深部开采岩爆机理数值分析方法与应用

应用自行开发的岩石破裂与失稳分析数值工具（RFPA系统），模拟了深部开采中岩爆的发生，发展全过程，用应用场分布再现了岩爆和破坏失稳的机理，并结合辽宁抚顺红透山铜矿深部开采及其岩爆问题，进行数值模拟。结果表明，岩爆的发生是可以预测的，并提出了岩爆预测新方法。     

A comprehensive geomechanical method for the assessment of rockburst hazards in underground mining

Rockburst hazard in mining industry all over the world is one of the most severe hazards. It is becoming increasingly common because of the ever-growing depths of mining operations accompanied by the increasing strength of rocks. One of the most difficult issues is to predict this hazard before the mining operations, whether geophysical investigations have been conducted or not. Polish experience in this field shows that in such cases an effective solution can be the geomechanical method. Therefore, extensive studies on rockburst hazard should focus on three main aspects:(1) rock mass and rock(and coal)predisposition to rockburst–laboratory tests and empirical analyses based on lithology,(2) identification of the potential places with stress and elastic energy concentration in the rock mass within the area planned for exploitation, and(3) the assessment of the impact of mining tremors on the surface. This preliminary geomechanical analysis assesses the propensity of the rock mass to dynamic breakage and provides quantitatively the level of rockburst hazard. The paper presents Polish experience in rockburst hazard assessment with the use of geomechanical method, as well as some solutions and examples of such analyses.     

Research on the Mechanism and Prevention of Rockburst at the Yinxin Gold Mine

The occurrence and nature of shaft rockburst in the Yinxin gold mine are recorded and analyzed. Rockburst happens along an obvious south-north orientation. The ground and surrounding rock stresses are measured in this mine. The research indicates that the directivity of rockburst is closely related to geological structure and to abnormal distri-bution of ground stress in some parts of the mining area. The mechanism of past rockbursts is discussed based upon the theory of fracture mechanics. Some rockburst release measures and their execution in the Yinxin Gold Mine are de-scribed. These measures have been successful in eliminating rockburst.     

A new empirical chart for rockburst analysis in tunnelling: Tunnel rockburst classification(TRC)

Rockburst is defined as a phenomenon with immediate dynamic instability under excavation unloading conditions of deep or high geostress areas. Inadequate knowledge and lack of characterizing information prevent engineers and experts from achieving appropriate prediction results related to the rockburst behaviour. In this study, a data set including 220 rockburst instances was collected for rockburst classification via the geostatistical method. An update of the 2D graph, the tunnel rockburst classification(TRC)chart, was introduced based on analysing three indicators, namely, elastic energy index(Wet), tangential stress in rock mass(rh), and uniaxial compressive strength(rc). Distribution and correlation of data were drawn on 2D plot, and the boundaries of rockburst were distinguished according to the achieved interpolate points by kriging method. Hierarchically, the validation phase was performed using an additional set of 28 case histories obtained from several projects around the world. The results showed that the TRC chart with an average error percentage of 3.6% in the prediction of rockburst had a significant and effective implementation in comparison to the exiting heuristic systems. Despite the initial character of the prediction, the described chart may be a helpful tool in the first steps of design and construction.     

煤岩体的强度弱化减冲理论

冲击矿压实质是煤岩体能量积聚与释放的过程,当煤岩体中所积聚的弹性应变能达到其极限冲击能时,就可能发生冲击矿压.煤岩体的强度弱化减冲理论,就是在强冲击危险区域,采取松散煤岩体方式,降低强度和冲击倾向性,使得应力高峰区向岩体深部转移,并降低应力集中程度,从而使发生冲击矿压的强度降低,这样煤岩体中所积聚的弹性应变能达不到最小冲击能,因此可防治冲击矿压的发生.煤岩体的强度弱化减冲理论在三河尖矿的生产实践中得到了有效的证明.     

平煤十一矿微震监测系统优化布置及应用

根据十一矿己二下山采区的采掘接替关系,提出了时空预测技术,确定了冲击地压重点防治区域.对微震监测站布置进行了优化,共布置了14个地下测站和2个地面测站.根据矿震监测记录,分析了微震信号的频谱特征和能量特征.结果表明,距矿震地点较近的震动频谱范围较宽,能量较大,低能量的震动有利于能量的释放,强矿震前会出现矿震能量和次数的静默期,最后,建立了十一矿强矿震危险监测防治体系,提出了冲击地压的解危措施.     

隧道施工中的岩爆及时预测

岩爆是高地应力条件下隧道及地下洞室开挖中围岩因卸荷而发生的岩片爆裂松脱、剥落、弹射的地质灾害。本文研究了岩爆形成机制和岩爆的主要影响因素,指出岩爆的发生主要与岩石性质、地质条件和应力状况有关。为了避免或减少岩爆造成的损失,需要正确预测岩爆,其中重要工作是及时测量地应力的大小和岩石抗压强度。针对高地应力条件下隧道及地下洞室施工过程中,经常发生岩爆的地质灾害,需要进行及时的预测预报,预报要求快捷、简便、实用。其中岩石抗压强度采用点荷载强度仪容易进行确定,主要困难是如何及时进行地应力测量。本文改进了门塞式应力恢复法,推导了切向应力的计算公式,确定了公式中的等效应力系数。将该方法应用于大广南高速公路鄂赣隧道施工过程中的岩爆预测预报,预测结果与实际情况符合较好,有效地指导了岩爆的防治,并减少了相应的损失。     

华丰井田4煤层顶板砾岩水突出影响因素分析

在分析砾岩分布特征及其水文地质特征的基础上,以矿山压力控制理论为指导,运用岩层沉降理论推断了华丰矿1409工作面在采厚为6.5m的情况下,导水裂隙带发育高度为96.2m,揭示了导水裂隙能够导致顶板砾岩水突出.结合矿山压力观测资料和顶板突水量资料,阐述了矿山压力和顶板砾岩突水突出之间的因果影响关系.根据2407工作面冲击地压监测资料,阐明冲击地压对顶板突水的促进作用.建立了顶板水沿工作面下平巷突出运移的模型,阐明了斑裂线是导致砾岩水大量突出的主要导水通道.     

Heavy rockbursts due to longwall mining near protective pillars:A case study

Rockburst represents a very dangerous phenomenon in deep underground mining in unfavourable conditions such as great depth, high horizontal stress, proximity of important tectonic structures, and unmined pillars. The case study describes a recorded heavy rockburst in the Czech part of the Upper Silesian Coal Basin, which occurred during longwall mining near the protective pillar. The artificial dividing of geological blocks and creation of mining protective pillars(shaft pillars, crosscut pillars etc.) is a dangerous task in light of rockbursts occurring mainly due to overstressing of remaining pillars. A simple model of this situation is presented. Natural and mining conditions are analysed and presented in detail as well as registered seismicity during longwall mining in the area. Recorded rockbursts in the area of interest are described and their causes discussed. Many rockbursts near protective pillars were recorded in this mining region. Methodical instructions for rockburst prevention in proximity of protective pillars as well as for gates driving were devised based on the evaluation of rockburst causes. The paper presents these principles for prevention.     

华亭煤田冲击地压定向解危技术

针对华亭煤田各煤矿冲击地压显现时底板鼓起严重的现象,采用横向(巷道横截面)卸压和纵向(沿巷道走向)卸压相结合的方式来消除冲击危险.在巷道两脚布置钻孔,水平应力在钻孔上分解后形成的静摩擦力会挤压底板使之向下运动,并通过两侧钻孔卸压爆破形成底板裂隙区来隔断底板深部传来的应力;同时在巷道中每隔一段距离设置一个破碎带,破碎带起到"弹簧体"的作用,吸收沿巷道走向方向水平应力所带来的能量.研究表明,经计算定向解危方法吸收能量(10~8J)远大于微震系统已经测得的矿区冲击危险源产生的能量级别(10~6J),对底板型的冲击地压现象能够起到很好的防治作用.现场实施情况良好,有效减轻了煤矿巷道底板鼓起的现象.     

基于基因表达编程和粒子群优化鲁棒混合计算模型的深部地下矿井岩爆分类

在深部地下采矿中，岩爆因具有许多不利影响（如对人员、设备、隧道/地下矿山工作面和开采周期等的影响）而被视为不确定性风险。由于其不确定性的特征，对岩爆趋势的准确预测和分类具有一定难度，且已有研究成果较少。提出一种基于基因表达编程（GEP）和粒子群优化（PSO）的鲁棒混合计算模型GEP-PSO，用于预测和分类深部开口的岩爆趋势，提高了预测和分类的准确性。在建立GEP-PSO模型的过程中，评估GEP模型中不同数量的基因（1~4）和连接功能（例如，加法、提取、乘法和除法）。收集246次岩爆发生的地质和施工因素，用于建立岩爆分类的GEP-PSO模型；应用处理数据集缺失值的技术改进数据集的属性；用相关矩阵选取潜在输入参数的特征；建立13个混合GEP-PSO模型，得到各模型的精度。结果表明：在GEP结构中具有3个基因和乘法连接函数的GEP-PSO模型具有最高的准确度（80.49%）。将获得的最佳GEP-PSO模型的结果与基于相同数据集开发的各种已有模型进行比较，结果表明，选择的GEP-PSO模型结果优于已有模型，表明提出的GEP-PSO模型在岩爆等级的预测和分类方面的准确性显著提高，可以应用于深开挖工程中，以准确预测和评估岩爆敏感性。     

岩(煤)壁中滑移裂纹扩展的冲击矿压模型

大量的研究表明,冲击矿压是由岩（煤）壁附近的剥离薄层的屈曲破坏而形成．运用断裂力学原理,分析了在岩（煤）壁附近压应力集中区内原生裂纹的亚临界扩展、贯通以及与自由表面的相互作用使裂纹沿最大压应力方向扩展,最终形成平行于自由表面的岩（煤）壁薄层的机理．建立了岩（煤）壁附近压裂纹的非时间相关和时间相关的２种滑移扩展方程,特别是与时间相关的亚临界扩展方程的建立,可使冲击矿压判据中引入时间参量．通过对裂纹未贯穿前的膨胀导致的自由面位移分析及薄层屈曲的能量计算,可为冲击矿压的预测预报提供新的理论依据．     

基于能量原理的岩爆机理及应力状态分析

讨论了岩石破坏与能量耗散、能量释放的内在联系.基于能量原理,指出了岩爆发生的机制与特点,证明岩爆是发生在储存有高弹性应变能的硬脆性岩体中的地质灾害.结合圆形洞室围岩应力分布,分析了发生岩爆的地下洞室围岩的应力状态及相应的灾变位置.     

安庆铜矿深部开采稳定性研究

在参考大量资料的基础上，针对安庆铜矿深部大直径深孔法开采的稳定性进行研究．经计算分析，认为安庆铜矿深部典型矿岩具有弱一中等程度的岩爆倾向性．运用块体理论分析结构面产状对深部开采稳定性的影响；通过对工程岩体的评价，认为安庆铜矿深部岩体质量级别为Ⅲ级．通过数值模拟得出合理的开采顺序；为减小爆破振动提出合理的爆破方式。     

Influence of deviatoric stress on rockburst occurrence:An experimental study

As mining delves deeper into the crust, it is necessary to investigate the complex rock responses associated with higher stress gradients. Therefore, it is essential to better understand the mechanisms associated with the rockburst phenomenon. However, due to the large-scale and difficult monitoring of real mining excavations, laboratory scale tests must be utilised to determine the conditions conducive to burst. To this end, this research focuses on the implementation of a new rockburst testing apparatus to replicate the stress conditions of a rock mass excavation at the time of bursting. This apparatus allows the determination of rockburst stresses and a relationship between deviatoric stress and in-situ pressure/depth. Using this relationship it is then possible to estimate the standardised stress levels for a certain rock type which might lead to rockburst occurrence. Furthermore, it is demonstrated that with increasing in-situ pressure, the likelihood(measured as a lower differential stress) and the extent(indicated by the increasing range of deviatoric stress) of rockburst increases. These findings provide valuable information about the conditions necessary for bursting in deep mining.     

“铁篦子”方案在岩爆区的应用

为减少岩爆控制的规模,采用“铁篦子或钢筋排”方案对其进行研究。利用隧道开挖后周围岩体的弹性能密度计算不同岩爆等级发生时的动能;根据前期对NJ—TBM隧洞地应力的反分析成果,结合工程区域采取应力释放孔等措施,确定不同岩爆区的最大岩块及其最大速度,且假定最大岩块以最大速度向钢板/钢筋进行冲击,从而建立“铁篦子或钢筋排”方案计算模型;基于该模型,将所提出的“铁篦子或钢筋排”方案分别应用到强岩爆区、中等岩爆区以及弱岩爆区。结果表明:在强岩爆区(钢拱架间距1.5 m,每延米30根Φ=20 mm“铁篦子”的方案)中岩爆区(钢拱架间距1.7 m,每延米20根Φ=22 mm“铁篦子”的方案)弱岩爆区(钢拱架间距2.0 m,每延米20根Φ=20 mm“铁篦子”的方案)均未使钢筋出现塑性区。因此,所提出的方案不会产生塑性区。     

Seismological method for prediction of areal rockbursts in deep mine with seismic source mechanism and unstable failure theory

The research on the rock burst prediction was made on the basis of seismology, rock mechanics and the data from Dongguashan Copper Mine (DCM), the deepest metal mine in China. The seismic responses to mining in DCM were investigated through the analyses of the spatio-temporal distribution of hypocenters, apparent stress and displacement of seismic events, and the process of the generation of hazardous seismicity in DCM was studied in the framework of the theory of asperity in the seismic source mechanism. A method of locating areas with hazardous seismicity and a conceptual model of hazardous seismic nucleation in DCM were proposed. A criterion of rockburst prediction was analyzed theoretically in the framework of unstable failure theories, and consequently, the rate of change in the ratio of the seismic stiffness of rock in a seismic nucleation area to that in surrounding area, dS/dt, is defined as an index of the rockburst prediction. The possibility of a rockburst will increase if dS/dt>0, and the possibility of rock burst will decrease if dS/dt<0. The correctness of these methods is demonstrated by analyses of rock failure cases in DCM.     

Stress spatial evolution law and rockburst danger induced by coal mining in fault zone

In order to explore the influence of coal mining disturbance on the rockburst occurring in fault zone, this research constructed a mechanical model for the evolution of fault stress, and analyzed the influence of the ratio of horizontal stress to vertical stress on the stability of fault, and the spatial distribution of the stress in fault zone as well as its evolution rule. Furthermore, the rockburst danger at different spatial areas of fault zone was predicated. Results show that: when both sides of the working face are mined out, the fault zone in the working face presents greater horizontal and vertical stresses at its boundaries but exhibits smaller stresses in its middle section; however, the ratio of horizontal stress to vertical stress is found to be greater at middle section and smaller at boundaries. As the working face advances towards the fault, the horizontal and vertical stresses of the fault firstly increases and then decreases; conversely,the ratio of horizontal stress to vertical stress keeps decreasing all the time. Therefore, if the fault zones are closer to the goaf and the coal wall, the stress ratio will be smaller, and the fault slip will be more prone to occur, therefore rockburst danger will be greater. This research results provide guidance for the rockburst prevention and hazard control of the coal mining in fault zone.     

断层影响下冲击地压多参量预测预报研究

针对深部冲击地压发生机理的复杂性及日趋严重性,在考虑断层活化影响下,提出冲击地压多参量预测预报理论并成功应用于义马跃进煤矿的冲击地压预报,为今后深部构造影响下冲击地压的预测预报提供了参考．     

Prevention of rockburst by guide holes based on numerical simulations

We studied variations in the stress field around guide holes drilled during tunnel excavation to understand the mechanical mechanism by which these holes help prevent rockburst. The study used elasto-plastic analysis of a circular chamber under non-axisymmetrical loads. The results showed that the unloading of in-situ stresses, and the forming of a secondary stress field, leads to a severe change in the stress field around the guide holes. This causes the formation of an X-shaped area of plastic deformation, which prevents the rockburst. Adopting a sub-model finite dement technique, we analyzed the factors that influence the distribution of the plastic area, such as the guide hole distribution and the in-situ stress state. The calculations showed that higher initial stresses result in greater adjustment to the stress field. When the stress concentration is greater the size of the plastic area surrounding the guide hole is larger. A multi-row distribution of the guide holes shaped like a quincunX can increase the interconnectivity of the plastic areas and allow the plastic area to extend from the tunnel wall deep into the surrounding rock. An optimized design was put forward based on the distribution of the plastic area around guide holes and the factors that influence it.