基于粗糙度特征和强度特性的砂浆-岩石界面剪切破坏机理研究

Two mediums contact interface, that widely exists in rock engineering and of which the shear strength is usually quite small, is significant to the safety of rock engineering. To reveal the shear failure mechanism of contact interface considering roughness and materials strength, uniaxial compressive tests, Brazilian tests, direct shear tests, morphology measurement of interface and adhesion stress tests are about to be employed in the process of investigation. Mortar-rock interface, a common contact interface in rock engineering, are about to be investigated using a combination method of laboratory tests, numerical simulations and theoretical analysis as follows: (a) the relations between rough parameters, mortar strength and adhesion stress of contact interface; (b) the influence of mortar strength on the failure modes of interface asperities; (c) the influence of mortar strength and rough characteristics on shear behaviors of mortar-rock interface. Based on experimental results, 3D direct shear models with different rough interfaces or mortar strengths for mortar-rock interfaces are established in particle flow code, the shear behaviors of different rough interface and various material strengths mortar interfaces are mainly simulated, and then the failure mechanism of interface asperities are denoted and a 3D parameter is proposed to represent the evolution of interface roughness under shear loadings. Finally, a new shear criterion for mortar-rock interface controlled by multi-factors including surface roughness, material strength and adhesion stress, is established, and the reliability and application scope of the proposed shear criterion predicting the shear strength of mortar-rock interface is also analyzed. The shear criterion for mortar-rock interface can be referred in relevant rock engineering design.

广泛存在于岩体工程中的二元介质接触界面因其抗剪力学性质较差，对岩体工程的安全具有重要影响。为了揭示考虑粗糙度和材料强度的接触界面剪切破坏机理，本项目以单轴压缩测试、巴西劈裂测试、直剪试验、界面粗糙度测试及粘结力测试为基础，针对岩体工程中常见的砂浆-岩石界面，运用室内试验、数值模拟和理论分析相结合的方法，分别研究粗糙度参数和砂浆强度与界面粘结力的相关性、砂浆强度对界面粗糙体破坏方式的影响、砂浆强度和粗糙特征对砂浆-岩石界面剪切力学行为的影响。基于室内试验数据，以PFC3D建立不同粗糙度和不同材料强度的砂浆-岩石界面三维直剪模型，重点模拟不同粗糙度界面、不同砂浆强度的界面剪切力学行为，进而揭示界面粗糙体破坏的力学机理和确定表征界面粗糙度特征演化的三维参数，最终建立多重因素影响下的砂浆-岩石界面剪切强度准则，并分析该剪切强度准则的适用条件及其预测剪切强度的可靠性，为相关工程设计提供参考。

岩土工程中广泛存在两种材料相互接触问题，对水泥砂浆-岩石界面形貌特征和剪切力学性质的研究，可借鉴岩石节理表面形貌特征和剪切力学性质的研究方法和试验设备。本项目试验与理论相结合的方法研究界面粗糙度与界面粘结力的相关性，建立与界面法向粘结力具有最大相关性的三维表征参数，还研究砂浆体材料强度对界面剪切力学性质的控制作用，砂浆与岩石抗压强度差异对剪切荷载作用下界面粗糙体演化的差异，进而从数值模拟角度重复与补充室内砂浆-岩石界面剪切试验，验证剪切试验与界面粗糙度和材料强度的变化关系。项目从2015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9篇，EI收录4篇。培养6名硕士研究生（毕业5名，在读1名），1名博士研究生（在读）。指导研究生获得湖南省优秀硕士学位论文1篇。