程潮铁矿深部开采岩爆预测

 程潮铁矿经过近40 a的开采,已初步进入深度开采阶段。为预测岩爆发生可能性及其烈度,对程潮铁矿深度－430～－700 m的部位多种岩样进行岩石力学试验,提出岩爆倾向性的多种判据。通过理论预测法分别对各种岩样的倾向性及烈度进行预测,得到程潮铁矿围岩的岩爆倾向性顺序,总结出可能强度较高的几种岩石类型及其所在深度;最后结合模糊数学综合预测法,针对已有多种指标进行岩爆倾向的综合评价,得到矿区总体岩爆倾向性及岩爆临界深度,为矿区开采设计和岩爆监测预报提供了依据     

深埋硬岩矿床岩爆控制研究

冬瓜山铜矿是我国开采的首家有岩爆倾向的深埋硬岩金属矿山，对此开展了岩爆控制研究。应用该矿床典型岩石的变形全过程试验及峰值荷载变形条件下的松弛试验等室内试验结果和现场岩爆调查资料，分析了该矿矿岩的岩爆倾向性和井巷岩爆特性，从岩爆控制角度，采用数值分析方法以能量释放率为衡量指标，对采场结构参数、开采步骤等进行了优化。在此基础上，提出该矿床开采采用控制能量释放、减少能量储存、合理支护和进行岩爆监测等岩爆控制的原则和措施。     

基于地应力现场实测与开采扰动能量积聚理论的岩爆预测研究

高地应力诱发的岩爆灾害是目前深部地下工程经常遇到的工程地质问题。现场地应力测量是岩爆预测的重要前提,根据三山岛金矿深部测量和岩体赋存状况的特点,优化应力解除测量技术并在矿区深部进行现场实测。提出采场岩爆发生的2个必要条件,即岩石具备储备高应变能的特性和采场具备高应变能积聚的应力环境。基于地应力实测与岩石力学室内试验结果,采用多准则判据对矿区深部发生岩爆的倾向性做出定性分析与评价。FLAC3D数值模拟分析揭示深部开采引起的采场围岩能量积聚、分布状况及变化规律。首次采用地震学的知识,对三山岛金矿未来深部开采过程中可能诱发岩爆的地点和级别做出预测。研究成果为深部地下工程岩爆的预测、预报提供新的思路和途径。     

Prediction and prevention of rockburst in metal mines——A case study of Sanshandao gold mine

Rockburst is a kind of artificial earthquake induced by human activities,such as mining excavations.The mechanism of rockburst induced by mining disturbance is revealed in terms of energy in this context.For understanding the rockburst mechanism,two necessary conditions for the occurrence of rockburst are presented:(1)the rock mass has the capability to store huge amount of energy and possesses a strong bumping-prone characteristic when damaged;and(2)the geological conditions in the mining area have favorable geo-stress environments that can form high-stress concentration area and accumulate huge energy.These two conditions are also the basic criteria for prediction of rockburst.In view of energy analysis,it is observed that artificial and natural earthquakes have similar regularities in many aspects,such as the relationship between the energy value and burst magnitude.By using the relationship between energy and magnitude of natural earthquake,rockburst is predicted by disturbance energy analysis.A practical example is illustrated using the above-mentioned theorem and technique to predict rockburst in a gold mine in China.Finally,the prevention and control techniques of rockburst are also provided based on the knowledge of the rockburst mechanism.     

基于弹性应变能岩爆倾向性评价方法研究

 岩爆是深部矿产资源开采与地下工程建设中必须解决的关键科学问题之一。以岩石强度与整体破坏准则为基础,从弹性应变能是岩爆发生的内在动力出发,建立了岩爆烈度分级预测模型。研究表明：该模型考虑了原岩应力(地应力)、岩体完整性、岩石抗拉强度及泊松比对岩爆影响,反映了岩爆发生的力学要求、脆性要求、完整性要求及储能要求;揭示了岩爆既可沿洞室中心呈轴对称分布,也可揭示洞室不同部位的岩爆烈度会出现明显不同。针对无、弱、中等及高岩爆活动4个级别,提出了3个分级界限值(3、10和110)。利用已有的岩爆经典模型与本文模型,对国内一些重大深部岩石工程岩爆情况进行了预测,结果表明基于弹性应变能岩爆分析模型与实际情况吻合的较好。因而,弹性应变能的岩爆分析模型,对岩爆预测具有重要的意义。     

Experiments on rockburst proneness of pre-heated granite at different temperatures: Insights from energy storage,dissipation and surplus

Many underground engineering projects show that rockburst can occur in rocks at great depth and high temperature, and temperature is a critical factor affecting the intensity of rockburst. In general, temperature can affect the energy storage, dissipation, and surplus in rock. To explore the influence of temperature on the energy storage and dissipation characteristics and rockburst proneness, the present study has carried out a range of the uniaxial compression (UC) and single-cyclic loading–unloading uniaxial compression (SCLUC) tests on pre-heated granite specimens at 20 °C–700 °C. The results demonstrate that the rockburst proneness of pre-heated granite initially increases and subsequently decreases with the increase of temperature. The temperature of 300 °C has been found to be the threshold for rockburst proneness. Meanwhile, it is found that the elastic strain energy density increases linearly with the total input strain energy density for the pre-heated granites, confirming that the linear energy property of granite has not been altered by temperature. According to this inherent property, the peak elastic strain energy of pre-heated granites can be calculated accurately. On this basis, utilising the residual elastic energy index, the rockburst proneness of pre-heated granite can be determined quantitatively. The obtained results from high to low are: 317.9 kJ/m³ (300 °C), 264.1 kJ/m³ (100 °C), 260.6 kJ/m³ (20 °C), 235.5 kJ/m³ (500 °C), 158.9 kJ/m³ (700 °C), which are consistent with the intensity of actual rockburst for specimens. In addition, the relationship between temperature and energy storage capacity (ESC) of granite was discussed, revealing that high temperature impairs ESC of rocks, which is essential for reducing the rockburst proneness. This study provides some new insights into the rockburst proneness evaluation in high-temperature rock engineering.     

Numerical modeling for rockbursts:A state-of-the-art review

As the depth of excavation increases,rockburst becomes one of the most serious geological hazards damaging equipment and facilities and even causing fatalities in mining and civil engineering.This has forced researchers worldwide to identify different methods to investigate rockburst-related problems.However,some problems,such as the mechanisms and the prediction of rockbursts,continue to be studied because rockburst is a very complicated phenomenon influenced by the uncertainty and complexity in geological conditions,in situ stresses,induced stresses,etc.Numerical modeling is a widely used method for investigating rockbursts.To date,great achievements have been made owing to the rapid development of information technology(IT)and computer equipment.Hence,it is necessary and meaningful to conduct a review of the current state of the studies for rockburst numerical modeling.In this paper,the categories and the origin of different numerical approaches employed in modeling rockbursts are reviewed and the current usage of various numerical modeling approaches is investigated by a literature research.Later,a state-of-the-art review is implemented to investigate the application of numerical modeling in the mechanism study,and prediction and prevention of rockbursts.The main achievements and problems are highlighted.Finally,this paper discusses the limitations and the future research of numerical modeling for rockbursts.An approach is proposed to provide researchers with a systematic and reasonable numerical modeling framework.     

一种新的岩爆倾向性指标

从岩石的变形和破坏过程中的能量储存和能量耗散出发，指出岩石的单轴抗压强度与单轴抗拉强度之比值可以表征结构较完整岩石的弹性变形能的储存能力以及峰值前后的应变量之比值可以表征岩石的能量储存与耗散之间的相对大小，提出用这两种比值的乘积作为岩爆倾向性指标。采用铜陵有色金属公司冬瓜山深部矿床的典型矿岩进行试验，对这种新的岩爆倾向性指标与现有的岩爆倾向性指标进行对比分析，结合该矿床实际的岩爆调查，说明新指标可以较好地表征岩石的岩爆倾向性，并提出了这种新指标判据的初步建议。     

基于采动顶、底板岩层损伤的冲击地压预测

为探索微震法预测冲击地压的原理和应用技术,在装备高精度微地震监测设备的煤矿,开展采掘过程连续的岩体破裂现场监测,使用自主研发的采动岩体破裂规律分析和冲击地压预测软件MapRAS进行预测研究和工程应用。发现采动过程岩体微破裂在顶板和底板的深度扩散是产生冲击地压的大概率事件;提出采动顶、底板深度损伤是冲击地压成核重要因素的观点。建立应用微震数据辨识顶、底板采动破裂损伤深度的函数关系式和算法。分析显示顶板和底板深度损伤存在联动,与顶板关键层的周期破断及其后效相对应,反映出顶板、底板的加–卸载过程,在华亭煤田多显现为巷道底板破断型冲击地压。经工程应用检验,预测效能较高,应用效果良好。     

Discussions on rockburst and dynamic ground support in deep mines

The paper is a summary of discussions on four topics in rockburst and dynamic ground support.Topic1 is the mechanisms of rockburst.Rockburst events are classified into two categories in accordance with the triggering mechanisms,i.e.strain burst and fault-slip burst.Strain burst occurs on rock surfaces when the tangential stress exceeds the rock strength in hard and brittle rocks.Fault-slip burst is triggered by fault-slip induced seismicity.Topic 2 is prediction and forecasting of rockburst events.Prediction for a rockburst event must tell the location,timing and magnitude of the event.Forecasting could simply foresee the probability of some of the three parameters.It is extremely challenging to predict rockbursts and large seismic events with current knowledge and technologies,but forecasting is possible,for example the possible locations of strain burst in an underground opening.At present,the approach using seismic monitoring and numerical modelling is a promising forecasting method.Topic 3 is preconditioning methods.The current preconditioning methods are blasting,relief-hole drilling and hydrofracturing.Defusing fault-slip seismicity is difficult and challenging but has been achieved.In very deep locations(3000 m),the fracturing could extend from the excavation face to a deep location ahead of the face and therefore preconditioning is usually not required.Topic 4 is dynamic ground support against rockburst.Dynamic ground support requires that the support system be strong enough to sustain the momentum of the ejecting rock on one hand and tough enough on the other hand to absorb the strain and seismic energies released from the rock mass.The current dynamic support systems in underground mining are composed of yielding tendons and flexible surface retaining elements like mesh/screen and straps.Yielding props and engineered timber props are also used for dynamic support.     

急倾斜煤层开采冲击危险性数值模拟研究

对北京昊华能源股份责任公司的长沟峪煤矿的急倾斜煤层进行三维数值模拟,利用ANSYS有限元软件单元"处死"的功能真实模拟4槽工作面的开挖过程,对沿巷道走向和沿煤层走向推采不同距离时的塑性应变云图和应力云图进行分析,得出数值模拟结果与现场实际开采情况基本吻合,说明ANSYS有限元数值模拟方法可为冲击地压的防治工作和煤矿的安全开采提供参考。     

矿震监测定位系统的研究及应用

为确定矿震发生的时间、地点、震级，结合煤矿实际情况，研制一套国内首台具有自主知识产权的矿区千米尺度破坏性矿震监测定位系统。该系统采用在矿区地面布置4个子台，子台由三分向加速度传感器组成，拾取振动波信号。为保证4个子台矿震数据的时间精度，采用GPS网络授时作为时间基准，通过对振动波的频率、振幅等特征分析，对矿震波进行自动识别，排除放炮等振动信号。各子台矿震信号通过网络传输到中心测控机，中心测控机对各子台进行远程控制管理，监控各子台的工作状态。中心测控机对数据进行处理和分析，计算矿震发生时刻，通过振动波持续时间计算矿震震级，采用3种方法计算矿震发生位置。该系统可为矿井迅速准确组织救灾、减少损失提供依据。同时，通过对每天矿震发生的时间、次数、位置、震级进行统计分析，可对未来的矿震发生趋势进行预测。系统的运行情况表明，监测结果与实际矿震较吻合，定位结果小于规定的误差上限。     

阜新矿区深部高瓦斯矿井冲击地压研究

阜新矿区冲击地压的特点是发生冲击地压事故的区域地质构造复杂、深部开采、瓦斯含量高且瓦斯压力大，煤层及其顶底板积聚了大量的弹性势能，当煤体受到采掘活动的扰动时，弹性势能释放而发生冲击地压。进入深部开采后，冲击地压开始频繁发生，说明大采深是冲击地压发生的直接原冈。对于高瓦斯矿井，为避免瓦斯灾害而加大瓦斯抽放量，使煤层中大量瓦斯经解吸、渗流而排出，改变了煤体的物理力学性质，造成由瓦斯灾害向冲击地压事故的转变，冲击地压的频度和强度均明显增加。控制瓦斯抽放量可达到既降低瓦斯突出危险又避免冲击地压发生的目的。在有冲击地压危险倾向的采区，采用煤层注水措施，改善因瓦斯抽放造成的煤体脆性度增加的状况，可以降低冲击地压危险。     

玲珑金矿深部开采岩体能量分析与岩爆综合预测

 玲珑金矿是石英脉型金矿床, 目前开采深度已超过500m , 未来开采深度将超过1 000m。对此类矿床赋存条件的地下矿山, 深部开采时可能遇到的一个突出问题就是岩爆。根据系统的工程地质调查、地应力场现场实测、岩石力学试验、三维有限元数值模拟的结果, 采用多种岩爆判断准则, 分析了玲珑金矿深部开采时围岩中的能量分布规律和发生岩爆的可能性, 提出了防治岩爆的建议措施。     

Phenomena and theoretical analysis for the failure of brittle rocks

Rockburst, an unstable failure of brittle rocks, has been greatly concerned in rock mechanics and rock engineering for more than 100 years. The current understanding on the mechanical mechanism of rockburst is based on the Coulomb theory, i.e. compressive-shear failure theory. This paper illustrates a series of tensile and tensile-shear fracture phenomena of rockburst, and proposes a methodology for the analysis of fracture mode and its energy dissipation process based on Griffith theory. It is believed that: (1) the fracture modes of rockburst should include compressive-shear, tensile-shear and pure tensile failures; (2) the rupture angle of rock mass decreases with the occurrence of tensile stress; (3) the proportion of kinetic energy in the released strain energy from a rockburst may be much larger than that transferred into surface energy; and (4) the understanding on the tensile and tensile-shear failure modes of rockburst may change the basic thinking of rockburst control, i.e. from keeping the reduction in initial compressive stress σ3 to restricting the creation of secondary tensile stress.     

基于物元矩阵和理想点法的岩爆烈度预测

针对岩爆烈度预测问题,采用物元矩阵和理想点法进行了相关研究。在综合考虑影响岩爆发生的主要因素的基础上,以影响岩爆烈度的围岩最大切向应力与岩石单轴抗压强度比σ_θσ_c、岩石单轴抗压强度与岩石单轴抗拉强度比σ_cσ_t和弹性能量指数w_et等三个常用影响因子为评价指标,并且通过改进的层次分析法和熵值法相结合的组合赋权法来评价各个指标的影响程度,构建了岩爆烈度的物元矩阵,以靠近岩爆烈度理想点的远近程度为判断标准,基于此原理建立了岩爆烈度预测的物元－理想点模型。最后,将该模型应用于秦岭隧道、灵宝东峪矿区和冬瓜山铜矿的岩爆烈度预测中,结果表明,该模型的预测结果与实际岩爆烈度基本一致,验证了该模型的可行性。同时,将本文模型和ANN法、Bayes法以及DDA法进行比较,预测结果大致相同,且该模型不需要任何先验知识,求解过程完全由样本驱动,可操作性较强,进一步证明了该模型的合理性和有效性。     

基于经验方法的铁矿深井围岩岩爆倾向性预测

岩爆是深埋工程建设面临的关键技术难题,岩爆风险的准确预测与评估至关重要。深埋矿山岩爆风险主要取决于围岩应力水平和围岩强度之间的矛盾,岩体条件(岩性、岩石强度、岩体完整程度)是岩爆发生的物质基础,是否产生岩爆和岩爆风险程度则主要取决于围岩应力水平和状态。某铁矿深井巷道群规模大、布置方案复杂,最大埋深达到接近2 300 m,文中采用FLAC^3D软件平台编制了基于经验方法的通用性岩爆倾向性预测分析程序,评估了不同深度铁矿深井巷道群围岩的应力型破坏风险,并给出支护措施建议。研究所采用的分析技术和成果在国内具有一定首创性,特别适用于满足工程前期对地下洞室群围岩岩爆风险实现快速评估的现实需求。     

基于微震监测技术的矿山高应力区采动研究

 冬瓜山铜矿是目前国内开采最深的金属矿山之一,岩石具有典型的岩爆倾向性,最大应力为38 MPa,为控制岩爆的发生及制定高应力区采矿的战略,2005年矿山引进南非ISS国际公司的微震监测系统,实现对采矿引起的岩体应力、应变状态的实时监测。简单介绍冬瓜山矿微震监测系统的布置;基于一段时间内监测到的有效事件,对井下首采区地震事件的时间与空间分布进行研究;利用可视化工具JDI对事件的相对集中区域进行圈定,并与井下生产活动相结合,分析原因;还提出对井下工程岩体危险识别的手段,并用实际发生的事件验证;综合研究成果,制定以微震监测技术为基础的高应力区采动分析的工作程序,为目前矿山的安全生产提供依据。     

基于LSTM多变种模型的岩爆微震参数预测研究

岩爆是深地工程和深部资源开采中必须要解决的核心问题之一。基于改进的LSTM神经网络,提出了用于时间序列预测的LSTM微震多参数预测模型,包括单变量时序预测模型和多元平行序列预测模型。并以峨汉高速大峡谷隧道微震监测数据对模型进行验证,同时与多项式回归方法结果进行对比分析。结果表明:单变量预测模型中堆叠式LSTM(S-LSTM)的预测精度最高;多变量预测模型中卷积LSTM(CNN-LSTM)对累积视体积和能量指数具有最好的预测效果,且余下几种LSTM模型仍可准确实现各参数演化趋势的预测,其精度均优于多项式回归分析方法。研究可为正确识别岩爆当前活动及未来状态的危险性提供理论支撑,为及时掌握岩爆未来活动状态提供重要依据。