中文摘要：

利用大型直剪仪对土—混凝土接触面的应力应变特性进行研究，研究不同法向应力条件下光滑接触面的剪切变形特性，并构建相应的剪切本构模型。试验结果表明：接触面τ－δ关系曲线为峰值型，但是随着法向应力的增大，峰值趋势减缓。光滑接触面剪切破坏强度符合摩尔－库伦破坏强度理论，光滑接触面的黏聚力和摩擦角小于红黏土自身，阐述了接触面破坏的原因。通过对光滑接触面的剪胀（缩）特性研究，发现存在区分剪胀和剪缩的临界法向应力，并给出了计算方法。此外，探讨直剪试验双曲线模型参数的确定方法，求出适合的双曲线参数，通过该模型可以求得一定法向应力范围内任意双曲线模型参数。

英文摘要：

This paper utilized the large direct shear apparatus for soil and concrete interface stress and strain characteristics research.The smooth interface shear deformation characteristics under the condition of different normal stresses were investigated and the appropriate shear constitutive model was built.Experimental results show that the relationship curve between the τand δis peak type,but with the increase of normal stress,peak value trending down.Smooth interface shear strength accords with Mohr -Coulomb failure strength theory,the contact surface cohesion and friction angle is smaller than red clay.The cause of the shear failure surface oc-curred in the contact surface.Based on research of the dilatancy and shrinkage characteristics of smooth inter-face,it is found that there exists a critical normal stress which distinguishes shear dilatancy and shrinkage of soil.Moreover,corresponding method for calculating the critical normal stress was proposed.Discussing the di-rect shear test method for determining the model parameter of hyperbola,and found out the suitable hyperbolic parameter.Then any hyperbolic model parameters under a range of normal stress can be obtained through the model.