中文摘要：

为研究高填方路堤压实土率相关变形特征,对不同压实度的非饱和压实土分别开展了不同加载速率以及不同围压条件下的CD三轴剪切试验,探讨了不同工况下压实土的剪切强度指标;借助GDS饱和土静态三轴仪的围压控制器来间接测定非饱和压实土体变的途径。试验结果表明：压实土强度及变形特征具有明显的时间相依性,加载速率越大,压实土的抗剪强度越高,超固结变形特性越强,抗剪强度指标黏聚力c值增幅较大、内摩擦角φ值增幅较小;低围压下,压实土呈应变软化及剪胀变形,且压实度越高,应变软化及剪胀变形越显著,c值增加明显、φ值增加缓慢。采用基于下负荷面的弹黏塑性本构模型对路基压实土的率相关变形特征进行表征,预测结果与试验数据吻合良好,表明该模型适用于高填方路堤长期沉降分析。

英文摘要：

To investigate the rate-dependent deformation characteristics of subgrade compacted clay of high-filled embankment, a series of CD triaxial shear tests on the unsaturated compacted clay with different compaction degrees is carried out under different loading rates and confining pressures, and the shear strength parameters under different working conditions are examined. A method is proposed for indirectly measuring the volume change of unsaturated compacted clay, i.e. using the confining pressure controller of GDS saturated static triaxial system to obtain the volume change. The experimental results show that the strength and deformation of compacted clay shows significant time-dependent characteristics. At the greater loading rate, the shear strength is higher and the over-consolidated properties are stronger, and the value of cohesion c increases more quickly but the value of the internal friction angle φ increases more slowly. Under low confining pressure, compacted clay shows dilatant and softening behavior. As the compacting degree increases, shear dilatancy and strain softening become more and more pronounced, shear strength index c increases quickly, whereas φ increases slowly. An elastic-viscoplastic constitutive model based on the subloading yield surface is adopted to describe the rate-dependent deformation characteristics of the over-consolidated compacted clay. The predictions of the proposed model are in good agreement with the experimental data, showing that the proposed model is suitable for analyzing the long-term settlement of high-filled embankment.