公路路堤下长短桩复合地基沉降数值模拟研究

Numerical Simulation Research on Settlement of Long-short Pile Composite Foundation under Highway Embankment

为了在公路路堤下长短桩复合地基沉降数值模拟计算中建立合适的几何模型。本文通过某二级公路桥头跳车病害处治中长短桩复合地基沉降的理论计算结果和FLAC3D数值模拟研究结果对比,确定了FLAC 3D在数值计算过程中,最佳的深度取3.5×b,最佳的宽度取4.5×b(b为路基底宽度);以及在长短桩复合地基单元划分上,长桩、短桩和桩间土分别直接建模,形成桩单元和土体单元,研究结果显示:该方法比长桩、短桩和桩间土形成复合土体单元数值分析所得沉降值更接近理论计算所得沉降值。该研究可为为今后公路路基沉降数值模拟建模提供参考。

This paper aims to establish a suitable geometric model in the numerical simulation calculation of the settlement of the long-short-pile composite foundation under the highway embankment.Based on the comparison of the theoretical calculation results of the long-short pile composite foundation settlement with the FLAC3 D numerical simulation research results in the treatment of the vehicle jumping disease at the bridgehead of a secondary highway,this paper determines that the best depth is 3.5×b in the numerical calculation process of FLAC 3 D and the best width is 4.5×b(b is the width of the road base).In addition,the long pile,the short pile,and the soil between the piles are directly modeled to form the pile element and soil element.The settlement value obtained by numerical analysis is closer to the theoretical settlement value than that of the long pile,the short pile,and the soil between the piles.The research results can provide references for the numerical simulation modeling of roadbed settlements in the future.