粉土混凝土界面与粉土剪切对比试验研究

Comparative Shear Test Study on Silt-concrete Interface and Silt

采用自制的大型直剪仪开展不同含水量条件下黄泛区粉土-混凝土界面剪切及粉土直剪试验,研究不同含水量下粉土-混凝土界面及粉土剪切力学特性。试验结果表明:粉土-混凝土界面和粉土直剪的剪切应力-剪切位移曲线均为应变硬化型;粉土直剪的剪缩变形明显大于界面剪切结果;相同条件下,粉土-混凝土界面的剪切强度大于粉土的直剪强度,随着含水量的增大,粉土-混凝土界面与粉土剪切强度的差异逐渐减小,粉土趋近饱和时,两者强度基本相同;粉土直剪破坏时的剪切位移大于界面剪切破坏时的剪切位移;粉土直剪的黏聚力和界面黏聚力、摩擦角随含水量的增大均近似呈线性减小趋势,粉土直剪的内摩擦角随含水量增加呈现先缓慢后加速减小的变化趋势。

A self-developed large direct shear apparatus was used to carry out the silt-concrete interface and silt shear tests in the yellow flood area under different water content. Through comparative analysis, the shear mechanical properties of the silt-concrete interface and silt under different normal stresses and water content were studied. The results showed that the shear stress-shear displacement curves of the silt-concrete interface and the silt exhibit strain hardening characteristics.The shear shrinkage deformation of the silt direct shear test is significantly greater than the silt-concrete interface. Under the same normal stress and water content, the shear strength of the silt-concrete interface is greater than that of the silt. As the moisture content increases, the difference in the shear strength between the silt-concrete interface and the silt gradually decreases. When the silt is close to saturation, the strength of the two is basically the same. In addition, the shear displacement of the silt under direct shear failure is greater than that at the silt-concrete interface. The cohesive force of silt, the cohesive force and friction angle of the silt-concrete interface are approximately linearly decreasing with the increase of water content, and the internal friction angle of silt increases slowly and then accelerately decreases as the water content increases.