黄土加筋路堤的数值模拟及性能分析

采用FLAC数值方法对黄土加筋路堤施工全程进行模拟,基于室内压缩试验和FISH动态模量输入的方法来描述土体的压实,利用土体在不同围压下的压缩模量来计算其变形模量,并用该法对宁夏黄土地区高速公路某路堤加筋试验工程进行了模拟,模拟结果和实测值较为接近。结果显示:随着路堤施工的推进,长短筋材发挥的作用不断变化,在路堤填土高度不高时,长短筋材受力区别不明显,填土高度增大时,短筋受力逐渐减少,长筋受力不断增大;并且,据长筋的受力特点可以分为3个区域:边缘区、受力区,内部区。对黄土路堤加筋效果的评价不仅应包括对筋材和路堤稳定性的提高,而且还应包括筋材对路堤不均匀沉降和基底土压力的调整作用。研究结果为土工合成材料在黄土中的推广应用提供了有益的探索。

Performance Analysis of a Reinforcing Loess Embankment Using Numerical Method

The construction process of loess reinforcement embankment is modeled using FLAC.Based on uniaxial compression test and dynamic modulus input technique with programmable FISH,the compact quality of loess can well be depicted.The method used to(calculate) loess deformation modulus under different pressures is proposed,and the compaction performance can be well modeled.A(reinforcing)(expressway)(embankment) in Ningxia is modeled using this method,and the results are close to the field data.As the(embankment) constructed,the mechanical performances of long geogrid and short geogrid are different.When the embankment becomes higher,the tension force of short geogrid weakens;while the tension force of long geogrid increases quickly.The comment on the effect of reinforcement should not only include embankment stability improvement,but also should include the effect of adjusting uneven(settlement) and base stress of embankment.These results may help promote the application of geosynthetics in loess embankment.