土工布加筋土的三轴蠕变试验研究

Triaxial creep tests on geotextile reinforced soil

基于自行研发的大尺寸三轴蠕变试验仪,开展不同围压、加筋层数的素土和加筋土的三轴蠕变试验,得到不同偏应力、不同加筋层数下土体的蠕变特性和加筋对土体加固的机制,提出一种可以描述加筋土"应力–应变–时间"关系的PH经验模型,得到所获取的模型参数与加筋层数和偏应力的关系;并基于Burgers元件模型,建议一种加固效果系数来评价加筋前后对土体刚度的影响程度,结果表明:随着加筋层数的增加,其加筋效果呈线性增加,与高填方工程中以增加压实度的方法来减小工后变形相比,在填料中增加筋材具有更佳效果。

The triaxial creep tests considering different confining pressures and geotextile reinforced layers were conducted using the large scale triaxial creep apparatus developed in-house. The creep properties and reinforcement mechanism under different deviatoric stresses and reinforced layers were obtained. The proposed PH model for reinforced soil described the relationship among stress, strain and time and the parameters of the PH model under different influence factors were obtained. Finally, the coefficient of reinforcement effect was established to evaluate the impact of stiffness under different reinforced layers. The results showed that the reinforcement effect was improved linearly as the increase of the reinforced layers. In comparing with the increasing compaction degree of the high fill, the reinforced materials reduce the post-construction deformation more effectively.