Pervious concrete is an innovative eco-friendly construction material. Through the application of mineral admixtures and microscopic analysis to optimize its performance and analyze its mechanisms, its traits as a sustainable building option may be further improved. This study primarily examines the impact of the optimal blend quantities of fly ash, silica fume, and reinforcing agent on the attributes, micro-morphology, and phase composition of porous concrete. The optimal admixture was chosen after analyzing the effects of various factors on the mix ratio and properties of permeable concrete. To understand the degree of impact, performance tests were conducted on the 28-day compressive strength, water permeability coefficient, and porosity. Furthermore, the micro-mechanisms of the admixtures and reinforcing agents on the properties of permeable concrete were analyzed from a microscopic point of view using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. This research found that the advantageous properties of permeable concrete were enhanced by the simultaneous integration of appropriate quantities of fly ash, silica fume, and reinforcing agent. This resulted in a 28-day compressive strength of 18.33 MPa and a permeability coefficient of 8.27 mm/s. Compared with the unadulterated mineral admixture, the optimal admixture of fly ash, silica fume, and reinforcing agent at the same time increased the 28-day compressive strength by about double; the permeability coefficient was reduced by 36%, but it was still at a high level; and the measured porosity did not differ much from the designed porosity. Through thorough microanalysis, the hydration reaction was significantly improved, which could enhance the microstructure and pore structure of the concrete. This was supported by a substantial increase in the macroscopic compressive strength and a decrease in the water permeability coefficient, which were consistent with the aforementioned enhancement found in the microanalysis.

淮北临涣煤矿7煤与下部9煤的煤层间距平均为28.5 m,属于近距离煤层,开采方式为上行开采,此时7煤作为被保护层,受到9煤开采影响,回采巷道可能存在围岩变形程度大,支护方式选取困难的问题.以被保护层7111工作面机巷为研究对象,进行支护技术研究.通过理论分析巷道变形与破坏机理后,针对不同巷道地段设计了3种支护方案,运用FLAC3D软件模拟下煤层开采后被保护层回采巷道在3种支护方式下围岩应力分布特征和顶底板、两帮位移及塑性区范围.结合现场实测分析后,表明支护方案和参数设计比较合理,为上行开采回采巷道支护提供了有效的方法.

面对特殊时期的严峻考验,全国各高校的春季开学被迫延期,线上教学被推到了教学前台.针对线上教学的特殊性,如何管理线上课堂及提高教学质量与效果尤为重要.以地下工程施工课程的线上教学为例,从线上课堂管理、教学方法、教学内容、作业设计等方面进行了浅析探讨,以提高学生线上学习的主动性和学习效率,达到提高教学质量与效果.

为了给地震区域的灾后重建和防灾减灾工作提供重要帮助,同时给类似滑坡灾害危险性评价提供参考,开展对2018年日本北海道地震的研究.2018-09-06日本北海道厚真町发生M w 6.6级地震,触发了大量山体滑坡,造成人员伤亡和重大财产损失,引发社会广泛关注.基于0.3 m空间分辨率的Pleiades-1卫星震前震后高清遥感卫星影像进行滑坡目视解译,共圈定12586处滑坡.选取高程、坡度、坡向、曲率、T PI(坡位指数)、距水系距离、距道路距离、距震中距离、地层岩性9个因子作为滑坡的影响因子.基于GIS平台,应用确定性系数(CF)模型开展北海道地震滑坡危险性评价,评价结果将研究区分为极低危险区、低危险区、中危险区、高危险区、极高危险区五类,得出滑坡危险性评价区划图,并利用ROC曲线对评价结果精度进行检验,正确率为85.3％,表明基于确定性系数模型得出的滑坡危险性评价结果与实际滑坡结果比较吻合.

Aiming at the difficulties during the support of high-stress fractured soft rock roadway in deep mine, a comprehensive surrounding rock management method of bolt-net-cable-grout coupling support is proposed and the mechanism of interaction between coupling support and surrounding rock is analyzed by numerical simulation. The effectiveness of the coupling support is proved by an application in the east wing return-air roadway in the Qingdong Coal Mine of Huaibei Mining Group. The results show that the surrounding rock plastic zone near the sidewall and floor of high-stress fractured soft rock roadway is larger than that near the roadway roof, and its distribution range can be reduced by using the coupling support. And, the coupling support can improve the reliability of roadway support and the stability of surrounding rock by reducing the axial stress of anchor bolts, the stress concentration of surrounding rock caused by anchor bolt, the roadway surface displacement, and deep displacement of surrounding rock.

伊犁州位于新疆西北部,黄土分布范围较广,境内降雨丰沛.近年来,随着人类工程活动的增强,黄土滑坡灾害进一步加剧.以新疆伊犁州伊宁县某滑坡密集区域为研究区,在Google Earth平台上采用人工目视方法解译出3424处滑坡.选取高程、坡度、坡向、地形位置指数(TPI)、距道路距离、距河流距离、距断层距离、多年平均降雨量、归一化植被指数(NDVI)共九个滑坡影响因子,运用信息量法进行滑坡易发性评价.将研究区的滑坡易发性分为极低易发区、低易发区、中易发区、高易发区和极高易发区,采用感受性曲线(ROC)对评价结果进行检验.结果 表明:信息量模型训练集和验证集的成功率均在80％以上,信息量模型的评价结果较为理想;高易发区和极高易发区内滑坡数量有2660个,占滑坡总数的77.69％,滑坡面积为2.2 km2,占滑坡总面积的60.27％.基于GI S和信息量法的滑坡易发性评价结果可以为该区域地质灾害防灾减灾工作提供科学依据和可靠参考.

2019年"利奇马"台风诱发了安徽省宁国市多处山体滑坡.为研究东南沿海地区台风暴雨滑坡的分布规律,以宁国市为例展开研究,基于降雨前后的Planet卫星影像,采用人工目视解译法在ArcGIS上获取滑坡分布.根据数字高程模型(DEM)、地质图及降雨数据提取高程、坡度、坡向、地层和降雨量共5个影响因子进行统计分析.研究结果表明:研究区面积3567 km2,解译滑坡414个,滑坡总面积1.42 km2,南部区域的滑坡点密度最大;在高程[300 m,600 m)、坡度[20°,30°)、东南坡向、地层为震旦系、降雨量[300 mm,350 mm)区间的滑坡数量最多.研究结果可为进一步研究东南地区降雨滑坡的易发性评价提供基础,也可为当地防灾减灾提供参考.

The rapid development of the domestic economy has stimulated the demand for construction in cold areas. In recent years, a large number of domestic construction projects have been slowly transferred to cold areas. For example, construction and transportation are facing increasingly serious problems due to the extremely cold weather in the cold areas. The freezing and thawing disasters of rocky slopes in cold regions are one of the major problems that must be solved in slope engineering. Therefore, it is of great value to study the stability of rock slopes in cold regions. In this paper, the freeze-thaw cycle test is selected for research, and the mechanical characteristics of the freeze-thaw damage of the fractured rock mass and the mechanism of fracture failure are carefully analyzed. The uniaxial experiments and freeze-thaw cycle mechanics tests will be used to study the mechanical properties of fractured rock masses freeze-thaw damage and explore the coupling effect of freeze-thaw on the fractured rock masses and the law of changes in the damage caused. The research results show that: (1) We use the same type of rock mass (2 pieces of Y1 type rock mass) as the research sample to pass the cyclic freeze-thaw test. From 25 freeze-thaw cycles to 65 freeze-thaw cycles, the initial 5.5mm gradually increases to 19mm. By the end of the test, large-scale cracking occurred on the surface of the rock mass; (2) Under the combined action of a single load and a freeze thaw environment, the damage of the fractured rock samples (Y1-Y4) is deeper than the intact rock sample. indicating that the length of the cracks and the number of freeze-thaw cycles of the rock sample have a great influence on the damage of the rock, and the inclination angle of the cracked rock has a relatively small influence on its mechanical damage. Rock freeze-thaw damage belongs to fatigue failure. The effect of load and freeze-thaw on rock damage has significant nonlinear characteristics, and the coupling effect makes the total damage slowly weakened. The initial damage situation and rock lithology determine the freeze-thaw cycle and damage expansion feature.

By lots of creep test researches, artificial frozen clay shows an obvious creep behavior under high deviatoric stress. When artificial frozen clay in low stress level, a viscoelastic creep deformation presents. While in high stress level, viscoplastic creep deformation presents. On the basis of Nishihara model, parabolic viscoelasto-plastic creep constitutive model is constructed by adding a viscoelastic element and parabolic yield function instead of plastic yield. The modified Nishihara model can describe the shear creep characteristics of artificial frozen soil well. Based on niche technology, genetic algorithm and viscoelasto-plastic theory, the model of viscoelasto-plastic displacement back analysis for artificial frozen soil has been set up by finite element program generator (FEPG). With the measured data, displacement back analysis is conducted during the excavation of deep freezing shaft. And the obtained parameters of mechanical model for frozen soil agree with the test results. The deviation between numerical calculation results and measured data is less than 6%;so the inversion results verify the feasibility of the model. The constitutive model parameters, which obtained by displacement back analysis for artificial frozen soil, can reflect the average of frozen wall construction process and effective freezing range. So it has wide representation and important engineering significance for frozen wall stress field, displacement field and stability prediction.

Aiming at problems of bad cutting effect,low hole utilization for hard rock excavation in coal mines,different cutting model tests were conducted by using concrete as similar material.Different blasting effects were analyzed from the cutting volume,blasting hole utilization and fragmentation.Wedge-shaped millisecond cutting was adopted in which middle blasting holes are 200 mm deeper than other cutting holes with 1or 2 branches explosives and 2 sections of millisecond electric detonator.The experimental results indicate that middle blasting holes increase free surface and overcome rocks clips;and the millisecond blasting extends the delay time of detonation gas with a rational broken particle size and even lump size,then enhances the blasting hole utilization and cutting volume.

According to the support features of deep rock roadway,a study on the mechanism and analysis of mechanical properties of bolt-shotcrete support in deep rock roadway was done,combined with the actual conditions of a prototype of inclined belt conveyor roadway in west wing of Wanbei mine.Deformation and failure rule of surrounding rock in deep rock roadway by different supporting methods was analyzed with numerical calculation software.What's more,the stress,displacement and plastic zone changing of surrounding rock were systematically analyzed under bolt-shotcrete support and shotcrete support comparatively,and the bolt spacing changing in bolt-shotcrete support was analyzed at the same time.The numerical results showed that the bolt-shotcrete support significantly increased the strength and bearing capacity of surrounding rock,and effectively controlled the deformation and stability in deep rock roadway.

Aiming at some shortcomings of bad cutting effect, low hole utilization and small circulation footage in hard rock excavation, rapid excavation technology by drilling and blasting is proposed to improve the blasting effect for hard rock roadway from depth of blast hole, cutting form, layout of blast holes and smooth blasting. 1) Medium-deep hole is adopted to increase cycle footage; 2) Wedge-shaped cutting is benefit to overcome the rock clips and raise holes utilization in hard rock; 3) Millisecond blasting can greatly prolong action time of detonation gas and decrease maximum stress in boreholes with a rational broken particle size and even lump size; 4) Large diameter bole for the cutting hole and small diameter hole for the contour hole can save the drilling time and ensure the blasting quality. Application results show that the new rapid drilling and blasting technology can greatly increase circulation footage and hole utilization, improve formation quality of roadway and surrounding rock stability, realize average month drill footage at 120 meters and the maximum at 152 meters.

In order to research the expansive deformation performance of shrinkage-compensating steel fiber reinforced shotcrete, orthogonal test was done in this paper with expansive agent content and steel fiber content as variable. And the test results showed that restrictive expansion ratio was gradually increased when curing in water, while reducing in air. The difference between restrictive expansion ratio and free expansion ratio used to make self stress by stretching steel bar and steel fiber. Meanwhile the maximum self stress is 0.58MPa, and the minimum self stress is 0.23 MPa in concrete. What's more, both the maximum self stress and the minimum self stress could meet the requirements for self stress of shrinkage-compensating concrete.

Experiments are carried out to study the hard sandstone under uniaxial compression and different confining pressures with triaxial compression by the rock mechanics testing machine RMT-150B in deep coal mine,and basic mechanical properties of sandstone are measured.According to the rock stress-strain curves,strength properties and deformation characteristics of deep-seated rock are analyzed.The results show that rock compression strength increases by 40.3% with confining pressure from 10 to 15 MPa.The deformation and failure pattern of sandstone are closely related to confining pressure.The slope of main stress difference-strain curves are steep significantly with the increasing of the confining pressure.Based on the mechanical properties of rock,the 42 mm in diameter drill bit is adopted for the cutting holes and the 32 mm in diameter drill bit is used for the surrounding holes in order to save the drilling time.The different steps of millisecond inclined cutting with medium-length hole are proposed,and the depths of 2.2-2.5 m for blasting hole are reasonable which are beneficial to the footage.The surrounding hole with small diameter is beneficial to the roadway forming.

According to testing and analysis of mechanical properties of rock,double bench cutting was adopted with large-diameter hole,large-diameter cartridge,other holes with small diameter hole in order to improve blasting effect.By measuring the operations of the time,construction processes were optimized with rational allocation of drilling implements.Results indicate that this method increases excavation efficiency and implements rapid excavation.

论文分析了祈东煤矿92采区原矸石运输系统现状及存在的问题,对原矸石运输系统进行优化设计和改造,通过施工2个矸石眼,将原来绞车出矸改为胶带结合梭车出矸.工程实践表明:改造后的矸石运输系统缩短了运输距离,简化了矸石装载和运输环节,提高掘进速度和效率,掘进进尺增加了41.7%,节约成本,工期缩短2个月,实现安全生产和高效快速掘进.

Based on the comprehensive analysis on the factors affected to the depth of the blasting borehole,according the borehole drilling equipment,mine safety regulations,month advanced rate,circulated operation mode and the test study,a conclusion was made that the conventional rock driller could have an optimized borehole depth of 2.2~2.5 m.As for the hard rock,in order to save the borehole drilling time,a large diameter bole for the cut hole could improve the drilling rate and the small diameter borehole for the contour hole could ensure the blasting quality.

随着招生规模的扩大,以及招生收费制度改革的进一步深化,高校中贫困生的人数逐年上升,高校贫困生问题已成为我国高等教育改革和发展的一个焦点问题。为了准确掌握贫困生的基本状况及其存在的问题,更好地开展贫困生的教育和管理,帮助他们克服困难,顺利完成学业,对安徽理工大学2003、2004、2005三个年级的1800名学生进行问卷调查。实际回收问卷1763份,有效问卷1708份,统计结果:贫困生531人,占被调查人数的31.09%。

Through analyzing the impact of Huainan mining area ecological environment to subsidence pool waters and the species changes of plankton in excavating coal subsidence pools of different time order, the response of the plankton in it to the mining area ecological changes was inquired, from which it was found that in the initial stage of subsidence Bacillariophyta-Euglenophyta were the dominant; in the metaphase with the increase of nutrition level, Chlorophyta-Cyanophyta became the main algae in waters; after a long time of high eutrophication level, the circumferential environment of the subsidence pool was stabilized gradually, the influence factors also tended to be simplified, and Bacillariophyta-Euglenophyta became again dominant algae. The species of zooplankton showed an evident downtrend and the dominant species were also changed. This explained that the succession of the plankton in subsidence pools differed from general reservoirs and lakes.

Having analyzed geothermal temperature materials of 38 drills, the depth of the invariable temperature zone is 16m in this area and it's temperature is 15. 5 ℃. The average of geothermal gradient is 2. 80℃/100m. Based on that, the characteristics of geothermal temperature were analyzed and the equation was set up. The temperatures of water bursting aquifer were calculated by equation. Compared them with the actual temperature of water bursting, they are consistency. The result offers scientific basis for distinguishing the source of water bursting.