A series of large direct shear tests were carried out to investigate the effect of roughness on residual shear strength of red clay-concrete interface. The results show that the shear stress-shear displacement curves are characterized as strain softening and the residual shear strength increases with the increase of the surface roughness. The roughness on residual strength decreases with the increase of the magnitude of normal stress. The residual friction coefficient of interface (i.e. residual strength divides by normal stress) increases with the increase of roughness and eventually approaches internal friction coefficient of soil, indicating the internal shear failure of soil occures. The residual cohesion of interface dramatically increases while the residual friction angle increases as a results of the increase of roughness.%进行红黏土与混凝土结构接触面大型直剪试验,研究粗糙度对接触面残余强度的影响.试验结果表明:红黏土-混凝土结构接触面剪切应力-剪切位移曲线特征为应变软化型,结构面粗糙度增加能够明显提高接触面残余剪切强度,但这种影响随法向应力的增大而逐渐弱化;接触面残余摩擦因数(即残余强度与法向应力比值)随粗糙度增大而增大,最终接近或者超过土体内部残余摩擦因数,此时,接触面的剪切破坏发生在土体内部;结构面粗糙度对接触面的残余黏聚力的影响较大,而对残余摩擦角的影响较小.
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