危岩破坏突变机制与激振效应研究

Perilous rock avalanche is an important subject carrier for the applied mechanics, especially the environmental disaster mechanics. In allusion to the scientific issue, the mutation mechanism of perilous rock rupture and the excitation effect, adopting some research methods, such as the fracture mechanics, mutation theory, elastic dynamics, conformal transformation theory and model experiment, etc. to study on the stress field at the end region of dominant fissure, the elastic strain energy of perilous rock mass, the mutation mechanism of perilous rock and the excitation effect of perilous rock avalanche, etc. In terms of the dominant fissure of perilous rock, with the solutions of two pivotal issues, the calculation method for the fracture stress intensity factors in the dominant fissure of perilous rock and the propagation mechanism for the excitation wave of perilous rock avalanche in slope rock mass of the group incident perilous rock development. It reveals the elastic stress field in the end region of dominant fissure; it quantizes the relationship between the fracture stress intensity factors and the length of linking patch in the dominant fissure; it constructs the mutation model of perilous rock rupture; it proposes the calculation methods for the set-out violent-slide acceleration and velocity of perilous rock mass, excitation energy and excitation stress produced by perilous rock avalanche; and it depicts the incidence and influence degree for the excitation of perilous rock avalanche in the group incident perilous rock region. Research results possesses positive significance in enriching the discipline connotation of applied mechanics, advancing the research of its application in the disaster reduction of perilous rock avalanche and improving the disaster prevention level of perilous rock avalanche.

危岩崩塌是应用力学尤其是环境灾害力学的一个重要学科载体。本项目针对危岩破坏突变机制与激振效应这一科学问题，采用断裂力学、突变理论、弹性动力学、保角变换理论和模型试验等研究方法，对危岩主控结构面端部应力场、危岩体弹性应变能、危岩破坏突变机制、危岩崩塌激振效应等方面进行研究。着眼于危岩主控结构面，通过对"危岩主控结构面断裂应力强度因子计算方法"和"危岩崩塌激振波在群发性危岩发育的边坡岩体内的传播机理"两个关键问题的解决，揭示危岩主控结构面端部的弹性渐进场，量化主控结构面断裂应力强度因子与主控结构面贯通段长度之间的关系，构建危岩破坏突变模型，提出危岩体剧动启程加速度和启程速度、危岩崩塌产生的激振能量和激振应力的计算方法，有效刻画群发性危岩区域内危岩崩塌激振影响范围及影响程度。研究成果对于丰富应用力学的学科内涵、推进其在危岩崩塌灾害减灾中的应用研究、提高危岩崩塌灾害防治水平具有积极意义。

危岩崩塌灾害是一种全球性泛生型地质灾害，其在边坡表面存在部位有隐蔽性、失稳破坏有突变性、致灾后果由灾难性，国内外学者对危岩破坏机制认识尚不清晰，危岩崩塌减灾亟待大量基础理论支撑。边坡表面的危岩几乎都不是单独存在，而是由多个危岩体组成的已聚集体，其破坏易造成群发性灾害。危岩聚集体中某一危岩体失稳瞬间必然快速释放应变能，产生激振效应，引发周围危岩体链式失稳，本项目重点对危岩突变失稳机理及其产生的激振效应进行研究，属于实施危岩群发性崩塌灾害研究的重要基础理论研究环节。.采用振动力学、断裂力学、突变理论、信号处理、模型试验等研究方法和手段，开展了危岩聚集体破坏振动方程、危岩突变断裂破坏、危岩断裂稳定性、地下工程建设对危岩的动效应等理论研究，进行危岩破坏激振效应模型试验，依据试验结果分析危岩破坏激振信号的概率统计特征、局部信息和细节信息特征、频域特征。项目研究发表论文24篇（EI收录12篇），出版学术专著1部，授权发明专利4项、实用新型专利3项，科学解译了诱发危岩崩塌灾害的动力学机制，完成了拟定的研究目标。以本项目成果为理论核心，获得两项标志性成果，一是“陡高边坡危岩崩塌断裂演化机制与减灾关键技术”，二是“山区公路城镇危岩崩塌灾害及工程高切坡减灾理论与技术”，均达到国际领先水平。.研究成果显著提升了对产生危岩崩塌灾害的科学认知水平，危岩崩塌灾害勘察精度得到显著提高，在危岩崩塌灾害工程勘察和灾害治理方面有广阔应用前景。