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1.
矿山工程地质中往往存在断层和采空区,微震信号传播经过断层和采空区时,其传播规律必然会发生改变,因此研究特殊地质结构微震信号传播规律具有重要意义。基于惠更斯原理,考虑不同层状岩体中微震波传播速度不同,建立了非均匀介质条件下微震波的波面方程,进而获得波面半径与入射角之间的关系。结合室内相似材料模型实验,验证了波面方程的适用性,同时总结了断层、采空区对微震信号传播的影响特征。研究结果表明：微震信号穿过断层的用时更长,断层的存在导致信号的能量（最大振速）发生较大幅度的衰减;微震信号穿过断层后会以原来的速度继续传播,信号能量的衰减并不会使微震信号的传播速度发生衰减;微震波穿过断层时的入射角越大,穿过断层的用时越长,信号的能量衰减越多;采空区的存在导致微震信号的传播速度发生衰减,震源与监测点之间的距离越近,采空区对微震信号相对传播速度的影响越大。 相似文献
2.
为分析采动地震波煤岩响应及其波场特性,构建顶板岩层和煤层2种传播介质接收采动地震波的多通道微震监测系统,研究2种介质采动地震波的传播和衰减特征。研究结果表明：顶板岩层接收到采动地震波的平均波速、加速度均高于煤层,2种介质中的地震波加速度均与爆破装药量成正相关,与传播距离、介质密度负相关。采动微地震波能量、信号时长随传播距离分别呈指数、线性衰减,近爆心处煤层传播微地震波能量、信号时长均高于顶板,超过一定距离后顶板高于煤层;采动微地震波传播距离有限,顶板的有效传播距离高于煤层,地震波有效传播距离与爆破装药量线性正相关。采动地震波低频部分的品质因子高于高频部分,顶板岩层的品质因子高于煤层。研究成果有助于地震波传播介质选取、检波器布设优化。 相似文献
3.
以忻州窑矿8939工作面为工程背景,运用弹性板理论分析坚硬顶板破断期间释放的弹性能量值,并利用FLAC3D数值模拟划分工作面回采期间的高应力区域,同时根据分形理论分析微震事件的时间分布、空间分布与冲击地压的内部关联。研究结果表明:坚硬顶板断裂前,悬露顶板由于旋转下沉不断对工作面前方煤体缓慢加载,由于过程缓慢,应力与能量不断向煤岩体深部转移,不易发生冲击地压。当顶板断裂时,会瞬间释放大量的弯曲应变能,对工作面周围煤体产生强大的脉冲作用,若脉冲能量超过冲击地压的临界值,则发生冲击地压的可能性较大。且冲击地压发生之前,煤岩体处于非稳定状态,会与外界积极交换能量,此时微震事件处于活跃期,当微震能量超过一定数值或微震事件的分维值低于某临界值时,易发生冲击地压。 相似文献
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5.
To assess rock burst prone zones in the lower seam during multi-seam mining, a rock burst hazard assessment method for use in multi-seam mining was established. According to the observed geological evolution, the feasibility of using upper layer coal mining data to determine the rock burst risk zone of the lower coal seam is explained. Then, we established the energy density risk index (EDRI) and proved that the EDRI more accurately reflected the potential rock burst region than the multi-factor coupling analysis method. Finally, we established the rock burst hazard assessment method for use in multi-seam mining by using the EDRI of the upper coal to divide the rock burst risk zone in the lower coal. From the accuracy and validity analysis of this assessment method, we find that the critical energy induced rock burst, and the damage area of a rock burst in the lower coal seam were all located in the high-risk zone derived from this assessment method. To quantify the effectiveness and practicability of this assessment method, the structural similarity (SSIM) index, from image quality assessment research, was introduced. The SSIM index between predicted-high-risk map and actual high-risk map index was 0.8581, which shows that the established rock burst hazard assessment method in multi-seam mining can be used to predict rock burst risk zones in the lower seam. 相似文献
6.
A method of tremor risk estimation on the basis of seismic emission registered in mining exploitation zones is presented in this paper. A considerable part of the emission registered in these conditions, is generated by mechanical devices used in the mine (miner transporters etc.). Therefore, it is not possible to evaluate the risk of mining rock-bursts properly on the basis of interpretation of emission using known theories and models describing rock mass fracturing. In a new approach presented in this paper, the tremor risk is determined on the basis of time variation of a parameter describing the attenuation of seismic vibrations of the rock medium. The attenuation is assessed from the analysis of seismic emission registered in the frequency range from 30 Hz to 1000 Hz. Information about this parameter is encapsulated in the seismic emission regardless of the means of its generation. The method of estimating the temporal variations of attenuation is based on the analysis of signal envelopes of the microseismic emission. Attenuation trends can be interpreted in a straightforward way. As the stress values keep increasing, the following processes take place in the rock mass: compaction (hardening), dilatancy (softening), and then possibly tremors. At the compaction stage attenuation values are lower, while they increase at the dilatancy stage. This mechanism has been proven in practice. Our results can be used for monitoring tremor risk. 相似文献
7.
Seismic hazard studies were conducted for Gaziantep city in the South Anatolia of Turkey. For this purpose, a new attenuation
relationship was developed using the data of Zaré and Bard and accelerations were predicted employing this new equation. Deterministic
approach, total probability theorem and GIS methodology were all together utilized for the seismic assessments. Seismic hazard
maps with 0.25° grid intervals considering the site conditions were produced by the GIS technique. The results indicated that
the acceleration values by the GIS hazard modelings were matched with the ones from the deterministic approach, however, they
were underestimated comparing with the total probability theorem. In addition, the GIS based seismic hazard maps showed that
the current seismic map of Turkey fairly yields conservative acceleration values for the Gaziantep region. Therefore, the
constructed GIS hazard models are offered as a base map for a further modification of the current seismic hazard map. 相似文献
8.
淮北矿区主采煤层多存在岩浆岩侵入现象，且具有侵入煤层多、分布面积广、侵入方式复杂等特点，常规地震勘探无法保证其解释精度。针对该问题，以全数字高密度三维地震勘探数据体为基础，对比分析不同岩浆岩侵入状态的地震响应特征；综合利用基于地层物性差异的地震多属性分析技术、基于波形差异的地震相分析技术和基于阻抗差异的测井约束波阻抗反演技术，进行煤层岩浆岩侵入区的识别与解释，精细雕刻其空间分布规律。研究表明:薄层岩浆岩侵入区以测井约束的波阻抗反演解释精度高，厚层岩浆岩侵入区预测则综合地震属性分析与地震相分析结果。因此，根据矿区的煤层分布和岩浆岩侵入特征，综合运用地震属性技术、地震相技术与波阻抗反演技术，能有效刻画出岩浆岩侵入煤层的分布范围。 相似文献
9.
应用覆岩空间结构学术观点对孤岛顶煤综放采场冲击矿压机制及其控制技术进行研究。根据覆岩关键层的岩性、层位、范围等因素,覆岩关键层空间结构分为覆岩空间大结构和基本顶有限矿压结构。孤岛顶煤采场冲击矿压发生机制：①孤岛顶煤综放采场 ? 型空间大结构形成过程是集中压力逐渐增加的过程,是该时间段发生冲击矿压的力源;②采场基本顶形成最下位 ? 型空间结构后,随着工作面推进,基本顶块体产生滑落失稳,造成工作面冲击矿压现象。通过对分段来压理论、基本顶结构失稳理论和坚硬顶板预断裂理论对覆岩关键层空间结构运动的控制作用研究,提出采用覆岩空间结构理论分析、分阶段降低放煤率、坚硬覆岩预爆泄压技术、覆岩坚硬岩层破裂的微地震监测技术等方式方法预防冲击矿压的发生。 相似文献
10.
Microseism Induced by Transient Release of In Situ Stress During Deep Rock Mass Excavation by Blasting 总被引：1，自引：0，他引：1
Jianhua Yang Wenbo Lu Ming Chen Peng Yan Chuangbing Zhou 《Rock Mechanics and Rock Engineering》2013,46(4):859-875
During deep rock mass excavation with the method of drill and blast, accompanying the secession of rock fragments and the formation of a new free surface, in situ stress on this boundary is suddenly released within several milliseconds, which is termed the transient release of in situ stress. In this process, enormous strain energy around the excavation face is instantly released in the form of kinetic energy and it inevitably induces microseismic events in surrounding rock masses. Thus, blasting excavation-induced microseismic vibrations in high-stress rock masses are attributed to the combined action of explosion and the transient release of in situ stress. The intensity of stress release-induced microseisms, which depends mainly on the magnitude of the in situ stress and the dimension of the excavation face, is comparable to that of explosion-induced vibrations. With the methods of time–energy density analysis, amplitude spectrum analysis, and finite impulse response (FIR) digital filter, microseismic vibrations induced by the transient release of in situ stress were identified and separated from recorded microseismic signals during a blast of deep rock masses in the Pubugou Hydropower Station. The results show that the low-frequency component in the microseismic records results mainly from the transient release of in situ stress, while the high-frequency component originates primarily from explosion. In addition, a numerical simulation was conducted to demonstrate the occurrence of microseismic events by the transient release of in situ stress, and the results seem to have confirmed fairly well the separated vibrations from microseismic records. 相似文献
11.
岩体破裂矩张量反演方法及其应用 总被引：1，自引：0，他引：1
地震及岩体失稳破裂过程中,破裂机制、震源参数及破裂能量等信息均可通过矩张量方法求解,文中详细介绍了矩张量基本理论,对比分析了绝对矩张量反演法、相对矩张量反演法、混合型矩张量反演法等3种常用方法的优缺点。在详细归纳、总结国内外相关文献的基础上,就水压致裂、采矿及深埋隧道等工程领域综述了矩张量反演理论在岩体工程中的应用现状,并结合其在德国黑林根矿区微震事件震源机制分析中的应用实例,表明通过矩张量反演获取的震源机制解及震源参数等信息,在岩体工程灾害预警及防治、水压致裂过程监测和控制等领域具有重要作用。最后分析了影响矩张量反演精度的因素及应用于岩体工程领域时存在的不足,包括定位精度低、波形识别及处理困难等问题,并对其在采矿、石油等岩体工程领域的应用前景、改进措施及需进一步研究的问题等进行了探讨,为矩张量反演方法的推广应用提供重要的参考。 相似文献
12.
In this work, an attempt has been made to evaluate the spatial variation of peak horizontal acceleration (PHA) and spectral
acceleration (SA) values at rock level for south India based on the probabilistic seismic hazard analysis (PSHA). These values
were estimated by considering the uncertainties involved in magnitude, hypocentral distance and attenuation of seismic waves.
Different models were used for the hazard evaluation, and they were combined together using a logic tree approach. For evaluating
the seismic hazard, the study area was divided into small grids of size 0.1° × 0.1°, and the hazard parameters were calculated
at the centre of each of these grid cells by considering all the seismic sources within a radius of 300 km. Rock level PHA
values and SA at 1 s corresponding to 10% probability of exceedance in 50 years were evaluated for all the grid points. Maps
showing the spatial variation of rock level PHA values and SA at 1 s for the entire south India are presented in this paper.
To compare the seismic hazard for some of the important cities, the seismic hazard curves and the uniform hazard response
spectrum (UHRS) at rock level with 10% probability of exceedance in 50 years are also presented in this work. 相似文献
13.
微震信号在层状岩体中传播规律的研究对于实现震源准确定位具有重要的现实意义。在天然岩体中，微震信号在岩层中传播的速度，不仅受其内部因素即岩石自身物理性质的影响，还受外部因素如地质结构面、断层及采空区等条件的影响。通过室内试验的方法对微震信号在不同岩层及采空区处的传播规律进行研究。结果表明：波速随着传播距离的增加而逐渐衰减，且岩层密度越大衰减越慢；穿过的结构面数量越多，微震信号传播速度衰减比例越大；能量的衰减与波速的衰减一致。采空区断面横截面积越大，微震信号通过的用时越长；采空区周围岩石密度、弹性模量等物理性质的数值越大，微震信号通过时衰减越少。边际谱分析结果表明：断层对频率高的微震信号阻碍作用更强。 相似文献
14.
15.
页岩气地震识别与预测技术 总被引：2，自引：0，他引：2
依据页岩气的地质特点及当前地震勘查技术的水平,指出地震在识别和追踪页岩储层空间分布（包括埋深、厚度以及构造形态）方面具有明显的优势;综合利用测井及地质资料,对页岩储层有机质丰度、含气性等参数进行解释及优选敏感的地球物理参数,进而建立储层特征与地震响应的关系,以此反演预测页岩气储层有利区;运用相干与曲率等属性分析技术、宽方位甚至全方位地震各向异性分析技术、叠前反演技术、横波分裂技术等,可解决储层裂缝和岩石力学特征问题,直接为钻井和压裂工程技术服务;与压裂技术配套发展的微地震监测技术,可实时提供压裂过程中产生的裂缝位置、方位、大小以及复杂程度,并对储层改造方案的有效性作出准确评价。 相似文献
16.
The use of logic trees in probabilistic seismic hazard analyses often involves a large number of branches that reflect the uncertainty in the selection of different models and in the selection of the parameter values of each model. The sensitivity analysis, as proposed by Rabinowitz and Steinberg [Rabinowitz, N., Steinberg, D.M., 1991. Seismic hazard sensitivity analysis: a multi-parameter approach. Bull. Seismol. Soc. Am. 81, 796–817], is an efficient tool that allows the construction of logic trees focusing attention on the parameters that have greater impact on the hazard.In this paper the sensitivity analysis is performed in order to identify the parameters that have the largest influence on the Western Liguria (North Western Italy) seismic hazard. The analysis is conducted for six strategic sites following the multi-parameter approach developed by Rabinowitz and Steinberg [Rabinowitz, N., Steinberg, D.M., 1991. Seismic hazard sensitivity analysis: a multi-parameter approach. Bull. Seismol. Soc. Am. 81, 796–817] and accounts for both mean hazard values and hazard values corresponding to different percentiles (e.g., 16%-ile and 84%-ile). The results are assessed in terms of the expected PGA with a 10% probability of exceedance in 50 years for rock conditions and account for both the contribution from specific source zones using the Cornell approach [Cornell, C.A., 1968. Engineering seismic risk analysis. Bull. Seismol. Soc. Am. 58, 1583–1606] and the spatially smoothed seismicity [Frankel, A., 1995. Mapping seismic hazard in the Central and Eastern United States. Seismol. Res. Lett. 66, 8–21]. The influence of different procedures for calculating seismic hazard, seismic catalogues (epicentral parameters), source zone models, frequency–magnitude parameters, maximum earthquake magnitude values and attenuation relationships is considered. As a result, the sensitivity analysis allows us to identify the parameters with higher influence on the hazard. Only these parameters should be subjected to careful discussion or further research in order to reduce the uncertainty in the hazard while those with little or no effect can be excluded from subsequent logic-tree-based seismic hazard analyses. 相似文献
17.
Józef Kabiesz 《Geotechnical and Geological Engineering》2006,24(5):1131-1147
During hard coal mining operations conducted under conditions of rockburst hazard, one of the most important preventive measures
can be the prediction of occurrence time and location of the strong seismic mine tremors of energy E
s ⩾ 104 J. This is a very difficult task and the way it is being currently performed appears to be unsatisfactory. Therefore, attempts
have been made to use neural networks, specifically trained for this application. The paper presents an approach for determining
an influence of the type and shape of the input data on the efficiency of such a prediction. The considerations are based
on a selected example of the seismic activity recorded during longwall mining operations conducted in one of the Polish mines. 相似文献
18.
Anye Cao Linming Dou Wu Cai Siyuan Gong Sai Liu Yongliang Zhao 《Arabian Journal of Geosciences》2016,9(3):232
Anomalous information identification is a key issue for seismic hazard prevention in underground mining. Velocity tomograms can image the stress redistribution around coal face and provide better understanding of strata failure mechanisms. In this paper, based on microseismic events recorded during mining operation, passive tomographic imagings have been presented to assess strong tremor hazard and locate high seismic activity zones around an island coal face under super-thick strata. The zones of high velocity or velocity gradient anomalies have been found to correlate well with the distribution of strong tremors, indicating that velocity tomography is feasible for seismic hazard assessment and risk region division in underground mining. 相似文献
19.
The Dynamic Evaluation of Rock Slope Stability Considering the Effects of Microseismic Damage 总被引：1，自引：1，他引：0
N. W. Xu F. Dai Z. Z. Liang Z. Zhou C. Sha C. A. Tang 《Rock Mechanics and Rock Engineering》2014,47(2):621-642
A state-of-the-art microseismic monitoring system has been implemented at the left bank slope of the Jinping first stage hydropower station since June 2009. The main objectives are to ensure slope safety under continuous excavation at the left slope, and, very recently, the safety of the concrete arch dam. The safety of the excavated slope is investigated through the development of fast and accurate real-time event location techniques aimed at assessing the evolution and migration of the seismic activity, as well as through the development of prediction capabilities for rock slope instability. Myriads of seismic events at the slope have been recorded by the microseismic monitoring system. Regions of damaged rock mass have been identified and delineated on the basis of the tempo-spatial distribution analysis of microseismic activity during the periods of excavation and consolidation grouting. However, how to effectively utilize the abundant microseismic data in order to quantify the stability of the slope remains a challenge. In this paper, a rock mass damage evolutional model based on microseismic data is proposed, combined with a 3D finite element method (FEM) model for feedback analysis of the left bank slope stability. The model elements with microseismic damage are interrogated and the deteriorated mechanical parameters determined accordingly. The relationship between microseismic activities induced by rock mass damage during slope instability, strength degradation, and dynamic instability of the slope are explored, and the slope stability is quantitatively evaluated. The results indicate that a constitutive relation considering microseismic damage is concordant with the simulation results and the influence of rock mass damage can be allowed for its feedback analysis of 3D slope stability. In addition, the safety coefficient of the rock slope considering microseismic damage is reduced by a value of 0.11, in comparison to the virgin rock slope model. Our results demonstrate that microseismic activity induced by construction disturbance only slightly affects the stability of the slope. The proposed feedback analysis technique provides a novel method for dynamically assessing rock slope stability and can be used to assess the slope stability of other similar rock slopes. 相似文献
20.
导水裂隙带发育高度是矿井水害预测的重要技术参数之一。以彬长矿区文家坡煤矿4103工作面为研究对象，利用井-地联合微震监测技术对顶板导水裂隙带发育特征进行研究。研究结果表明:深埋煤层开采时，微震事件超前工作面回采位置发育，超前影响角最大为35°，最小为28°；断层的存在降低了覆岩稳定性，相较于正常基岩，更易在回采影响下发生应力集中和破坏；断层加大了微震事件发生的超前距，而采空区则使微震事件的高密度区向其所在部位发生偏移，加剧覆岩破坏程度，增大导水裂隙带发育高度；垂向上，4103工作面监测区内的微震事件高密度区域主要集中在高程+400~+520 m，结合微震事件数量和能量分布特征，判定4103工作面垮落带发育高度为50 m，垮采比13.16，导水裂隙带发育高度为117 m，裂采比为30.79。该成果可为彬长矿区类似煤矿深埋煤层顶板导水裂隙带发育高度研究及顶板水防治提供重要依据。移动阅读 相似文献