Research On The Formation Mechanism And Monitoring And Warning Of Collapse Controlled By The Bottom Rock Cell

Based on the analysis on the typical examples of collapse, for the indented controlling at the bottom of the engineering geological conditions and the cause of the collapse mechanism are analyzed in detail. So that, the collapse mechanism concept model is established. Through the fracture mechanics analysis method, framework and model simulation method and the numerical simulation method, study the collapse deformation and failure mechanism deeply. Finally has carried on the monitoring and early warning research of this kind of collapse. The main results are as follows:(1) By means of formation mechanism analyses of Weining county Yaoyanjiao collapse and Xiaotunyan collapse, summarize the influence factors of crack-toppling and crack-falling collapses, which mainly are the steep rock mass structural plane combination, on hard under the soft lithologic combination, strong weathering(physical, chemical weathering), at the bottom of the concave cavity, trailing edge control structural plane and rainfall, etc.(2) The deformation and failure of crack-toppling and crack-falling collapses is divided into three stages: Concave cavity expansion stress adjustment stage, vertical structure surface tension extension stage and failure stage.(3) Concave surface of tip cavity depth and master structure positively related to the complex stress intensity factor; Master structure of the penetration rate and master structure surface of tip complex stress intensity factor is related(4) The crack-toppling collapse of critical depth of the concave cavity dumping type rainfall is negatively related to the fall in the natural state. Micro cracks produced in the process of stress concentration will make the master control the intensity of structural plane is weakened and the characterization of the fracture toughness of rock crack propagation resistance value decreased(5) Collapse are analyzed in detail, through the physical simulation experiment, the physical model under the gravity stress field characteristics of deformation and failure. Stage, to put forward three deformation and destruction, the concave cavity expansion stress adjustment phase, the vertical structure of the surface tension extension stage, buckling failure stage and effective verification.(6) The crack-toppling and crack-falling collapses are simulated by UDEC, qualitatively analyzes the changes of stress and displacement.(7) In this paper, based on the analysis of the acceleration time curve, a criterion for judging the stage of acceleration and deformation is put forward. According to the curve fitting of the velocity reciprocal method, the method and the model are established.(8) In this paper, basing on the fracture mechanics analysis method to determine collapse criterion index early warning. Established the crack-falling collapses under the condition of gravity and rainfall warning model based on the collapse of the stability, the selected master structure surface penetration rate for early warning criterion; besides, Establishing crack-toppling collapses under the condition of gravity and rainfall early warning model based on the stability of the collapse, selected the concave cavity depth and penetration rate of the main structure and main structural plane fissure water level for early warning criterion.