Scholarlink

<p>Bentonite is widely regarded as a primary buffer/backfill material for engineered barrier systems in high-level radioactive waste repositories. However, desiccation-induced shrinkage and cracking can significantly compromise the integrity and safety of these barriers. Shrinkage tests integrated with Micro-CT scanning and 3D reconstruction were conducted on compacted bentonite to quantitatively analyze the evolution of cracking networks. The results reveal persistent shrinkage anisotropy, with the final axial shrinkage strain (13.64%) being notably higher than the radial strain (12.37%). CT analysis identifies three distinct stages of crack evolution: matrix shrinkage, rapid propagation, and stabilization. As desiccation proceeds, internal cracks transition from isolated micro-cracks into a highly connected network. The total cracking ratio increases from 1.55 to 3.44%, with connected cracks accounting for over 85% of the total crack volume, emphasizing that connectivity is the primary factor governing structural degradation. Fractal dimensions exhibit a logarithmic increase over time, reflecting growing geometric complexity. To address the overestimation of skeletal shrinkage in traditional soil shrinkage curves (SSC), a corrected model incorporating internal crack volume is proposed. The correction leads to a 1.14% reduction in the shrinkage limit (from 13.49 to 12.35%). The improved model provides a more accurate shrinkage deformation for bentonite across a wide range of water contents, which is essential for the long-term safety assessment of geological repositories.</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

Correction of soil shrinkage curve for compacted bentonite considering desiccation crack volume: a CT-based fractal analysis

  • 期刊论文

  • 发表日期：

    2026年7月27日

查看全文
  • Geng Niu,
  • Chunyuan Zhou,
  • You Gao,
  • Xiao Han,
  • Pengpeng Wang,
  • Tiande Wen

摘要

Bentonite is widely regarded as a primary buffer/backfill material for engineered barrier systems in high-level radioactive waste repositories. However, desiccation-induced shrinkage and cracking can significantly compromise the integrity and safety of these barriers. Shrinkage tests integrated with Micro-CT scanning and 3D reconstruction were conducted on compacted bentonite to quantitatively analyze the evolution of cracking networks. The results reveal persistent shrinkage anisotropy, with the final axial shrinkage strain (13.64%) being notably higher than the radial strain (12.37%). CT analysis identifies three distinct stages of crack evolution: matrix shrinkage, rapid propagation, and stabilization. As desiccation proceeds, internal cracks transition from isolated micro-cracks into a highly connected network. The total cracking ratio increases from 1.55 to 3.44%, with connected cracks accounting for over 85% of the total crack volume, emphasizing that connectivity is the primary factor governing structural degradation. Fractal dimensions exhibit a logarithmic increase over time, reflecting growing geometric complexity. To address the overestimation of skeletal shrinkage in traditional soil shrinkage curves (SSC), a corrected model incorporating internal crack volume is proposed. The correction leads to a 1.14% reduction in the shrinkage limit (from 13.49 to 12.35%). The improved model provides a more accurate shrinkage deformation for bentonite across a wide range of water contents, which is essential for the long-term safety assessment of geological repositories.