论地质岩性对煤矿压力的影响与支护策略

本文从地质岩性方面出发,研究地质岩性对煤矿压力的影响,煤矿主要成分是沉积岩,因此就从沉积岩这个角度来研究煤矿压力的影响,最后提出了一些支护策略。

煤矿巷道矿山压力分布规律与矿压防治分析

六家煤矿在软岩条件下的矿山压力问题,一直是影响生产安全的难题。为了确保矿区稳定与工人安全,分析六家煤矿巷道矿山压力分布规律,并制定科学有效的矿压防治措施尤为关键。本文基于充分的工程资料和实际生产数据,结合西二采区南翼三、四段的详细概况,对六家煤矿巷道的矿山压力分布规律进行系统性分析,并对矿压防治提出建设性意见。

煤矿安全生产压力容器事故风险管理体系在东林煤矿的应用

选取东林煤矿8大类主要煤矿事故中的压力容器事故为分析对象,以《重庆市突发事件风险管理操作指南(试行)》的"六表一图"为核心框架,开展国有煤矿压力容器事故风险评估工作。首先,列出"煤矿压力容器事故风险目录",得到"煤矿压力容器事故风险采集表";其次,计算"煤矿压力容器事故风险损害后果"和"煤矿压力容器事故风险可能性",绘制"煤矿压力容器事故风险矩阵",得出煤矿压力容器事故风险等级值;再次,根据煤矿压力容器事故风险评估的汇总结果,提出风险的管理标准、技术措施、管理措施和应急准备措施。通过研究,为国有煤与瓦斯突出矿井的压力容器事故风险管理提供一个应用示范案例。

煤矿实用液压压力机的设计与性能分析

阐述了煤矿机械设备维修用液压压力机(用废旧液压元件和材料制造)设计的主要内容,简要说明了其结构特点,并分析了液压系统的性能。

Support failure of a high-stress soft-rock roadway in deep coal mine and the equalized yielding support technology： a case study

Abstract There are many soft-rock roadway coal mines in China. The surrounding rocks of the high-stress soft-rock roadways in deep mine are especially difficult to be supported using the traditional supporting way. In this study, the south wing rail roadway on the second level of Yunjialing coal mine in China was used as an example to analyze the deformation and failure characteristics and influencing factors of roadway. On this basis, this study proposed the equalized yielding support idea which employs the yielding rings to realize the pressure equalization on the bolts and cables in the section. To achieve this purpose, the first bolt-mesh-cable equalizing pressure yielding support was integrated with the second grouting reinforcement. The results proved that the yield rings of the bolts and cables on the spandrel of the arched roadway firstly developed yielding deformation; then the deformation extended to the vault of the roadway; the bolts and cables achieved a yielding extreme value of 15 and 18 tonnes, respectively. The roadway surrounding rock tended to be stable at the 26th day after the maintenance. The equalizing pressure yielding supporting technology plays a moderate pressure-releasing and actively controlling role on the surrounding rocks in the soft-rock roadway with large deformation.

Energy dissipation rate: An indicator of coal deformation and failure under static and dynamic compressive loads

Dynamic disasters in Chinese coal mines pose a significant threat to coal productivity. Thus, a thorough understanding of the deformation and failure processes of coal is necessary. In this study, the energy dissipation rate is proposed as a novel indicator of coal deformation and failure under static and dynamic compressive loads. The relationship between stress-strain, uniaxial compressive strength, displacement rate, loading rate, fractal dimension, and energy dissipation rate was investigated through experiments conducted using the MTS C60 tests(static loads) and split Hopkinson pressure bar system(dynamic loads). The results show that the energy dissipation rate peaks are associated with stress drop during coal deformation, and also positively related to the uniaxial compressive strength. A higher displacement rate of quasi-static loads leads to an initial increase and then a decrease in energy dissipation rate, whereas a higher loading rate of dynamic loads results in larger energy dissipation rate. Theoretical analysis indicates that a sudden increase in energy dissipation rate suggests partial fracture occurring within coal under both quasi-static and dynamic loads. Hence, the energy dissipation rate is an essential indicator of partial fracture and final failure within coal, as well as a prospective precursor for catastrophic failure in coal mine.

Numerical simulation and analysis of underground pressure in the 101 fully-mechanized top coal caving face of the Tingnan Coalmine

The forms of roof break,roof fall,and effects of the region scope in a fully mechanizedtop-coal caving (FMTC) face of the 101 fully-mechanized top coal caving face ofthe Tingnan Coalmine were analyzed by UDEC and FLAC^(3D) software.The analysis resultconfirms the phenomenon of roof falling,roof-off-strata,roof breaking,first weighting,periodicweighting and stress concentration,redistributions of surrounding rock and so on.Itprovides the gist to analyze the law of roof movement,characteristic of confining pressure,and to determine the formative structure forms of the immediate roof and main roof duringthe caving process.These results and the underground pressure observation results are inagreement.

Realizing of Optimization of Binder Backfill Material Under Certain Strength with Fuzzy Sets

The main factors deciding the compressive strength of binder backfill body are tailing density and binder dosage in binder backfill materials. Based on the antecedent of certain pulp density, the method of increasing the tailing density and reducing the binder dosage, or the manner of cutting down the tailing density and gaining the binder dosage are taken to guarantee the strength of backfill body. The problem that should be solved is how to determine the tailing density and the binder dosage rationally. This paper tries to realize the correct selection of the tailing density and the binder dosage in computer with the method of fuzzy mathematics.

中国综采放顶煤开采现状及展望

近年来,中国特厚煤层综采放顶煤开采在理论研究和实践方面取得了显著进展。中国特厚煤层储量比重占42％左右,由于放顶煤开采具有独特的优势,已日益引起人们的关注。本文进一步探索顶煤移动和破碎的规律、矿山压力显现、放煤步距与回采率合矸率关系、合理的采放高度比、不断完善放煤工艺和设备、适用条件和范围以及综采放顶煤开采的主要问题及其对策等,力求综采放顶煤开采在技术上、经济上、安全上进一步完善提高,实现中国高产高效现代化工作面和矿井。

Technical scheme and application of pressure-relief gas extraction in multi-coal seam mining region

A pressure relief gas extraction technical model of a typical mining area is proposed based on coal and gas simultaneous extraction theory. Flac3 Dwas employed to model vertical stress and displacement contour plot characteristics of non-outburst coal seam(No. 4) on top of outburst coal seam(No. 2) along strike and incline directions. Field investigations were also conducted to verify the scientific nature of the simulation. The results demonstrate that gas pressure in No. 2 coal seam dropped to approximately 0.55 MPa in the pressure relief multi-coal seam. The highest expansion rate of the coal mine reached up to 2.58%.The pressure-relief angle was 76° along the incline direction and 60° along the strike direction. As the expansion rate and pressure-relief angle increased and the gas pressure decreased, a large amount of gas flowed into the gob of No. 4 from No. 2 coal seam and was later discharged through specific gas pipes,which eliminated No. 2 outburst risks. This study resulted in positive outcomes in that gas extraction time was reduced by 13.5 days, due to pressure relief, and drilling work load was reduced by 0.1161 m/t coal. This method ensures that gas is discharged from the outburst coal seam quickly and safely,demonstrating that the proposed technical model of pressure-relief gas extraction is effective in a multi-coal seam region.

Study on gob-side entry retaining technique with roadside packing in longwall top-coal caving technology

Pointed out some technical difficulties of gob-side entry retaining with roadside packing in longwall top-coal caving technology (LTCT), and analyzed the function mecha-nism of roadside filling body. Theory analysis shows the mechanical properties of high water material fit for the feature of deformation of gob-side entry retaining in LTCT, and gob-side entry retaining in LTCT face is one of effective ways to increase the recovery ra-tio of mining district.

Experiment study on the propagation laws of gas and coal dust explosion in coal mine

The experiment of gas and coal dust explosion propagation in a single lanewaywas carried out in a large experimental roadway that is nearly the same with actual environmentand geometry conditions.In the experiment,the time when the gas and coal dustexplosion flame reaches test points has a logarithmic function relation with the test pointdistances.The explosion flame propagation velocity rises rapidly in the foreside of the coaldust segment and comes down after that.The length of the flame area is about 2 timesthat of the original coal dust accumulation area.Shock wave pressure comes down to therock bottom in the coal dust segment,then reaches the maximum peak rapidly and comesdown.The theoretical basis of the research and assemble of across or explosion is suppliedby the experiment conclusion.Compared with gas explosion,the force and destructiondegree of gas and coal dust explosion is much larger.

Review of roadway control in soft surrounding rock under dynamic pressure

The basic characteristics of the soft rock roadway under the dynamic pressure are analyzed. At the same time, the three fundamental approaches for controlling the surrounding rock are proposed, which are improving the surrounding rock strength, lowering the rock mass stress and selecting the reasonable supporting technology. The research results are elucidated, including the distribution of the surrounding rock plastic zone, the movement and damage of the surrounding rock under the dynamic pressure, controlling the floor heave through reinforcing the roadway walls and corners, the new route to develop the roadway metal supporting technique, the key theory and technique for the bolt supporting in the coal roadway, the performance and prospect of the ZKD high water content quick setting material, and so on. Finally, some personally views are put forward about the roadway metal supporting, bolt supporting, new material and the stress relief under the high stress condition.

Stability assessment of the freeway over the gob of coalmine

The freeway passes over the gob area of the Zaibo coalmine or its neighbor- hood when it is built. It is a noticeable problem that the construction of freeway and the underground coal mining interact, especially the deformation and destruction of the gob area of the coalmine influence the long-term stability of the freeway. In the paper, based on the actual data of the exploration about the gob area of Zaibo coalmine and the built project of the freeway,the variety rule of the coal beds below the freeway was studied by using of FEM during the process of coal mining. The statuses of the stresses and strains,the varieties of the plastic area were simulated in the whole rock mass. The characters of stresses and deformation of the gob area of the coalmine were analyzed and evaluated after the freeway built. The long-term stability of the gob area was pre- dicted. The deformation of the gob area under the freeway has not been finished, and the relative measures must be taken.

加强锚杆+W钢带+锚索+网联合支护强度在冲击地压巷道中的应用

煤矿巷道施工后在短时间内顶板帮部巷道变形,巷道出现锚杆、锚索托盘变形、顶板出现网兜坠顶、两帮出现不同程度的鼓出等现象。通过优化支护参数、加强支护措施等效果较好,进一步保障了矿井安全生产。

Strata behavior investigation for high-intensity mining in the water-rich coal seam

This paper describes a specific case of mining in a water-rich coal seam in western China. Water inrushes,roof caving and other disasters induced by intensive mining operation could pose great threats to the safety of coal mines. The strata behavior during the high-intensity extraction in the water-rich coal seam is analyzed by employing the numerical simulation method and in situ monitoring. The results show that about 10 m ahead of the workface, the front abutment pressure peaks is at 34.13 MPa, while the peak of the side abutment pressure is located about 8 m away from the gateway with the value of 12.41 MPa; the height of the fracture zone, the first weighting step and the cycle weighting step are calculated to be 45,50 and 20.8 m, respectively; pressure distribution in the workface is characterized by that the vertical pressure in the center occurs earlier and is stronger than those on both ends. Then, the results above are verified by in situ measurement, which may provide a basis for safe mining under similar conditions.

Dust removal efficiency of high pressure atomization in underground coal mine

To master theoretical calculation for dust removal efficiency of high pressure atomization in an underground coal mine, the corresponding atomization characteristics and dust removal efficiency were both comprehensively studied in theory by virtue of related theories of hydromechanics and aerosol.According to actual measurements of flow coefficients and atomization angles of X-type swirl nozzle,computational formula was derived for atomized particle sizes of such a nozzle in conjunction with relevant empirical equation. Moreover, a mathematical model for applying high pressure atomization to dust removal in underground coal mine was also established to deduce theoretical computation formula of fractional efficiency. Then, Matlab was adopted to portray the relation curve between fractional efficiency and influence factors. In addition, a theoretical formula was also set up for removal efficiency of respirable dust and total coal dust based on dust size and frequency distribution equations. In the end,impacts of dust characteristic parameters on various dust removal efficiencies were analyzed.

Effect of variation in gas distribution on explosion propagation characteristics in coal mines

In order to investigate the effect of variation in the distribution of gas on explosion propagation characteristics in coal mines, experiments were carried out in two different channels with variation in gas concentration and geometry. Flame and pressure transducers were used to track the explosion front velocity. The flame speed (Sf) showed a slight downward trend while the methane concentration varied from 10% to 3% in the experimental channel. The peak overpressure (Pmax) dropped dramatically when compared with normal conditions. As well, the values of Pmax and Sf decreased when the methane concentration dropped from 8% to 6%. The flame speed in the channel, connected to a cylinder with a length varying from 0.5 to 2 m, was greater than that in the normal channel. The peak overpressure was also higher than that under normal conditions because of a higher flame speed and stronger pressure piling up. The values of Pmax and Sf increased with an increase in cylinder length. The research results indicate that damage caused by explosions can be reduced by decreasing the gas concentration, which should be immediately detected in roadways with large cross-sections because of the possibility of greater destruction caused by more serious explosions.

bStudy on constitutive relationship of coal based on conventional triaxial compression test

Constitutive relationship of coal under triaxial compression must be determined during solving the theoretical calculation and numerical simulation about coal body failure. This paper carried out conventional triaxial compression test on No.3 coal of Baodian Colliery using MTS815.03 servo-controlled rock mechanical test system. The results indicate that the failure process of coal can be divided into 5 stages： densification stage, apparent linear elastic deformation stage, accelerated inelastic deformation stage, fracture and developing stage and plasticity flow stage. Combined with the test results, the constitutive relationship model of coal can be simplified as the four segments of straight line model of elastic-plastic hardening-plastic softening-residual perfectly plastic. Through fitting calculation of test data, the segmented constitutive equation of coal can be obtained.

DEEP COLLIERY PRESSURE BUMPS AND ITS PREVENTIONS UNDER THE ACTION OF ABUTMENT PRESSURE

Based on field measurement, the relations was introduced between mining bepth and the peak value places of abutment pressures in long wall face of the deep colliery with caving method to handle goaf, and the reasons aod kinds of pressure bumps are analysed under the action of tbe moving and constant abutment pressures formed by the method of long wall caving or room and pillar mining, and the relative precautions were put foward to prevent the pressure bumps in deep mining.