Characteristics of strong disturbance to rock mass in deep mining
PENG Ruidong1,2 ,XUE Dongjie2 ,SUN Huafei2 ,ZHOU Hongwei1,2
深部岩体具有高地应力、高地温、高渗压的独特赋存环境,其采动影响远较浅部复杂。通过将深部岩体的赋存环境和深部开采的扰动特征两方面相结合,系统分析了深部岩体开采中的强扰动特性。首先对扰动激励的动静组合特点进行了分析。根据深部开采中的应力变化路径,给出了不同深度类型下原岩应力状态以及扰动应力状态的分布区域,揭示了深部开采中应力变化更加复杂的必然性,并初步给出了考虑赋存深度、开采工艺、岩体重度、残余应力以及采动速度影响的岩体卸荷速率计算公式。根据深部开采中的动力扰动类型和波动传播规律,分析指出了深部岩体中的流体压力传播特征,揭示了深部动力扰动时间延长和扰动范围扩大的特点。然后基于扰动状态概念(DSC)对扰动影响水平进行了分析。通过对深部岩体能量蓄积、能量耗散以及释放规律的分析,定义了基于能量特征的扰动函数,可以籍此构建基于DSC的深部岩体统一本构模型,并定量描述深部岩体扰动的大小。最后定性描述了深部岩体开采中开挖扰动区的分布特点以及相应的应力应变状态,将其划分为原岩弹性区、开挖损伤区(EDZ)以及开挖破碎区,其中开挖损伤区又可分为峰前损伤区、塑性流变区、外部损伤区。并初步给出了开挖损伤区大小的计算公式,讨论了各项参数的意义及影响因素。研究表明,深部岩体的高应力状态以及复杂的多场多相耦合环境使其在更大范围内受到扰动的影响,EDZ的范围将显著增大,并表现出复杂的时空演化特征。利用扰动状态概念(DSC)建立的扰动函数,以及基于能量分析建立的开挖损伤区(EDZ)大小计算公式,可以定量刻画深部扰动的程度,分别反映了深部扰动激励增大和扰动影响增大的特点。
Deep rock mass exists in a kind of environment with high geostress,high temperature and high pressure. The influence of mining on it is complex than that on shallow rock. The strong disturbance to deep rock mass was analyzed systematically by combining the surrounding environment of deep rock mass and the disturbance characteristics of deep mining. Firstly,the cooperation between static and dynamic disturbance were examined. According to stress paths in deep mining,both the distribution of initial geostress state and that of disturbance stress state under different depth ranges were given,which reveals the complicated char-acteristics of stress paths in deep mining. Thereby a preliminary formula to calculate unloading velocity was proposed based on rock depth,mining method,rock gravity,residual stress and excavating speed. According to the type of dynamic disturbance and the law of stress wave propagation in deep mining,the characteristics of fluid pressure propagation in deep rock mass was pointed out. Thus it is inferred that the disturbance scope in deep rock mass is extended and the disturbance time is prolonged. Then the influence of disturb- ance was investigated according Disturbed State Concept (DSC). A disturbance function based on energy feature was defined by analyzing the energy storage,energy dissipation and energy release of deep rock mass,which would be a- dopted to build a unified constitutive model of deep rock mass based DSC. Such function can quantitatively describe the disturbance in deep rock mass. Lastly,the distribution of excavation disturbance zone in deep rock mass mining and the corresponding stress-strain state were described qualitatively. It is suggested to be divided into Initial Elastic Zone,Excavation Damaged Zone ( EDZ) and Excavation Fracture Zone,where Excavation Damaged Zone is divided into Inner Damage Zone,Plastic Disturbed Zone,and Unloading Damage Zone. A formula was given to calculate the size of Excavation Damaged Zone. Each pa-rameter in the formula was explained and the influence on them were dis- cussed. The study shows that the disturbance to rock mass in deep mining become more severe due to the high stress state of the deep rock mass and the complex multi-field coupling of multiphase environment,and thus the range of EDZ is increased significantly with more complex temporal and spatial evolution. The disturbance function based on DSC and the formula calculating EDZ size based on energy analysis can quantitatively describe the extent of disturbance in deep rock mass. They reflect the increase of disturbance stimulus in deep rock mass and the increase of disturbance effect in deep rock mass respectively.
rock mass;deep mining;disturbance;energy;damage;excavation disturbance zone
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会