Type of major water hazards and study of countermeasures in Shennan Mining Area

By analysing the hydrogeological conditions of this region and the coal mines hereof, together with the water hazards troubled Shennan mine area in recent years, this paper summarized six types of mine water hazards. As per the basic characteristics, geological distribution, threat degree and difficulty of prevention of various water hazards, along with the practice of water prevention in the mining area, this article proposed effective technical measures for the prevention and control of different water hazards and laid a solid foundation for the safe production in the mining area.

Analysis of the Risk of Water Breakout in the Bottom Plate of High-Intensity Mining of Extra-Thick Coal Seams

In order to clarify the danger of water breakout in the bottom plate of extra-thick coal seam mining, 2202 working face of a mine in the west is taken as the research object, and it is proposed to use the on-site monitoring means combining borehole peeping and microseismic monitoring, combined with the theoretical analysis to analyze the danger of water breakout in the bottom plate. The results show that: 1) the theoretically calculated maximum damage depth of the bottom plate is 27.5 m, and its layer is located above the Austrian ash aquifer, which has the danger of water breakout;2) the drill hole peeping at the bottom plate of the working face shows that the depth of the bottom plate fissure development reaches 26 m, and the integrity of the water barrier layer has been damaged, so there is the risk of water breakout;3) for the microseismic monitoring of the anomalous area, the bottom plate of the return air downstream channel occurs in the field with a one-week lag, which shows that microseismic monitoring events may reflect the water breakout of the underground. This shows that the microseismic monitoring events can reflect the changes of the underground flow field, which can provide a reference basis for the early warning of water breakout. The research results can provide reference for the prediction of sudden water hazard.

Robust water hazard detection for autonomous off-road navigation

Existing water hazard detection methods usually fail when the features of water surfaces are greatly changed by the surroundings, e.g., by a change in illumination. This paper proposes a novel algorithm to robustly detect different kinds of water hazards for autonomous navigation. Our algorithm combines traditional machine learning and image segmentation and uses only digital cameras, which are usually affordable, as the visual sensors. Active learning is used for automatically dealing with problems caused by the selection, labeling and classification of large numbers of training sets. Mean-shift based image segmentation is used to refine the final classification. Our experimental results show that our new algorithm can accurately detect not only ‘common’ water hazards, which usually have the features of both high brightness and low texture, but also ‘special’ water hazards that may have lots of ripples or low brightness.

AN INSTRUCTURAL SYSTEM MODEL OF COASTAL MANAGEMENT TO THE WATER RELATED HAZARDS IN CHINA

Coastal lowlands have large areas of hazard impact and relatively low capacity of prevention to the water related hazards,which have been indicated by the wide_spread flood hazards,high percentages of land with high flood vulnerability.Increasing population pressure and the shift of resources exploitation from land to sea will force more and more coastal lowlands to be developed in the future,further enhancing the danger of water_related hazards.In this paper,the coastal lowlands in the northern Jiangsu province,China,were selected as a case study.The Interpretation Structural Model (ISM) was employed to analyze the direct and indirect impacts among the elements within the system,and thereby,to identify the causal elements,middle linkages,their expressions,and relations.

Neutron Induced Fission Track Estimation of Uranium Concentration and Its Associated Health Hazards in Drinking Water of the Faisalabad Industrial City

Drinking water plays a major role regarding quality of human life because polluted water is the main cause of many types of diseases. Besides other pollutants, high concentration of uranium above a certain level in drinking water is also hazardous. As water and food are the main sources of uranium intake, it is absolutely imperative that their level of concentrations is monitored regularly for safety of the general public. In this regard, trace amount of uranium in drinking water samples collected from different locations of Faisalabadcity has been carried out using Neutron Induced Fission Track Technique. The water samples along with the standard of known uranium concentration were poured and dried over Lexan track detectors and then irradiated with thermal neutrons in Reactor. After etching, the tracks produced in the detectors as a result of 235U (n, f) reaction were counted under an optical microscope. The uranium concentration was determined by counting and comparing the observed fission track density in the samples and the standard. The observed uranium concentration in the studied water samples varied from (1.04 ± 0.30) μg·L-1 to (21.08 ± 2. 95) μg·L-1 with an average value of (7.39 ± 1.30) μg·L-1 and is found to be within safe limits as far as uranium related health hazards are concerned.

陕西省煤矿典型水灾隐患特征及治理技术

陕西省煤炭资源丰富,2022年煤炭产量达7.46亿t,是我国主要产煤省份之一。由于全省煤矿区地质及水文地质条件差异明显,煤矿水灾类型多样,随着近年煤炭开采强度的增大,水灾事故时有发生,防治水形势较为严峻。以煤炭赋存条件为基础,系统总结区域水文地质结构特征,界定典型水灾类型及各类水灾影响区域分布,论述典型水灾的形成机理及特征,并提出了相应的防控技术。研究表明:(1)陕西省主要煤炭产区分为陕北、黄陇、渭北三大区,陕北侏罗纪煤田主要有顶板松散沙层水灾隐患、厚层砂岩水灾隐患、溃水溃沙灾害,局部区域分布有烧变岩对煤矿造成水灾隐患;黄陇煤田主要受顶板巨厚砂岩水灾隐患、离层溃水隐患、泥砂溃涌灾害隐患威胁;陕北石炭—二叠纪煤田和渭北煤田,主要受到煤层底板奥陶系灰岩水灾隐患威胁。(2)陕北侏罗系煤田顶板水灾隐患主要为顶板含水层受开采导水裂隙带扰动形成,导水裂隙波及砂岩含水层或松散沙层可形成持续大流量涌水,部分区域充水强度较大,在短时间水量较大超过排水系统能力时造成顶板水灾,在薄基岩区域垮落带直接导通松散沙层时可转变为溃水溃沙灾害,导水裂隙带影响到烧变岩富水区域时可形成瞬时水量大且持续的烧变岩水灾;黄陇煤田顶板巨厚砂岩含水层受采动导水裂隙带波及形成高强度持续涌水并可能形成顶板水灾,当含水层下部隔水层厚度较大时,可能形成离层溃水灾害,当近煤层顶板岩层松软遇水易崩解时可转变为泥砂溃涌灾害;陕北石炭—二叠纪煤田和渭北煤田,煤层开采底板扰动破坏带或断层等构造导通奥陶系灰岩含水层时,会引发极为严重的底板突水灾害,该类灾害具突发性强、瞬时水量大的特征。(3)各区域的顶板水灾隐患治理技术主要包括钻孔疏泄、注浆治理、开采参数控制等,底板水灾隐患治理技术主要包括区域注浆加固及封堵等;烧变岩水灾隐患主要采取帷幕注浆与钻孔探放有机结合的防治技术。

Environmental Assessment of Natural &Anthropogenic Hazards and Impact on Seawater Desalination along Red Sea Coast of Saudi Arabia

The major part of the eastern coastline of Red Sea belongs to Saudi Arabia, which provides great potential for desalination activities, but not entirely free of risk as in general it is not environment-friendly. In recent years, the rapid urbanization processes on west coast of Kingdom have resulted in substantial growth of commercial and industrial centers that added to more water demand. As a consequence, reliance on desalinated water has increased markedly over the last few decades. As a leading producer of desalinated water, Saudi Arabia used to process more than 3.29 million m3/day from its plants along the Red Sea coast. At the same time, any adequate backup plan lacks to meet regular water demand(s) in case of unforeseen emergencies. Present integrated research studies have identified some of the natural and anthropogenic hazards, which may pose major threats to quality of seawater as well as to the desalination facilities themselves. In view of these hazardous conditions, the overwhelming dependence on seawater desalination appears to be in jeopardy and may affect water management strategy and future socioeconomic development. It is therefore suggested the need of alternate options for cultivation of standby water resources and other management strategies parallel to the seawater desalination on similar priorities.

基于主量元素地球化学的岩屑层位源解析

近年来,岩屑录井在“华北型”煤田底板灰岩层注浆加固工程中发挥了重要作用。然而,现有的岩屑录井仅停留在颜色、颗粒大小及形貌特征等物理指标的识别上,难以精准判层,钻孔设计“顺层率”难以保障,制约着底板灰岩水害区域治理效果。基于石炭纪太原组薄层灰岩及其碎屑岩夹层的元素地球化学差异特点,选取淮北煤田桃园煤矿为研究区,对太原组上段薄层灰岩L_(1)灰~L_(4)灰地层(注浆治理目的层为L_(3)灰)垂直钻孔岩心进行取样,利用X射线荧光光谱仪(XRF)定量测定了薄层灰岩及其夹层的主量元素背景值,通过聚类分析、因子分析等数理统计手段建立薄层灰岩主量元素地球化学识别模式;同时对地面定向钻水平分支孔岩屑同样开展主量元素测试,并基于已建立的地球化学识别模式进行岩屑层位源解析以及识别模式验证。结果显示:高CaO丰度、烧失量(LOI)可以作为注浆加固改造目的层L_(3)灰的特征指标,MgO(0.5%±)、MnO(0.03%±)、P_(2)O_(5)(0.08%±)丰度可作为注浆目的层上覆标志层J3的识别指标;聚类分析识别模式可有效区分太原组一灰~三灰(L_(1)灰~L_(3)灰);以元素因子得分建立的识别模式可以将太原组碎屑岩夹层与薄层灰岩进行有效区分;以岩样地球化学背景值运行判别模型得到的Fisher判别方程对注浆目的层L_(3)灰岩屑来源解析的准确率为100%。基于上述认识,论证了以确保设计“顺层率”为目标的水平分支孔岩屑地球化学源解析方法应用之可行性,进而提出了一种地面定向钻“顺层率”控制技术方案。本研究基于元素地球化学理论,对地面定向钻岩屑携带的特征地球化学信息进行了目的层层位辨识,在现场快速定量测试技术手段的支持下,可为解决华北型煤田底板灰岩水害区域注浆改造顺层难题提供了新的思路。

侏罗系宝塔山砂岩突水风险预测及限制边界疏降技术

内蒙古上海庙矿区新上海一号煤矿发生国内首次也是目前唯一的侏罗系煤层开采底板宝塔山砂岩突水淹井事故;开展了侏罗系煤层开采底板强富水宝塔山砂岩突水危险性评价方法和防控技术的研究工作。首先,明确了“11·25”事故的突水水源为侏罗系延安组下部的宝塔山砂岩含水层,且煤层与底板宝塔山砂岩之间隔水层具有强度低、软化系数小、胶结性差的特点,属地质软岩。其次,以“含水层厚度、含水层富水性、含水层渗透性、含水层水压力及18煤底板隔水层有效厚度”为主要指标建立突水评价体系,将宝塔山砂岩含水层突水危险性分区被划分为安全区(32.21%)、威胁区(37.53%)及危险区(30.26%)三种类型,并通过实例验证了评价模型的准确性。最后,结合底板隔水层工程地质特性,分析采用“断层注浆形成局部限制边界+群孔疏降”的方法防控宝塔山砂岩突水。设定“疏放水开始至1号钻场退出疏放水工作、2号、3号和4号钻场持续进行疏放水工作至3号钻场退出、2号和4号钻场持续进行疏放水工作至模型补排平衡”的疏降方案。依据规范得出注浆后最大帷幕渗透系数为2×10^(-2) m/d,当断层注浆后帷幕渗透系数为2×10^(-2)~2×10^(-8) m/d时,疏放水量为402万~347.8万m^(3),安全区占矿区的比例为43.34%~67.37%。结合注浆成本、疏放水量和安全性,帷幕渗透系数为2×10^(-4) m/d时即可有效保证矿井安全生产和技术经济效益。断层注浆局部限制边界+疏放水联合技可有效防控宝塔山砂岩水害,研究工作对我国西部侏罗纪煤田开发底板水防治具有重要意义和工程实践价值。

某固废资源综合利用项目产生水淬渣的危险特性鉴别研究

为明确某固废资源综合利用项目中产生水淬渣的危险特性,通过属性判断、腐蚀性鉴别、急性毒性初筛、易燃性鉴别、浸出毒性鉴别、反应性鉴别、毒性物质含量鉴别等手段对水淬渣是否具有危险特性进行鉴别。鉴别结果表明,在生产工艺不变、原辅料来源稳定、原辅料配比稳定且相关生产设备运行良好,生产工况稳定的情况下,鉴别对象水淬渣不属于危险废物,可作为一般工业固体废物进行管理和处置。

An Evaluation of Manure Management Strategies, Phosphorus Surface Runoff Potential and Water Usage at an Arkansas Discovery Dairy Farm

Manure management is an essential component of dairy production. Nutrient-laden, field-applied dairy manure often serves as a fertilizer source, but can also pose environmental threats if not properly managed. The Haak dairy farm, located in Decatur, Arkansas, was granted a permit by the Arkansas Department of Environmental Quality (ADEQ) to employ a unique method in treating and storing cattle manure generated during the milking process. This method includes minimizing water use in wash water, dry scraping solids to combine with sawdust for composting and pumping effluent underground into a sloped concrete basin that serves as secondary solid separator before transporting the manure effluent into an interception trench and an adjacent grassed field to facilitate manure nutrient uptake and retention. The Arkansas Discovery Farm program (ADF) is conducting research to evaluate the environmental performance of the dairy’s milk center wash water treatment system (MCWW) by statistical analysis, characterization of phosphorus (P) migration in soil downslope from the inception trench, temperature measurements, and nutrient analysis of a stored dry stack manure/sawdust mixture. Goals included determining possible composting effectiveness along with comparisons to untreated dairy manure and quantifying the use of on-farm water. Results from this research demonstrated that: 1) The MCWW was effective at retaining manure-derived nutrients and reducing field nutrient migration as the MCWW interception trench had significantly higher total nitrogen (TN) (804.2 to 4.1), total phosphorus (TP) (135.6 to 1.5), and water extractable phosphorus (WEP) (55.0 to 1.0) concentrations in milligrams per liter (mg⋅L-1) than the downhill freshwater pond respectively;2) temperature readings of the manure dry stack indicated heightened levels of microbial and thermal activity, but did not reach a standard composting temperature of 54°C;3) manure dry stack nutrient content was typically higher than untreated dairy manure when measured on a “dry basis” in ppm, but was lower on an “as is basis” in ppm and kg/metric ton;and 4) water meter readings showed that the greatest use of on-farm water was for farm-wide cattle drinking (18.77), followed by water used in the milking center (3.45) and then followed by human usage (0.02) measured in cubic meters per day (m3⋅d-1). These results demonstrate that practical innovations in agricultural engineering and environmental science, such as the Haak dairy’s manure treatment system, can effectively reduce environmental hazards that accompany the management of manure at this dairy operation.

极端环境隧道建造面临的主要问题及发展趋势

聚焦艰险山区、深水海域与城市敏感区3类极端环境,全面梳理和总结了在此环境下隧道建造面临的主要问题、相关技术突破和未来发展趋势。针对艰险山区中极高地应力、高地温、高海拔以及活动断裂带等极端条件,总结分析围岩和隧道的变形机制、破坏机制及防护措施,并指出未来可通过大数据、机器学习等手段建立更精准的预测模型,以实现隧道建造过程的实时监控和风险评估;针对深水海域中高水压、高烈度地震、强侵蚀环境等极端条件,分析多因素耦合下沉管法及盾构法隧道管片及接头的劣损和破坏机制,总结提升其力学和耐久性能的主要技术措施,并提出未来仍需针对海底隧道管片接头的防水、抗震及抗侵蚀性能开展更深入的研究,以形成完整的理论和技术体系;针对城市敏感区隧道穿越既有隧道、敏感建构筑物、地下障碍物等挑战,总结分析盾构法和顶管法施工环境响应规律、地层变形评估方法和控制技术措施,提出未来可采用机器学习等技术辅助隧道建设,以提升预测和控制的准确性,减小建设过程对城市环境的扰动。目前,相关研究成果为极端环境下的隧道工程建设提供了重要支撑,但部分技术仍需进一步在实践中完善并形成规范,以指导后续的工程建设;而随着新一代信息技术的发展,未来隧道建造必将朝着数字化、智能化、自动化的方向发展,从而保障极端环境下隧道建设的安全、绿色、高效。

我国煤层水害基本架构及发展情势

为了解决煤炭资源安全高效开发过程中面临的煤层水害问题,基于近20余年间煤层水害事故的统汇分析,提出了“隐蔽突水致灾因素”萌生、煤层水害“三要素”定型、多要素耦合孕灾、突破临界状态激发灾变和灾变后负效应显现等5个煤层水害的主体构成阶段,依据各阶段独立属性特征,将煤层水害概括为顶板水害、底板水害和老空水害3个主类,以及巨厚基岩含水层高势能涌(淋)水、岩溶陷落柱导升突水、同位水平空间侧向涌水等11个子类,并对不同类型煤层水害的孕灾致灾诱因、发育发展过程机理、灾变显现特征等进行阐述。最后,对我国煤层水害的未来发展情势做了简要展望和分析。

煤矿防治水“三区”划分方法及其水害防治意义

为系统性认识矿井各类水害问题,规范化管理矿井防治水工作,国家矿山安全监察局于2022年6月将针对老空水防治的“三区”管理工作推广到顶板水害、底板水害以及构造水害等更多水害类型中。然而各地煤矿在防治水“三区”划分过程中暴露出水害致灾因素和水害治理情况等与划分标准结合不紧密,并且技术上未针对不同煤层和采区进行区别划分,同时划分区域范围和划分结果的规范性和时效性存在不统一。据此,结合防治水“三区”划分的目的,对比了新“三区”划分与老空水“三区”划分的异同,明确了以水文地质条件勘查程度、水害隐患分析、水害治理情况为要素的划分原则,理清了“三区”划分的技术路径;结合我国常见的5种煤矿水害类型特征,提出了不同类型水害的划分方法,即:地表水害应根据井田内地表水体的分布发育特征以及大气降水、滑坡等地质灾害对开采的影响程度等进行划分。顶板水害应根据导水裂隙带范围内是否存在富水性强或者富水性中等静储量丰富含水层、松散含水层等对开采造成威胁进行划分。底板水害应根据煤层带压开采区域底板隔水层厚度与矿压破坏带深度之间的关系以及底板突水系数大小进行划分。老空水害应根据矿井及周边矿井老空积水分布范围、积水量情况进行划分,构造水害应根据井田内断层、陷落柱、溶洞等地质构造和不良地质体的富水性、含水性、与水源导通情况进行划分;总结了划分工作的要点和难点,即:明晰划分时空范围、综合分析划分标准、明确“三区”管理职责、动态转换划分结果等;在此基础上,选择水害类型多样和水文地质条件复杂的典型煤矿井,遵循划分原则,根据划分标准,分煤层、分采区划分了可采区、缓采区、禁采区,并加以详细的解释说明;阐明了开展“三区”划分工作具有提升综合探测水平、强化预测预报能力、找准水害治理方向的水害防治意义,以期指导和规范我国煤矿防治水“三区”划分工作。

Characteristics of water inflow and chemical grouting treatment of a Liu Yuanzi Coal Mine shaft in the Ordos Basin

During shaft constructing, a borehole water inflow of 30 m3/h was encountered in Liu Yuanzi Coal Mine in the southwestern Ordos Basin, whose aquifer is mainly cretaceous. On the basis of regional hydrogeological conditions, a mercury intrusion method and scanning electron microscope were used in this study. We conclude that the loose, porous and easily collapsible clay particles of the cretaceous aquifer rock mass were the major geological cause for water hazards during the construction of the shaft. We propose an approach of chemical grouting from the working surface and in the end succeeded in blocking the water.

基于“两带”探查技术的顶板水害危险性分析——以伯方煤矿为例

应用钻液漏失量观测、岩芯采取统计、钻孔电视观测和钻孔电阻率动态监测等多种“两带”探查技术方法,对伯方煤矿3煤开采的覆岩导水裂隙带发育特征进行研究,分析3煤采动影响下的顶板水害危险性。研究结果表明:3213工作面导水裂隙带发育高度为87.66 m,发育至K9砂岩含水层;垮落带发育高度为22.61 m,发育至2煤下部K8砂岩含水层。3313工作面垮落带最大高度为煤层顶板20~21 m,至2煤顶板砂岩含水层;导水裂隙带最大高度为煤层顶板83~87 m,至K9砂岩含水层。由此计算得出的垮落/采厚比为3.58~3.76,裂缝/采厚比为14.85~15.56。3煤回采产生的导水裂隙可造成二叠系下石盒子组和山西组砂岩含水层与3煤采空区的连通,含水层地下水岩导水裂隙向下渗流,增加了顶板水害的风险。建议矿井严格落实顶板水害防治的相关要求,降低采动裂隙对矿井正常生产的影响。

隐伏火烧区烧变岩含水层水害治理技术研究

我国西北地区烧变岩分布范围广、孔隙裂隙发育、富水性强,是当地的主要含水层,其中的隐伏火烧区烧变岩地表遗迹不明显、发现难度大,煤矿开采一旦导通烧变岩含水层将导致水害事故,同时会破坏烧变岩含水层水资源。为治理隐伏火烧区烧变岩水害并保护烧变岩含水层水资源,分析我国烧变岩分布特征及烧变岩水对煤矿开采影响,研究隐伏火烧区烧变岩探查和治理技术,开展隐伏火烧区烧变岩含水层水害治理的示范应用,结合现场监测数据分析评价陕西柠条塔煤矿南翼隐伏火烧区含水层水害治理和水资源保护效果。结果表明:我国烧变岩主要分布于以昆仑山-秦岭-大别山为界的北方地区,隐伏烧变岩主要分布在鄂尔多斯盆地东北部、伊犁盆地南缘,被第四系松散层覆盖;隐伏火烧区烧变岩含水层与风化基岩含水层大多直接接触且连为一体,水力联系密切;烧变岩水害防治措施主要有留设烧变岩含水层防隔水煤柱、疏降烧变岩含水层积水和帷幕截流,其中截水帷幕可有效解放烧变岩含水层压覆的煤炭资源,解除烧变岩水害威胁并保护烧变岩含水层宝贵的地下水资源;通过精确探查出隐伏火烧区范围、布设注浆钻孔,将隐伏火烧区烧变岩含水层隔离为若干个含水体,断绝截水帷幕内外的水力联系,可保障工作面不受烧变岩水威胁,同时实现烧变岩水资源保护;柠条塔煤矿S1232工作面和S1233工作面隐伏火烧区烧变岩含水层治理后,其回采期间涌水量降至20m^(3)/h以内,工作面得以安全回采,截水帷幕内侧水位下降,外侧水位逐渐抬升,烧变岩水资源得到有效保护。

弱胶结巨厚砂砾岩含水层离层突水机制研究

安新煤田主采煤层上覆巨厚弱胶结砂砾岩含水层,富水性弱,但多个工作面回采期间发生突水,查明突水机制是矿井水害防治的关键。通过水文地质特征分析,阐明了砂砾岩含水层厚度分布特征和富水性分区特征。采用岩石单轴抗压强度、三轴声发射、X衍射试验等方法,获得了顶板隔水层岩石物理力学性质。基于关键层理论分析、导水裂隙带与采动富水异常区层位关系及相似模拟试验成果,建立了4种条件下巨厚砂砾岩含水层突水的水文地质结构模型,揭示了砂砾岩含水层不同条件下的突水机制,并明确了研究区突水点的突水机制,提出了隔水保护层失稳导致突水的工程判据。研究结果表明:研究区东部局部区域含水层富水性中等,以往多次突水均发生在弱富水区;砂砾岩含水层下顶板泥岩中黏土矿物含量达到59.6%,亲水性强,具有良好的隔水作用;但在采动作用下顶板隔水层岩体卸压后强度降低,厚度较薄时,受上部岩层载荷和采动富水区静水压力作用易发生破坏,成为良好导水通道;砂砾岩含水层物理力学性质特殊,采动扰动后孔隙裂隙发育,形成了富水变化异常区;弱胶结砂砾岩突水的强度与下部基岩特征、导水裂隙带发育高度、隔水保护层厚度等因素相关;研究区弱胶结砂砾岩发生突水的工程判据为正常区隔水保护层厚度小于30 m,受背斜构造影响区隔水保护层厚度小于60 m。弱胶结巨厚砂砾岩含水层离层突水机制及工程判据对西部矿区水害防治提供了借鉴。

蒙陕接壤区典型煤层开采顶板周期性变形破坏及涌水响应特征

【目的】煤矿开采扰动破坏覆岩含/隔水层结构,造成集中涌水,影响矿井安全生产。【方法】以面临典型顶板砂岩水影响的蒙陕接壤区主采煤层3-1煤开采涌水过程为研究对象,采用物理相似材料模拟、数值仿真模拟、现场原位监测3种方法,并通过周边地质和开采条件相似矿井实测数据对比,分析3-1煤典型工作面开采煤体支承压力周期性演变规律、采空区覆岩垂直位移演变规律,定量获取实验室尺度顶板周期来压瞬间微震能量事件变化特征,综合确定顶板导水裂隙带随采发育特征,以及顶板涌水随覆岩周期来压变化趋势。【结果和结论】结果表明:工作面开采覆岩初次来压步距约40 m,周期性来压步距12~28 m,覆岩破断瞬间围岩周期性来压呈现“先增后稳定”的趋势,在推进至第5次周期来压(推进距离约140 m)时,超前支承压力达到最大,覆岩周期性来压、破断瞬间垂直位移峰值随采呈现“之”字型变化特征,同样,位移监测数据、微震事件总能量、事件频次等综合指标指示,在第5次周期来压瞬间,覆岩垂直位移变幅达到最大值,塑性区发育高度基本稳定;导水裂隙带发育最大高度在120 m左右,将直接沟通顶板直罗组砂岩含水层,地下水随采涌入过程呈现两种波动变化趋势,工作面全局尺度上呈现长周期“阶梯式”增长趋势,“阶梯式”增长周期约800 m,局部尺度呈现短周期“振荡”变化趋势,振荡周期16~48 m,并表现出与覆岩来压周期之间的较强关联性。研究结果为工作面涌水量预测以及防排水系统布设提供参考。

饮用水中的微塑料及其拉曼光谱检测技术研究进展

塑料的发明和应用已逾百年,给日常生活带来了极大的便利。塑料制品及成分经过破碎降解后形成微塑料(MPs),环境中的MPs可进入饮用水,其污染和潜在的健康危害逐渐受到重视。MPs的定性和定量检测仍处于发展阶段,拉曼光谱(RS)是目前较常用的一种较灵敏的非破坏性的无损光学分析技术。本文重点介绍了饮用水中MPs的来源、潜在危害以及RS检测的研究进展,旨在提高对饮用水中MPs污染的认知和对研发MPs检测技术的重视。