高寒冻融区岩质边坡加速破坏机理及时效评价

Aiming at the aging damage and induced disasters of rocky slope after the action of freeze-thaw cycle in Alpine area, this project make “timeliness” of accelerated failure for rocky slope under the action of freeze-thaw cycle as the research object. At first, revealing the differences of rock timeliness damage mechanism under different cycles, different temperature and different moisture content conditions by macroscopic and microscopic multi-scale tests, including complete rock rheological test after different freeze-thaw cycle times, fractured rock rheological test under the conditions of different humidity and temperature, acoustic emission monitoring and microscopic scanning electron microscopy.. On this basis, timeliness mechanical model that can reasonably describe cycle damage under the action of temperature will be put forward through rigorous mechanics theory(Cyclical-damage rheological mechanics model). it can establish fracture degradation simulation method, and timeliness dynamic stability evaluation method for Alpine slope, which can evaluation progressive spalling failure and depth effect of rocky slope. . Finally, the above theory will be verified and improved on the background of high-steep rock slope along the Sichuan-Tibet railway. The reveal of accelerated failure mechanism of rock slope under the action of freeze-thaw cycle and the establishment of the timeliness evaluation method could provide fundamental theory basis for slope hazard prediction and key project life cycle assessment in the cold highland area.

针对高寒山区岩质边坡在冻融后的时效破坏及诱发灾害问题，本项目以周期冻融作用下岩质边坡加速破坏的“时效性”为研究对象，首先通过不同冻融次数、不同湿度和不同温差条件下岩石流变试验、声发射监测和电镜微观扫描等宏细观多尺度测试，获得冻融循环作用后岩石劣化损伤的时效性，针对性地获得不同循环次数、不同温差和不同含水率条件下岩石时效性破坏的差异规律，揭示冻融循环作用后岩石蠕变损伤特性和加速破坏机制。在此基础上，提出合理描述温度周期损伤作用下时效性力学模型（周期性-损伤流变力学模型），建立时效性动态稳定性评价方法，评价冻融作用后边坡的长期稳定性，以及坡表渐进剥落破坏的时效性和深度效应。最后，以川藏铁路沿线岩质高边坡为背景，通过现场观测验证和完善上述理论。冻融循环作用下岩质边坡加速破坏机制的揭示和时效评价方法的建立可为高寒山区边坡灾害预测、重大工程寿命评估提供基础性理论依据。

高寒区边坡冻融时效与长期稳定性的研究是当前亟待解决的前瞻性研究课题。通过开展常规三轴与三轴蠕变试验、共面断续岩桥直剪试验以及冻融循环、常规单轴与声发射试验，揭示冻融作用下岩石蠕变损伤特性，不同岩性裂隙岩石冻融损伤破坏机制，并建立了冻融循环损伤流变模型和边坡时效稳定性评价方法。研究成果能应用于高寒山区岩质边坡工程稳定性分析和工程寿命预警，提高我国寒区边坡工程稳定性预测水平。.本项目发表SCI论文11篇，EI论文13篇，中文核心期刊7篇，授权相关专利3项，申请软件登记2项，省部级一等奖1项。研究成果应用于川藏线选线工程，解决了岩体变形预警、潜在滑动面识别等一系列重大工程技术难题。本项目的成果对于高海拔地区岩质滑坡灾害的预测预警研究具有重要的科学意义，也能服务和应用于我国西南地区重大地质灾害预报工作。