常/变法向应力作用下密砂-混凝土接触面剪切力学性状试验研究

Experimental study on shear mechanical properties on dense sand-concrete interface under constant and varying normal stress

通过大型直剪仪对密砂-混凝土接触面进行了常法向应力和变法向应力作用下的剪切试验,分析了剪切面剪应力和体应变的变化特征,建立了密砂-混凝土接触面剪切的数学模型。结果表明:在常法向应力剪切试验中,密砂-混凝土接触面的抗剪强度符合摩尔库伦定律,抗剪残余强度与法向应力之间成直线关系,体应变与法向应力密切相关;在变法向应力剪切试验中第二级法向应力作用下,密砂-混凝土接触面的剪应力最大值与相应的常法向应力作用下的抗剪残余强度相同,但其体应变比相应常法向应力作用下的体应变小。在常法向应力作用下,密砂-混凝土接触面的剪应力-剪切位移关系曲线可用三折线拟合;在变法向应力作用下,密砂-混凝土接触面的剪应力-剪切位移关系曲线可用三折线-双曲线拟合。

A series of large-scale direct shear tests of dense sand-concrete interface under constant and varying normal stress were carried out by using large-scale direct shear apparatus to analyze the characteristics of shear stress and volumetric strain and mathematical models of dense sand-concrete interface were established. The results show that in the constant normal stress-shear tests,the shear strength of dense sand-concrete interface satisfies the Mohr-Coulomb criterion,the relationship between residual strength and normal stress is linear,and the volumetric strain is closely related to the normal stress. Under the second order normal stress of the varying normal stress-shear tests,the maximum shear stress is identical to the residual strength under the constant normal stress but the volumetric strain is smaller. The relationship between the shear stress and the shear displacement under the constant normal stress can be fitted with the tri-linear,and the relation ship between them under the varying normal stress can be fitted with the tri-linear-hyperbolic curve.