To investigate particle size and gradation of crushed stone on interface shear strength and dilatancy of soil-structure, a series of large scale direct shear tests were performed considering four uniform particle samples and three graded samples. Based on the results of tests, the influence of particle size, grain-size distribution, roughness and normal stress on interface shear behavior were discussed. The results show that soil particle size has pronounced effect on shear strength of interface, and interface shear strength increases with the increase of particle size. Interface shear strength of graded samples is greater than that of uniform samples which has the same mean particle size. The deformation of interface changes from shear contraction to dilatancy under low normal stress and presents obvious contraction under high normal stress. The response of shear strength and deformation of rough interface is significantly larger than that of smooth interface under the identical condition.%为了研究碎石料颗粒粒度与级配对土与结构接触面剪切强度与变形的影响,采用大型直剪仪分别进行4种不同粒度的单粒组碎石料以及3种不同连续级配碎石料与混凝土结构接触面的直剪试验,研究颗粒粒度、级配形式、结构面粗糙度以及法向应力对接触面剪切特性的影响.研究结果表明:颗粒粒度对碎石料与结构接触面的力学特性有显著影响,接触面剪切强度随颗粒平均粒度的增大而增大;而当平均粒度相同时,连续级配碎石料与结构接触面的剪切强度明显比单粒组碎石料与结构接触面的剪切强度高;接触面的体积变形在低法向应力下表现为先剪缩后剪胀,而在高法向应力下接触面则发生明显剪缩;在相同条件下,粗糙接触面的剪切强度和变形量(剪胀或剪缩)均比光滑接触面的高.
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