Research On Mechanical Mechanism Of Low-Angle Dip Bedded Rock Slope Failure Regularity

As one of the main geological disasters, there are more than 50000 perilous rocks in the area of the Three Gorges reservoir which threaten more than 800 thousands people's lives and tens of billions Yuan in property. The chained regularity for perilous rock to develop was discovered according to the reconnaissance in site of plenty of perilous rocks, which provides theoretical reference for the control technique of perilous rock supporting and support-anchoring. Supported by the National Natural Science Foundation"RESEARCH ON THE MECHANISM OF THE PERILOUS ROCK FAILURE", the mechanics process of chained regularity for perilous rock to develop was researched, and gained the main conclusions as follow:(1) It is the geomorphy where the chained regularity for perilous rock to develop is very obviously that the low-angle dip bedded rock cliff geomorphy compose of soft-rock bed and hard-rock bed, which controls the perilous rock's development by chained regularity, at the same time, the chained regularity for perilous rock to develop changes the local geomorphy.(2) The macro-mechanics process of the development of the control fissure was controlled by the neo-tectonic stress filed, and then the chained regularity of perilous rock to develop was controlled by the neo-tectonic stress filed.(3) According to the micro mechanics analysis of the micro-chain's development, at the first stage, the hard rock upon the soft rock was under compression condition at vertical direction and was under tensile condition at horizontal direction by unloading and the rock mass was under static balance at the first stage; during the process of the critical rock cell formed, the rock mass upon neutral plane was under tension and the rock mass below neutral plane was under compression, the length of critical rock cell and the location of the crack point was calculated; to the initial damage rock, the damage factor, the movement equation of the damage front area and the local damage area of control fissure tip were calculated; the fracture angle and the stress intention factor of control fissure was gained by the solution of different fracture model of control fissure under different load after the control fissure formed.(4) The duration of the macro-chain of perilous rock was calculated by the analysis of the duration of critical rock cell formed, the duration of the control fissure damaged and the duration of the control fissure fractured; the distinguishing of the mode of the chained regularity for perilous rock to develop was gained by compared with the duration between different micro-chain in different macro-chain.(5) According to the numerical simulation of the chained regularity of SIMIANSHAN perilous rock to develop, the maximal principal stress in the perilous rock was tension stress or the critical state from compression stress to tension stress during the development of the chained regularity; the minimal stress is tension stress during the whole process of the macro-chain development; the stress concentration will be occurred at the local area near the rock cell when the critical rock cell formed, which will cause the destroy of the rock upon the rock cell and make the micro-chain develop; the rock is under tensile condition during the development of the chained regularity, and then the perilous rock block will be formed and destroyed in easy.The mechanics development process of the perilous rock chained regularity was opened out by the above research, the realization of the mechanism for perilous rock to develop and the pertinence & validity of control engineering was improved.