Prolonged and intensive mining operations in the Huainan Coal Mining Area (HCMA), have damaged its environment, jeopardizing the Huainan city’s sustainability. However, there is a lack of studies on the primary influence factors and evolutionary patterns of the ecological environment vulnerability (EEV) in the HCMA. Therefore, this study employed 12 indices such as elevation, slope, and soil type to establish the evaluation index system, used the sensitivity-resilience-pressure (SRP) model and analytic hierarchy process (AHP) to study the evolutionary patterns and primary influencing factors of the EEV in the HCMA from 2010 to 2020. The results showed that (1) in terms of time, EEV was generally moderate and gradually weakening. In terms of spatial distribution, EEV was generally high in the northwest, low in the central, and highest in the southeast, decreasing then increasing from northwest to southeast. (2) The ecological conditions in the northern new coal mining area and the southern old coal mining area were generally improving. Coal mining and vegetation cover primarily affected the north, and coal mining and ecological restoration projects primarily affected the south. The southeastern built-up area’s ecological environment showed minimal change and it was primarily impacted by urban construction activities. (3) Coal mining and the implementation of ecological environment management and restoration projects are the primary factors influencing the EEV of the HCMA. The ecological environment management and restoration projects such as filling mining, comprehensive recycling and utilization of coal gangue, backfilling of subsidence areas, in CMSWA can reduce the ecological vulnerability of local areas and improve their ecological environment.

The geomorphic evolution of the Xindiangou small watershed on the Loess Plateau in China is influenced by many factors, resulting in very complex evolutionary characteristics of erosion, morphology, and development. Since 1952, a number of soil and water conservation projects have been implemented in the watershed, especially the large-scale project of returning farmland to forest and grass since 1999, which has significant impact on the erosion characteristics of the loess. This paper takes a unique perspective of the watershed geomorphic system and its watershed geomorphic entropy (WGE) and clarifies the geomorphic erosion characteristics of the Xindiangou small watershed. The results show that in the past 45 years, the entropy change of WGE of this watershed has generally shown the characteristics of entropy decrease and local entropy increase. The watershed is dominated by erosion in general, but due to the large-scale implementation of various soil and water conservation projects, especially the Project of Returning Farmland to Forests and Grasslands (RFFG), the landform erosion intensity has been greatly reduced and local increase in the entropy change of WGE has appeared. These projects have achieved good ecological effects after 11 years of implementation.

Groundwater flow and contaminant transport are significantly influenced by hydrofacies heterogeneity, which remains a central focus of research in hydrogeology. In this study, borehole lithological data and hydrogeological section data were used to develop three-dimensional models of aquifers and hydrofacies for typical Cenozoic unconsolidated aquifers in the Zhangji mining area, Huainan, China. Deterministic, stochastic, and deterministic-stochastic coupling models were developed to characterize hydrofacies heterogeneity. The effectiveness of these models was evaluated by comparing the modeling results with hydrogeological sections. While the highly generalized deterministic model struggles to capture the stochastic characteristics within layers, the stochastic model is more effective in predicting sedimentary patterns in complex regions. The deterministic-stochastic coupling model, which integrates both structural and stochastic characteristics of aquifers using transition probability geostatistics, demonstrated superior fitting performance when hydrofacies proportions within layers were similar. However, when the proportion of one hydrofacies within a layer becomes excessively dominant, the model tends to overemphasize the dominant hydrofacies while neglecting those with lower proportions. If a reasonable hydrofacies delineation mechanism can be established and the three methods can be integrated in a complementary manner, the accuracy of characterizing aquifer heterogeneity will be further improved.

To study the influence of coal mining on the hydrogeochemical process of groundwater, taking Guqiao Coal Mine, Huainan coalfield as an example, 32 groundwater and 4 surface water samples, 4 mine drainage samples and atmospheric precipitation were collected in the mine, and the hydrochemical type, TDS, and TH were analyzed using Piper diagram, principal component analysis, and chemical analysis of water samples. The relationship between Cenozoic and Permian aquifers was discussed and the potential mineral phases in groundwater were determined by Phreeqc software. The results show that hydrogeochemical processes of aquifers in the study area are mainly the dissolution of halite and cation exchange and desulfurization of in the Permian sandstone fracture. Inverse modeling was used to verify hydrogeochemical responses in diverse paths. Consequently, shallow groundwater and surface water are connected, and the two main kinds of water have relatively independent hydrogeochemistry. This suggests that the sealing properties of the hydrogeological in the coal field are good. These data analysis methods and results could be useful for the interpretation of groundwater evolution and the management of groundwater disaster in areas of long-term mining.

The heterogeneity of hydrofacies is represented as spatial variability on different scales, and it has a significant impact on the behavior of groundwater flow and pollutant transport. However, effectively characterizing hydrofacies heterogeneity on different scales remains one of the most challenging problems in hydrogeology. In this study, an upscaling hydrofacies simulation (UHS) framework is proposed by integrating the upscaling borehole generalization (UBG) approach and transition probability geostatistics (TPG). A new UBG approach for generating virtual boreholes with equivalent hydrofacies information based on relatively high-density borehole lithological data is proposed, and the TPG is used to delineate the multiscale facies distribution. The results show that the UBG approach can significantly reduce borehole data volume while retaining the key equivalent hydrofacies information on a coarser scale. The UHS method can well characterize the overall distribution of equivalent hydrofacies on coarser scales, with the minor-component hydrofacies underestimated and the major-component hydrofacies overestimated to a lesser extent, and more equivalent facies appearing in strong heterogeneous areas. These results demonstrate that the UHS method can provide valuable capacity insights and advantages in characterizing hydrofacies heterogeneity on different scales using such high-density borehole lithological data.

针对以往研究大多仅利用统计方法确定地质灾害预警临界雨量阈值,难以顾及不同滑坡体所具有地层、岩性等条件的不足,利用改进信息量模型构建安徽省滑坡灾害预警分区,通过耦合有效雨量和临界雨量获得全省75 个典型滑坡点的临界雨量阈值,对其进行分区空间插值,并据此构建安徽省滑坡灾害气象预警模型.研究结果表明,该模型比现有预警模型的预警级别更准确,空间精度更高,克服了现有模型预警级别偏低,预报范围较宽泛的不足.

矿区地面沉降具有"快速"位移和高度非线性的特点,常用的DInSAR和SB AS InSAR均无法获得连续高精度的地面沉降监测结果.本文基于覆盖淮南丁集煤矿的17景Sentinel-1 SAR影像分别进行累积DInSAR和SBAS InSAR处理,利用Kriging插值对两种差分干涉技术得到的结果进行集成,获取2020年10月17日～2021年4月17日期间的矿区地面沉降信息,并对监测结果进行评估和分析.研究结果表明:丁集煤矿开采沉降现象严重,监测时段内丁集煤矿共有4个沉降漏斗,DInSAR和SBAS InSAR监测到的沉降位置、范围和变化趋势基本吻合,但两者所得的沉降量差异较大.而基于Kriging插值的DInSAR和SBAS InSAR集成结果,在沉降漏斗边缘区域很好地保持了 SBAS InSAR的监测精度,并且有效地解决了SBAS InSAR在沉降漏斗区无法获取高相干像元产生空洞的问题,得到了连续高精度的矿区地面沉降结果,为矿区沉降监测提供了有效途径.

黄土高原流域地貌系统的地貌演化特征十分复杂，尚有诸多科学问题有待进一步深入研究。以往研究大多集中在流域地貌演化的侵蚀和发育特征等某一方面，缺乏从流域地貌系统及其势能信息熵的视角深入剖析野外多岩土层黄土小流域地貌演化特征的研究。为此，基于系统论的观点和方法，构建多岩土层黄土小流域地貌系统及其势能信息熵的数学模型，并以辛店沟小流域为例，对其地貌演化特征进行研究。结果表明：（1）构建的野外多岩土层黄土小流域地貌系统的概念模型及其势能信息熵的数学模型能够有效对辛店沟小流域进行数值模拟。（2）以黄土侵蚀作用为主的辛店沟小流域从2000—2019年的地貌演化过程是其势能信息熵的熵减过程和黄土地貌不断侵蚀的过程。（3）辛店沟小流域的势能信息熵能较好地反映该小流域的地貌演化阶段和地貌侵蚀过程。

The warning accuracy, false alarm rate and timeliness of regional geological hazard early warning models (GHEWMs) have an important impact on significantly reducing the damage caused by geological hazards. Most of the existing regional GHEWMs are based on forecast rainfall. Due to the influence of rainfall forecast accuracy and other factors, its early warning accuracy, false alarm rate and timeliness are still difficult to meet the needs of engineering applications such as disaster avoidance, mitigation and prevention of geological hazards. Therefore, this paper proposes a regional GHEWM based on the hourly rainfall series (HRS) of real-time automatic rainfall stations. Based on the data of 689 geological hazards that have occurred in Huangshan City from 2018 to 2021 and the corresponding rainfall data of automatic rainfall stations, the model uses the dynamic time warping (DTW) algorithm on the Spark big data platform to extract the historical HRS of each geological hazard and calculates the highest similarity between it and the current HRS in parallel. By coupling the probability of occurrence of geological hazards and the highest similarity of the above-mentioned HRS, a regional GHEWM based on real-time rainfall big data is finally constructed. The research results show that the model's early warning accuracy reaches 85%, and the false alarm rate is only 15%, which can predict the possibility of geological hazards after the next 3 h.

Hydrofacies distribution and heterogeneity influence groundwater flow and solute transport. The characterization of hydrofacies distribution is challenging because of the scarcity of observation data, and because of the various types of uncertainties in whatever observation data exist and in the geostatistical methods used. This paper presents a method to integrate geophysical data and borehole data to improve the characterization of hydrofacies distribution and to reduce uncertainty in the simulations of porous media, in particular, unconsolidated sedimentary clay/sand environments in unsaturated states. A sandbox experimental investigation was conducted by the combined use of drilling and electrical resistivity tomography (ERT). Borehole data reveal the vertical variation in hydrofacies in the model, and ERT data can well represent the continuity of hydrofacies in the profiles. A histogram probability matching method was used to assimilate the two kinds of data. The ERT profile was converted into a hydrofacies section based on a cutoff value of resistivity, and then a series of highly credible virtual boreholes were extracted from the hydrofacies profiles. Finally, the transition probability geostatistics (TPG) method, based on the Markov chain, was employed to simulate the hydrofacies distribution. The results show that the ERT data, as a kind of high-density soft data, can provide more lithological information for TPG simulation. The presented method with TPG can construct a relatively high-accuracy hydrofacies model by the combined use of ERT geophysical data and borehole data.

Mapping of groundwater distribution potential over space, built by synergizing environmental variables and machine learning models, was of great significance for regional water resources management. A total of 245 wells were identified based on field survey in the Chihe River basin in Anhui province, out of which 172 wells locations were randomly used for training the machine models and the other 73 wells for validation process of machine models. Thirteen environmental variables including elevation, slope, slope aspect, plan curvature, profile curvature, topographic wetness index (TWI), drainage density, distance to rivers, distance to faults, lithology, soil type, land use, and normalized difference vegetation index (NDVI) were used to build the spatial database of this research. Three GIS-based machine learning models were used for mapping the groundwater distribution potential: logistic regression (LR), deep neural networks (DNN) and random forest (RF). Then, the applicability of those models was evaluated by the evaluation index of mean absolute error (MAE), root mean square error (RMSE) and correlation coefficient (R). The final results indicated that the potential of regional groundwater distribution is concentrated in moderate to high potential areas. Among them, the moderate to the high potential distribution area in the LR model accounted for 81.14% of the total area, 90.36% and 87.55% in the DNN model and the RF model, respectively. In addition, three machine learning models can be implemented for prediction of groundwater distribution based on the three evaluation indexes, among which the LR model performs more prominently. The good prediction capabilities of machine learning technologies can provide a reliable scientific basis for spatial prediction of groundwater distribution and management of water resources.

含水介质的空间分布及其非均质性对地下水流和溶质运移有着重要的影响.以淮南顾桥矿区作为研究对象,为了刻画矿区松散层含水介质的空间分布,使用转移概率地质统计方法建立含水介质的随机模型,对矿区水文地质结构的空间连续性和空间变异性进行表征;并将随机模拟得到的顾桥矿区含水介质剖面图与矿区原始水文地质剖面进行对比.结果表明,基于转移概率地质统计模拟方法可以比较准确地刻画矿区的水文地质结构;模拟剖面与原始水文地质剖面的比较显示模拟结果与实际含水介质空间分布情况有较好的一致性,转移概率地质统计方法在对含水介质非均质性刻画中具有较好的适用性.

To disclose the distribution characteristics, the situation of flow and storage, and processes along flow paths of shallow groundwater in Tan-Lu fault zones, nine hundred and seven groundwater table elevations data and one hundred hydrochemical samples of shallow groundwater were taken from the Tan-Lu fault zone in Anhui province to analyze the characteristic of groundwater distribution. The geographic information system (GIS) method was used to analyze the spatial distribution characteristics of groundwater tables, total dissolved solids (TDS) and chloride ion (Cl − ). Geophysical prospecting, drilling material and regional hydrogeological survey were utilized to disclose groundwater storage and flow regime in the fault zone. The results show that the Tan-Lu fault zone in Anhui province has controlled groundwater flow into the Jiashan basin, Hefei basin, Chaohu area and Qianshan basin, which developed from north to south in this area. Groundwater in theses basins have recharged from surrounding areas to form a water storage space. Geophysical prospecting and drilling technology revealed that the Tan-Lu fault zone provided a flow channel and storage space for ground-water. Faults provide preferential channels in some areas for the groundwater flow and circulation, eventually deep hot-water flows upward and discharges in the form of hot-springs. The identification of the groundwater flow pathway can help to provide a reliable scientific basis for regional spatial development and utilization of groundwater resources.

安徽省马鞍山市浅层地下水受到了一定程度的污染,但其水化学特征及其影响因素尚未得到有效揭示.为此,以马鞍山市为研究区,在分析浅层地下水的化学特征基础上,运用数理分析、敏感性分析、主成分分析以及聚类分析等方法,揭示研究区浅层地下水的水化学特性及其影响因子.结果表明,研究区浅层地下水的化学类型主要为HCO3-Ca型;指标Mn、Fe、A1、NH4+、Zn、F-、NO2-的相对极差为11.89～39.62,变异系数为127.25～457.06,其离散程度最高、波动性最强,表明上述指标容易受到矿业开采、水产养殖等各类人类活动影响.该市地下水质量整体状况良好,总体受人为影响程度较大;凹山矿区地下水质量较差,主要受到采矿业活动影响;南部石臼湖与姑溪河一带的水产养殖也在一定程度上影响了该地区的地下水质量.

文章以安徽省明光市为研究区,选取高程、坡度、坡向、平面曲率、剖面曲率、地形湿度指数(topo-graphic wetness index,TWI)、河网密度、公路缓冲区、断裂缓冲区、水系缓冲区和岩性特征为地下水潜力分析(groundwater potential analysis,GWPA)评价因子;基于现场调查数据,运用多重共线性分析方法优化评价因子,利用训练数据集构建证据权(weights-of-evidence,WoE)模型;在ArcGIS软件中通过空间叠加方法完成对研究区GWPA,将研究区内地下水潜力分为低、中、较高、高4类.结果表明:该方法具有较好的精度,方法简单易操作;研究区中、高潜力区占比分别为34.76％、22.98％,模型的接受者工作特征(receiver operating char-acteristic,ROC)曲线下面积值为0.7835;评价结果与验证数据集特征相符合,可为区域水资源管理提供参考.

文章以合肥市肥东县为研究区域,从地形地貌、工程地质条件、水文地质条件和地质灾害风险度4个方面选取7个指标构成了建设用地适宜性评价体系,采用G1法和层次分析法(analytic hierarchy process,AHP)的线性组合确定了各个指标的权重,以ArcGIS为平台对各个指标进行空间分析叠加,通过K-means聚类分析将建设用地适宜性分成4类.结果表明:肥东县建设用地适宜和较适宜区域共1891.32 km2,占工作区面积的83.55％;较不适宜区域共266.22 km2,占工作区面积的11.76％;不适宜区域共106.07 km2,占工作区面积的4.69％,涉及乡镇有店埠镇、包公镇和长临河镇等.此次评价与肥东县发展规划相吻合,不仅可以为肥东县的城乡建设发展提供宏观上的把握,还可以为各乡镇的发展政策提供可行性的建议.

宿州矿区由于长期煤炭开采,不仅形成了浅层地下水降落漏斗,而且造成了不同程度的地下水污染,其污染现状及主要形成原因尚不清楚.为此,本文利用研究区水土污染调查获取的21个地下水样品的NO3-等13项污染指标开展地下水污染源解析工作.在采用改进内梅罗综合污染指数法对研究区浅层地下水环境质量进行评价的基础上,利用因子分析和反距离权重插值方法对研究区浅层地下水进行污染源及空间分布特征解析.研究结果表明:(1)研究区浅层地下水受到了重度污染,以Ⅳ类水为主,污染较严重的指标为NO3-、Mn、Fe和F-.(2)研究区浅层地下水主要包括4个污染源:原生地质环境(F1),其高值区分布在桃园煤矿及其周边;矿坑排水和矸石山淋溶作用下形成的矿业废水(F2),其在桃园和钱营孜煤矿及其周边地区污染较为严重,其余矿区也存在一定程度的矿业废水污染;由生活垃圾、人畜排泄物造成的农村污水(F3),其污染地区主要为朱仙庄和芦岭煤矿一带;由化肥施用引起的农业污染(F4),其高值区集中在朱仙庄煤矿及其周边区域.地下水水质的主要影响因素是浅层地下水原生地质环境和矿业废水,其中约有51.040％的污染来源于原生地质环境及煤矿矿业污染的混合污染,约有11.841％的污染来自煤矿矿业废水,其余污染主要来源于农村生活和生产污水以及农业面源污染.(3)研究区浅层地下水主要污染区域为桃园和钱营孜煤矿一带,祁南和祁东煤矿污染相对较轻,朱仙庄和芦岭煤矿水质较好.(4)建议对矿区地下水主要污染源及污染途径进行综合防治:加强矿坑排水口的污水达标排放监管力度;煤矿企业采用生产建筑材料等方法提高矸石的综合利用率;进一步加强与矿区污水、垃圾填埋处理等相关的基础设施建设.

Mastering hydraulic conductivity of rock mass is an important way to precisely describe hydrogeological characteristics of a certain region. Hydraulic conductivity is a significant indicator to reflect the rock mass’ permeability. The studies of hydraulic conductivity estimation models have important implications for the development of actual engineering. In the existing estimation models of hydraulic conductivity, the single-factor model cannot take into consideration of the comprehensive influence of various factors on hydraulic conductivity in the area, and the parameters selection of the multi-factor model lacks the flexibility and its application is limited when some parameters are difficult to be obtained, etc. The classification and comparative analyses of the positive and negative correlation parameters are conducted based on public data. We propose a set of high-fitting hydraulic conductivity estimation models, which are the PNC (Positive and negative correlation) model. The research results show that the fitting result of the PNC model (R2=0.964 and R2=0.801) is superior to that of the HC model (R2=0.905 and R2=0.563) in No. 1 study area. In No. 2 study area, the fitting result of the PNC model (R2=0.959) is superior to that of the RMP model (R2=0.927). In No. 3 study area, the fitting result of the PNC model (R2=0.94 to 0.99) is also better than that of the ZRF model (R2=0.92 to 0.99). By using Nash-Sutcliffe coefficient (NSE) to carry out the error analyses of the model, it is found that the error coefficients of 5 in 7 sets of data are above 0.95. It further illustrates the convenience and reliability of the PNC model, which can provide a certain reference for estimating and verifying hydraulic conductivity in actual engineering.

沟谷网络是黄土高原流域地貌的重要侵蚀产沙区和最主要的产沙运移通道,深入了解沟谷网络的形成过程和演化特征,对黄土高原小流域的水土保持综合治理、生态恢复和流域地貌演化过程研究具有重要意义.然而,流域内部沟谷网络的发育演化过程与整个流域地貌演化过程的相互作用机制尚未得到有效揭示.该文基于室内人工降雨试验条件下获取的9期人工模拟黄土小流域DEM数据,提出一种表征流域地貌系统内部沟谷网络演化有序程度的方法,并利用小流域地貌系统的势能信息熵及其熵变规律对沟谷网络演化过程及其变化特征进行研究.结果表明:在该实验条件下,以侵蚀为主的均质黄土小流域在地貌发育的幼年期,势能信息熵呈不断减小态势,沟谷网络有序性不断增强,在幼年期末达到最高;进入壮年期后,势能信息熵呈缓慢增加态势,沟谷网络有序性受到一定程度破坏,演化特征与该系统势能信息熵的熵变特征及流域地貌侵蚀发育阶段高度一致,流域地貌的势能信息熵和沟谷网络有序演化特征能有效指示流域地貌的侵蚀发育阶段.

This study experimentally and numerically investigated the influence of the inertial effect of fluid flow on the non-Darcy coefficient (beta). The results showed that the non-Darcy coefficient (beta), apparent permeability (k(a)), and hydraulic aperture (e(h)) decreased with the increase of Reynolds number (Re), which indicated that the non-Darcy coefficient depended on the geometric properties of a single fracture and the fluid inertial effect. The quantification model of the non-Darcy coefficient was improved. Under the guidance of fluid inertial effect, the beta performed a positive power-law relationship with e(h); under the coupling effect of fluid inertial effect and fracture geometric properties, the beta behaved negative power-law relationship with e(h), which was similar to the non-Darcy coefficient quantitative model that ignored the fluid inertial effect in the previous study. Therefore, the geometric properties were the dominant ones for fracture flow when it was affected by the coupling effect of geometric properties and inertial effects. Then, the quantitative model of the non-Darcy coefficient was improved. Based on the improved non-Darcy coefficient quantitative model, a new critical Reynolds number prediction model (CRN model) was constructed. Compared with other CRN models, the new CRN model considering the coupling effect of fluid and media properties could more accurately predict the critical Reynolds number (Re-c) in rough single fractures, which further proved the existence and importance of the inertial dependence of the non-Darcy coefficient.