灰岩地区危岩座滑破坏与解体机制研究

The limestone area is about a quarter of total land area in China, in the area, the unstable rock blocks and collapse is severe, which basically rests at a backward situation of analyzing the hazard of unstable rock blocks and collapse by using the research results in sandstone areas. This project aime at the failure mechanism and disintegration mechanism of 60% to 70% unstable rock blocks under the sinking-sliding failure pattern in limestone areas, it adopt research methods, indoor model test, rock mechanics, fracture mechanics, energy equilibrium theory, mutation theory and numerical simulation etc., to investigate on the geological model of unstable rock blocks, sinking-sliding failure mechanism and disintegration mechanism of unstable rock blocks and other aspects. According to the character of quasi-masonry structure for the unstable rock blocks in limestone areas and based on the solution of two key problems, to scientifically construct the geological model and the fracture mechanics model of quasi-masonry structure for the unstable rock blocks in limestone areas, it establish geological model and mechanics model of the unstable rock blocks in limestone areas; it built mutation model of the unstable rock blocks failure by adopting energy calculation and it obtains formulas to calculate elastic-impulsive velocity and elastic-impulsive acceleration of the unstable rock blocks failure. Hereby, it reveales the sinking-sliding failure mechanism of unstable rock blocks; it quantify the tension-shear disintegration mechanism at the top of quasi-masonry structure and the pressure-shear disintegration mechanism at the bottom of quasi-masonry structure and it proposes the practical discrimination standard of unstable rock blocks disintegration in limestone areas. Research results provide positive significance for accelerating the theory study of unstable rock blocks and collapse in limestone areas and for forecasting the hazard of unstable rock blocks and collapse scientifically.

我国灰岩地区占国土总面积四分之一左右，区内危岩崩塌灾情严重，基本停留在采用砂岩地区的研究成果分析灰岩地区危岩崩塌灾情的落后局面。本项目针对灰岩地区占60～70%的座滑破坏模式危岩的破坏与解体机制这一科学问题，采用室内模型试验、岩石力学、断裂力学、功能平衡原理、突变理论、数值模拟等研究方法，对危岩地质模型、危岩座滑破坏机制、危岩解体机制等方面进行研究。着眼于灰岩地区危岩类砌体结构特征，通过对"科学构建灰岩地区危岩类砌体结构地质模型"和"科学构建危岩类砌体结构断裂力学模型"两个关键问题的解决，构建灰岩地区危岩地质模型和力学模型，基于能量计算构建危岩破坏突变模型，获得危岩破坏弹冲加速度和弹冲速度计算式，据此揭示危岩座滑破坏机制，量化类砌体结构顶部拉剪解体机制和类砌体结构底部压剪解体机制，提出灰岩地区危岩解体实用判别标准。研究成果对于推动灰岩地区危岩崩塌理论研究、科学预测危岩崩塌灾情具有积极意义。

我国灰岩地区占国土总面积四分之一左右，区内危岩崩塌灾情严重，本项目针对灰岩地区危岩具有类砌体结构特征的破坏与解体机制这一科学问题，通过有限元数值模拟分析危岩体顶部拉剪区域随危岩悬高比、高宽比及倾斜角度的变化规律及危岩体底部拉剪区域随危岩高宽比和倾斜角度的变化规律，构建了其断裂分析模型，获得了其危岩解体判据；依托类砌体型危岩体系统能量方程，构建了危岩体解体的判据，以望霞W2危岩为例，预测该危岩体偏转到倾角为34°时可能发生解体，解释了类砌体型危岩座滑过程中断裂解体的突发性特征；通过突变理论获得了危岩体突发性失稳瞬间弹性能转换为危岩体动能的表达式、破坏时剧动速度及弹冲加速度表达式。通过室内小尺度模型试验分析了不同高宽比、倾角及粘结方式下类砌体型危岩解体特性。通过室内试验探讨了含结构面的岩石压剪破坏规律及含软弱基座危岩体的破坏机制研究；建立了复杂缓倾角的岩体边坡层间荷载和稳定系数的计算方法；对压剪滑动型危岩失稳的机制进行了研究；通过数值模拟探讨危岩软弱基座采空区对危岩稳定性的影响。其研究成果对于推动灰岩地区危岩崩塌理论研究、科学预测危岩崩塌灾情具有积极意义。