Study On Mining Disturbance Response Characteristics Of Deep Digh Stress Rock Mass

With the increase of mining depth and mining intensity increasing, rock bursts in coal mines has become increasingly severe and complicated. The original stress field is influenced by multitudinous factors such as high ground stress, high ground temperature, high water-pressure blasting and excavation dynamic disturbance (three "high" and one "disturbance") in hard rock deep metal mines exploitation. High ground stress and strong disturbance is the root of dynamic disaster, such as rock burst. For hard rock in metal mines under high geo stress, the dynamic disturbance caused by continuous mining which was conducted on it, the stress concentration of the original stress field may lead to rock damage easily. During the rock failure process, a lot of elastic potential energy was released, as a result, many disasters appear. The stress and energy state of deep rock mass has a key effect on the disturbance response. Therefore, the paper based on the state of deep rock mass in situ analysis, and take stress and energy evolution as the main line to analyze the causing mechanism and dynamic response characteristics of deep mining disturbance. The results are as follows:1. Deep engineering rock mass is more than a field, heterogeneous, and multiple state of complex geological body, based on the research of the existing theories and engineering analysis, put forward such as stress, temperature and entropy state function to characterize in situ state of rock mass, analyzed the characteristics of stress field and energy field. Tectonic stress field is a potential field, position nonexclusive, instability and deformation fields. China’s current coal mining depth is1000～1500m, tectonic stress is given priority to with horizontal stress, growth significantly with the increase of depth, and size distribution is more dispersed. Aiming at the shortcomings of that using the stress and strain state space to analysis deep dynamic disaster response, Discusses the construction of stress and strain gradient and energy density gradient state space system, through the existing state space mapping to establish corresponding constitutive and guidelines.2. Through indoor test, the load-unload disturbance response characteristics of high stress rock is analyzed. The analysis found the LURR of elastic modulus, acoustic emission, deformation ratio changed as stress level. Especially when the rocks are in a high stress state which is about to destroy, the LURR would suddenly increases to a certain value, and this phenomenon is common before rock the critical instability whatever the lithology and ultimate strength of the rock. The stability of the rock can be measured through the LURR. Through the triaxial unloading test analysis, find an inflection point exists on the rock elastic-plastic ratio curve before destruction, the turning points of stress state has important significance for predicting rock instability In view of the energy is difficult to obtain in the field, put forward to establish the relationship between energy dissipation and acoustic emission characteristics. Experimental analysis shows that there is a positive correlation relationship between energy dissipation of rock mass and the acoustic emission. At last, based on the above analysis of characteristics of disturbance response to put forward the risk of shock rock mass should be a dynamic "material parameters", based on which to define the disturbance impact risk potential and impact strength. Disturbance response characteristics such as LURR can be used to quantitative analysis the impact of risk potential and impact strength of rock mass.3. It is easily to curse geological hazard such as fault rock burst and mine earthquake when near-fault coal exploitation initiated redistribution of stress and energy in fault and its adjacent rock mass. According to seismic stress triggering theory, the dynamic model of coulomb stress changes in fault plane caused by mining disturbance is established, and characteristics criterion of disturbance effect caused by near-fault exploitation is advanced. The characteristics criterion includes stress criterion area criterion and gradient criterion expressed by coulomb stress changes. The higher the stress level and the coulomb stress gradient, the bigger the potential risk of triggering dynamic disaster. On the basis of this theory combining with numerical simulation technology, analyze the fault disturbance effect during Near-Fault Coal Exploitation in Baodian mine, and the results of the analysis is roughly tallying with the actual situation.4. The in-situ state rock mass may contain with different energy storage properties in practical engineering. When this in-situ state is disturbed, the response of different energy storage rock mass is different, and interaction mechanism is also different, which causes the condition of system dynamic impact and impact strength are also different. Based on the analysis of the mechanism of interaction between two body systems and instability condition, mining disturbance rock burst source model is established, the rock burst source are dynamic in time and variable boundary in space. The rock burst source mechanics, impact conditions and energy evolution characteristics in this process is analyzed. The correlation between impact strength, spatial scale and stress drop is analyzed. The conclusion is that rock burst source dimension in Huating mining is km range. According to the coupling response of two body interaction and by monitoring the impact stress related source area to put forward the idea of building shock disaster monitoring system.