Study On The Excavation Unloding Dynamic Effect And Stability Evolution Rule Of The Open-pits Rock Slope

Safety and stability problems of the open-pits rock slope mining engineering arewidespread all over the world, and have make up a large proportion of engineeringgeological accidents in our country. Artificial excavation changes the initial stressfields of the rock slope, causing the rock slope readjust its stress field distribution,which will not only change the steady state of the slope at the time, but also affect itsstability evolution process in the future, even lead to serious engineering accidents andendanger the life safety of the mine workers sometimes. Therefore, the evaluation ofthe open-pits rock slope stability is increasingly prominent. Studying on the stabilityevolution law and disaster prediction criterion of this kind rock slope has importantscientific theory value and practical engineering significance.Aiming at the stability problems existed in the excavation process of the open-pitsrock slope, taking the slope practical engineering of Jinchuan Group quartz open-pitsstope as an example, this paper build up the finite element analysis model of theopen-pits rock slope by the ABAQUS finite element analysis software, and studyingthe evolution law of the excavation unloading dynamic increment displacementresponse ratio and the displacement vector angel. On the basis of this study, throughthe comparative analysis and validation of the numerical simulation and engineeringpractice results, the following conclusions are obtained:1. Through the study of the changing law of the stress field and the displacementfield on the condition of the excavation unloading of the open pits rock slope, analyzeand interpret the change features of the dynamic effect and displacement responseduring the stability evolution process.2. Based on the fundamental theory of the damage mechanics and elastic-plasticmechanics, study the value and curve change rule of the excavation unloading dynamicincrement displacement response ratio when the slope is in different deformingstage(undamaged elastic deformation stage, damaged elastic deformation stage,damaged plastic deformation stage, overall instability critical deformation stage). 3. Based on the fundamental theory of holographic prediction and multivariateinformation prediction; analyze the eigenvalue and space-time evolution law of theexcavation unloading displacement vector angel when the slope is in differentdeforming stage.4. Synthesize the above research results of the two parameters under o thecondition of pen-pits rock slope excavation unloading, posterior analysis andevaluation of the slope engineering practice of Jinchuan Group quartz open-pits stopewere conducted, the study result is basically agree with the actual stability evolutiontendency of the slope. Therefore, these two parameters can be used to evaluate andcalculate the stability of open-pits rock slope under the condition of excavationunloading, having the practical feasibility.