【作者】 唐红梅；

【导师】 鲜学福；

【作者基本信息】 重庆大学 ， 安全技术及工程， 2011， 博士

【摘要】 危岩崩塌是一种全球性泛生型山地灾害,是我国矿山生产、山区公路、水运交通、山地城镇的重大地质安全隐患,每年造成直接经济损失超过20亿元。如2009年6月5日重庆市武隆县鸡尾山发生特大型山体崩塌,80余人遇难;2009年7月25日四川省汶川县国道213线都江堰至汶川高速公路44km+200彻底关大桥处发生山体崩塌,落石砸断桥墩,桥面坍塌,2辆货车坠入岷江,死亡6人,经济损失1亿元左右。显然,着眼于单体危岩系统实施群发性崩塌灾害的形成机制及减灾技术研究,是矿业、交通、城建减灾的国家需求,也是安全与减灾学科发展的逻辑需求。本文采用现场调查、模型试验、数值模拟、地貌学、断裂力学、运动学、波动理论、传感技术等研究方法,对危岩崩塌演化规律、危岩稳定性、群发性崩塌激振效应、崩塌落石运动路径、群发性崩塌运动力学机制及应急减灾与安全警报技术等科学问题进行深入系统研究,取得的主要研究性成果如下:(1)针对三峡库区大范围砂岩或灰岩与泥岩软硬相间的岩石边坡,揭示了岩腔的形成机制,包括差异风化机制和压裂风化机制;提出了缓倾角岩质边坡危岩崩塌的宏观链和微观链概念,据此揭示了危岩群发性崩塌的链式演绎规律,可分为简单模式和复合嵌套模式两类。(2)基于极限平衡原理,从作用在危岩体上的荷载类型及荷载组合、稳定性评价标准、不同类型危岩等方面系科学修正了危岩稳定性分析方法;着眼于危岩主控结构面断裂扩展是危岩破坏本质这一的科学认识,采用断裂力学构建了危岩断裂稳定性分析方法,该方法可以连续表征危岩体的实时稳定性,是实施突发性崩塌灾害应急安全警报的科学依据。(3)分析了陡崖上危岩块之间的相互作用力学关系,基于损伤和断裂力学探讨了群发性危岩块崩落序列,验证了危岩链式规律;构建了危岩块崩落产生的激振效应对相邻危岩块的动力振动力学方程,通过实验验证了危岩崩落激振效应,理论计算值与试验值基本趋于一致。建立的动力激振方程符合客观实际.(4)基于下垫面岩土介质动力恢复系数试验,通过建立的最大冲击力公式反演碎石土垫层的法向恢复系数,介于0.258-0.314之间,符合客观实际;将崩塌落石的运动阶段划分为自由坠落、初始碰撞、空中飞行和后继碰撞等形式,建立了不同运动形式下落石运动速度及运动距离的计算方法,提出了落石运动形式判别标准,并通过现场试验及数值模拟予以验证。(5)推导了群发性崩塌体底部空气压缩方程,通过崩塌体空气压缩特性试验,初步获得了崩塌体底部空气外泄系数与崩塌体速度之间的关系曲线,通过空气压缩试验得到了不同高度、不同孔隙比下的气垫作用的气垫荷载和外泄系数及临界外泄系数,成果对于深入开展群发性崩塌体运动过程研究有重要的积极意义。(6)针对危岩突发性崩塌灾害应急减灾需求,研发了危岩应急锚固、应变型钻孔应力传感器、压电型钻孔应力传感器、落石消能棚洞及崩塌灾害安全警报系统等新技术及专用设备,为崩塌灾害应急安全警报及防灾避灾提供了技术保障。将前述主要研究成果浓缩为4个创新点:(1)基于三峡库区危岩崩塌链式演化规律和危岩块之间的力学关系,运用断裂力学和等效弯矩作用产生的应力强度因子、等效应力强度因子等构建了危岩崩落的时间方程,揭示了软弱基座陡崖上危岩的崩落序列。(2)针对坠落式危岩,建立了危岩崩落的激振模型,基于断裂力学和波动理论构建了激振效应下的断裂联合应力强度因子方程,基于能量构建了危岩崩落瞬间启程速度、质点位移速度、激振波强度的计算方法,系统揭示了危岩崩落激振效应。(3)通过试验揭示了碎石土垫层的法向恢复系数介于0.258-0.314之间,将崩塌落石的运动阶段划分为自由坠落、初始碰撞、空中飞行和后继碰撞等形式,据此提出了落石运动路径计算新方法。(4)针对危岩突发性崩塌灾害防治需求,研发了危岩应急锚固、应变型钻孔应力传感器、压电型钻孔应力传感器、落石消能棚洞及崩塌灾害安全警报系统等新技术及专用设备。更多还原

【Abstract】 Perilous rock is a global and widely generated geologic hazard, which has a great geological hidden danger for the safety on mining product, mountainous highway, shipping traffic and mountainous towns. The direct economic loss exceeds two billion Yuan per year. For instance, on 5th, June, 2009, in Wulong County, Chongqing City, Jiwei Mountain had a oversized collapse, it caused over 80 dead. On 25th, July, 2009, on the Chediguan Bridge, position 44km+200, the highway from Dujiangyan to Wenchuan in G213, Wenchuan County, Sichuan Province, it arose mountainous landslip, and the rockfall broke the bridge pier, collapsed the bridge deck, caused 2 trucks fell into Min River, 6 dead and about one hundred million Yuan economic loss. Obviously, to take research on the formation mechanism and disaster reduction technology of massive collapse by single rockfall system is the national demand for the disaster reduction of mining, traffic and urban construction and the logical demand for the development of safety and disaster mitigation science.This paper adopts some research methods, such as, field survey, model experiment, numerical simulation, geomorphology, fracture mechanics, kinematics, wave theory, sensor technology, etc., to process some scientific problems on perilous rock systematically, for example, evolutional rules of rock avalanche, stability of perilous rock, ringing effect of massive collapse, movement routes of landslip rocks, mechanism of movement mechanics on massive collapse, technology on the emergency response, disaster mitigation and safety alarm, etc. The main innovative achievements are as follows:(1) According to the large-scale rock slope in the syncline structural zone within soft-hard interphase sandstone (limestone) and mudstone around Three Gorges Reservoir area, it reveals the developing mechanism of rock cavity, including difference weathering mechanism and fracturing weathering mechanism. It proposes concepts of macroscopic chain and microcosmic chain about landslip in rock slope with gentle inclined angle. Based on that, it posts the chained evolution rule of massive collapse, and divides the rules into two types, simple model and composite nested model.(2) It constructs the stability analysis method of perilous rock systematically, with the limit equilibrium theory, load types and combination on rock mass, stability evaluation standard and calculating methods on the coefficient of stability for different perilous rocks, etc. To focus on the fracture propagation at the dominant structural plane of perilous rock, is a scientific cognition for the essence of perilous rock failure. This article adopts the fracture mechanics to build stability analysis method of perilous rock’s fracture, this method can reflect the online stability of perilous rock mass continuously, and it is the scientific basis for the emergency safety alarm of abrupt collapse hazard.(3) It analyzes the interactional mechanics relationship among perilous rock masses on the cliff, it discusses the rock avalanche sequence of packets collapse by damaage and fracture mechanics and it tests and verifies chained regular of perilous rock ,and it constructs the mechanics equations for dynamic vibrating on the ringing effect of perilous rock avalanche to the adjacent rock mass. It confirms ringing effect of perilous rock Landslip through the experiments, for that, the theoretical calculation is basically consistent with the experimental value, and the established dynamic vibrating formula accords with the objective reality.(4) Based on the dynamic recovery coefficient test on the lower cushion geotechnical medium, through the established maximal impact force formula to inverse the normal recovery coefficient of gravel cushion. The coefficient value lies between 0.258~0.314 and it accords with the objective reality. This paper divides the movement of landslip into four steps, free fall, initial collision, in-flight state and subsequent collision. It establishes calculating methods of the rock masses’motional velocity and distance under different motional forms. It proposes the discrimination standard of rockfall motional forms. And it confirms those conclusions by field experiments and numerical simulation.(5) This paper deduces the air compression equations for the bottom air of massive collapse. Through the air compression characteristic test of landslip rock mass, it primarily obtains the relation curve between air leakage coefficient at the bottom of collapse and the speed of collapse, and by the model of air compression experiment, it gains load of air cushion, air leakage coefficient and critical leakage coefficient at different height and different pore ratio. The production takes important positive significance for the further study on the movement process of packets collapse.(6) To aim at the emergency and hazard mitigation demand for the abrupt rock avalanche hazards of perilous rock, it develops a series of new technology and special equipment, such as, jury anchorage for perilous rock, borehole stress sensor of strain-type, borehole stress sensor of piezoelectric-type, energy dissipation shed-hole of rockfall and the safety alarm system, etc. It provides technical support for the emergency safety alarm and prevention of collapse hazard.To condense the above main research production into 4 innovations:(1) According to the mechanical relationship between the chained evolution rule of landslip and perilous rock mass in Three Gorges Reservoir area, this thesis adopts fracture mechanics, the produced stress intensity factors and equivalent stress intensity factors by the effect of equivalent bending moment, etc. to construct the time equation about the rockfall of perilous rock. And it reveals the collapse sequence of perilous rock on the cliff with soft base.(2) To take falling perilous rock as an aim, it establishes the vibrating model of rock avalanche. Based on fracture mechanics and wave theory, it constructs the formula of stress intensity factors under ringing effect. According to the collapse energy, it builds the calculating methods of transient departure speed, particle displacement speed and vibrating wave intensity for landslip. And it reveals the ringing effect of perilous rock systematically.(3) Through experiments, this thesis reveals that the normal recovery coefficient value of gravel cushion lies between 0.258~0.314, and it divides the movement of landslip into free fall, initial collision, in-light state and subsequent collision forms. Hereby, it puts forward some new calculating methods for the movement route of rockfall.(4) To aim at the prevention demand for the abrupt rock avalanche hazards of perilous rock, it develops a series of new technology and special equipment, such as, jury anchorage for perilous rock, borehole stress sensor of strain-type, borehole stress sensor of piezoelectric-type, energy dissipation shed-hole of rockfall and the safety alarm system, etc.更多还原