循环冻融作用下非贯通结构面抗剪阻力劣化机理与演化规律研究

Freeze-thaw cycle dramatically decreases shear resistance of non-persistent joint, which is vastly related to stability of rock engineering in frigid area. To reveal deterioration mechanism and evolution law of shear resistance for non-persistent joint under freeze-thaw treatment. In the project, a number of laboratory tests including measurement of rock surface roughness, mechanical properties of rock and ice, shear test of rock-ice interface, and shear test and freeze-thaw cycle test of non-persistent joint are adopted to investigate the influence of rock surface roughness and frozen temperature on shear behavior of rock-ice interface, distribution rule and computing method of frozen-heaving force and effect of frozen temperature and freeze-thaw on shear strength of non-persistent joint and cracking mechanism of joint tip. On basis of laboratory results, the numerical simulation software, particle flow code, is adopted to establish direct shear model for rock-ice interface and non-persistent joint respectively, to model shear behavior of rock-ice interface with different persistence ratio under various frozen temperature and number of freeze-thaw cycles. According to obtained tested results and numerical results, using theoretical method to reveal shear resistance deterioration mechanism of non-persistent joint under freeze-thaw cycle, and a model for computing frozen-heaving force between joint surfaces is established, finally a model for predicting shear strength of non-persistent joint under freeze-thaw cycle effect is established, which is benefit to offer referee for rock engineering construction in frigid area.

循环冻融导致非贯通结构面剪切力学性质劣化，影响寒区岩体工程稳定性。为了揭示冻融作用下非贯通结构面剪切力学性质劣化机理与演化规律，本项目以岩石表面粗糙度测试、岩石与冰力学性质测试、岩-冰界面直剪试验、冻结非贯通结构面的循环冻融和直剪试验为基础，分别研究粗糙度和冻结温度对岩-冰界面剪切阻力的影响、非贯通结构面内冻胀力分布规律与计算方法、冻融下非贯通结构面开裂机理、冻结温度与循环冻融对非贯通结构面剪切阻力的影响。基于室内试验结果，运用颗粒流软件建立岩-冰界面直剪模型和非贯通结构面直剪模型，分别模拟不同冻结温度下岩-冰界面直剪力学行为，不同连通率和冻结温度下非贯通结构面直剪力学行为。在试验数据与数值模拟结果基础上，辅以理论分析，进而揭示冻融作用导致非贯通结构面力学性质劣化机理，尝试建立结构面内冻胀力计算模型，最终建立冻融作用下非贯通结构面长期抗剪强度预测模型，为寒区相关工程建设提供参考。

本项目通过室内试验研究、理论研究、数值分析等方法，研究了非贯通节理岩体在冻融循环条件下的冻胀力分布演化规律，以及节理岩体冻融损伤破坏机理，并通过直剪试验进一步深入研究了冻融条件下节理岩样的剪切力学性质，以研究非贯通节理岩体的抗剪影响因素为基础，进而扩展至冻融循环对非贯通节理岩体剪切力学性质作用规律，最终针对冻融循环作用下非贯通节理岩体的抗剪公式进行了理论研究和适用性验证。项目从2018年1月开始实施，按照原制定的年度研究计划开展相关研究，每年均提交了年度进展情况报告，最终按照计划完成了研究任务。 通过4年的研究，项目已完成原定的目标。通过及时总结和发表高质量的学术论文，共发表学术期刊论文18篇，被SCI收录18篇，ESI高被引论文3篇。授权国家发明专利5项。培养6名硕士研究生，1名博士研究生。