【作者】 陈国祥；

【导师】 窦林名；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2009， 博士

【摘要】 冲击矿压是矿山开采中发生的煤岩动力灾害之一,特别是在褶皱区因地应力异常,冲击矿压致灾的强度及其危害越显突出。论文在褶皱区地应力实测和地质调研的基础上,分别采用实验、理论分析、数值模拟和工程实践等研究方法,进行了应力场中试件降压冲击破坏效应的实验,提出了冲击矿压发生的临界最大主应力机理,探讨了褶皱区最大水平应力和采动应力分布规律,分析了褶皱区应力场分布规律与冲击矿压的关系以及巷道围岩冲击危险性的关键影响因素,最后给出了适合褶皱区的工作面及巷道防冲优化布置方案和解危对策,并在现场进行了实践。设计了降压破坏实验装置,并利用SANS材料实验机进行了应力场中试件降压冲击破坏效应的实验研究,研究表明,试件降压破坏时脆性破坏特征明显,降压破坏具有突然性,且试样降压破坏时与冲击破坏效应密切相关的应力降、应力降速率以及声电信号强度均与初始轴向应力、初始侧向应力和试样强度呈正相关的关系,即试样所承受的初始轴向应力、初始侧向应力或强度越高,发生降压破坏时其破坏越剧烈,能量释放也越大。从能量耗散与释放的原理出发,分析了煤岩体冲击破坏的应力判据和能量准则,提出了冲击矿压发生的临界最大主应力机理。在此基础上,通过侧压力系数λ对巷道两帮和底板围岩体临界最大主应力的影响分析,研究了最大水平应力对冲击矿压的作用机制,认为随着侧压力系数λ的增大,巷道两帮实际承受的最大主应力减小,而其发生冲击破坏的临界最大主应力却在增长,帮部冲击危险性随之减弱;巷道底板发生冲击破坏的临界最大主应力虽在增大,但其实际承受的最大主应力也在增大,且增长速率更快,冲击危险性增大。采用FLAC数值模拟软件对褶皱区的最大水平应力和采动应力分布规律进行了模拟,研究表明,褶皱核部的最大水平应力比翼部大,翼部的最大水平应力比背斜处大,且最大水平应力集中在坚硬岩层中,夹在坚硬岩层中间的较软岩层应力相对较低。与仰采推进相比较,从背斜往向斜的方向俯采推进时,煤岩体内应力集中程度更高;先开采位于褶皱向斜附近的工作面,再开采位于翼部的工作面后,前者内侧的水平应力、支承压力集中程度降低,且最大水平应力影响范围减小。而先开采位于褶皱翼部的工作面,再开采位于向斜附近的工作面后,后者内侧的应力集中程度更高。探讨了褶皱区应力场分布规律与冲击矿压的关系,并分析了支承压力、扰动应力波等影响褶皱区巷道围岩冲击危险性的关键影响因素,解释了褶皱区众多冲击矿压现象。基于以上研究成果,提出了适合褶皱区的工作面及巷道防冲优化布置方案和解危措施。以褶皱区两个冲击矿压灾害严重的煤矿为例,通过地应力实测和数值模拟方法研究了原岩应力分布状态,得到了最大水平应力的分布状况;应用提出的防冲思路及对策,进行了工作面防冲优化布置以及弱化顶板岩层和帮部煤体防治冲击矿压的工程实践研究。更多还原

【Abstract】 Rockburst is one of the dynamic catastrophe phenomena during coal mining. Especially in fold areas, the catastrophe intensity and the harm induced by rockbursts are more obviously prominent. Through in-situ stress measure and geological survey, research approaches such as numerical simulation, experiments, theoretical analysis and engineering practice were adopted. Experiment on rockburst failure effect of samples under unloading condition in stress field was conducted, mechanism of the critical maximum principal stress on rockburst was presented, rules of distribution of the maximum horizontal stress and mine-induced stress field were studied, and relation between stress field in fold areas and rockburst along with other key influential factors on rockburst of strata of roadway in fold areas were analyzed. Finally, design project of optimizing coalface and roadway layout for preventing rockburst in fold areas were presented and its practice application was given.Rockburst failure effect of samples under unloading condition in stress field was studied with unloading experimental equipment designed and SANS materials testing machine chose. The results show that brittle fracture characteristics of the samples is obvious and sudden under unloading condition. Furthermore, the stress drop, the stress drop rate and intensity of AE&EME signals which closely related to rockburst failure effect are positive correlated to the initial axial stress, the initial lateral stress and uniaxial compressive strength of the samples. That is, much higher the value of the initial axial stress, the initial lateral stress and uniaxial compressive Strength of the samples are , more severe the failure is, the greater energy of the samples releases under unloading condition.From energy dissipation and energy release principles, stress criterion and energy criterion of rockburst failure were analyzed and mechanism of the critical maximum principal stress on rockburst was presented. Based on this, through analysis on variation of the critical maximum principal stress of both sides and floor of roadway under different lateral stress coefficientλ, mechanism of the maximum horizontal stress on rockburst was studied. The results show that, along with increase of the different lateral stress coefficientλ, the value of actual maximum principal stress of both sides of roadway decreases, but the critical maximum principal stress on rockburst increases, so danger of rockburst of both of roadway weakens. The critical maximum principal stress of floor of roadway on rockburst increases, but the value of actual maximum principal stress also increases and increases faster, so danger of rockburst of floor of roadway augments. By FLAC numerical simulation software, rules of distribution of the maximum horizontal stress and mine-induced stress field were studied. The results indicate that the maximum horizontal stress of the axis of fold structure is higher than that of the wing parts and the maximum horizontal stress of the wing parts is higher than that of anticline. The maximum horizontal stress concentrates at hard rock seam, but stress in soft rock seam in the middle of hard rock is correspondingly low. The results also indicate that convergence of stress is more higher when advancing downhill from anticline to syncline compared to advance in the direction of rising. In addition, Mining the coalface near the syncline firstly,then mining the coalface near the wing parts,the concentration of the horizontal stress and abutment stress inboard the coalface near the syncline decreases with different degrees and the affected area of the horizontal stress reduces. Mining the coalface near the wing parts firstly,then mining the coalface near the syncline, the concentration of the horizontal stress and abutment stress inboard the coalface near the syncline are higher.Relation between stress field in fold areas and rockburst was analyzed and other key influential factors on rockburst of strata of roadway in fold areas were analyzed, such as rock compressive strength, the abutment stress and stress waves disturbance. Many rockburst phenomena in fold areas were explained. Based on the above research results, design project of optimizing coalface and roadway layout for preventing rockburst and countermeasure of structure type rockburst prevention in fold areas were presented.Finally, acted as the application example of two coal mines with serious rockburst hazard in fold areas, the distribution of initial stress was studied by the measurement of in-situ stress and numeric simulation, the distribution of the maximum horizontal stress was obtained. Applied the presented idea and countermeasure of structure type rockburst prevention, engineering practice of optimized coalface and roadway layout design as well as weakening roof and coal side for preventing rockburst were studied.更多还原