极端温差区裂隙岩体边坡劣化损伤机理与安全控制

Under the coupling of temperature stress and frost-heave stress, the basic mechanical properties of the slope rockmass in extreme temperature difference region (hereinafter ETDR) deteriorate continuously, and the geological disasters such as collapse, landslide show a tendency of frequent occurrence. Taking the slope with fractured rockmass in the ETDR as the research object, the mechanism of freezing and thawing damage and the mechanism of slope stability degradation are studied systematically, based on on-site geological survey, rock mechanics parameter tests, geomechanical model tests, 3D printing technology, and numerical simulation and analysis, etc. And the mechanism of hydrothermal migration and crack propagation of fractured rockmass under extreme temperature difference environment are explored. The feedback mechanism based on temperature fatigue effect in surface and deep slope is revealed. An early warning method and safety control technology for identification and prediction of fractured rock slope disasters under extreme temperature difference environment are presented. The results can provide technical support for geotechnical engineering construction and disaster prevention and mitigation, and it can show great theoretical and engineering significance for slope stability evaluation and early warning in ETDR.

极端温差区边坡岩体在在温度应力与冻胀应力耦合作用下，基本力学性质不断劣化，崩塌、滑坡等地质灾害呈多发趋势。本项目拟以极端温差区裂隙岩体边坡为研究对象，基于现场地质调查、岩石力学参数测试、地质力学模型试验、3D打印技术、数值模拟分析相结合等手段，对边坡裂隙岩体冻融损伤机理及边坡稳定性退化机理开展系统研究。探索极端温差环境下裂隙岩体水热迁移机理与裂纹扩展规律研究，揭示坡体表层及深部基于温度疲劳效应的反馈机制，提出极端温差环境下裂隙岩质边坡灾害辨识预警方法及安全控制技术。项目成果可为寒区的岩土工程建设及防灾减灾提供技术支撑，对寒区边坡稳定性评价与预警具有重要的理论与工程意义。

我国在冻土地区的建设工程日益增多，部分冻土地区不仅昼夜温差大而且不同季节的气温温差悬殊，存在明显的极端温差。周期性冻融作用致使边坡岩体逐渐崩解、开裂，崩塌滑坡等地质灾害频发，对极端温差区边坡岩体劣化损伤机理与安全控制技术开展研究尤为迫切。.本项目以极端温差区工程岩体为研究对象，基于现场地质调查、岩石力学参数测试、地质力学模型试验、数值模拟等手段，对裂隙岩体冻融损伤劣化机理、冻融边坡的稳定性退化机理及边坡防护技术进行了研究。基于室内岩石力学试验，揭示了极端温差环境下完整岩石温差疲劳效应与裂纹扩展规律，对其非线性剪胀变形、劣化过程的宏细观损伤演化规律进行了系统研究；探究了裂隙岩体损伤劣化模式及冰~水~岩界面力学反馈机制，提出了含裂隙岩石的宏细观损伤模型并进行验证。基于含单裂隙岩体的冻融劣化试验及冻融裂隙边坡的稳定性退化模型试验，阐明极端温差条件下裂隙岩质边坡稳定性退化机理，分析了不同冻融循环阶段边坡岩体温度场、变形场、冻胀力、宏观变形等特征。基于数值模拟分析手段，探究了裂纹扩展规律和冻结率对边坡劣化的影响，研究了冻胀力作用下边坡结构面贯通及失稳过程。选择聚丙烯腈纤维混凝土及聚丙烯腈纤维内掺钢纤维混凝土为岩体冻融防护喷层材料，构建了极端温差条件下裂隙岩质边坡防冻技术。.项目成果可为寒区岩土工程建设及防灾减灾提供技术支撑，对寒区边坡稳定性评价与预警具有重要的理论与工程价值。