粗糙度对接触面处土石混合体剪切特性的影响

对于土与结构接触面相互作用的研究基本上是对于一般粘土或者砂土,而对于土石混合体结构接触面的相互作用研究较少。利用德国研制的ADS-500/HL-200大型直剪试验仪探究接触面粗糙度对土石混合体与结构接触面力学特性的影响以及在特定粗糙度下,通过下移结构面法探究剪切带的特性。试验结果表明:随着接触面粗糙度的增大,接触面的内摩擦角略有增大,粘聚力不断增大;在不同的粗糙度下,法向压力从200 kPa增加到600 kPa,剪切过程中的竖向位移逐渐减小,但当法向压力从600 kPa增大到800 kPa时,土石混合体在剪切过程中的竖向位移增大;在法向压力为200 kPa、400 kPa、600 kPa时,土石混合体的剪切带厚度为L₁cm(6 cm≤L₁≤8 cm),在法向压力为800 kPa下,土石混合体的剪切带厚度为L₂ cm(4 cm≤L₂≤6 cm)。

Effect of Roughness on Shear Behavior of Interface between Soil-rock Mixture and Structure

The research on the interaction between soil and structure contact surface is mainly about general clay or sandy soil, but the research on the interaction between soil and rock mixture structure contact surface is less. The ADS-500/hl-200 large direct shear tester developed in Germany was used to investigate the influence of contact surface roughness on the mechanical characteristics of contact surface between soil-rock mixture and structure, and the characteristics of shear zone were investigated by means of the method of moving structural surface downward under specific roughness.The results show that with the increase of roughness of the contact surface, the internal friction Angle of the contact surface increases slightly and the cohesive force increases continuously. When the normal pressure increases from 200 kPa to 600 kPa with different roughness, the vertical displacement in the shear process gradually decreases, but when the normal pressure increases from 600 kPa to 800 kPa, the vertical displacement of soil-rock mixture in the shear process increases. Under the normal pressure of 200 kPa, 400 kPa and 600 kPa, the shear zone thickness of soil-rock mixture is L₁cm(6 cm≤L₁≤8 cm), and under the normal pressure of 800 kPa, the shear zone thickness of soil-rock mixture is L₂cm(4 cm≤L₂≤6 cm).