Scholarlink

<p>Elucidating the mechanical response and strength degradation mechanism of saw-tooth filled structural planes under cyclic shear loading is pivotal for accurately assessing long-term stability in rock mass engineering. Through cyclic shear tests with varying filling degrees (<i>κ</i>) and normal stresses (<i>σ</i>), combined with stress analysis of saw-tooth convex bodies to determine the transformation conditions of failure modes, this study establishes a logarithmic strength degradation accumulation model considering the coupling effect of normal stress and filling degree. The results indicate that the shear behavior of such structural planes shows significant cyclic number dependence and filling degree sensitivity. The curve of unfilled planes exhibits stage-wise behavior dominated by interface friction. For filled structural planes, due to the friction-fracture-debris sliding effect of the gypsum interlayer, a wide stable platform of shear stress forms during the 2 ~ 6 cycle stage. Higher filling degrees delay the yield-type steady-state response, and the filling medium transforms the failure mode from rigid convex body contact failure to interlayer-convex body composite failure, with mechanisms categorized as wear-sliding-gnawing failure, shear fracture failure, and tensile fracture failure. Each 0.5 increase in filling degree reduces peak shear strength by an average of 18.8%, and at <i>κ</i> = 1.5, the strength is 53% lower than at <i>κ</i> = 0. The initial cyclic strength degradation rate under high normal stress (2.4&#xa0;MPa) is 1.67 times that under low stress (0.6&#xa0;MPa), where convex bodies are prone to large-volume shear failure, with 60% of strength loss occurring in the first 3 cycles. After 8 ~ 10 cycles, peak and residual strengths converge. Based on multi-factor weight analysis, 0.836&#xa0;MPa is determined as the characteristic representative value of peak shear strength under comprehensive working conditions. The established model effectively predicts the strength degradation process of structural planes with gypsum and clayey sand, with strong agreement between predicted and measured values. It can effectively quantify the multi-factor coupling effect, providing theoretical support for the long-term stability evaluation of rock mass engineering.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Experimental Study on Cyclic Shear Behavior of Saw-Tooth Filled Structural Planes

  • 期刊论文

  • 发表日期：

    2026年2月21日

查看全文
  • Xu-tang Xu,
  • Zi-Long Dai,
  • Tong-Shu Wu,
  • Ye-qing Cai,
  • Xiang Xu,
  • Wen-bin Jian

摘要

Elucidating the mechanical response and strength degradation mechanism of saw-tooth filled structural planes under cyclic shear loading is pivotal for accurately assessing long-term stability in rock mass engineering. Through cyclic shear tests with varying filling degrees (κ) and normal stresses (σ), combined with stress analysis of saw-tooth convex bodies to determine the transformation conditions of failure modes, this study establishes a logarithmic strength degradation accumulation model considering the coupling effect of normal stress and filling degree. The results indicate that the shear behavior of such structural planes shows significant cyclic number dependence and filling degree sensitivity. The curve of unfilled planes exhibits stage-wise behavior dominated by interface friction. For filled structural planes, due to the friction-fracture-debris sliding effect of the gypsum interlayer, a wide stable platform of shear stress forms during the 2 ~ 6 cycle stage. Higher filling degrees delay the yield-type steady-state response, and the filling medium transforms the failure mode from rigid convex body contact failure to interlayer-convex body composite failure, with mechanisms categorized as wear-sliding-gnawing failure, shear fracture failure, and tensile fracture failure. Each 0.5 increase in filling degree reduces peak shear strength by an average of 18.8%, and at κ = 1.5, the strength is 53% lower than at κ = 0. The initial cyclic strength degradation rate under high normal stress (2.4 MPa) is 1.67 times that under low stress (0.6 MPa), where convex bodies are prone to large-volume shear failure, with 60% of strength loss occurring in the first 3 cycles. After 8 ~ 10 cycles, peak and residual strengths converge. Based on multi-factor weight analysis, 0.836 MPa is determined as the characteristic representative value of peak shear strength under comprehensive working conditions. The established model effectively predicts the strength degradation process of structural planes with gypsum and clayey sand, with strong agreement between predicted and measured values. It can effectively quantify the multi-factor coupling effect, providing theoretical support for the long-term stability evaluation of rock mass engineering.