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<p>Aiming at the instability problem of engineering structures caused by the water absorption and softening of bentonite, the influence mechanism of water content on mechanical behavior and the preparation optimization parameters have been revealed through specimen characterization, scanning electron microscopy, laboratory tests, and DEM simulation. Innovatively, methods for determining the stress–strain threshold based on the resistance curve and the dominant crack based on digital image correlation have been proposed, solving the subjectivity problems of traditional stage division and crack discrimination. The results show that a water–cement ratio of 30% and a drying temperature of 40&#xa0;°C are optimal preparation parameters. As the water content increases , the compressive strength non-linearly decreases from 2.0&#xa0;MPa to 0.2&#xa0;MPa, and the failure mode transitions from brittle fracture (peak strain = 2%) to brittle-creep composite failure (peak strain = 2.4–3.4%), and finally shows complete softening and local shear instability (peak strain &gt; 5%). DEM simulation shows that, with low water content (0–5.9%), the sudden expansion of cracks is accompanied by the concentration of vertical force chains, while, for specimens with high water content, the horizontal contact force chains decrease sharply, showing the characteristics of softening and flow. The research results have reference value for the stability evaluation and water content regulation of bentonite engineering.</p>

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Failure Characteristics and Mechanical Evolution Laws of Bentonite Under Different Moisture Contents

  • 期刊论文

  • 发表日期：

    2025年5月29日

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  • Yi Wang,
  • Xiangrui Meng,
  • Guangming Zhao,
  • Yingming Li,
  • Mingyuan Yang

摘要

Aiming at the instability problem of engineering structures caused by the water absorption and softening of bentonite, the influence mechanism of water content on mechanical behavior and the preparation optimization parameters have been revealed through specimen characterization, scanning electron microscopy, laboratory tests, and DEM simulation. Innovatively, methods for determining the stress–strain threshold based on the resistance curve and the dominant crack based on digital image correlation have been proposed, solving the subjectivity problems of traditional stage division and crack discrimination. The results show that a water–cement ratio of 30% and a drying temperature of 40 °C are optimal preparation parameters. As the water content increases , the compressive strength non-linearly decreases from 2.0 MPa to 0.2 MPa, and the failure mode transitions from brittle fracture (peak strain = 2%) to brittle-creep composite failure (peak strain = 2.4–3.4%), and finally shows complete softening and local shear instability (peak strain > 5%). DEM simulation shows that, with low water content (0–5.9%), the sudden expansion of cracks is accompanied by the concentration of vertical force chains, while, for specimens with high water content, the horizontal contact force chains decrease sharply, showing the characteristics of softening and flow. The research results have reference value for the stability evaluation and water content regulation of bentonite engineering.