岩土工程学报2026，Vol.48Issue(5)：1082-1091,10.DOI:10.11779/CJGE20250151
冻融循环作用下含裂隙砾岩力学特性及宏微观破坏机理
Mechanical properties and microstructure failure mechanism of conglomerate with prefabricated fissures under freeze-thaw cycles
摘要
Abstract
Freeze-thaw cycles are critical factors influencing rock landslides in high-altitude mountainous regions.In this study,rock samples from the Lagangcun landslide in a high-altitude area are collected to conduct triaxial unloading tests on fractured conglomerates subjected to varying freeze-thaw cycles.The mechanical properties,energy evolution,acoustic emission characteristics,and multi-scale structural features are systematically analyzed to elucidate the freeze-thaw degradation mechanism of conglomerate with prefabricated fissures.The results demonstrate that the peak strength of the samples progressively decreases with increasing freeze-thaw cycles.After 60 freeze-thaw cycles,compared to untreated samples,the peak strength of intact specimens under confining pressures of 10 MPa,20 MPa,and 30 MPa decreases by 44%,48%,and 70%,respectively.Under identical confining pressure and freeze-thaw cycles,samples with longer pre-existing fractures exhibit lower peak strength and greater susceptibility to failure.Both the absorbed and dissipated energies during rock failure decreased with freeze-thaw cycle,indicating that less energy is required to induce failure.As freeze-thaw cycles increase,the average acoustic emission energy per second diminishes,the number of rupture points declines,and the failure duration is shortened.The failure mode transitions from X-shaped shear failure to tensile-shear conjugate failure.At the macroscopic scale,the secondary cracks or fractures are closely associated with pre-existing fissures.Microscopic analysis reveals that crack propagation intensified with freeze-thaw cycles.Compared to untreated samples,4 cm pre-fractured specimens after 40 and 60 cycles show crack volume increases of 1.71%and 1.83%,respectively,with more pronounced cracking along pre-existing fractures,highlighting the exacerbated damage in fractured rocks.These findings clarify the strength degradation law of conglomerates under freeze-thaw conditions,providing critical insights for engineering construction and rock mass stability in alpine regions.关键词
冻融循环/力学特性/能量演化/声发射/劣化机理Key words
freeze-thaw cycles/mechanical properties/energy evolution/acoustic emission/deterioration mechanism分类
建筑与水利引用本文复制引用
黄婉滢,温韬,陈宁生..冻融循环作用下含裂隙砾岩力学特性及宏微观破坏机理[J].岩土工程学报,2026,48(5):1082-1091,10.基金项目
国家自然科学基金项目(42477174) （42477174）
西藏自治区科技项目(XZ202402ZD0001,XZ202502YD0003,XZ202301YD0034C) （XZ202402ZD0001,XZ202502YD0003,XZ202301YD0034C）
青海省基础研究计划项目(2024-ZJ-904)National Natural Science Foundation of China(Grant No.42477174) （2024-ZJ-904）
Science and technology program of Tibet Autonomous Region(Grant Nos.XZ202402ZD0001,XZ202502YD0003,XZ202301YD0034C) （Grant Nos.XZ202402ZD0001,XZ202502YD0003,XZ202301YD0034C）
Qinghai Province Basic Research Program Project(Grant No.2024-ZJ-904). （Grant No.2024-ZJ-904）
