常/变法向应力下松砂-混凝土接触面剪切力学性状试验研究

Experimental research on shear properties of loose sand-concrete interface under constant / varying normal stress

利用Shear Trac-Ⅲ大型直剪仪对松砂-混凝土接触面进行了常/变法向应力作用下的剪切试验,分析了剪切过程中剪应力和剪切面体应变的变化特征,建立了能够反映松砂-混凝土接触面剪切力学性状的数学模型,并给出了模型参数的确定方法。试验结果表明:在常法向应力作用下的剪切试验中,松砂-混凝土接触面的剪应力及体应变与法向应力密切相关;在变法向应力作用下的剪切试验中,松砂-混凝土接触面的抗剪强度与相应的常法向应力的抗剪强度相同,但其体应变小于相应的常法向应力作用下的体应变;在常法向应力作用下,松砂-混凝土接触面的剪应力-剪切位移关系可以用双曲线模型表示;在变法向应力作用下,松砂-混凝土接触面的剪应力-剪切位移关系可以用分段双曲线模型表示。

A series of shear tests of loose sand-concrete interface under constant/varying normal stress were carried out by using Shear Trac-Ⅲ large direct shear apparatus. The characteristics of shear stress and volumetric strain were analyzed, and some mathematical models were developed to reflect the shear mechanical properties of loose sand-concrete interface. In addition, the determine method of model parameters was provided. It is concluded that the shear strength and the volumetric strain of loose sand-concrete interface are closely related to the normal stress in the constant normal stress-shear tests. In the varying normal stress-shear tests, the shear strength is identical to that of the constant normal stress, but the volumetric strain is smaller. Based on the test data, the relationship between the shear stress and the shear displacement under the constant normal stress can be fitted with the hyperbolic curve; and the relation between them under the varying normal stress can be fitted with the piecewise hyperbolic curve.