高速公路拓宽工程中填筑材料对新老路堤变形特性的影响

Effects of construction materials in expressway widening on deformation characteristics of new and old embankments

为解决填挖交界路基非均匀沉降,在填土中分层铺设土工格网等土工加筋材料。基于非线性弹塑性Drucker Prager模型,采用有限元参数分析方法,结合现场沉降观测资料,探讨路堤填筑材料物理参数对新老路堤附加变形、差异沉降、路堤横坡变化影响规律及土工格栅处治交界处路基非均匀沉降机理。研究结果表明:填筑体压缩模量高且密度低,有利于改善新老路堤不均匀变形和差异沉降的状况;黏聚力c对拓宽路堤竖向附加变形影响较比摩擦角φ大;土工格栅对减小路堤表面的竖向变形效果并不明显,但能有效提高新路堤安全系数及新老路堤的整体稳定性。

The reinforcement materials such as geo nets layered were placed in the filling soil in order to solve the problem of unequal settlement of sub grade at the cut to fill location. Based on Drucker-Prager model, the additional deformation on the new and old embankments, differential settlement, the changing law of the embankment cross slope and the mechanism of using geonets to treat this kind of unequal settlement were analyzed by finite element method and tests on settlement. The results indicate that high compression modulus and low density will help to improve the old and new non-uniform deformation and differential settlement of embankment; Cohesive fore c has the greater affect on the vertical additional deformation of the widening embankment compared to the angle of internal friction Ф. The reduced vertical deformation of the surface by geo grid embankment is not obvious, but it can effectively improve the safety coefficient of the new embankment and the overall stability of the new and old embankments.