基于蠕变试验的黄土高填方工后沉降规律数值研究

Numerical analysis of the post-construction settlement regularity of loess-high filled embankment based on creep test

为了研究黄土高填方工后沉降规律,开展一系列压实黄土一维固结蠕变试验,分析含水率及压实度对黄土蠕变特性的影响,验证了Burger蠕变模型在描述压实黄土应变与时间关系上的适用性,在该模型基础上,运用FLAC3D计算了黄土高填方工后沉降规律。结果表明:轴向加载瞬时,试样变形速率较大,随着时间的推移,变形速率减小并趋于稳定,压实黄土蠕变随含水率的提高而增加,随压实度的提高而减小。工后沉降对填料压实标准更敏感,在一定压实度和含水率范围内,工后沉降与含水率和压实度呈线性关系。可以通过高填方工后沉降速率和时间关系曲线上的拐点位置判断工后沉降稳定时间,填料压实度越低、含水率越大,拐点越靠后,沉降稳定的时间越长。

In order to study the post-construction settlement regularity of loess-high filled em-bankment,the author has conducted a series of uniaxial compression creep tests with compacted loess,analyzed the effect of the moisture content and compaction on creep properties of compac-ted loess.The applicability of Burger model on the relationship between strain and time of the compacted loess is verified.With this model as the constructive FLAC3D is used to calculate the settlement of post-construction of the loess high embankment.The results show that the deform-ation rate of the sample is larger at axial instant loading and as the time goes on,the deformation rate decreases and tends to be stable;with the moisture content the creep deformation of loess is increasing,the degree of compaction get lower with the improvement of compact degree.The post-construction settlement is more sensitive to the compaction standard of the loess.The post-construction settlement is a linear relation with moisture content and compaction degree within a certain range.The inflection point position on the vs-t curve of high earth filling work post settle-ment can be used to estimate the stability time of the post-construction settlement.The lower of the compaction degree of filling materials,the higher moisture content of the filling materials will be,the more rear of the inflection point is,the longer of the post-construction settlement to sta-ble will be.