FLAC3D在海底隧道涌水量预测中的应用

通过分析FLAC3D软件的基本特征、解析特点和本构模型,在分析研究区地质条件的基础上,采用半无限空间的水文地质计算模型,确立了研究区的模拟方案。结合某海底隧道具体水文地质和工程地质情况,以其中的9个典型剖面模拟计算为例阐述了其在海底隧道涌水量预测中的应用。将计算结果与经验解析法的结果进行了比较分析,阐述了FLAC3D数值模拟法的适用条件和工况。总结出了一些有益于隧道施工组织设计和排水设计的结论,对指导工程实践具有一定参考价值。     

一次夜间弓形回波特征分析

针对2012年7月13—14日一次发生在高空槽前暖湿环境中产生短时强降水和7—9级雷雨大风的夜间弓形回波系统,进行了天气过程分析和数值模拟,发现弓形回波系统由两个多单体雷暴合并发展,强降水特征明显,在弓形回波的弓形顶点经过的浙江北部的嘉兴到上海青浦、宝山等一线出现了长距离的直线大风。分析表明,在整层湿度较大的环境中,来自对流系统南侧的中高层干暖气流卷人,加强了雷暴中降水的蒸发冷却作用,导致雷暴中的下沉运动明显增强,是产生长距离直线大风的关键环境因素;弓形回波系统后侧维持向前、向下倾斜的后侧人流急流,与雷暴内的下沉运动共同作用增强了风暴前侧的气压梯度,是产生此次弓形回波大风的主要原因;强低空环境风垂直切变阻止了冷池快速离开风暴主体,弓形回波前侧的阵风锋与低层环境风垂直切变形成的匹配涡对使得前侧新生对流垂直发展,是该弓形回波系统发展、维持的关键机制。     

基于遗传算法和BP神经网络的矿井涌水量预测

为避免BP神经网络极易陷人局部解的问题,针对遗传算法具有全局寻优的特点,提出了用遗传算法优化BP神经网络预测方法,并以刘桥二矿为例,对其矿井涌水量进行了预测。首先选取刘桥二矿区的2005年3月至2006年12月的矿井涌水量数据进行分析,然后使用遗传算法优化BP网络的初始权值和阈值,最后使用BP神经网络进行训练。将其成果与纯BP网络算法进行比较,结果表明：遗传算法优化BP神经网络的预测方法的预测精度高于纯BP网络算法,将其应用于矿井涌水量预测是有效可行的。     

华蓥山矿区龙滩煤矿开采系统涌水量分析比较

龙滩煤矿位于华蓥山背斜中段,水文地质条件较为复杂,在井巷开拓过程中发生过多起突水事故,严重影响了煤矿生产。在分析矿区水文地质条件及矿井充水因素的基础上,认为长兴组含水层是矿井的间接充水含水层,龙谭组含水层是煤层顶板直接充水含水层,茅口组含水层是煤层的底板直接充水含水层,运用大井法、水平廊道法和比拟法．对矿井开采系统涌水量进行了预算,并对结果进行分析对比,最后建议采用比拟法的计算结果作为矿井涌水量的评价结果．为矿井建设提供了依据。     

A system-level modelling perspective of the KwaZulu-Natal Bight ecosystem,eastern South Africa

The KwaZulu-Natal Bight comprises the only sizeable shelf region on the eastern coast of South Africa, and is influenced by both the Agulhas Current on its seaward side and rivers and estuaries on its landward side. Established knowledge of the effect of the Agulhas Current includes the influence on nutrient concentrations in the bight of a semi-permanent upwelling cell at its northern border (St Lucia) and, to a much lesser extent, of a semi-permanent eddy feature at its southern extremity. Current modelling efforts, however, point to a very important role of land-derived nutrients, which supplement the productivity of food webs of the bight. This connectivity of the bight to its adjacent ecosystems has various implications. First, its productivity has traditionally been viewed via phytoplankton growth, whereas ecosystem modelling efforts point to a very high reliance on imported detritus (mainly land-derived) in order to sustain especially the rich benthic food web. The benthos in the bight dominates the food web, and is in marked contrast to the upwelling system of the west coast of South Africa (Atlantic Ocean) where water-column productivity dominates. Second, the importance of the connectivity of the Thukela Bank prawn-trawling ground to estuarine nursery areas, which has been modelled quantitatively, highlights the significance of this particular ecosystem connectivity for fisheries and also for the Thukela Bank food web. Heterogeneity across the bight is apparent for nutrient turnover rates (carbon, nitrogen, phosphorus), CNP content and stoichiometry, whereas nitrogen is a limiting nutrient across the entire bight. The food web near the Thukela River is richer in nutrient content and more active (higher turnover rates) compared to the northern and southern parts of the bight. This environmental heterogeneity was also apparent from the CNP content and stoichiometry of the various species and species groups in the bight. Requirements to take the hydrodynamic, biogeochemical and first ecosystem modelling efforts towards a meaningful predictive capability are discussed. The importance of adopting a system-level view of the bight and its connected systems for realistic exploration of global change scenarios is highlighted.     

呼吉尔特矿区矿井涌水特征及其沉积控制

鄂尔多斯盆地呼吉尔特矿区属于“水压高、水量大、富水性不均一”的深埋侏罗纪煤田区,各矿井面临较严重的水害防治压力,为了弄清该地区矿井涌水特征及其沉积控制条件,开展了沉积相与顶板钻孔出水层位、钻孔涌水量、工作面涌水量等方面的相关性研究,结果表明：呼吉尔特矿区导水裂缝带范围内,主要发育曲流河沉积相的延安组真武洞砂岩段和直罗组七里镇砂岩段,岩性为细粒-中粗粒砂岩。直罗组早期发育了一套河流相沉积,对延安组顶部的强烈冲刷侵蚀,导致矿区中部的门克庆、母杜柴登井田范围内2^-1煤层缺失,并形成了较厚的七里镇砂岩段;矿区两侧的2^-1煤层较完整,其上覆七里镇砂岩较薄。七里镇砂岩含水层是工作面回采过程中的最主要充水含水层,各矿井的工作面顶板疏放水钻孔涌水量差异显著,古河床冲刷带中部的矿井钻孔涌水量普遍大于古河床冲刷带两侧,与顶板地质沉积相有较好的对应关系。煤层顶板地质条件（沉积相）的差异性,控制了各矿井工作面回采过程中涌水量大小;直罗组古河流冲刷带两侧广泛发育的富水条带,则影响工作面涌水量的变化规律。     

湖南道县铁锰矿Ⅱ矿体岩溶矿区矿坑涌水量分析

矿坑涌水是矿山地下开采面临的首要问题,合理的涌水量预测方法是目前国内外研究的热点和难点所在。本文以湖南省道县铁锰矿Ⅱ矿体-50 m开采水平为例,利用有限差分数值方法对矿坑开采的涌水量进行模拟与分析。计算结果表明,涌水量主要来自于车子江的补给,但东部、南部、北部及降雨的补给量所占比例增大,说明Ⅱ矿体涌水量来源较广泛。综合分析,数值法所计算出的不同季节、不同雨强特征的涌水量,更符合矿区实际条件,模拟结果可以作为矿区开采设计的依据。      

江西井冈山鹅岭隧道的工程地质调查与涌水量预测

江西井冈山鹅岭隧道是新建衡阳-茶陵-吉安铁路的关键性控制工程,洞身全长10 455 m,最大埋深750 m。该隧 道的地质构造复杂,断裂发育,岩石破碎,水量丰富。其涌水量是该隧道设计和施工的重要参数。在区域地质和构造调 查的基础上,本研究选择不同渗水岩性段进行了多口钻井（DK）及其水文地质试验,获得了一批宝贵的第一手隧道工程 地质和水文地质资料和数据。通过对这些资料和数据的分析和研究,确定了不同地质体的出水量和渗透系数。继而,按 钻井位置将该隧道划分为9 个不同涌水区段,运用不同方法对各个区段的涌水量进行了精细计算,预测5 个区段涌水量大, 分别为DK7+280-DK7+550（最大赋水段）、DK6+625-DK7+280（中等赋水段）、DK8+875-DK10+085（中等赋水段）、 DK11+570-DK11+770（中等赋水段）和DK13+570-DK13+930（中等赋水段）,施工过程中很可能产生突发涌水现象,建 议施工设计中采取有效防护措施,高度重视这些区段的工程质量。实践证明,本文的研究结果对嗣后的该隧道设计和施工 发挥了积极的指导作用,提高了施工质量。     

Numerical Experiments of the Influences of the Transport Variation through the Korea Strait on the Japan/East Sea Upper Layer Circulation

Numerical experiments were performed in order to investigate the effects of variations of the transport through the Korea/Tsushima Strait, an inlet of the Japan/East Sea, on the upper layer circulation in the JES based on a 10-month transport observation from May 1999 to March 2000 (Perkins et al., 2000). All external forcings to the model were annual mean fields, except the transport variation through the Korea Strait. In the experiments where the periodic variation of the transport repeated continuously sinusoidally by several periods, strong variability of sea surface height (SSH) was detected in the region extending from the Korea Strait to the Japanese coast due to the geostrophy of the buoyancy forcing at the Korea Strait. The region along the Korean coast is more sensitive to the long-term variations than the short-term (≤60-day period) ones. In two experiments forced by realistic and monthly mean transport, the difference of rms of sea surface height was largest at the Japanese coast and relatively large at the East Korean Warm Current separation region (128∼130°E, 39∼41°N) and to the east of Yamato Rise. The distribution of difference of eddy kinetic energy at 100 m depth between the two experiments was similar to that of the rms of SSH. In the distributions of mean SSH and mean kinetic energy at 100 m depth the realistic transport invokes eddy variability to interact with mean current resulting in the changes of the mean SSH and the mean kinetic energy at the East Korean Warm Current separation region, but it does not produce conspicuous changes in the mean fields of entire JES compared with the mean fields forced by the seasonal transport.     

低层垂直风切变和冷池相互作用影响华北地区一次飑线过程发展维持的数值模拟

春夏季我国华南地区水汽充足,飑线可以在短时间尺度迅速增长。为探究水汽含量对飑线升尺度增长过程的影响,利用WRF模式对2020年5月11日华南地区的一次飑线进行数值模拟,分析华南飑线系统升尺度增长机制,并研究不同层次水汽的变化对其强度及结构的影响。分析显示此次飑线发生在“上干下湿”的不稳定层结中,存在高空急流与低层切变相互配合。模拟结果显示,前期广东省西南部的最大对流有效位能(MCAPE)较大,利于不稳定能量在此积累,同时此处的低层垂直风切变较大,飑线线性结构能更好地维持,随后南移与暖区对流合并,尺度进一步增长。水汽试验表明,MCAPE值主要受低层水汽的影响,低层水汽越多,雷暴高压更强,较大的MCAPE值及低层垂直风切变使得对流后向新生尺度增长,维持时间更长。减小中层水汽后地面强降水减少,对流强度减弱且很快分散为对流单体,但当飑线移动到MCAPE值大值区时又一次发展形成线性结构。因此增加低层水汽或减少中层水汽后的环境利于对流新生,但减少中层水汽后中层干空气相对而言使得线性结构难以维持。进一步研究飑线内部结构表明,垂直运动及后向入流也能影响飑线的尺度增长,此次对流系统中较强的后向入流增强了上升运动,同时形成向前的出流,造成地面大风天气。增强低层水汽后,对流后部层状云区范围更大,系统中的上升运动更强,且保持垂直,利于对流长时间维持;减小中层水汽后,对流强度减弱,回波顶高度降低。发展阶段后向入流增强,干冷空气迅速下沉,地面冷池增强,向前的出流形成大风天气。