground

以快速拉格朗日有限差分法程序FLAC为平台,建立软土地区桩柱式路基的数值分析模型,研究了桩柱式路基的力学行为。分别用桩单元、绳索单元模拟桩柱、筋材,分析了路基的沉降、侧移、孔压与稳定特性,及桩柱、筋材的内力分布,比较了桩柱式路基与传统土石方路基的特点,对桩柱、筋材、路堤与地基的设计参数对路基沉降和地基侧移的影响进行敏感性分析。分析结果表明,桩柱式路基表面的最大沉降、差异沉降仅为传统土石方路基的1.48%、1.40%,地基侧移仅为传统土石方路基的0.88%,因此,桩柱式路基力学行为优良。

Based on FLAC（fast Lagrangian analysis of continua） of 2D explicit finite difference method, a numerical simulation model was established to investigate the mechanical behavior of pile-column-supported subgrade （PCSS） over soft ground. Pile, column and reinforcement geogrid were modeled by using pile elements and cable elements respectively, the surface settlement, groUnd lateral displacement, pore water pressure, stability of the subgrade were studied, the internal force distributions of pile, column and reinforcement geogrid were analyzed, the characteristics of PCSS and traditional subgrade were compared, and the influences of design parameters for pile, column, embankment, reinforcement geogrid and foundation on subgrade settlement and foundation lateral deformation were studied. Analysis result shows that compared with traditional subgrade, the ratios of the maximum surface settlement, differential settlement of subgrade, the maximum lateral deformation of foundation are 1.48%, 1.40% and 0.88% respectively, so the mechanical behavior of the subgrade is better. 2 tabs, 11 figs, 10 refs.