基于不同结构强度软粘土长期强度特性研究

Study on the long-term strength characteristics of soft clay with different structural strength

天然软粘土一般具有结构性,土的结构性反映其内部颗粒孔隙连结及空间组合,决定了土体的物理力学效应,是软粘土长期强度的重要内在影响因素。为研究结构性强弱不同对软粘土长期强度特性的影响,人工制备含水率相同而结构强度不同的土体,对其进行三轴不固结不排水蠕变试验。试验结果表明,软粘土由于存在结构性,其长期强度具有明显差异。通过对不同结构强度土体蠕变等时曲线进行分析,建立了考虑结构强度影响的软粘土长期强度经验模型。利用本文建立的经验模型,以结构屈服应变(1.9%)作为人工结构性软粘土蠕变变形的破坏准则,结果表明预测值与试验值较为吻合,验证了本文建立的考虑结构强度影响的土体长期强度预测关系式的合理性。

The natural soft clay generally has structure,which is one of the important internal factors affecting the long-term strength of soft clay.And the structural properties of soil can reflect its internal particle pore links and space combination,and determine the physical and mechanical effects of soil.In order to study the effect of structural strength on the long-term deformation property of soft clay,creep tests under unconsolidated-undrained conditions were done on artificial soil with the same moisture content while different structural strengths.And the results show that the long-term deformation property difference is obvious,due to different structural strength of soft clay.The hydrogeology of soil samples is analyzed and studied,and the empirical formula of long-term strength of soft clay with the effect of structural strength is obtained.Using the empirical formula proposed in this paper,the structural yield stress(1.9%)was used as the failure criterion of creep deformation of artificial structural soft clay,the results show that the predicted value was coincident with the test results,and the rationality of the long-term strength prediction formula is verified,which considering the effect of structural strength.