中文摘要：

针对新旧路堤的不均匀沉降问题，结合山区高填方加筋工程，开发离散一连续耦合程序，局部加筋区域采用离散元PFC模拟，外围区域采用连续单元FLAC模拟，分析土工格栅在新旧路堤的受力分布，研究加筋区域土体细观参数的变化，揭示土工格栅处治新旧路堤的细观机理。结果表明：离散一连续耦合方法可作为精细化分析的有效手段；在沉降未达到稳定前，细观上加筋层孔隙率逐渐减小，接触数增大，滑动比变化十分剧烈，宏观上土体进一步压密，加筋层中的土工格栅拉力逐渐增大，筋材加筋作用开始显现；在沉降稳定后期，加筋层孔隙率进一步减小，部分区域孔隙率增大发生剪胀，滑动比数值均较小，一般在8％以下，宏观上表现为沉降已完成。

英文摘要：

Aimed at uneven settlement of new and old embankment, combined with high embankment reinforcement engineering in mountain areas, the discrete-continuous coupling procedure was developed. The discrete element PFC was adopted to simulate local reinforced region, and continuous element FLAC was adopted to simulate peripheral region. The force distribution of geogrid was analyzed in old and new embankment and the changes of the mesoscopic parameters in soil reinforcement interface region were studied, for revealing mesoscopic mechanism of geogrid treated new and old embankment. The results show that discrete-continuous coupling method can be used as an effective means for meticulous analysis. Before the settlement reaches stability, in the mesoscopic view, the porosity gradually decreases, coordination number increases, and slip ratio changes violently on the reinforced layer. In the macroscopic view, soil is further consolidated, geogrid tensile increases gradually, and geogrid reinforcement effect begins to be obvious. In the stability period, the porosity on the reinforced layer further decreases, part of the regional and slip ratio is small, generally below 8%. porosity increases with the occurrence of dilatancy, Embankment settlement has been completed in the macroscopic view.