长江中下游地区地下水中Mn元素的背景特征及其形成

该文论述了长江中下游地区地下水锰元素的背景特征及其与地下水的含水介质成分、上覆岩土性质、氧化还原环境、地下水的迳流条件、地下水及土壤酸碱度的关系.研究结果表明,长江中下游地区地下水中Mn元素含量,在区域上分布特点为江汉平原东部区〉长江三角洲南部区〉鄱阳湖区.     

采用DPIV技术研究浅水平板岛屿尾流

人们对于尾流的研究大都针对绕流体在展向非常长的情形,但是在天然环境和水利工程中出现的多为水深相对很浅的流动。由于槽底和自由水面的限制,浅水域中的尾流有着与深水尾流不同的流动规律。采用数字粒子图像测速(DPIV)技术,在长30m、宽3.5m、高1m的水槽中比较系统地量测了浅水中绕平板岛屿的尾流区流场。分析了大尺度旋涡的运动规律,得到了尾流流动形式随尾流稳定性参数的变化规律。目前如此大尺度浅水岛屿尾流的定量实验研究并不多见。     

A Physical and Numerical Investigation on the Stability of Shallow Tunnels in Strain Softening Media

Summary The behaviour up to failure of shallow underground openings is discussed on the basis of some laboratory, small-scale model tests and of finite element simulation. The experimental results are first illustrated. They were obtained from two-dimensional (plane strain) and three-dimensional tunnel models tested under standard gravity conditions. Then, the phenomenon of strain localisation that characterizes the medium surrounding the model tunnels is discussed, recalling two alternative approaches for its numerical interpretation. On this basis, a finite element procedure for strain softening analyses is outlined and applied to the simulation of the tests in both two- and three-dimensional conditions. The comparison between experimental and numerical results leads to some conclusions on the influence of strain localisation on the overall behaviour of shallow tunnels and on the stability of their headings.     

Influence of groundwater level change on vegetation coverage and their spatial variation in arid regions

Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application of geo-statistics. Results showed that the variance curve of the groundwater depth and vegetation coverage displays an exponential model. Analysis of sampling data in 2003 indicates that the groundwater depth and vegetation coverage change similarly in space in this area. The Sangong River Basin is composed of upper oasis, middle ecotone and lower sand dune. In oasis and ecotone, influenced by irrigation of the adjoining oasis, groundwater level has been raised and soil water content also increased compared with sand dune nearby, vegetation developed well. But in the lower reaches of the Sangong River Basin, because of descending of groundwater level, soil water content decreased and vegetation degenerated. From oasis to abandoned land and desert grassland, vegetation coverage and groundwater level changed greatly with significant difference respectively in spatial variation. Distinct but similar spatial variability exists among the groundwater depth and vegetation coverage in the study area, namely, the vegetation coverage decreasing (increasing) as the groundwater depth increases (decreases). This illustrates the great dependence of vegetation coverage on groundwater depth in arid regions and further implies that among the great number of factors affecting vegetation coverage in arid regions, groundwater depth turns out to be the most determinant one.     

太原盆地地下水资源模拟研究

山西省太原盆地由于地下水长期超采,引发了地下水降落漏斗、地面沉降等环境地质问题。通过GMS建立地下水水流三维数值模型,基于模型预测了现状开采条件下地下水水位的变化趋势,并提出合理利用地下水资源的措施,为地下水资源的优化管理提供科学依据。     

Spatial-Temporal Ground Deformation Study of BaotouBased on the PS-InSAR Method

Ground subsidence is an emerging geological hazard in Baotou,Inner Mongolia.Four areas of Baotou with relatively large subsidence range and rate were selected for analysis.Focusing on investigation of ground subsidence using PS-InSAR technology,a total of 43 frames of ALOS PALSAR images yielded a SAR data span from December 2006 to January 2011,allowing ground subsidence scope,subsidence velocity,time-series deformation to be obtained.Major causes and influencing factors of the ground subsidence are closely related to soft soil consolidation and compaction and the decrease in the level of groundwater caused by increased development and utilization of groundwater.     

基于尺度因素的地下水随机分析

针对小尺度的各态历经假设的失效,研究了小尺度上多孔介质特性参数统计特征。利用基于K-L(Karhunen-Loeve)展开和混沌展开的谱模型,分析了尺度大小对地下水流动的影响。结果表明,尺度大小导致了特征值系列和特征函数系列的变化,尺度的变化对水头、含水量、流速影响程度不同;水头和流速方差与尺度相关,尺度越大,水头和流速方差越大;研究尺度的变化对水头、含水量、流速均值产生的影响较小。     

新亚欧大陆桥(河南段)经济带地下水资源形势的研究

新亚欧大陆桥,是又一条连接亚欧大陆的“黄金通道”。陆桥的开通,给河南城市群的崛起和城乡产业经济的发展带来了契机。作为经济可持续发展限制因素之一的地下水资源,在陆桥（河南段）经济带范围内,能否满足沿线经济对地下水的需求？研究结论是：地下水形势不容乐观,潜力尚有８７×１０８ｍ３／ａ,同时还存在超采量３８８×１０８ｍ３／ａ,城乡开发地下水强度不一,已引发多种环境地质问题,对陆桥（河南段）经济带的发展构成了严重威胁。为缓和陆桥（河南段）沿线用水矛盾,必须遵循“因地制宜,量水为出,适度开发,统一规划”的原则,在开源、节流、管理上做好用水文章,充分发挥地下水资源的整体效益,实现陆桥（河南段）经济带地下水的可持续开发利用。     

浅层地震勘探在安阳市地震小区划中的应用

浅层地震勘探是城市地震小区划中不可缺少的重要勘探手段之一。本文介绍了浅层地震勘探在安阳地震小区划中的应用实例,着重论述不同地震地质条件下采取灵活多变的技术措施,获得明显的地质效果。     

黄河流域地下水资源、主要环境地质问题及对策建议

本文在重新汇总黄河流域地下水资源量的基础上 ,提供黄河流域天然补给资源总量为453 .54亿m3 /a,其中淡水为 40 3 .51亿m3 /a,微咸水补给约 50 .0 3亿m3 /a。可开采资源总量为2 1 2 .2 4亿m3 /a,其中淡水为 1 82 .42亿m3 /a,微咸水约 2 9.82亿m3 /a。总结分析了黄河流域主要环境地质问题的发展趋势 ,提出了水资源利用方面的一系列宏观对策建议。