高填方加筋新旧路堤现场试验与数值模拟分析

ANALYSIS BETWEEN NUMERICAL AND FIELD TESTS OF HIGH FILL REINFORCED WIDENING EMBANKMENT

结合山区高速公路拓宽工程,对土工格室处治高填方新旧路堤进行现场试验,分析加宽高填方路堤侧向位移、沉降及土压力变化规律,研究格室处治效果。在现场试验的基础上,采用三维薄膜单元模拟土工格室的立体加筋性能,建立三维弹塑性模型,分析土工格室受力特点,通过对相关参数的敏感性分析,揭示高填方加宽路堤的变形规律。结果表明,采用三维薄膜单元,能较好地反映土工格室处治现场高填方新旧路堤的规律。与现场试验相比,利用数值试验不仅能得到现场的加筋效果,而且还能通过分析筋材与填料参数的变化和筋材铺设间距来研究格室处治高填方路堤的规律,从而可进一步探讨格室加筋的机制。高填方路堤在加宽路基自重荷载作用下沉降主要集中在加宽路堤的中上部,侧向位移从路基顶面到底部依次逐渐减少。土工格室所在层位起到扩散荷载、减少侧向变形和不均匀沉降的作用。填料与筋材模量愈高,加筋间距愈小,加筋效果愈好,较为合理的铺设间距为2～3m。该研究成果对高填方路堤加筋处理和新旧路基结合部处理均有借鉴意义。

Associating with mountain freeway widening project, the field test of high fill old and new embankments of geocell treatment was carried out to analyze the lateral displacement, settlement and soil pressure laws of high fill embankment, and the effect of geocell treatment is also studied. Based on field test, the three-dimensional thin membrane element is used to simulate geocell, and three-dimensional elastoplastic model is proposed. The geocell reinforced characteristics and the deformation law of high fill widening embankment by the sensitivity analysis of the relevant parameters are analyzed. The results show that the three-dimensional thin membrane element can better reflect treatment effect that geocell reinforces high fill embankment. Compared with the field test, the field reinforced effect by using numerical experiments is achieved, and the law of geocell treatment of high fill embankment through the analysis of parameter change of geocell, filling and the spacing of reinforcement materials is also achieved, and thus geocell reinforced mechanism is further discussed. Under itself gravity loads of widening embankment, the vertical displacement mainly is concentrated in the upper part of the widening embankment and lateral displacement gradually is reduced from the top surface to the bottom of embankment. Geocell layer plays the role in decentralizing the load transfer, reducing the lateral deformation and differential settlements. The higher moduli of filling and reinforcement material are, and the smaller reinforcement spacing is, and the reinforcement effect is better. The reasonable distance for the geocell spacing is 2 - 3 m. These conclusions may be useful to the design and analysis of reinforced-embankment on high fill and the interface between new and old embankments in widened embankment.