To meet the requirements of the mine's variable frequency ventilation system for underground air quality moni-toring,a mine air quality evaluation method based on an improved Random Forest algorithm is proposed.The method aims to accurately monitor the air quality inside the mine,providing important references for the popularization and application of the variable frequency ventilation system to effectively ensure safe production and protect miners' health.Firstly,the sources of pol-lutants in the mine air and their potential hazards to miners' health are analyzed,and five major pollutants(CO,SO2,H2S,NO2,and dust)are selected as evaluation factors to establish the evaluation standards.Secondly,the Random Forest algorithm is improved using the Area Under the Curve(AUC)of the Receiver Operating Characteristic(ROC)curve to comprehensively evaluate mine air quality.The experimental results show that the model performs well,with a minimum generalization error of only 0.017 7 and a maximum classification accuracy of 97.72%on the test data.Based on the improved algorithm,a mine air quality evaluation system was developed.This system can effectively assess mine air quality with high robustness and accuracy,providing new insights for smart mine construction and mine air quality evaluation.
Pile inventory is a common practice in terrestrial laser scanner applications. However, there are two main challenges when using the traditional terrestrial laser scanning (TLS) for pile inventory. One is the high cost and the other is the unreachability problem within a limited space. This letter develops a cost-effective system combining two single-pulse scanners and a rangefinder. The sensors are coupled together on a sliding rail to collect 3-D points for pile inventory. The proposed system is applied to an indoor scenario in a gold and copper open-pit mine. We investigate the effect of inclination angles on the point cloud. In addition, the generated point clouds are compared with those obtained by an advanced scanner in simultaneous localization and mapping configuration. The comparison shows higher completeness when using our proposed system. Cross-validation results show ~99.9% repeatability of the proposed system for pile inventory.
The stiffness theory of rockburst plays a crucial role in understanding and preventing rockburst events. This theory evaluates the severity of rockbursts through the difference in stiffness. As a fundamental theory, many new theories have emerged from the stiffness theory, and its applications in mines and deep tunnels are diverse. In this paper, we provide a systematic review of the development process, application status, and application field of rockburst stiffness theory from the perspective of theoretical derivation, laboratory testing, and field application. We also identify key and difficult problems in stiffness theory, such as the determination method of stiffness, the influence of post-peak slope, and the study of rockburst criteria. In addition, based on the existing issues related to stiffness determination, exploration of stiffness changes during rockburst development, and low adaptability in predicting rockburst intensity, we propose the influence of the blasting body-surrounding rock stiffness on the spatial-temporal characteristics, intensity, and mechanism of rockburst, dynamic variable stiffness tests, and stiffness theoretical criteria for determining the rockburst intensity as areas for further research on the stiffness theory of rockburst.
In recent years,with the rapid development of robot technology and artificial intelligence technology,more and more mining enterprises begin to use robots for inspection and monitoring,in order to improve production efficiency and reduce the cost of manual inspection.However,due to the complex and changeable mine environment,there are a large number of ob-stacles and dangerous factors,traditional inspection robots often cannot meet the actual demand,it is necessary to introduce some advanced scene understanding and machine vision technology,in order to improve the robot′s navigation and obstacle a-voidance ability.In this paper,a navigational obstacle avoidance method of mine inspection robot based on integrated scene un-derstanding and machine vision is studied.First of all,the mine environment is identified and positioned by machine vision technology to obtain the position and surrounding scene information of the current robot.Then,the scene understanding technol-ogy is used to analyze the mine scene,including identifying various ores,equipment and personnel,and detecting and classif-ying obstacles in the mine environment.Finally,the integrated scene understanding and machine vision information are applied to the navigation and obstacle avoidance control of the robot.The experimental results show that the proposed method can effec-tively improve the robot′s navigation and obstacle avoidance ability in complex mine environment,have certain significance for promoting the construction of intelligent mine,improving mine production efficiency and reducing inspection cost.
In order to effectively identify the danger area of slope and accurately judge the stability state of slope,a set of"face-point-surface"slope comprehensive evaluation method based on fuzzy comprehensive evaluation method,MSARMA method and FLAC3D was proposed.Firstly,according to the composition and structural characteristics of the on-site slope rock mass,disaster factors were summarized,while assignment criteria for discrete and continuous variables were divided based on the landslide body characteristics and spatiotemporal distribution.Following,based on the comprehensive evaluation principle of fuzzy mathematics,the high and steep side stability in the multi-factor influence regions was comprehensively evaluated,while the spatial division of the unstable region was determined.Finally,the slope potential slip surface in the unstable zone of the western side was utilized as the calculation model object,while the sensitivity analysis of the slope impact factor was conducted through the MSARMA method,and the sensitivity factors were determined.The FLAC3D finite difference method was utilized for numerical simulation analysis,and the conclusion was drawn.Taking Antaibao Open-pit Coal Mine as an example,its unstable area was divided and the evolution law of displacement field under sensitive factors such as seepage and vibration was ob-tained.The results showed that under natural conditions,the maximum displacements in X and Y directions of the slope are 30 cm and 41 cm,while under seepage conditions,the maximum displacements in X and Y directions of the northwest slope are 45 cm and 70 cm,respectively.Under the action of earthquake,the displacements at the bottom of the north slope and the west slope change little,while the displacement at the top is larger.Based on the above results of numerical simulation,the design scheme of slope reinforcement and monitoring in unstable region was proposed to ensure the stability of the whole slope.The in-tegrated evaluation method could provide reference for the stability analysis of similar high and steep rock slopes.
The hydrogeological conditions of the Zhongjiu Iron Mine are complex,the top and bottom lithology of the de-posit are mainly Gushan Formation and Zhouchongcun Formation,and the surrounding rock of the mine is mainly class IV bed-rock with poor rock integrity.In the underground development project of the auxiliary shaft construction of the mine project,the-550 m horizontal water pump room has a large section span and the surrounding rock is broken,and the disturbance of the surrounding water silo blasting leads to the cracking,deformation,settlement of the top wall rock at the connection between the-550 m horizontal central substation and the water pump room,and even the risk of falling.In this regard,combining the tech-nical advantages of curtain grouting and anchor cable support,the combined support and reinforcement technique of curtain grouting and long anchor cable is put forward,and the concrete construction technical scheme is designed.The basic idea of this technique is to make full use of the grouting curtain to cement the broken roof into a whole,and then use a long anchor ca-ble to fix the joint roof to the stable rock,and finally complete the connection between the central substation and the water pump house by expanding the brush.According to the above technical ideas,the design of key technical parameters of curtain grouting and long anchor cable support at different positions is discussed in detail,and the effect of curtain grouting and long anchor cable support is analyzed in detail by numerical simulation coupling analysis method.The study results show that through curtain grouting construction,the reinforcement curtain can be formed on the roof of the joint and the two sides of the surrounding rock,and the properties of the surrounding rock at the joint can be greatly improved.The proposed combined sup-port technology scheme and related technical parameter design have a certain reference value for the stability control of under-ground surrounding rock in similar mines.
Environmental pollution caused by industrial solid waste is a major obstacle to cleaner production.In order to achieve sustainable development,magnesium slag(MS)and fly ash(FA)are recovered as cementing materials,and then mixed with tailings(TL)to make a paste filling material that can be used in mining engineering.The rheological properties,mechanical properties and pore structure evolution of backfill with different fly ash content and tailings content were studied.In this process,the following conclusions are obtained:① With the increase of fly ash content,the mini-slump value first increases and then decreases.When the fly ash content is 20%,the fluidity of backfill is the best.② Uniaxial compressive strength in-creases with the increase of curing age and fly ash content,and decreases with the increase of tailings content.Backfill with low fly ash content develops slowly in the early strength,while backfill with high fly ash content develops rapidly in the early strength.③ The critical pore size and porosity decrease with the increase of fly ash content.The greater the fly ash content is,the greater the critical pore size decreases.With the increase of tailing content,the critical pore size and porosity increase gradually.
In order to solve the problem of comprehensive utilization of solid waste in graphite mines,the Luobei Yunshan graphite mining waste rock and spherical graphite tailings were used to replace standard sand in cement mortar to prepare elec-tric heating boards.Under the conditions of 7.41%content of spherical graphite tailings,7%content of stone powder,and com-plete replacement of standard sand by mining waste rock,the influence of the forming method and size of electric heating boards on their mechanical and electrical properties was explored.The results showed that the electric heating plate prepared by vibra-tion compaction has high mechanical strength,with a flexural strength of 7.48 MPa and a compressive strength of 26.76 MPa.The electric heating plate prepared by spraying method has good electrical properties,with a volume resistivity of 1.91 Ω·m.By using vibration compaction forming method and changing the size of the electric heating plate,the mechanical strength and volume resistivity of the thin plate are higher than those of the thick plate,with a flexural strength of 7.48 MPa and a compres-sive strength of 35.78 MPa.The final proportion of solid waste usage reaches 75.6%,which can provide theoretical reference for the subsequent production of electric heating plates.
In view of the serious dust pollution in the underground crushing chamber,the conventional wet dust collector is difficult to effectively remove fine particles.On the basis of integrating the advantages of various wet dust collectors,a wet composite dust removal device embedded with adjustable Venn tube and fiber grid is designed,and an experimental platform is established.Experimental study on the embedded adjustable venturi tube,fiber grating wet composite effect of dust removal de-vice for fine particles of dust catcher,by changing the angle of spread of venturi tube,fiber grating structure parameters,the sin-gle factor and multi-factor orthogonal experiment,determine the embedded adjustable venturi-fiber grating wet the best parame-ters of compound dust removal device.The experimental results show that when the wind speed of venture-tube is 22.7～33.6 m/s,the diffusion angle of venture-tube is 5°～6°.When the diameter of fiber grid is 0.3 mm,the spacing of fiberboard is 3～5 cm,the number of fiberboard layers is 2～4,and the liquid-gas ratio is 0.3～0.6 L/m3,the removal efficiency of fine dust reaches 99%.Compared with single embedded adjustable Venturi and wet dense fiber grid,the removal efficiency of fine dust with particle size less than 3 μm is 5.4%and 6.6%higher respectively,and the removal effect of fine dust is better.
The goal of creating montmorillonite-based artificial algal crusts is to stabilize the topsoil layer,prevent surface erosion,fix the matrix lead,and avoid the threat of tailing lead leaching to ecological security.These artificial cyanobacterial biocrusts are being built in semi-arid lead mining areas because of the extreme environmental problems,such as water short-age,surface degradation,and lead pollution.In this work,lead-based sandy soil was covered with artificial algal crusts made of Microcoleus steenstruppi and montmorillonite(MT).The optimal input of montmorillonite to encourage the growth of cyanobac-teria was achieved by studying the morphological changes of artificial cyanobacterial biocrusts and tracking the changes of bio-logical markers of algal crusts.The capacity of artificial cyanobacterial biocrusts on matrix lead to fix lead and its detoxification process were investigated by the use of particle size,Zeta potential,SEM-EDS,lead chemical form,FTIR,and XRD analysis.The findings revealed that M500 had the highest development of cyanobacteria,with a substantially greater filament density than M0.On day 62,M500,the best treatment group,had a chlorophyll a level that was 1.9 times higher than M0.Cyanobacterial fila-ments,extracellular polymers,and montmorillonite can all include matrix lead.On day 62,M500,the best treatment group,had a chlorophyll a level that was 1.9 times higher than M0.Cyanobacterial filaments,extracellular polymers and montmorillonite can all include matrix lead.On day 62,the ideal treatment group M500 had a total solid lead level of 231.97 μg/cm2,which is 1.2 times that of M0.Montmorillonite encourages the transformation of unstable weak acid exchangeable and carbonate-bound lead compounds into more stable organic-bound and residual lead compounds during the lead fixation process.The transformation of matrix lead into extremely low solubility basic lead carbonate and basic lead phosphate is promoted by artificial cyanobacterial biocrusts,according to characterisation.Thus,the artificial cyanobacterial biocrusts based on montmorillonite increase their fix-ing effect on the matrix lead and achieve the body′s detoxifying impact by lowering the bioavailability of lead.This work disclo-ses the lead fixation mechanism of artificial cyanobacterial biocrusts and offers for the first time a novel way for treating lead polluted soil utilizing clay type artificial cyanobacterial biocrusts.Additionally,it has significant theoretical and practical impli-cations for the practice of green water and green mountain engineering.It offers a sustainable and scientific management tech-nique for ecological restoration in semi-arid lead poisoned mining sites.
Aiming at the existing problems in D mining area of Jinchanghe Lead-zinc Mine,which included excessive consumption in main mining area,low grade of lead and zinc,amount of excavation work,difficulty in filling and the high cost,the mechanical model of plate and shell structure was established by applying the theory of elasticity to reveal two caving sta-ges,analyse the initial falling height of goaf roof of 11～38 m,26～58 m and 41～87 m under different schemes,and calculate the following stable caving height reaching 1.5～2.0 times the span of goaf.At the same time,according to the stope parameters and the characteristics of loose body,it was analyzed that the falling arch floor can be naturally squeezed when falling 67～100 m.In order to prevent the surface dislocation collapse,it was proposed to squeeze the temporary pillars by waste rock filling in time strengthening the pillar support capacity and limiting the caving of the large area.Based on this,different mining schemes of open stope method,pillar retaining open stope method and open stope timely filling were designed.Through the comparison of initial caving height of goaf roof,pillar bearing value and recovered ore volume,the open stope timely filling scheme was recom-mended to ensure the safety of D mining area.
The substrate interface plays a very important role in the crystal growth and gas sensing properties of gas sens-ing materials.It not only provides nucleation sites for the growth of crystals,but also controls the microstructural morphology of the sensing materials,thereby further affecting their gas sensing properties.This paper mainly summarizes the effects of conven-tional substrates such as silicon substrate,glass substrate,Al2 O3 substrate,AAO substrate and clay mineral substrate on the growth characteristics and gas sensing properties of gas sensing materials.The structural characteristics of several substrates,the methods and properties of interface control,and the growth and characteristics of gas sensing materials were analyzed.The conventional substrates have relatively stable physical and chemical properties,which is beneficial to obtain gas sensing materi-als with high crystallinity,large specific surface area and excellent gas sensing properties.However,there are still some struc-tural characteristics that are not conducive to material growth,such as smooth surface,lattice mismatch,low high-temperature resistance and poor acid/alkali resistance.Therefore,the interface control of the substrate in the material growth process is nec-essary to ameliorate defects and obtain gas sensing nanomaterials with superior performance.Clay mineral substrate can solve some problems existing in conventional substrate,but the structure and performance of substrate still need to be improved and optimized.Then,based on the research progress at home and abroad,the effects of interfacial control methods such as precious metal catalyst layer regulation,porosity treatment,seed layer pretreatment and binary composite preparation on the micro-mor-phology and gas sensitive properties of gas-sensing nanomaterials were discussed.The future development direction of gas-sens-ing nanomaterials prepared by substrate method was also prospected.The improvement and development of the substrate will improve the performance of gas-sensing nanomaterials and promote the application of semiconductor gas sensors in mines,which is of great significance to the green development of mining resources.
Water-retaining mining,subsidence reducing mining,waste rock and tailing filling were the core contents of green mining in non-coal underground mines.The review shows filling mining was the fundamental way to realize green mining,but filling mining was not only relatively high in cost,practice had shown that uneven settlement and high underground pressure of deep mining could also not be eliminated.In this paper,the green mining concept based on the top-cutting and pressure-re-lief theory is put forward,and these technical assumptions of green mining and safe mining of ore-body under various occur-rence conditions are expounded.The research shows that cutting off the roof of a certain depth by controlled blasting and build-ing up rock-fill dam supporting the roof,it can not only eliminate or transfer the high underground pressure,but also control the roof settlement by the rational distribution of this spring-like structure,it can also be used as an retaining wall for filling min-ing.In the steeply inclined forsaken stope,blasting loose rock is directly discharged into the unsolidified cemented filling body,which can not only greatly reduce the filling cost,but also improve the strength of the filling retaining wall.Green mining idea based on the theory of top-cutting and pressure-relief is the only way to realize safety,green mining and full mining of pillar.
In order to reduce the accumulation of phosphogypsum(PG)and sulfur-fixing ash(SFA)in the environ-ment,avoid the risks to the natural environment and minimize the environmental pollution,a new composite adsorption material of phosphogypsum/sulfur-fixing ash(PG/SFA)was prepared by one-step high-temperature calcination method with PG and SFA as raw materials,and the uranium[U(Ⅵ)]of PG/SFA was studied by batch static adsorption method.Based on the strong U(Ⅵ)affinity of PG/SFA,the deep purification treatment of uranium mine water produced in the process of U(Ⅵ)mining was studied.Finally,the adsorption mechanism of PG/SFA for U(Ⅵ)was discussed by means of SEM,FTIR and XRD.The results show that the adsorption capacity of PG/SFA for U(Ⅵ)can reach 84.6 mg/g under the conditions of pH of 6.0,PG/SFA adsorbent dosage of 0.02 g,adsorption time of 60 min,initial concentration of U(Ⅵ)of 125 mg/L and adsorp-tion temperature of 40℃.The adsorption of U(Ⅵ)by PG/SFA accords with pseudo-second-order kinetic model and Langmuir isothermal adsorption model.The coexistence of anions and cations(Ba2+,Sr2+,Ni2+,Ca2+,Cl-,NO-3,CO2-3,F-)in water has little effect on the U(Ⅵ)adsorption performance of PG/SFA.In real uranium mine water,the removal rate of U(Ⅵ)by PG/SFA can reach 99.8%,the distribution coefficient(Kd)is as high as 1.46×106 mL/g,and the effluent U(Ⅵ)concentration is as low as 0.003 mg/L.The adsorption mechanism of U(Ⅵ)by PG/SFA is mainly that Ca2+ and PO3-4 in PG/SFA react with UO2+2 by precipitation,and then autunite Ca(UO2)2(PO4)2·3H2 O mineral phase structure is formed on the surface of PG/SFA.Therefore,the utilization of industrial solid waste phosphogypsum and sulfur-fixing ash can be used as efficient adsorption materials for uranium mine water,thus achieving the goal of"treating waste with waste".
In order to remove the heavy metals in bottom mud of mine water bodies non-pollutionally,three kinds of che-lating agents namely EDTA,GLDA and MGDA,were used to extract heavy metals Cd,Cu and Ni under various conditions,while analyzing their underlying mechanisms.Experimental methods such as batch extraction and BCR extraction were used to compare and analyze the influence of EDTA,GLDA and MGDA,as well as different factors,on the efficiency of heavy metal ex-traction from mine water sediments.The results revealed that the optimal leaching time varied depending on the heavy metal el-ement and the chelating agent used.pH was identified as the primary influencing factor for chelating agent efficiency in heavy metal extraction.Additionally,an increase in chelating agent concentration significantly improved the removal rate of heavy met-als,with cumulative cyclic leaching resulting in a minimal improvement of less than 5%in heavy metal removal efficiency.The chelating agents facilitated the removal of heavy metals from mine water sediments by altering the speciation of heavy metals.Under ambient temperature conditions,the most suitable conditions for the three chelating agents were as follows:for EDTA,leaching time of 16 hours,pH=4,n(EDTA)∶n(HMs)= 6∶1,with two cycles of leaching;for GLDA,leaching time of 8 hours,pH=4,n(GLDA)∶n(HMs)= 4∶1,with three cycles of leaching;for MGDA,leaching time of 8 hours,pH=4,n(MGDA)∶n(HMs)= 6∶1,with three cycles of leaching.Under these optimal conditions,the removal rates for Cd from great to small were in the order EDTA,GLDA and MGDA,for Cu,MGDA,EDTA and GLDA,and for Ni,MGDA,GLDA and EDTA.Green chela-ting agents GLDA and MGDA demonstrated their potential to replace traditional chelating agent EDTA,offering improved cost-effectiveness and environmental friendliness.Following treatment with Na2 S,heavy metal recovery rates exceeding 95%were a-chieved,with the heavy metal content in the leachate meeting national discharge standards and thus suitable for direct disposal.The findings of this study provide valuable theoretical support for the application of chelating agents in the removal of heavy metal pollution from mine water sediments.
Intercalation and exfoliation can greatly improve the diameter to thickness ratio,specific surface area and other product specifications of kaolin.It is a key technology for high-end applications of kaolin in biomedicine,rubber,coating,ad-sorption,catalysis and other fields,and has very important significance for the high quality utilization of kaolin mineral re-sources.This paper mainly summarizes the research progress of kaolin intercalation and exfoliation at home and abroad in re-cent years.The influences of intercalation agent type,kaolin origin and intercalation reaction conditions(temperature,water content and time)on kaolin interlayer spacing and intercalation rate were analyzed.The influences of intercalation technologies such as assisted intercalation and multiple intercalation replacement on kaolin interlayer spacing and intercalation rate are ex-pounded.The influence laws of different process parameters on intercalation efficiency were analyzed,and the exfoliation tech-nologies such as physical exfoliation,chemical exfoliation and physical and chemical exfoliation were described.The influences of exfoliation equipment and process parameters on the layer spacing,layer thickness,specific surface area,pore volume and morphology of kaolin from different producing areas were analyzed.Then,based on the research progress at home and abroad,the problems of intercalation and exfoliation technology,such as intercalation mechanism,intercalation agent pollution,low di-ameter to thickness ratio of kaolin and instability of nanosheets,were discussed in depth,and the future development direction of kaolin intercalation and stripping was prospected.The development and popularization of green and efficient intercalation ex-foliation technology is of great significance to the production of high-end kaolin mineral powder and the development and utili-zation of high-performance materials in downstream industry.
In order to control the quality and stability of high bench parallel blasting slopes,based on traditional pre-splitting blasting technique,a semi spaced hole guided pre-splitting blasting technique was proposed.The stress distribution law and crack expansion of the separated hole guided pre-splitting blasting were analyzed.The study results show that the semi spaced hole played a guiding role in the upper unfilled section of the empty hole,forming tensile stress concentration,and strengthening the charging section at the bottom of the blast hole to form compressive stress concentration,make up for the in-sufficient charging of normal holes and overcome the deep clamping effect of blast holes.Four schemes were selected for semi spaced hole charging,namely 1.5,2.0,2.5,3 kg,and hole spacing of 0.6,0.7,0.8,and 0.9 m.Numerical analysis and on-site experiments were conducted on the semi spaced hole technology scheme.The results indicated that when the charging a-mount was 2.5 kg and the linear charging density was 0.42 kg/m,the hole spacing was selected as 0.8 m,which maximized energy utilization and ensured the penetration of the bottom blast hole.The study have a certain reference significance for the practice of boundary blasting in open-pit mining.
In order to obtain the suitable process parameters for preparing porous magnesium carbonate trihydrate by a-queous solution,the effects of magnesium source,reaction temperature,reaction time,additive type and dosage on the phase composition and microstructure of the product were studied by XRD and SEM.The results showed that porous magnesium car-bonate trihydrate crystals with an average diameter of 10 μm and good sphericity could be obtained with magnesium chloride as magnesium source,ammonium carbonate as carbon source,and 1%glucan added at the reaction temperature of 58℃and reac-tion time of 200 min.The type and amount of additives have no effect on the phase composition of the product,but have a great effect on the morphology.The type of magnesium source and reaction temperature have significant influence on the phase com-position and morphology of the product.The growth mechanism analysis showed that dextran formed a network structure in solu-tion,and the[MgO6]octahedral growth unit reacted with the hydroxyl group on the dextran chain to form sheet crystals.At the same time,the network structure formed by the long chain of dextran acts as a limited template for the formation of porous spheres.The network structure makes the growth units of magnesium carbonate trihydrate grow along the direction of dextran ch-ain,and finally forms porous spherical magnesium carbonate trihydrate crystals.
Timely and accurate assessment of the emergency capability of metal mine can provide scientific guidance to improve the emergency capability of metal mine.According to relevant laws and regulations,combined with literature analysis and field investigation,the model system of emergency capacity assessment of metal mine is established.This system uses inter-pretation structure model method and consists of four first-level indexes and 20 second-level indexes.The first-level indexes in-clude emergency prevention capability,emergency preparation capability,emergency response capability,and emergency rescue capability.On the basis of comparative analysis of various assessment index weight determination methods,rough set(RS)theo-ry and expert scoring method are chosen to determine the weights of assessment indexes of metal mine emergency capability.This method can fully reflect the objectivity of data and enhance the accuracy of assessment result.The emergency capability assessment method based on extension theory is discussed and can effectively solve the incompatibility problem of indexes in comprehensive assessment.This method is applied in a metal mine and obtains accurate and objective assessment results.It is scientific and practical,can effectively reduce the accident risk of metal mine.
In order to effectively reduce rock burst disaster in underground stope and reasonably control the deformation of surrounding rock in stope,tailings are generally used to fill underground goaf.The traditional strength of tailings is difficult to play a role in complex underground space,especially in the freeze-thaw cycle environment of high-cold and high-altitude mining areas.Therefore,it is necessary to ensure that the backfill in freeze-thaw environment has good mechanical properties.In order to study the effect of freeze-thaw cycle on the mechanical behavior of the fiber-modified backfill,firstly,the fiber with the per-centage of non-mass(0,0.2%,0.4%,0.6%,0.8%,1.0%)was mixed with the filling slurry for mixing,and then the fiber-backfill mixture was mixed for 0,5,10,15 freeze-thaw cycles.The variation trends of slump,uniaxial compressive strength and splitting tensile strength of fiber-modified backfill mixture with fiber content and number of freeze-thaw cycles were also dis-cussed.The results show that the cyclic freeze-thaw can significantly reduce the mechanical properties of the fiber modified backfill mixture,and the appropriate incorporation of fiber plays a major role in improving the mechanical properties of the backfill.When the fiber content is 0～0.6%,the strength of the backfill can be effectively improved,while when the fiber con-tent is more than 0.6%,the physical properties of the backfill will be degraded.In addition,the incorporation of fiber is easy to fuse with the water in the filling body and play a role in fixing water,thus inhibiting its fluidity.
