Mining Depth Research Articles

Study on the influence of mining disturbance on the variation characteristics of vegetation index: A case study of Lingwu Mining Area

The vegetation growth environment has been seriously affected by the high-intensity mining of coal resources in ecologically fragile mining areas in the Western China. To understand the spatial and temporal variation characteristics of vegetation index in mining area is the precondition of exploring the protective mining methods of surface vegetation. Based on the Landsat-8OLI and Sentinel-2A remote sensing image data from 2016 to 2020, the SBAS-InSAR technology and Arcgis spatial analysis tool were employed in this study; the spatial-temporal evolution of normalized differential vegetation index (NDVI) was analyzed from the mining area scale by regression slope and correlation coefficient. The 10 mm subsidence contour range on the typical working face was extracted as the mining disturbance range. At the scale of the working face, the influence law of mining technical parameters and occurrence conditions on surface vegetation index was revealed. The results show that: (1) Lingwu mining area has relatively low surface vegetation coverage, which conforms to the partial normal distribution; the average NDVI in the southwest of the mining area is greater than that in the northeast. (2) The vegetation growth process in the mining area presents a phenological periodic variation trend, and mining activities have a certain negative impact on the growth of surface vegetation. However, after regional vegetation restoration, the NDVI in the mining area shows a fluctuating growth trend. (3) In the pre-mining stage of the working face, the NDVI change trend of vegetation in the mining area is basically the same; in the mining stage of the working face, the mining influence is relatively small due to the lagging effect of mining subsidence; in the post-mining stage (1–2 years after mining), the growth of vegetation is seriously damaged, and NDVI of the mining area decreases significantly. (4) The mining area of working face is positively correlated with the decline scope of NDVI; the ratio of mining depth to mining thickness and bedrock thickness are negatively related to surface subsidence, which slows down the decline of NDVI; the loose layer on the surface has large thickness, which can also effectively slow down the destruction of vegetation in the subsidence area. The research results are of great significance for further understanding the influence of coal mining on surface vegetation elements in ecologically fragile mining areas in Northwest China.

Research into the Mechanism and Application of Liquid CO2 Phase-Transition Fracturing in a Coal Seam to Enhance Permeability

The geological structures of the coal fields in China are complex. With a continuous increase in the mining depth, the coal seams show the characteristics of high gas and low permeability, and the disaster potential for a coal and gas outburst intensifies in the process of coal mining. Gas drainage is one of the primary measures used to prevent and control gas disasters. Effectively improving the permeability of a coal seam requires urgent attention. Currently, the method of loose blasting is used in engineering to enhance the permeability of coal seams. However, the technology of loose blasting easily leads to the poor development of coal fractures or the severe crushing of coal, which will affect the gas drainage. Thus, this paper studied the technology of liquid CO2 phase-transition fracturing in a coal seam. COMSOL was used to determine the influence radius of the liquid carbon-dioxide phase-transition cracking, which was 13.4 m, and to design the scheme of the borehole. The field test was carried out in the 81,506th working face of the Baode Coal Mine. From the onsite-monitoring data, the results showed that the drainage effect increased by 293.9%, the gas-drainage concentration increased by 242.4%, the permeability coefficient of the coal seam increased by 3–7.75 times, and the permeability enhancement effect was good.

Stability of ore chutes in block caving

The geomechanical focus of the research presented in the article is mainly due to a number of problems that the iron ore mines in Gornaya Shoria face with an increase in the depth of mining. The high natural tectonic stress state of the ore province imposes certain restrictions on the technology and parameters of mineral extraction. The mining system now in use, with blasting and multi-point ore drawing under overlying rock mass using vibrating-and-hauling facilities is a structurally complex technology. It imposes severe requirements on the stability of outlets in the bottom of extraction blocks. One of the main disadvantages of block caving with ore drawing from the bottoms of the extraction blocks is the increased indentation of the block bottom with various-purpose openings. This circumstance prompts the search for new engineering solutions, including the revision of existing ones, to enhance the safety of ore production. To this effect, the mining practices undertake scientific substantiation of measures and recommendations for safe mining operations. In the article, on the basis of mathematical and physical modeling of the stress state of rock mass, the geomechanical assessment of the stability of the outlets in the bottom of the extraction block is given. It is revealed that the technology with massive block caving in rather difficult conditions of the geodynamic stress field and at the great depth of mining, with the accepted design parameters, becomes unsafe and is accompanied by both the loss of stability of rocks and the increased number of ore arching events in ore chutes. Therefore, identification of potentially hazardous places in the structural elements of the mining system, where accidents are possible, is a very popular technique in mine support design.

Determination of physical and mechanical properties of rocks using anti-burst destress measures

Rock bursts are traditionally one of the main problems in the mining industry. In recent years, with an increase in the depth of mineral mining, this problem has become more relevant. To prevent dynamic events induced by rock pressure, various combat methods have been developed at the present time. Among them, the most common approach to prevent rock bursts is destressing by creating local zones of yielding in rocks. This is possible with drilling a series of destress wells or by inducing fractures with blasting. However, for a more accurate assessment of the effectiveness of these measures, it is also necessary to research the change in the properties of rocks during their fracture. In this study, the special model mechanical tests were carried out to determine the strength and strain characteristics of solid sulfide ore samples in the complex loading conditions. Operation of the destress wells was simulated by making holes in the samples. To model destress blasting, softening of the model samples with holes, pressed into steel shells, was performed by exposing them to an explosive pulse from a detonating cord. Lateral compression of the samples by the steel shells created the three-step stress of 15, 30 and 45 MPa in them. In the subsequent uniaxial compression tests on the servo-hydraulic press with the transverse straining control, strength limits, strain characteristics and rock bursting susceptibility of the samples were determined.

Prevention of rock and gas outbursts in super deep-level mining in Internatsionalny Mine

The method of advanced perimeter blasting has found effective application in development heading and stone drivage. The method uses various drilling-and-blasting scenarios subject to the alteration ingeological and geotechnical conditions, and with regard to the spatial location of outburst-hazardous strata relative to the section of a mine road being driven. This article describes the actually implemented prevention of gas-dynamic events using the method of advanced perimeter blasting, and the case-study of the method applied in the outburst-hazardous carbonate rock mass in super deep-level mining in Internatsionalny Mine (depth of 1200 m and more). The records of the gas-dynamic events in the course of drivage with anti-outburst measures are analyzed. The semi-commercial tests of advanced perimeter blasting are described with patterns of drilling and blasting, and designs of charges in shooting outburst-hazardous beds. The effect of blasting on fracturing is estimated by calculation of the blast impact zones as function of the charge mass and length. The observations over variation in the geomechanical and geodynamic behavior of rock mass during drivage with the perimeter blasting efficiency control are analyzed. The studies included examination of geodynamic characteristics of dolomite rock mass susceptible to rock and gas outbursts and the performance evaluation of the preventive advanced perimeter blasting. The quantitative figures on gas-dynamic phenomena and events in striking and intersecting outbursthazardous dolomite beds are given in graphical form. The flow chart of the semi-commercial testing of advanced perimeter blasting is presented, and the fracturing zones induced by the explosion-generated shock in advanced perimeter blasting are calculated.

Influence of Coal Mining on Historical Buildings: Case Study in Shanxi

Numerous historical buildings exist in Shanxi Province, a major coal producing area in China, so there exist many overlapping areas between ancient wooden buildings and coal mining. Coal mining in overlapping areas will lead to surface subsidence, which will have an impact on historical buildings. Based on the distribution of historical buildings and the distribution and mining of coal resources in Shanxi Province, this paper concludes that the overlapping areas of coal mining and ancient wooden buildings in Shanxi Province are mainly concentrated in Changzhi City, and the Lu'an mining area in Changzhi City is selected as the research object. In addition, using the gray correlation analysis method, the surface subsidence coefficient, which characterizes the intensity of mining subsidence, is used as the reference sequence. Seven factors selected from the geological conditions and mining conditions of the Lu'an mining area are used as the comparison sequence to calculate the gray correlation between each influencing factor and the surface subsidence coefficient, and to obtain that geological factors such as the nature of the overlying rock layer, bedrock thickness and dip angle of the coal seam, and mining factors such as mining height, average mining depth and working face size largely determine the surface subsidence coefficient. The surface subsidence in the overlap area could largely be influenced by geological factors such as the nature of the overlying rock layer, bedrock thickness and coal seam inclination, and mining factors such as mining height, average mining depth and working face size. Finally, we investigate the possible effects of surface subsidence on ancient wooden buildings in the overlapping area with the surface subsidence and formation mechanism and propose technical measures to reduce the effects of surface subsidence due to coal mining on historical buildings in the overlapping area.

Failure mechanism and control of coal bursts triggered by mining induced seismicity in steeply inclined and extra thick coal seam

With the increase in mining depth, coal bursts have become a major challenge in the safe mining of steeply inclined and extra thick coal seams (SIETCSs). Based on a typical mining induced seismicity triggered coal burst (MSTCB) in SIETCS, a large-scale numerical model was developed using the Universal Distinct Element Code. The numerical model was calibrated and validated by laboratory results and field observations. The stress evolution, crack development and ejection velocity patterns in the MSTCB were analysed, and the effect of mining induced seismicity vibration velocity on the MSTCB was discussed. The results show that a triangular static stress concentration zone is formed in the coal on the roof side. And the high-energy mining induced seismicity leads to high dynamic stresses in the coal at the roof side rib and top of the headentry. Coal bursts occur under the superposition of static and dynamic stresses. The MSTCB results in tensile failure near the headentry surface and shear failure in the depth. The vibration velocity has a significant effect on the roof side rib and top of the headentry, while it has only a slight effect on the working face rib and bottom of the headentry. The dynamic stress and ejection velocity in the roof side rib and top of the headentry are positively correlated with the vibration velocity. Finally, measures for MSTCB prevention were proposed. The findings presented in this study can provide guidance for the prevention and control of MSTCBs in SIETCSs.

Mapping knowledge domains for mine heat hazard: a bibliometric analysis of research trends and future needs.

As the shallow mineral resources are nearly depleted, the mining of deep resources has become an urgent problem to be studied. The increase in mine depth can lead to the increase of mine heat hazard, which is a critical concern for mining safety/occupational health and safety. However, there are limited review articles available regarding the prevention of mine heat hazard. To fill in this gap, a bibliometric analysis and knowledge mapping of the field of mine heat hazard prevention are presented in this paper. A total of 314 papers from the Web of Science (WOS) core collection database that published between January 1998 and July 2022 were analyzed using VOSviewer and CiteSpace. China, South Africa, Poland, USA, and Australia are the top five countries in this field. The important journals are Applied Thermal Engineering, Applied Energy, Energies, and International Journal of Mining Science and Technology. In addition, the research focal points and two research fronts were identified and discussed. The knowledge base of mine heat hazard research focuses on mine cooling technology, energy efficiency optimization of cooling systems, thermodynamic theory, and occupational health. There are two research fronts. One is to use the numerical simulation method to study various problems such as simulate the performance of refrigeration systems and thermal comfort in mines. The second is to study the occupational health impact of climate change on miners. Therefore, this paper provides readers and academics with an overview of the intellectual structure and knowledge body that have been developed on the subject of mine heat hazard.

Research on Water-Conducting Fractured Zone Height under the Condition of Large Mining Height in Yushen Mining Area, China

Abstract Accurately predicting the development height of the water-conducting fracture zone (HW) is imperative for safe mining in coal mines, in addition to the protection of water resources and the environment. At present, there are relatively few fine-scale zoning studies that specifically focus on predicting the HW under high-intensity mining conditions in western China. In view of this, this paper takes the Yushen mining area as an example, studies the relationship between the water-conducting fissure zone and coal seam mining height, coal seam mining depth, hard rock scale factor, and working face slope length, finally proposing a method to determine the development height of the HW based on multiple nonlinear regression models optimized using the entropy weight method (EWM-MNR). To compare the reliability of this model, random forest regression (RFR) and support vector machine regression (SVR) models were constructed for prediction. The findings of this study showed that the results of the EWM-MNR model were in better agreement with the measured values. Finally, the model was used to accurately predict the development height of the hydraulic conductivity fracture zone in the 112201 working face of the Xiaobaodang coal mine. The research results provide a theoretical reference for water damage control and mine ecological protection in the Yushen mine and other similar high-intensity mining areas.

Investigating effects of mining on sedimentary properties of Lisar River (Guilan Province, Iran) using HEC_RAS model

ABSTRACT Increasing land development projects lead to demand for riverine mining, followed by erosion and deposition. The aim of the research was to assess the sedimentary impacts of mining activities on the Lisar River. The research material comprised environmental, hydraulic, and sedimentary information, mining history, and dimensions. Detailed topographic and TIN maps, and 55 cross-sections of the Lisar River mining, were prepared. This study simulates flow patterns in a quasi-unsteady condition and sediment transport capacity using the HEC-RAS model. The maximum change along the longitudinal profile of the river mining is 3 m. The spatial map of the mining in different river sections was determined based on the maximum allowable depth of mining. The present research recommends the Yang function use in simulations of the rivers with sandy-gravel texture accompanied with or without riverine mining and steep slope. Results indicate the current mining volume is up to three times the allowed capacity for the extraction from the Lisar River. The present research concluded that the management plan for spatial mining and measures for monitoring based on the spatial distribution of depositional and erosional sites is necessary for this and other such areas to conserve natural resources.

Development of a system for ranking geomechanical factors, which influence the stability of uranium mines workings

The subject of research presented in the article are processes that take into account the influence of geomechanical factors on the stability of mining workings of uranium mines. The purpose of this work is development of a system for ranking geomechanical factors by the degree of danger based on the analysis of risk factors that affect the stability of uranium mines. The work uses critical analysis and generalization of both own research results and the results of domestic and foreign authors. The geomechanical factors that affect the stability of the mining workings of uranium mines have been determined. It is shown that their influence has both a direct and an indirect effects due to the connection with mining-geological and technological parameters. The stability of the workings is significantly influenced by mining and technical factors (outcropping time, working space length, floor height, compression properties and structure of the backfill mass, chamber width, dynamics of cleaning works progress), mining and geological factors (depth of mining, thickness of the ore body, strength (deformation)) and physical and mechanical properties of the rock mass. In addition, the engineering and technical conditions of mine construction have a significant impact, in particular, the form and size of the workings, their orientation in the massif, the method of carrying out and supporting, the design and technology of fastening, etc. It is practically impossible to simultaneously take into account all factors in an analytical way, so it is necessary to select one or two main factors that are of decisive importance for the description of a specific geomechanical process. The originality of the work is the proposed ranking of geomechanical factors that affect the stability of mining workings of uranium mines. The ranking of geological, physical and mechanical factors on the stability of the chamber system elements at underground mining of uranium ores, according to the degree of attenuation of the influence, is as follows: strength of rocks → structure of the massif → angle of fall of the deposit → water content of the deposit → thickness of a seam. The ranking of the influence of support preparatory and capital workings on their stability, according to the degree of risk decrease, is as follows: no support → grid with anchors → sprayed concrete → wooden support → metal frame support with tightening → metal arches in concrete. Generalized ranking of the influence of the most significant factors on the stability of mining workings: geological, physical and mechanical factors → parameters of the development system → fastening technologies.

ГЕОМЕХАНІЧНЕ ОБҐРУНТУВАННЯ РОЗРОБКИ ПОТУЖНИХ ТА ВЕЛЬМИ ПОТУЖНИХ ПОКЛАДІВ БАГАТИХ ЗАЛІЗНИХ РУД В УМОВАХ ЗНАЧНИХ ГЛИБИН

Purpose. Improving the quality of the mined ore mass and reducing the operating costs for the extraction of minerals by taking into account the geomechanical state of the ore-rock massif. Methods. A complex method that includes analysis and generalization of previous studies, mine instrumental observations, numerical modeling by the finite element method, analytical studies and statistical data processing. Results. It has been established that the key factors influencing the choice of stable parameters of the structural elements of the stope panels of the stope blocks are: the parameters of the stress-strain state of the stope horizon, determined by the depth of mining, the thickness and dip of the ore deposit, the shape and size of the shear zone of host rocks; the procedure for working out stope panels according to the thickness and strike of the stope block; intensity of development of stocks of compensation spaces. At the same time, the stability of transport drifts and junctions with orts-arrivals depends on the length of their location before the contact of the host rocks of the lying side with the ore deposit, the thickness of the ore deposit and the geological macrostructure of the rocks of the sides, as well as the number of contacts of the stope panel with collapsed host rocks. The maximum possible stable parameters of exposures of compensation chambers, which are formed by explosive breaking of borehole charges, depending on the thickness of the ore deposit and the location of their center from the rocks of the hanging side, have been established. Scientific novelty. For the depth range of 1200–1500 m, the dependences of the stress distribution across the pull of the ore deposit on the horizon of mining have been obtained. Power-law dependences of the equivalent span width of the bottom of the stope panel, equivalent spans of stable horizontal and vertical outcrops on the location of the center of the stope panel along the thickness of the ore deposit on the host rocks of the hanging side have been established. Practical significance. The obtained dependencies allow choosing the most rational technological schemes for the mining of rich iron ore deposits, taking into account the stress-strain state of the ore-rock mass and the location of the stope panel according to the thickness of the deposit.

Validation of the Crack Mode-Changing Stress in Circular Tunnels Under Generalized Triaxial Tensile Stress States

In the past century, mining depths have increased profoundly from a few hundred meters to several kilometres following improvements in drilling techniques and instrumentation methods. In highly-stressed tunnels, the predominant failure mechanism of underground rock is controlled by stress-induced fractures parallel to the excavation boundaries in terms of spalling failures or, in some severe cases, a violent slab ejection that forms a V-shaped notch around the excavation walls. Such failures can seriously affect production and shut down the operation temporarily or even permanently. To better characterize, predict, and prevent these catastrophic failures, many laboratory tests and scaled model tunnels have been conducted under uniaxial and biaxial loading conditions, with limited studies also available under true triaxial stress states. This paper extends the previous studies on the impact of true triaxial loading conditions on the spalling failure in high porosity sandstone and investigates further the validation of a new Crack Mode-Changing Stress (CMCS) parameter, defined as the minimum principal stress required to change rock fracturing from splitting to a sliding failure mode. The results revealed that the minor principal stress can significantly affect the propagation of the stress-induced fractures of spalling failure along the tunnel sidewall.

Factors initiating crack formation during hydro-impulse loosening of outburst-hazardous coal seams

The article is dedicated to the exploitation of outburst-hazardous coal seams at significant depths. It is known that with the increase in mining depth in the gas-saturated coal-bearing massif, changes in its stress-strain state lead to specific manifestations of outburst-hazardous coal, such as spontaneous collapse, alteration of the aggregate state and structure of hydrocarbon compounds, changes in filtration properties, and so on. These features occur when compressive deformations are replaced by tensile (shear) deformations. There is a list of methods for impacting the massif to prevent the occurrence of gas dynamic phenomena. The main task of these methods is to create additional cracks throughout the thickness of the coal seam for effective gas filtration. Along with this, during mining operations, man-made factors arise. They create additional load and change the structure and properties of outburst-hazardous coal. The article deals with the factors of man-made impact on the heading part of the coal seam, which led to a decrease in the effectiveness of methods of preventing gas dynamic phenomena. The parameters of the processes that initiate the development of cracks around the filtration part of the well in the impulse mode of liquid injection, in the redistribution of stresses in the massif, and the case of self-destruction of coal in the heading part of the seam are considered. The theory of strength of materials is considered to establish their limit state and destruction. The paper presents the results of theoretical and experimental studies of the hydro-impulse loosening method for outburst-hazardous coal seams. The changes in deformation velocity were investigated under impulsive loading of coal relative to the modulus of elasticity in the range of 3∙102 MPa ≤ Е≤ 5∙102 MPa. It was established that all values of impulses of self-oscillations of liquid pressure are above the curve of the limit rate of development of deformations έ =10 s-1 at the value of the modulus of elasticity of coal E ≥ 3∙102 MPa. We concluded that during hydro-impulse impact modes with an injection pressure of more than 5 MPa, pressure pulses of ΔP ≥ 3 MPa with a frequency of f ≥ 0.8 kHz are created in the filtering part of the well. This leads to the development of shear deformations and initiates the cracks formation through-out the thickness of the coal seam. Research on hydro-impulse impact was conducted in the mines of the Donetsk Coal Basin. The Donbas region is characterized by the most complex mining-geological conditions, especially when working with outburst-hazardous coal seams. Keywords: gas dynamic phenomena, hydro-impulse loosening, сrack formation, coal-gas system.

Effect of structure and mining depth on hydraulic cutting velocity in rocks

Effect of structure and mining depth on hydraulic cutting velocity in rocks

EXPERIMENTAL STUDY ON THE EVOLUTION OF MICROPORE STRUCTURE SOFTENED BY NONPRESSURE WATER ABSORPTION STRENGTH OF SANDSTONE

With the increase of mining depth of a coal mine, the strength of the surrounding rock in deep roadways decreases due to the influence of groundwater, which seriously affects the safety of on-site personnel in production. To study the influence of water-rock interaction on the properties of surrounding rock, taking the sandstone in the deep roadway of Wanfu Coal Mine as the research object. The nonpressure water absorption experiment was carried out. According to the compression tests of key water content (0%, 0.8%, 1.6%, 2.4%, 3.3%), the mechanical evolution law of sandstone during water absorption was studied. At the same time, mercury porosimetry (MIP), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR) experiments are used to study the evolution of experimental microscopic pores. The strength-softening mechanism of sandstone in Wanfu Coal Mine is discussed. The results show the following: (1) The NMR T<sub>2</sub> spectrum curve of sandstone presented a single peak characteristic. With the increase of water content, the total spectrum area increases continuously, and the corresponding relaxation time of peak shifts to the right. According to the ratio of spectral area in the experimental process, the traditional process of water absorption is further divided into four stages: rapid water absorption, uniform water absorption, pore transformation, and stable water absorption, in which the pore transformation mainly occurs in stage III (31-113 h). (2) The strength of sandstone decreases nonlinearly with the increase of water content, and the degree of attenuation is affected by confining pressure. The softening degree of strength decreases with the growth of confining pressure. With the rise in water content, both cohesion and internal friction angle show a negative exponential decreasing trend. (3) Expansion of clay minerals and the restraint of a quartz skeleton during the experiment are reasons for the closure of pores; misalignment of quartz particles, the flow of pore water, and dissolution of soluble minerals will lead to pore enlargement during water absorption. (4) In addition to the lubrication of water film and the decrease of the cementation ability of clay minerals, the expansion and connectivity of the pore are also important aspects of the softening of sandstone and influence the final destructive form of sandstone.

Optimizations of the internal structure of the reel of a double rope winder

Due to the shortage of resources, the deep development of resources is imminent, and the superdeep mine hoist plays a leading role in the development process. According to the structure, the hoists can be divided into winding hoists and friction hoists. Winding hoists can be single-rope winding and multirope winding. With the increase of mining depth, friction hoists will have the disadvantage of increasing the mass of the tail rope, while wire rope diameter of single-rope winding hoists will increase with the increase of mining depth. So double-rope winding hoists can be used to balance the above two problems. Therefore, this study will use finite element analysis, and treat hoist reel as a uniformly pressurized shell, through the static and modal analysis of reel. Under the maximum static tension, this study gets the reel the force and deformation distribution. Through the change of the internal structure of the reel, it improves the reel force weakness and reduce the reel deformation. By reducing the deformation of the reel, this study tells how to reduce the tension difference of the wire rope. This study will improve the synchronization and stability of the hoisting system and provide an alternative and effective way for the deep development of the resources with the double-rope winding hoists.

Influence of sensor array on MS/AE source location accuracy in rock mass

As the mining depth increases, rock dynamic disasters become increasingly prominent. Microseismic monitoring has become an important technical means to monitor rock dynamic disasters, such as rockburst and roof collapse. The sensor array is the first step of signal acquisition and will seriously affect source location accuracy. The significant studies on error factors caused by sensor array arrangement to the location accuracy of microseismic (MS) and acoustic emission (AE) sources were discussed and summarized. The influences of the number of sensors, configuration of sensors and distance between sensors and source on MS/AE source location accuracy were analyzed. Subsequently, some principles of sensor arrays were given by combining with engineering practices and laboratory testing, and confirmed by a field application. In addition, the optimal arrangement scheme was discovered by considering the factors affecting the number, shape, and distance of sensors, which can greatly adjust the signal acquisition effect and improve the source location accuracy. Finally, some challenges and the corresponding coping strategies of sensor arrays were prospected to improve the MS/AE source location accuracy.

Research on the application of data mining technology in software engineering

The role of data mining in software engineering is obvious, but there is a lack of mining depth. In the past, engineering layout and function distribution problems in software development, and the framework construction was unreasonable. Therefore, this paper proposes a software system based on data mining technology. First, the software engineering project is divided, and the software engineering project design is carried out according to the interactive requirements to realize the preprocessing of software engineering. Then, according to the design criteria, the design collection of software engineering is formed, and the information system is analyzed in depth. MATLAB simulation shows that the design interactivity and accuracy of data mining are superior to traditional design methods under the condition that software engineering requirements are consistent.

Effects of High Temperature Treatments on Strength and Failure Behavior of Sandstone under Dynamic Impact Loads

With the increasing demand for resource consumption, the mining depths gradually increase, resulting in increases of temperature at tens or even hundreds of degrees. High temperature could damage to interior structures and alter the mechanical properties of rock mass. Therefore, studying the effects of temperature on dynamic mechanical properties and failure behaviors are of great significance for deep resources exploitation. In this study, to study the effects of high temperature treatment on the strength and failure behavior of typical sandstones, specimens were prepared and heated to different degrees. The longitudinal wave velocity, volume, and density of specimens before and after high-temperature treatment were examined. Then, the Thomas Hopkinson (SHPB) test was conducted on specimens with different air pressures and the dynamic stress-strain curve, peak stress, peak strain, and other dynamic characteristics were obtained. The variations regulations and failure behavior of sandstone under the effects of high-temperature treatments and different impact loads were analyzed and discussed from the aspects of stress-strain, peak strength, and peak strain. It was observed that with the increase of heating temperature, the average density, average wave velocity, peak strength, and average elastic modulus of the sandstone specimens all showed a decreasing trend and the highest decreasing rated occurred at the temperature between 600 °C and 800 °C. The obtained results provided a certain theoretical basis for deep mine exploitation, especially for mines with high temperature.