Dynamic analysis steps and general flow of fast lagrangian analysis of continua in 3 dimensions(FLAC3D) were discussed. Numerical simulation for influence of excavation and blasting vibration on stability of mined-out...Dynamic analysis steps and general flow of fast lagrangian analysis of continua in 3 dimensions(FLAC3D) were discussed. Numerical simulation for influence of excavation and blasting vibration on stability of mined-out area was carried out with FLAC3D. The whole analytical process was divided into two steps, including the static analysis and the dynamic analysis which were used to simulate the influence of excavation process and blasting vibration respectively. The results show that the shape of right upper boundary is extremely irregular after excavation, and stress concentration occurs at many places and higher tensile stress appears. The maximum tensile stress is higher than the tensile strength of rock mass, and surrounding rock of right roof will be damaged with tension fracture. The maximum displacement of surrounding rock is 4.75 mm after excavation. However, the maximum displacement increases to 5.47 mm after the blasting dynamic load is applied. And the covering area of plastic zones expands obviously, especially at the foot of right upper slope. The analytical results are in basic accordance with the observed results on the whole. Damage and disturbance on surrounding rock to some degree are caused by excavation, while blasting dynamic load increases the possibility of occurrence of dynamic instability and destruction further. So the effective supporting and vibration reducing measures should be taken during mining.展开更多
The purpose of this work was to explore the influence law of vibration load on rock mass structure and slope stability.Based on the type and transmission way of vibration stress wave,the main stress in the horizontal ...The purpose of this work was to explore the influence law of vibration load on rock mass structure and slope stability.Based on the type and transmission way of vibration stress wave,the main stress in the horizontal and vertical directions was analyzed and the superposition effect of the stress wave was revealed.After the mechanical analysis of the sliding mass,the calculation formulas of the anti-sliding force and the sliding force were derived and the damage mechanism of blasting vibration to the structural plane was defined.In addition,according to the structure and lithologic parameter of the slope as well as the vibration monitoring data,the west slope stability of Xiaolongtan open pit mine was analyzed.The results show that the time-dependent stability factor is proportional to the vibration speed and the peak values appear at the same time.Vibration load promotes the breakage of the structural plane leading to the drop of the west slope stability factor by 0.23%.Under the multipoint simultaneous blasting,the fluctuating laws of the stability factors are consistent.The more the start-up points are,the higher the weakening degree to the slope stability is.Under the multipoint allochronic blasting,the stability factor depends on the synthetic waveform structure of all vibration waves.The greater the blasting time difference is,the lower the weakening degree to the slope stability is.Selecting the reasonable quantity of start-up points and time difference could fully reduce the adverse influence of vibration load to slope stability.展开更多
基金Project (50490272) supported by the National Natural Science Foundation of China project(NCET-05-0687) supportedby Programfor New Century Excellent Talents project (040109) supported bythe Doctor Degree Paper Innovation Engineering of CentralSouth University
文摘Dynamic analysis steps and general flow of fast lagrangian analysis of continua in 3 dimensions(FLAC3D) were discussed. Numerical simulation for influence of excavation and blasting vibration on stability of mined-out area was carried out with FLAC3D. The whole analytical process was divided into two steps, including the static analysis and the dynamic analysis which were used to simulate the influence of excavation process and blasting vibration respectively. The results show that the shape of right upper boundary is extremely irregular after excavation, and stress concentration occurs at many places and higher tensile stress appears. The maximum tensile stress is higher than the tensile strength of rock mass, and surrounding rock of right roof will be damaged with tension fracture. The maximum displacement of surrounding rock is 4.75 mm after excavation. However, the maximum displacement increases to 5.47 mm after the blasting dynamic load is applied. And the covering area of plastic zones expands obviously, especially at the foot of right upper slope. The analytical results are in basic accordance with the observed results on the whole. Damage and disturbance on surrounding rock to some degree are caused by excavation, while blasting dynamic load increases the possibility of occurrence of dynamic instability and destruction further. So the effective supporting and vibration reducing measures should be taken during mining.
基金Project(2015M580491)supported by the China Postdoctoral Science FoundationProject(51404262)supported by the National Natural Science Foundation of China+1 种基金Project(2014XT01)supported by the Research Funds for the Central Universities,ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The purpose of this work was to explore the influence law of vibration load on rock mass structure and slope stability.Based on the type and transmission way of vibration stress wave,the main stress in the horizontal and vertical directions was analyzed and the superposition effect of the stress wave was revealed.After the mechanical analysis of the sliding mass,the calculation formulas of the anti-sliding force and the sliding force were derived and the damage mechanism of blasting vibration to the structural plane was defined.In addition,according to the structure and lithologic parameter of the slope as well as the vibration monitoring data,the west slope stability of Xiaolongtan open pit mine was analyzed.The results show that the time-dependent stability factor is proportional to the vibration speed and the peak values appear at the same time.Vibration load promotes the breakage of the structural plane leading to the drop of the west slope stability factor by 0.23%.Under the multipoint simultaneous blasting,the fluctuating laws of the stability factors are consistent.The more the start-up points are,the higher the weakening degree to the slope stability is.Under the multipoint allochronic blasting,the stability factor depends on the synthetic waveform structure of all vibration waves.The greater the blasting time difference is,the lower the weakening degree to the slope stability is.Selecting the reasonable quantity of start-up points and time difference could fully reduce the adverse influence of vibration load to slope stability.
