From the alternating-sign explosion response of rocks to the pendulum waves in stressed geomedia. Part IV

The scope of this expert and analytical review encompasses major achievements in the area of nonlinear geomechanics, geophysics, geomonitoring and advanced information technologies with a view to developing the natural and induced emergency prevention and response technology listed among the “national critical technologies” in the Russian Federation. The topical trends of the related R&D activities are basic research in physics and geomechanics of natural and induced failure source formation and growth in rocks and in mines, and creation of multi-layer geoinformation monitoring system for geomechanical and geodynamic safety in Russia. The authors believe that the described R&D activities may be the basis for an international multidisciplinary mega-project in geosciences: Engineering and Creation of the World’s Multi- Layer Geomechanical, Geodynamic and Environmental Safety Geoinformation Monitoring System.     

Effect of Pendulum Waves from Earthquakes on Gas-Dynamic Behavior of Coal Seams in Kuzbass

In the framework of the theory of interaction between nonlinear geomechanical and physicochemical processes in coal seams under mining and based on the piston mechanism of gas dynamic processes, it has experimentally been proved that nonlinear quasi-metric elastic pendulum waves from natural and induced earthquakes have influence on gas-dynamics in mines in Kuzbass. The objects selected to identify the interrelationship were the large earthquakes occurred in Kuzbass on November 9, 2016 (magnitudes 2.7 and 3.7) and the records of the quake-induced gas dynamic activity in the Alarda and Osinniki mines.     

Prediction and Prevention of Rock Bursts, Tectonic Shocks, and Technogenic Earthquakes from Positions of Nonlinear Geodynamics

When mining the mineral deposits, prediction and prevention of rock bursts, tectonic shocks, and technogenic earthquakes are considered from positions of nonlinear geodynamics. Conceptual model of the mine represents the open dynamic nonlinear natural and technical system whose geomechanical evolution is realized by alternation of adaptation and bifurcation stages.     

厚硬火成岩下突出煤层动力灾害致因研究

针对海孜煤矿主采煤层顶板上部厚层坚硬火成岩造成的突水、瓦斯突出、冲击地压和地表沉陷等煤岩动力灾害,采用煤样SEM（扫描电镜）分析、组分和反射率测定等方法,研究了厚硬火成岩下突出煤层物性参数特征,采用板应力拱平衡理论研究了采动离层裂隙发育规律,采用梁结构破断弹性理论研究了厚硬火成岩对冲击地压和突水的影响,以揭示厚硬火成岩下突出煤层动力灾害的致因。研究结果表明,巨厚火成岩的热演化和圈闭作用,导致下伏各煤层孔隙发育,吸附瓦斯能力增强,各煤层突出危险性增加;厚硬火成岩为矿井主关键层,受采动影响能长期保持不断裂,其下伏煤岩层的裂隙与离层能长期不闭合,能为卸压瓦斯抽采创造条件;但随着煤层的持续和大面积开采,厚硬火成岩突然破断滑落,破断过程中释放出大量能量并向周围传播,容易引起冲击地压、矿井水灾、瓦斯突出及地表沉陷等复合型动力灾害。     

Temperature dependence of microdamage accumulation in granite under impact fracture

It has been not once noticed that origination and accumulation of fractures in rocks in the full scale and in laboratory specimens have much in common. The lab test data on rock specimen deformation and fracture are often used to interpret natural seismic events. Usually the laboratory tests are carried out at room temperature, whereas the temperature of rocks at the depth of origination of rock bursts and earthquakes can reach a few hundred degrees. To assess the weight of this difference, the authors have obtained time series of acoustic emission impulses during origination of microcracks in granite specimens subjected to impact fracture at varied temperatures. The kinetics of damage accumulation and the cooperative effects differ greatly in the test temperature range from 20 to 600 °C.     

深部冲击地压巷道锚杆支护作用研究与实践

以义马常村煤矿深部冲击地压巷道为工程背景,介绍了深部冲击地压巷道围岩地质力学参数分布特征,分析了冲击地压巷道围岩变形与破坏特征及主要影响因素,揭示出锚杆支护对冲击地压巷道变形的本质作用是保持围岩完整性,在围岩中形成支护应力场,降低应力集中系数,改善巷道围岩应力分布,充分发挥围岩的抗冲击能力。提出冲击地压巷道支护形式选择原则,介绍了高冲击韧性锚杆支护材料力学性能及锚杆支护参数设计方法。针对常村煤矿21220下巷条件,提出以全长预应力锚固、高强度、高冲击韧性锚杆与锚索支护为主,以金属支架为辅的复合支护方式,并进行了井下工业性试验。矿压监测数据表明,该种支护方式与围岩的整体抗冲击能力强,能够有效控制深部冲击地压巷道变形与破坏。在冲击能量影响下,锚杆、锚索受力特征明显不同于普通巷道,呈波浪状或锯齿状变化趋势。     

Geomechanical substantiation of the resource-saving alternatives of the induced block caving method

The paper focuses on the improvement of the ore blasting efficiency in rock masses under the natural, gravity-tectonic and technogenic stresses. The safe and resource-saving process proposed by the authors for the induced block caving in deep hard rock mining reduces consumption of commercial explosives due to the rock pressure energy in the blasting process.     

动力扰动诱发煤层大巷冲击地压机理及其防控技术

为了提高深部矿井煤层大巷冲击地压动力灾害防控效果,基于高家堡煤矿冲击地压灾害发生特点与工程地质条件,通过动静载组合控制煤岩动态破坏的普适性理论方法进行探究,揭示了高家堡煤矿煤层大巷冲击地压致灾机理,明确了动静载复合应力场动力灾害防控途径.在此基础上,考虑煤层大巷服务年限长、 围岩应力集中程度高等特点,结合动力扰动诱发大...     

Wave prefracturing of solid rocks under blasting

Considering features of wave prefracturing (microfailure) of rocks under blasting, the authors put forward a new investigation approach with the use of relations of dynamic elastic stress distribution in rocks and theory of cracks. The obtained relation to estimate prefracturing zone size in relatively solid rocks under confined explosion involves pressure of gases in explosion chamber, rock pressure, crack resistance of rocks, characteristic dimension of natural jointing (presence of defects) and deformation characteristics of rocks. It is shown that dimension of prefracturing zone in rocks depends both on natural and production factors and can differ by a few times.     

抚顺煤田深部开采临界深度的定量判别

以抚顺煤田为工程背景,通过采动微震和瓦斯的现场观测与分析,得到深部开采临界深度是采动岩体的动力响应由线性转为非线性深度的认识。提出用采动岩体的视本构关系、采动微震的分形几何学特征和在浅部未发生过的特殊动力现象定量判断采动岩体力学行为的方法。结果表明,上述3项指标均指示700 m左右的深度是该煤田采动岩体力学行为发生非线性动力响应的临界深度。     

基于动静组合加载力学试验的深部开采岩石力学研究进展与展望

深部围岩开采前处于高静应力状态,开采(开挖)过程中不可避免承受机械或爆破开挖带来的开采扰动、卸载扰动以及应力调整扰动作用,属于典型的动静组合受力状态。用动静组合加载力学研究深部开采岩石力学问题更加符合深部围岩开采的实际情况。从深部围岩开采受力全过程出发,介绍了"岩石动静组合力学"概念和试验研究的提出过程,阐述了岩石动静组合力学试验研究从一维状态到二维状态再到三维状态的发展历程,并重点介绍了真三轴动静组合加载岩石力学试验系统的研制情况和取得的研究进展。根据对深部开采岩石力学科学认识的不断深入,结合动静组合加载岩石力学试验相关研究结果,揭示了深部岩石在各种动静组合受力状态下的力学响应、破坏特征以及能量规律,科学再现并解释了岩爆、板裂及冲击地压等非常规岩石破坏现象和机理。在此基础上,系统总结了真三轴动静组合加载岩石力学试验机的共同特点,并提出了未来研究的4个重点发展方向:(1)发展能实现"三维高静应力+卸载+冲击扰动"功能的真三轴SHPB动静组合加载试验机;(2)发展大尺寸岩石内部卸荷真三轴试验机;(3)基于三维动静组合加载岩石力学试验聚焦深部围岩发生岩爆灾害的能量机理;(4)开展深部原位保...     

朝阳煤矿深部冲击倾向性试验研究

冲击地压灾害防治是深部开采面临的重要难题之一。朝阳煤矿采深在600 m水平以上,后期开采将达到1 200 m。开采初期出现了微弱冲击动力现象,为评价深部煤层的冲击危险性,对不同地点煤层的力学性质与动态破坏特性进行了试验研究,获得了深部煤层冲击倾向性评判结果,同时对深部煤岩体浸水后对冲击倾向的影响进行了研究,为防治冲击地压提供了试验依据。     

深部矿山破碎围岩巷道控制技术研究

当矿山资源埋藏深度在500 m以上时,地压增大,深部开采容易诱发冲击地压等地质灾害。通过实验室岩石力学实验,采用巴顿岩体质量分类评价方法对某深埋矿山回采巷道围岩进行合理分类,可靠地评价围岩稳定性,选择合理开挖方法和支护形式,为支护设计、施工和管理提供科学的依据,可以有效地预防冲击动力灾害的发生。结合工程实际和FLAC^3D数值模拟软件,对某矿破碎围岩矿体回采巷道塑性区范围分布规律进行研究,以便对锚杆支护参数进行优化。研究成果的应用可减少深部开采冲击等动力灾害发生,为大采深破碎围岩矿体安全高效开采提供理论依据。     

From the alternating-sign explosion response of rocks to the pendulum waves in stressed geomedia. Part II

The article reviews research and development results in the sphere of designing unique apparatuses and equipment for modeling and in situ recording of nonlinear elastic waves and associated electro-magnetic emission in block-hierarchical rock masses in the condition of high stresses. The joint experimental outcomes and theoretical research findings gained by leading institutions of the Russian Academy of Sciences and its branches within recent decades, in the framework of integration interdisciplinary projects offer the methodology and instrumentation support for new promising systems of integrated geomechanical and geophysical monitoring of mining-induced earthquakes and rockbursts in Russian mines that may act as unique natural “laboratories” for both academic and applied research in geosciences.     

Measurement of rock movement under blasting in surface mines

A seismic sensing method has been tested in the conditions of a surfaced mine. As a result, dynamic strains of rocks exposed to different strength blasting have been measured with seismic equipment and the prevailing vibro-frequency range has been determined for blasting in rocks and in the dump area with the difference specified. The authors have proposed an approach to choosing parameters of a borehole longitudinal multichannel deformometer intended for deep rock displacement and deformation control.     

基于蝶形破坏理论的地震能量来源

地震发生时释放的巨大能量从何而来,一直以来都是还没有认识清楚的问题。考虑到两组地壳破裂带交叉部位强震频发的基本特点,基于蝶形破坏理论,构建以软弱异性体为中心的能量计算模型,提出了地震能量的计算方法。从软弱异性体围岩发生塑性破坏引发能量改变角度出发,数值模拟分析地震过程中有软弱异性体存在对地壳围岩能量分布的影响,探讨了自然地震触发的一般规律;以中国大陆西南地区含鲁甸ML6. 5级地震震中位置区域为地质背景,进一步对比分析有无软弱异性体条件下,地震震源能量与分布特征的变化规律。研究结果表明:地壳内部软弱异性体使其周围岩体应力重新分布,形成围绕软弱异性体的应力集中;随着挤压与张拉构造应力的加剧,软弱异性体围岩出现蝶形破坏区,蝶形破坏区蝶叶周围岩体集中的大量弹性能,是地震能量主要来源;软弱异性体使其周围岩体能量积聚特征呈指数型变化,且在软弱异性体围岩蝶形塑性破坏演化过程中会形成蝶形能量集中区,标志着系统由稳态向非稳态能量集中的转变;地震发生时软弱异性体周围岩体塑性破坏范围与积聚能量所处的状态决定了地震发生级别的大小,在蝶形塑性破坏的剧烈扩展阶段,微小的应力扰动即可引发整个围岩能量系统的灾变,引发大级别的自然地震。     

破碎岩体非线性渗流突水机理研究现状及发展趋势

在收集整理国内外相关资料的基础上,从非线性渗流理论方程、非Darcy渗流试验和非线性渗流数值模型方法等方面总结目前破碎岩体非线性渗流突水研究现状,认为破碎岩体渗流具有突水通道的非Darcy渗流特性、3种流场(Darcy层流、非Darcy高速流及Navier-Stokes紊流)动力学系统的统一性和突水3要素(含水层水源的Darcy流、突水通道的非Darcy流和开采扰动作用)中的应力扰动特性。据此,提出了破碎岩体非线性渗流突水机理研究的发展趋势:从矿山采动岩体渗流突水3要素这一渗流特征出发,通过试验和现场测试研究不同围压、水力梯度和流速条件下破碎岩石渗流规律,建立考虑应力作用的耦合Darcy,Forchheimer和Navier-Stokes方程混合流场的模型,提出有限单元弱形式和有限体积法耦合积分解算混合流场方法,把采动应力作用下含水层、冒落岩体破碎带和巷道整个突水水流路径连接在一起,Forchheimer流域的边界流量压力是动态变化的,可以有效解决破碎岩体非线性渗流模型存在的问题,能比较合理模拟采动应力作用下矿山突水瞬态流动全过程。     

Post-peak failure modulus in problems of mining geo-mechanics

This paper presents one of the geo-mechanical parameters — post-peak failure modulus. It is a parameter of great importance in solving various problems of mining geo-mechanics at the current level of experimental knowledge. Post-peak failure modulus is obtained through examining rock samples which are loaded in a stiff servo-controlled testing machine. Construction of the machine and its parameters enable obtaining stress-strain characteristics the total strain range of the rock which occurs as a result of increasing load until it reaches the level of residual stress. The most important application of post-peak failure modulus in mining geo-mechanics is using it in estimating the destruction of rocks and rock mass, forecasting rock mass proneness to rock bursts and estimating rock burst hazard, determining the optimum pace of advance for mining activities considering induced seismicity and rock mass proneness to rock bursts, dimensioning pillars in room-and-pillar systems and determining failure zones around workings of various shapes.     

兖州矿区深部开采大能量矿震规律和发生机理研究

兖州煤田矿井在回采的过程中,发生了多起大能量矿震事件,影响了井下的正常生产。通过研究原岩应力重塑影响下断层应力和能量的演化规律,进而对原岩应力破坏重塑后诱发断层构造型矿震过程进行了解释,最终揭示了原岩应力和构造应力耦合作用下矿震发生机理。