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.

Spatial correlation of the high intensity zone in deep-water acoustic field

The spatial correlations of acoustic field have important implications for underwater target detection and other ap- plications in deep water. In this paper, the spatial correlations of the high intensity zone in the deep-water acoustic field are investigated by using the experimental data obtained in the South China Sea. The experimental results show that the structures of the spatial correlation coefficient at different ranges and depths are similar to the transmission loss structure in deep water. The main reason for this phenomenon is analyzed by combining the normal mode theory with the ray theory. It is shown that the received signals in the high intensity zone mainly include one or two main pulses which are contributed by the interference of a group of waterbome modes with similar phases. The horizontal-longitudinal correlations at the same receiver depth but in different high intensity zones are analyzed. At some positions, more pulses are received in the arrival structure of the signal due to bottom reflection and the horizontal-longitudinal correlation coefficient decreases accordingly. The multi-path arrival structure of receiving signal becomes more complex with increasing receiver depth.

Effect of pruning intensity on soil moisture and water use efficiency in jujube(Ziziphus jujube Mill.) plantations in the hilly Loess Plateau Region, China

Jujube(Ziziphus jujube Mill.)is a traditional economic forest crop and is widely cultivated in hilly areas of the Loess Plateau,China.However,soil desiccation was discovered in jujube plantations.Pruning is recognized as a water-saving method that can reduces soil water consumption.In this study,we monitored the jujube plots with control(CK),light(C1),medium(C2)and high(C3)pruning intensities during the jujube growing period of 2012-2015 to explore the effect of pruning intensity on soil moisture and water use efficiency(WUE)of jujube plantations in the hilly Loess Plateau Region.The results showed that pruning is an effective method for soil water conservation in jujube plantations.Soil moisture increased with increasing pruning intensity during the jujube growing period of 2012-2015.C1,C2 and C3 pruning intensities increased soil water storage by 6.1-18.3,14.4-40.0 and 24.3-63.3 mm,respectively,compared to CK pruning intensity.Pruning promoted soil moisture infiltration to deeper soil layer.Soil moisture infiltrated to soil depths of 240,280 and>300 cm under C3 pruning intensity,220,260 and 260 cm under C2 pruning intensity,200,240 and 220 cm under C1 pruning intensity,and 180,200 and 160 cm under CK pruning intensity in 2013,2014 and 2015,respectively.Soil water deficit was alleviated by higher pruning intensity.In 2013-2015,soil water change was positive under C2(6.4 mm)and C3(26.8 mm)pruning intensities but negative under C1(-20.5 mm)and CK(-40.6 mm)pruning intensities.Moreover,pruning significantly improved fresh fruit yield and WUE of jujube plants.Fresh fruit yields were highest under C1 pruning intensity with the values of 6897.1-13,059.3 kg/hm^2,which were 2758.4-4712.8,385.7-1432.1 and 802.8-2331.5 kg/hm2 higher than those under CK,C2,and C3 pruning intensities during the jujube growing period of 2012-2015,respectively.However,C3 pruning intensity had the highest WUE values of 2.92-3.13 kg/m3,which were 1.6-2.0,1.1-1.2 and 1.0-1.1 times greater than those under CK,C1 and C2 pruning intensities,respectively.Therefore,C3 pruning intensity is recommended to jujube plantations for its economic and ecological benefits.These results provide an alternative strategy to mitigate soil desiccation in jujube plantations in the hilly Loess Plateau Region,which is critical for sustainable cultivation of economic forest trees in this region.

Effects of water application intensity of microsprinkler irrigation on water and salt environment and crop growth in coastal saline soils

Laboratory and field experiments were conducted to investigate the effects of water application intensity（WAI） on soil salinity management and the growth of Festuca arundinacea（festuca） under three stages of water and salt management strategies using microsprinkler irrigation in Hebei Province, North China. The soil water content（è） and salinity of homogeneous coastal saline soils were evaluated under different water application intensities in the laboratory experiment. The results indicated that the WAI of microsprinkler irrigation influenced the è, electrical conductivity（ECe） and p H of saline soils. As the WAI increased, the average values of è and ECe in the 0–40 cm profile also increased, while their average values in the 40–60 cm profile decreased. The p H value also slightly decreased as depth increased, but no significant differences were observed between the different treatments. The time periods of the water redistribution treatments had no obvious effects. Based on the results for è, ECe and p H, a smaller WAI was more desirable. The field experiment was conducted after being considered the results of the technical parameter experiment and evaporation, wind and leaching duration. The field experiment included three stages of water and salt regulation, based on three soil matric potentials（SMP）, in which the SMP at a 20-cm depth below the surface was used to trigger irrigation. The results showed that the microsprinkler irrigation created an appropriate environment for festuca growth through the three stages of water and salt regulation. The low-salinity conditions that occurred at 0–10 cm depth during the first stage（-5 k Pa） continued to expand through the next two stages. The average p H value was less than 8.5. The tiller number of festuca increased as SMP decreased from the first stage to the third stage. After the three stages of water and salt regulation, the highly saline soil gradually changed to a low-saline soil. Overall, based on the salt desalinization, the microsprinkler irrigation and three stages of water and salt regulation could be successfully used to cultivate plants for the reclamation of coastal saline land in North China.

Can regional economy influence China's water use intensity?:based on refined LMDI method

China experienced a decline of water use intensity in the 11th Five Year Plan,but the water use intensity actually increased in 2009.To the best of our knowledge,the index decomposition analysis method was rarely used to analyze changes in water use,and no decomposition analysis has investigated the role of regional economy in the decline of water use intensity.In this paper,we use logarithmic mean Divisia index(LMDI)techniques to decompose the change of water use intensity in the period 2006-2010.We find that the change of industrial water use intensity is confirmed as the dominant contributor to the decline in the overall water use intensity;the regional structure effect and the industrial structure effect is positive to the decline of overall water use intensity;the decline of China's water use intensity is mainly attributed to the effect of developed eastern provinces;meanwhile,the effect of central and undeveloped western is also positive to the decline of overall water use intensity;at least one out of three effects is positive to the decline of water use intensity in the different provinces;the intensity effect is positive and the industrial structure effect is positive to the declines of China's water use intensity based on chaining approach except the period 2008-2009,individually;and the deviation of regional structure effect and industrial structure effect between with regional economy and without regional economy in LMDI is 0.9 and2.3 m^3/10~4 RMB,respectively.

Influence of light intensity and water content of medium on total dendrobine of Dendrobium nobile Lindl

Objective: To ascertain the influence of light intensity and water content of medium on the total dendrobine of Dendrobium nobile(D. nobile).Method: The principal component analysis combined with total dendrobine accumulation was conducted to assess the yield and quality of D. nobile in all treatments. In the experiment, D. nobile plants were cultivated in greenhouse as tested materials, and complete test of 9 treatments was adopted with relative light intensities 75.02%, 39.74%,29.93% and relative water content of medium 50%, 65%, 80%. The plants were treated in June and harvested till December. Indexes including agronomic traits, fresh weight and dry weight of stem and leaf, ash content, extract, and dendrobine were measured.Results: Under the light intensity treatments of 75.02% with 50%, 65%, 80% water content of medium, the basal stems of plants were comparatively thicker with more leaves, and the fresh weight and dry weight of stems and leaves were significantly higher than other 6 treatments.Leaves in all treatments contained dendrobine. Under the light intensity treatments of 75.02%with 50%, 65%, 80% water content of medium, dendrobine content of leaves was lower while dendrobine contents of other treatments were more than 0.60%. After comprehensive assessment through the principal component analysis and total dendrobine accumulation, the results showed that 3 treatments with relative light intensity of 75.02% ranked the top three.Conclusions: In brief, the moderately strong light intensity and water content of medium from low to medium can facilitate the growth and yield of D. nobile plants, while light intensity from moderately weak to weak can enhance the dendrobine content.

Integrated assessment model of water resources constraint intensity on urbanization in arid area

Water has become a key restricting factor of the urbanization process in developing arid areas.Based on qualitative and quantitative methods,we constructed an integrated in-dicator system to assess the status of water resources and urbanization system in arid area,and established an AHP model reformed by entropy technology to evaluate the temporal and spatial variations of water resources constraint intensity on urbanization.This model is ap-plied to the Hexi Corridor,a typical arid area in NW China.Results show that,water resources constraint intensity on urbanization in the Hexi Corridor is bigger in the east and smaller in the west.It has changed from the less strong constraint type into the strong constraint type from 1985 to 2005,yet it decreased appreciably in recent years.At present,most areas in the Hexi Corridor belong to the less strong or strong constraint type.Through rational adjustment of water resources and urbanization system,the Hexi Corridor can still promote water resources sustainable utilization and accelerate the urbanization process.This study suggests that the integrated assessment model of water resources constraint intensity on urbanization is an effective method to analyze the conflicts between water resources and urbanization system in arid area.

Effects of water application intensity of micro-sprinkler irrigation and soil salinity on environment of coastal saline soils

To achieve the greatest leaching efficiency,water movement must occur under unsaturated flow conditions.Accordingly,the water application intensity of irrigation must be chosen carefully.The aim of this study was to evaluate the impact of the water application intensity of micro-sprinkler irrigation on coastal saline soil with different salt contents.To achieve this objective,a laboratory experiment was conducted with three soil salinity treatments(2.26,10.13,and 22.29 dS/m)and three water application intensity treatments(3.05,5.19,and 7.23 mm/h).The results showed that the effect of soil salinity on soil water content,electrical conductivity,and pH was significant,and the effect of the water application intensity was insignificant.High soil water content was present in the 40e60 cm profile in all soil salinity treatments,and the content was higher in the medium and high water application intensity treatments than in the low-intensity treatment.Significant salt leaching occurred in all treatments,and the effect was stronger in the high soil salinity treatment and medium water application intensity treatment.In the medium and high soil salinity treatments,pH exhibited a decreasing trend,with no trend change in the low soil salinity treatment,and the pH value was higher in the medium water application intensity treatment than in the other two treatments.These results indicated that the three intensities evaluated had no statistically different effect on the electrical conductivity of saturated soil-paste extracts(EC)in the upper 20 cm of the soil profile,and it would be better to maintain a lower value of the water application intensity.

Soil and Water Resources and Land Sustainable Productivity in the Catchment Area with Intensive Management in Hilly Red Soil Regions,China

Taking an example of Majiayu Catchment Area (14.15 ha) in Taoyuan County of HunanProvince, the soil and water resources dynamics, fertility evolution characteristics andland productivity changing situation were studied. Fixed observation results from 1993to 2002 showed that pools covering about 15% of total area could store up 10% of surfacerunoff, keep 78.1% of eroded soil and 65.4% of lost nutrients. The yearly ratio ofinterception and evapotranspiration in land, storage in pools and drainage was 7:2:1,which ensured the resources and nutrients equilibrium and a benign recycle in thecatchment area system, and benefited the aquatic culture and helped to resist seasonaldrought. Moreover, the results showed that soil erosion modulus decreased significantly,equal to or lower than soil loss tolerance (≤500 tkm-2) in reddish yellow soil regions.Soil organic matter, total and available N content in sloping land, dryland and paddyfield increased steadily (>10%); water storage enhanced by more than 20% in sloping landand dryland in drought season; crop production increased by more than 20%; and productionof trees, fruits, tea and fish as well as land productivity increased yearly.

王洼煤矿水库坝体下工作面安全开采高度研究

为解决水库坝体下开采安全性,提高煤炭资源回收率,以王洼煤矿水库坝体下110505工作面为研究背景,通过物理仿真模拟、数值模拟及理论分析等方法对覆岩裂隙发育规律及导水裂隙带高度展开研究。为避免矿井开采对地表水坝与水体破坏,针对导水裂隙带高度分析结果,提出了110505工作面限高开采方案。结果表明:工作面开采后地表形成“凹”型盆地,并产生拉伸裂隙,致使地表水位下降78%;现场实测导水裂隙高度为170.76 m,物理仿真模拟试验、数值计算、传统经验公式得出三者的导水裂隙带高度分别为162,164 m和120.57 m;方差修正系数对经验公式做出修正后,反推出限高开采的安全开采高度为2.6 m。研究揭示了工作面覆岩导水裂隙带高度发育规律及水库水体受采动影响的规律,为王洼煤矿后续此类条件下安全措施的制定提供了依据。

改进Mask RCNN的盾构隧道渗漏水检测方法

渗漏水是盾构隧道结构存在潜在损伤或缺陷的重要表征,快速、准确检测出渗漏水位置,对隧道安全运营和维护具有重要意义。现有的方法大多采用光学影像对隧道渗漏水进行检测,受隧道内空间和光线条件限制,难以获得高质量病害图片。因此,本文提出了一种基于激光点云数据与改进Mask RCNN相结合的渗漏水检测方法。首先对激光点云反射强度进行修正;然后生成灰度图像并建立渗漏水病害数据集;最后在Mask RCNN算法中引入空洞卷积和变形卷积,实现了隧道渗漏水病害的快速检测。利用某地铁采集的数据进行验证,结果表明,本文提出的改进Mask RCNN算法相较于原始算法和FCN算法检测精度均有明显提升,在盾构隧道渗漏水识别方面性能表现较好。

温度和光照强度对强壮硬毛藻氮磷营养盐吸收效果的影响

为了解温度和光照对强壮硬毛藻(Chaetomorpha valida)吸收营养盐效果的影响,探索其达到最佳吸收效果的环境条件,本文研究了该藻在不同温度(5、15、25℃)和光照[90000、180000、270000μmol photons/(m^(2)·s)]条件下对海水中常见营养盐成分的吸收效果。结果显示,强壮硬毛藻在5℃以上和90000μmol photons/(m^(2)·s)光照强度以上对水体中的NH_(4)^(+)-N、NO_(2)^(-)-N和PO_(4)^(3-)-P都有较好的吸收效果,但温度和光照对强壮硬毛藻吸收营养盐均有显著影响,在设定范围内,营养盐吸收速率与温度和光照强度均呈正相关关系。极差分析结果显示,温度的影响大于光照强度的影响。方差分析结果显示,光照强度和温度的主效应都极显著,而且具有叠加效应,吸收率最高的条件为25℃/270000μmol photons/(m^(2)·s)组合,该条件下,NH_(4)^(+)-N、NO_(2)^(-)-N和PO_(4)^(3-)-P的营养盐吸收率最高,3 h吸收率分别为(99.70±0.52)%、(99.99±0.01)%和(91.31±0.32)%。该藻的广温性吸收能力对我国北方地区低温和高温季节育苗用水和养殖尾水的净化具有非常重要的意义。

海面乳化溢油水包油乳化液的LIF接收光功率饱和强度分析

海面溢油的水包油乳化液对海洋造成严重的危害,水包油乳化液的识别以及定量分析,对于海洋污染的处理以及海洋环境的恢复具有重要意义。近年来一些研究对较薄的乳化溢油进行了定量分析,然而对于油层较厚的乳化溢油却鲜有深入的研究。激光照射到海面的水包油乳化液产生的荧光,在一定条件下会开始出现饱和而不再变化,针对这一饱和临界点以及相关范围的水包油乳化液的光谱特征进行研究。根据LIF探测系统接收到的光功率与BRRDF数值的关系,使用BRRDF模型对荧光光谱进行仿真。分析的油品使用Romashkino油和Petrobaltic油,分别代表深色不透明的油和明亮透明的油。提出一种针对厚度较大的水包油乳化液的荧光强度计算方法,计算出两种油在不同浓度和乳化时间下的乳化液出现荧光饱和的厚度。对计算结果进行比较可以看出饱和厚度随着浓度的增加而降低,随着乳化时间的增加而降低。分析结果显示,对于海水中的深色不透明的油的水包油乳化液,LIF接收到的荧光强度通常会出现饱和,因此单独使用LIF系统无法判断出超过饱和厚度的乳化液层的厚度。设计了一个4层神经元的神经网络,对饱和临界点附近的荧光光谱对乳化液浓度的识别能力进行验证。验证结果显示,不同浓度的水包油乳化液,只要达到或超过饱和厚度,其荧光光谱就具有较好的鉴别能力,可以用来区分不同浓度的乳化液。对于那些距离饱和厚度比较远的样本,荧光光谱具有分辨乳化液是否达到饱和厚度的能力。这些实验和结论将对较厚的水包油乳化液的识别和定量分析研究提供参考。

农田裂隙优先流对灌水模式/初始墒情响应机制及其模拟研究

农田灌溉管理过程中优先流降低水肥利用效率,加剧地下水污染风险。基于碘化钾-淀粉染色示踪试验,分析了地面灌DM、微喷灌WP1(20 mm/h)、微喷灌WP2(40 mm/h)处理下的裂隙优先流特征,验证了基于水量平衡的双域渗透模型的有效性,并采用4组初始体积含水率(0.20、0.25、0.30、0.35 cm^(3)/cm^(3))与5组灌水强度(12.0、24.0、36.0、48.0、60.0mm/h)旋转组合设计进行模拟应用分析。结果表明,WP1、WP2处理整体上水分以均匀的基质流形式入渗;DM处理下的土壤剖面染色区域在垂直方向上可明显划分为基质流区(0~6.9 cm)和优先流区(>6.9 cm)。此外,DM处理下的基质流深度、灌水均匀度显著(P<0.05)小于WP1、WP2处理,而其优先流指数及湿润锋弯曲度均极显著大于(P<0.01)WP1、WP2处理,这表明地面灌可以激活更多的优先流路径,增大优先流发育程度和空间异质性,降低灌水质量。基于水量平衡的双域渗透模型可有效预测不同灌水强度下的基质流深度和土壤剖面染色面积比变化趋势(R2≥0.9276、NSE≥0.8844、RSR≤0.0230),初始体积含水率和灌水强度旋转组合设计模拟结果表明,增加灌水强度或减小初始含水率会增加优先流的程度而降低灌水质量,故建议在农田灌溉管理过程中采用“高频少量”的灌水模式以减少优先流导致的水肥利用效率降低。该研究成果可为农田灌溉决策提供理论依据,其试验数据可为优先流模型优化与验证提供重要的数据支撑。

太湖流域水环境治理工程土地节约集约利用评价研究

土地节约集约利用评价及其障碍因子诊断对固守耕地红线、保障国家粮食安全具有重要意义,以太湖流域为例,从建设过程和建设结果两方面构建水环境治理工程土地节约集约利用评价体系,选择信息熵改进TOPSIS模型研究太湖治理工程土地节约集约利用现状及变化趋势,并通过障碍度模型进行障碍因子诊断。研究结果表明:太湖治理工程土地节约集约综合利用水平整体随着时间的推移呈平稳上升趋势,太湖治理工程土地集约利用水平排序依次为新孟河工程(0.564 4)、新沟河工程(0.480 5)、走马塘工程(0.431 6),均处于适度利用等级(Ⅲ级),存在较大提升空间;影响太湖治理工程土地节约集约利用的障碍因子存在差异,障碍度变化各不相同,但总体呈现障碍因子集中、重要障碍因子具有较为明显共性的特点。

动静载荷作用下矿井底板断层突水机制研究

断层突水是矿井生产中的重大灾害之一,针对矿井底板含水断层和保护层的空间位置关系,利用断裂力学理论建立了动静荷载、开挖卸荷和承压水共同作用下断层突水的力学模型,推导了断层发生活化的临界水压计算公式,并分析了临界水压的影响因素。结果表明:临界水压随断层长度的增加而减小,随卸荷系数的增加而减小,随侧压系数的增加而增加,随摩擦系数的增加而增大;临界水压随断层角度和动荷载的变化较为复杂,动荷载会促进或抑制断层的活化;断层活化是矿井底板发生突水的必要条件;断层贯通保护层未贯通距离H是发生底板突水的充分条件;推导了断底板保护层未贯通段的最小安全厚度H,并通过一组地质数据,验证了理论推导结果的合理与可靠性。

水生态文明城市建设对企业绿色创新的影响

以2006—2022年我国沪深两市A股水污染密集型上市公司为样本,运用双重差分模型分析了水生态文明城市建设试点政策对企业绿色创新的影响。研究结果表明,水生态文明城市建设试点政策实施以后,为满足经营合法性和利益相关者的环保诉求,水污染密集型企业绿色创新水平显著提升;且对于高耗水行业、非国有企业、位于经济发展水平较高城市的企业和面临较低环境不确定性的企业,该试点政策微观促进效果更明显;机制分析表明,相比于媒体关注,媒体压力能正向调节水生态文明城市建设试点与企业绿色创新之间的关系。

曝气强化三维电极对含油废水水-油微界面破乳机制研究

三维电极体系下曝气对含油废水破乳除油效果有着显著性增强。本研究采用新型三相三维电级工艺,通过正交实验优化曝气条件,深入探讨强化水-油微界面破乳过程的控制机制。实验结果表明,曝气量由2.0 L/min降低到1.5 L/min,此时的COD和含油量分别为107、1.35 mg/L,满足回注水标准,且明显提高了节能效率。将曝气条件加入数值模拟,利用COMSOL软件模拟乳化油滴破乳及聚集的过程。在电场和气场力的共同作用下,增加了油滴拉伸变形的程度,破坏水-油微界面膜的机械强度,加速油滴脱稳过程,进而快速发生团聚。这一研究对强化电化学处理含油废水,具有重大的指导意义。

采出水中核壳型荧光微球浓度的检测方法

聚合物微球调驱是改善水驱效果的主要技术之一。微球在地层中的运移以及能否在采出水中有效检出会直接影响调驱效果。因此,将荧光碳点引入微球调驱剂中,起到示踪的作用。荧光核壳微球调驱剂由含荧光碳点的核心微球溶液和壳层水溶液混合吸附而成。为了降低油水分离后采出水中的杂质对核壳荧光微球有效检出的干扰,首先对荧光微球的浓度与荧光强度进行线性拟合,验证该方法的可行性;然后用硅胶对地层采出水进行吸附,通过对比采出水吸附前后的荧光发射光谱,验证硅胶吸附的实用性;最后用硅胶对采出水配制的荧光微球进行吸附,绘制荧光强度和微球浓度的标准曲线。结果表明,在激发波长为347 nm的条件下,荧光微球的质量浓度与445 nm发射波长处的荧光强度具有良好的线性关系,相关判定系数(R^(2))为0.9870。经硅胶处理后,水驱采出水的荧光发射强度显著降低,硅胶吸附能有效去除采出水中的杂质。在激发波长为347 nm、荧光光谱仪狭缝为10~20 nm、微球质量浓度为1~1200 mg/L时,荧光核壳微球水分散液的质量浓度(x)与462 nm处的荧光发射峰值(y)呈正比线性关系,拟合方程为y=2497.1042+3.1847x,R^(2)为0.9972,置信度较高。荧光强度与核壳微球浓度的线性阶段可满足现场检测要求。该方法可为类似油藏荧光微球含量的定量检测提供借鉴。

河南省水资源集约利用与经济高质量发展耦合协调研究

研究河南省水资源集约利用与经济高质量发展的协调关系具有重要意义,在构建两者评价指标体系基础上,探讨了其发展趋势,分析了两者2005-2020年的耦合协调状况。结果表明:1)在水资源集约利用中,单位GDP用水量权重最高,单位灌溉面积粮食产量权重最低;在经济高质量发展体系中,第三产业占GDP比重权重最高,污水处理率权重最低。2)河南省水资源集约利用综合评价等级逐步提升,综合评价值呈波动增长态势。3)河南省经济高质量发展综合评价值稳步上升,综合评价等级逐步过渡为优秀。4)河南省两系统的耦合度与耦合协调度发展态势相似。耦合度类型大致处于高水平耦合,耦合协调类型不断优化。研究结果能较好反映河南省水资源集约利用与经济高质量发展的耦合协调关系,有助于积极推进河南省节水型城市建设,促进经济社会可持续发展。