青海托拉海冲洪积扇区水文地质及水质分析

研究区位于沙松乌拉山前托拉海冲洪积扇区,区内沉积了厚度较大的第四系松散沉积物,其岩性主要为卵砾石、砂砾石及砂层。含水层厚度大于50 m,为赋存地下水提供了良好的空间场所。该区因降水稀少,蒸发量大,松散岩类孔隙水主要接受托拉海河水的下渗补给,主要河水补给来源于托拉海东沟、西沟,其中托拉海西沟年平均流量较小。洪积扇中前部地区地下水位埋深一般为20~65 m,水量较丰富,水质较好。     

Effect of alcohol addition on the movement of petroleum hydrocarbon fuels in soil

Groundwater contamination by fuel spills from aboveground and underground storage tanks has been of growing concern in recent years. This problem has been magnified by the addition of oxygenates, such as ethanol and methyl-tertiary-butyl ether (MTBE) to fuels to reduce vehicular emissions to the atmosphere. These additives, although beneficial in reducing atmospheric pollution, may, however, increase groundwater contamination due to the co-solvency of petroleum hydrocarbons and by the provision of a preferential substrate for microbial utilisation. With the introduction of ethanol to diesel fuel imminent and the move away from MTBE use in many states of the USA, the environmental implications associated with ethanol additive fuels must be thoroughly investigated. Diesel fuel movement was followed in a 1-m soil column and the effect of ethanol addition to diesel fuel on this movement determined. The addition of 5% ethanol to diesel fuel was found to enhance the downward migration of the diesel fuel components, thus increasing the risk of groundwater contamination. A novel method using soil packed HPLC columns allowed the influence of ethanol on individual aromatic hydrocarbon movement to be studied. The levels of ethanol addition investigated were at the current additive level (approx. 25%) for ethanol additive fuels in Brazil and values above (50%) and below (10%) this level. An aqueous ethanol concentration above 10% was required for any movement to occur. At 25% aqueous ethanol, the majority of hydrocarbons were mobilised and the retention behaviour of the soil column lessened. At 50% aqueous ethanol, all the hydrocarbons were found to move unimpeded through the columns. The retention behaviour of the soil was found to change significantly when both organic matter content and silt/clay content was reduced. Unexpectedly, sandy soil with low organic matter and low silt/clay was found to have a retentive behaviour similar to sandy subsoil with moderate silt/clay, but little organic matter. It was concluded that sand grains might have a more important role in the adsorption of petroleum hydrocarbons than first realised. This method has shown that soil packed HPLC columns can be used to provide a quick estimate of petroleum hydrocarbon, and possibly other organic contaminant, movement in a variety of different soil types.     

Contamination of the Chalk Aquifer by Chlorinated Solvents: A Case Study of the Luton and Dunstable Area

A detailed investigation of contamination by chlorinated solvents of the Chalk Aquifer underlying the towns of Luton and Dunstable was undertaken to assess the extent, causes and mechanisms of pollution. The research programme incorporated land-use surveys, regional groundwater surveys, monitoring of groundwater abstraction points and aquifer profiling by means of the drilling of observation boreholes, the analysis of the recovered core material and the depth sampling of these and other boreholes.
Low-level solvent contamination of the Chalk Aquifer was found to be widespread with 'hotspots'of higher concentrations. At the drilling sites, both the saturated and unsaturated zones were contaminated with solvents, although free product was not observed. The presence of an additional contaminant, oil, at some sites was noted to influence the distribution of solvents within the aquifer.
Clean-up of the aquifer is not a practical option, and treatment of the groundwater at the abstraction points has been adopted.     

A Simplified Image Analysis Method to Study LNAPL Migration in Porous Media

A novel Simplified Image Analysis Method was developed and tested to assess the saturation distribution values for water and LNAPLs (Light Non-Aqueous Phase Liquids) in granular soils subjected to fluctuating groundwater conditions. This method, based on the Beer-Lambert Law of transmissivity, determines the saturation of water (S_w) and LNAPLs (S_o) by comparing the average optical densities (D_i) for each matrix element of the tested domain to the corresponding average optical densities for three base pictures of the same domain taken with two digital cameras attached to two different band-pass filters (λ=450 nm and 640 nm). Two equations with two unknowns (S_w and S_o) are defined for each mesh element, which enables the saturation distribution to be calculated under dynamic conditions. The three base conditions for the domain are: (i) fully saturated with water (D_i¹⁰), (ii) fully saturated with LNAPL (D_i⁰¹), and (iii) completely dry (D_i⁰⁰). The Simplified Image Analysis Method was then applied to analyze the behavior of two fluctuating groundwater systems, namely, two-phase air-water and three-phase air-water-LNAPL, in a one-dimensional column, 3.5×3.5×50 cm, filled with Toyoura sand. The mass balance of the drainage-imbibition three-phase air-water-LNAPL system showed a difference of just 4.7% in LNAPL, demonstrating that this non-intrusive and non-destructive method is reliable for providing water and LNAPL saturation distributions throughout the domain when studying the effects of porous soil contamination by LNAPLs subjected to dynamic conditions.     

LNAPL在二维空间的运移机制与分布特性研究

本文利用改进多谱图象分析方法,对实验获得的图象进行处理,获取不同时刻LNAPL含量差值(LNAPL Content Difference)在二维空间上的分布图。通过图象分析探讨LNAPL在非饱和带中非均质条件下的迁移机制和分布特性。结果说明,介质的非均质性和流体特性对污染物的迁移产生重大影响;在“油-气”二相体系中,LNAPL含量差值分布呈现出较好的对称性,而在复杂的“水-油-气”三相体系中,LNAPL含量差值分布呈现出不对称性和非均匀性,这种不均匀性也反映了毛细带中含水量分布的不均匀性。     

利用温度示踪方法探测基坑渗漏

建筑基坑的降水、防渗和支护工作需要了解地下水渗流场的分布、补给与排泄等规律，以便于作出有针对性的处理。温度是地下水运动的天然示踪剂，正常地层温度的分布是连续且规律的，在季节气温影响点(如钻孔温度曲线上的拐点)以下深部地层的温度将随着深度的增加而上升。但由于地下水的运动影响，会产生温度分布的异常现象。分析了钻孔中由于地下水流动对温度曲线的影响，根据地层中温度的异常变化判定地层渗流的分布情况，利用温深曲线的异常来提取地下水渗流场的有关信息，如确定地层的渗透性，强渗漏带，集中渗漏通道以及地下水的补给关系等。对南京地铁三山街站基坑进行了地下水温度示踪探测分析，发现地下连续墙深度不够，存在裂缝，隔水效果差，是基坑渗水的主要原因，由此造成了基坑周围地面的沉降，并提出了相应的处理措施。     

Geophysical investigations for groundwater in a hard rock terrain,Salem district,Tamil Nadu,India

The main aim of a geophysical investigation in a hard rock region is to solve different hydrogeological problems like depth of water table, basement rock, thickness of weathered zone/formation, structural and stratigraphic conditions relevant to groundwater conditions, and permeability of aquifers. A total of 54 vertical electrode soundings were carried out by Schlumberger electrode arrangement to signify complete lithology of the study area and interpretation was carried out by using curve matching techniques. From the study, 65 % of area is dominated by ‘A’ type curve indicating increasing resistivity with depth and 17 % by ‘K’ type representing a high-resistivity layer sandwiched between two low-resistivity layers. Four layer cases were also noted in 12 % of the study area indicating gradation between the weathered and fractured layers as a semi-weathered zone. Greater thickness has been identified in the weathered zone at the contact of peninsular gneiss and charnockite regions. The maximum, minimum, mean, and arithmetic mean were plotted and identified higher background resistivity values in charnockite. The overlay of maximum and minimum curves for different layers signifies variation of weathering intensity with depth or the presence of weaker zones. In general, lithology plays a significant control over weathering of rocks and groundwater potential.     

Environmental Impact Assessment Study: Leaching Of Chemical Contaminants From A Municipal Dump Site Hastsal,DELHI (Capital Of INDIA)

An Environmental Impact Study was carried mainly to assess the extent of groundwater contamination from a sanitary land fill (SLF) site, Hastsal, located in Western part of metropolitan city of Delhi. The characteristic of leachate generated from the site showed that it was acidic and yellowish in colour with very high concentration of dissolved solids, COD and BOD suggesting higher degree of inorganic and biodegradable organic materials. The results of groundwater analysis in term of BOD, TOC, COD, Conductivity revealed that the quality around the site upto a distance of 100 meter from the SLF boundary is being impacted due to infiltration of contaminated leachate. The bacteriological contamination also revealed that the water is not safe for public use. Impact on ambient air quality showed minor consequence. The level of hydrocarbon (HC), methane around the disposal site was found to be low. A management plan for the site for prevention of release of chemical contaminants to groundwater has been suggested.     

Contamination of Chalk Groundwater by Chlorinated Solvents: A Case Study of Deep Penetration by Non-Aqueous Phase Liquids

The transport behaviour of chlorinated solvents, both in the aqueous phase and as a dense non-aqueous phase liquid (DNAPL), in fissured microporous aquifers is reviewed. The presence of DNAPL in aquifers is especially serious as it is likely to be the main subsurface source of contamination and, given the slow rates of dissolution in groundwater, may persist for decades. However, the identification and quantification of DNAPLs in fractured aquifers present many practical problems and are often not achievable.
A case study of a Chalk site which had been contaminated by chlorinated solvents demonstrated that the use of a range of techniques, including depth profiling of solvent porewater concentrations in cored boreholes, can provide clear evidence for the presence of DNAPL at depth, although DNAPL was not itself observed. Theoretical considerations and field observations confirmed that DNAPL movement is via fractures rather than through the microporous matrix.     

Identifying Land Contaminated by Chlorinated Hydrocarbon Solvents

This paper provides a method of identifying land contaminated with chlorinated hydrocarbon solvents by sampling and analysing soil gas. Relationships are presented which enable levels of soil gas contamination to be related to levels of soil and groundwater pollution. Two case studies are presented. Soil gas surveying of an industrial site with severe groundwater pollution demonstrated that standards for contaminated land are insufficient to protect groundwater. Solvent levels in groundwater were one to two orders of magnitude higher than UK permitted concentrations in drinking water, whereas soil contamination values did not reach polluted levels. Surveying of a site occupied by a disused fire station showed significant differences in patterns of soil gas and groundwater pollution. This is explained by direct pollution of groundwater though the well at the site and/or possible flow of polluted groundwater to the site from adjacent areas.     

非饱和土成层场地波动问题的解析解及应用

现有地基场地波动问题研究中,多将地基土视为饱和、准饱和状态或单相介质,难以反映非饱和土体波动性质。在现有非饱和多孔介质波动理论的基础上,建立基岩上覆成层非饱和土复杂场地模型,采用传递矩阵法,分别求解了平面P波和SV波入射下基岩上覆成层非饱和土场地波动问题的解析解。通过与已有的基岩上覆单一非饱和土层波动问题的解进行对比,验证了该解的正确性。并利用该解答初步分析了当非饱和土层饱和度呈梯度变化时,地下水水位变化对地面运动的影响。分析结果表明:地下水位变化对地面运动的影响与入射波频率和入射角有关。相同频率下,当入射角较小时,地下水位变化对地表竖向位移的影响较大;地下水位变化对水平位移的影响随着入射角增加先增加后减小。相同入射角下,随着地下水位上升,地表竖向位移的峰值减小,峰值频率增加,而地表水平位移的峰值及峰值频率变化不大。     

Methoden zur Abschätzung der Verschmutzungsempfindlichkeit des Grundwassers

The increasing threat of groundwater contamination by pollutants has led to the development of methods to assess groundwater vulnerability on a regional scale. An assessment of groundwater vulnerability will also be required by the coming EU framework directive on water. The concept of groundwater vulnerability is discussed and available methods are presented. These include hydrogeological complex and setting methods, analogue relations and index methods, point rating and matrix systems, mathematical models and statistical approaches. The methods and their principal characteristics are explained and summarised with emphasis on their regional usability.     

青岛某项目水文地质勘察

水文地质勘察是工程勘察的重要组成部分,为提高工程质量,保证施工安全及建筑物安全,对施工场区所在地进行了详细的水文地质勘察,应用水文地质钻探手段,准确测量了施工场区地下水位以及地下水赋存类型、含水层厚度、地层渗透性等,进行水文地质分区,为抗浮设防水位参数的确定提供依据。     

基于连续介质模型的海底隧道渗流问题分析

 与普通山岭隧道不同,海底隧道的一个显著的特点就是有着无限的水源对海底隧道进行补给。海底隧道开挖引起的地下水渗流带来两方面的问题：一是结构水荷载的确定问题,二是涌水量的预测问题。将围岩看作各向同性连续介质,针对这两方面的问题进行研究。明确孔隙介质中水压力的实质;根据国内外最新研究成果,针对山岭隧道和海底隧道不同的边界条件,对各向同性渗透系数下平面半无限含水空间圆形隧道稳定渗流的涌水量和水压力分布的解析解进行分析;以青岛胶州湾海底隧道为工程背景,采用数值方法比较应力场对渗流场的影响,以及围岩渗透系数、水深、注浆圈渗透系数和注浆圈厚度的改变对围岩孔隙水压力和洞内涌水量的影响。分析结果表明：隧道开挖的成拱效应对围岩孔隙水压力的分布和洞内涌水量的大小影响不大;在不考虑渗流场和应力场耦合作用、水深一定条件下,渗透系数的改变不会影响毛洞孔隙水压力的分布;隧道洞内涌水量随着围岩渗透系数或围岩上覆海水深度的增大呈线性增大;注浆圈渗透系数的减小和注浆圈厚度的增大都可以达到减小隧道洞内涌水量的目的,在实际施工中应该在注浆的经济性和其堵水效果两方面进行综合分析,确定最优化的注浆参数。     

Sulfat-dominierter BTEX-Abbau im Grundwasser eines ehemaligen Gaswerksstandortes

In the area of a former gas-works in Düsseldorf (Germany) a soil and groundwater contamination with up to 100 mg/l BTEX (benzene, toluene, ethylbenzene and xylenes) was investigated. Benzene is the dominant aromatic hydrocarbon in the groundwater. The investigations show a natural biodegradation of BTEX by oxygen, manganese oxides, nitrate, ferric hydroxide and sulfate in the sand and gravel aquifer. Sulfate reduction is the most important degradation process in the contamined groundwater. As a product of sulfate reducion, sufids were formed in the sediments of the aquifer. A balance of oxidants is presented as a tool to quantify BTEX degradation and to differ this from sorption and dilution processes. In the contaminated area the degradation of aromatic hydrocarbons leads to the release of carbon dioxide. The highest free CO ₂ -concentration was found in the region of the groundwater table. Outgassing of CO ₂ is important and was verified by deep-specific soil-gas sampling. The knowledge of these processes in the subsoil is a requirement for making predictions for in-situ remediation effects.     

Contamination potential of tar sand exploitation in the western Niger-Delta of Nigeria: baseline studies

Exploitation of the tar sands in Ondo State in the Niger Delta is likely to result in some environmental contamination and adversely affect the living conditions of the farmers and fishermen in the area. Three wells were established where samples were taken at 1, 2 and 3 m depth. Although no hydrocarbon contamination was detected in the water from the surface and boreholes, saline intrusion was recorded. This study produces a baseline against which future contamination can be monitored so that preventative measures can be taken to mitigate the effects.     

裂隙岩体渗流-应力-温度耦合作用研究

基于对深层地下水资源的开采利用和对岩体工程中易发生的地质灾害预测防范研究的目的，提出了开展裂隙岩体渗流-应力-温度耦合作用研究设想。为环境工程学科中防灾减灾工作及水资源合理利用提供了一个新的研究方法。     

小浪底水库下采煤导水裂隙发育监测与模拟研究

 新安矿有8.00×107 t煤炭资源处在小浪底水库水体之下,煤厚变化大(0.0～18.8 m),现有的导水裂隙高度计算方法不能满足水体下采煤安全评价的要求,水体下采煤存在突水隐患。为确定开采过程中覆岩破坏上限及其是否导通地表水体,研究区在5个地面钻孔中进行超声成像观测,在5个井下钻孔中进行并行网络电法CT观测,并通过物理模拟和数值模拟进一步研究各种不同开采条件下的覆岩破坏过程。观测及模拟结果表明,导水裂隙发育最大高度主要取决于煤层采厚,两者之间为非线性关系,在此基础上给出相应计算公式,为结合其他突水影响因素确定安全可采分区提供可靠依据,并得到3个位于安全可采区内的工作面工业性试采成功的验证。     

不同岩溶形态场地抗浮水位取值研究

本文针对贵州岩溶场地,对4类不同岩溶形态下抗浮水位取值进行了研究,得到如下结论:①当场地潜水含水层厚度大于地基基础设置深度时,场地的最高地下水位与抗浮水位相同,当场区处于四周高、中间低的低洼地带及承压含水层分布区时地下水位低于抗浮水位;②抗浮水位取值可通过勘察期间场区地下水最高水位(H_kmax)、可能的意外补给造成该层地下水位的变幅值(ΔH₀)和该层地下水相对勘察时的最大变幅值(ΔH_e)三者之和进行求得;③大型岩溶洼地场区对有地下工程分布的建筑物应重点考虑抗浮影响,这与场区的历史水位、将来环境条件改变后可能存在的最高水位密切相关;基础下部发育大型空腔溶洞场地需要认真分析溶洞水环境特征;浅埋型岩溶暗河管道发育场地地下建筑物底板基础可能存在置于暗河顶部附近或穿过暗河管道两种情况,两者对抗浮水位取值均有不同程度的影响;承压含水层场地应通过水位变化线性图确定场地抗浮水位变化范围,整体地下建筑物按高值确定抗浮水位,分段地下建筑物区间高值确定。本文研究对岩溶地区工程建设有一定的指导意义。     

Landslide and mudflow disaster in disposal site of surplus soil at Higashi-Hiroshima due to heavy rainfall in 2009

The collapse of a filling occurred due to heavy rain in Higashi-Hiroshima City׳s Shiwa District at about 5:30 am July 25th, 2009. The filling was made of surplus soils, and it contained a mass of water supplied from rainfall and ground water flow of a permeable layer at the bottom of the filling. The collapsed soil flowed down and destroyed a house. In this paper, the cause of this disaster is discussed. The site of the disaster was used as the dumping site of surplus soils, after several changes of ground formation. The history of the geographical change was reconstructed by the image processing of old map, aerial photographs, result of 3-dimentional laser survey carried out after collapse and the measurement of thickness of collapsed soil by dynamic cone penetration test. According to the result of processing, the shape and the size of the filling before collapse was reconstructed. The relationship between the rainfall and the groundwater in the river sediments layer over which the filling was constructed was determined. A stability analysis of the filling was conducted considering the rise of the groundwater level in the filling and the laboratory measured strength parameters. The results of the stability analysis showed that the collapse would have taken place when the groundwater level rose by about 9 m due to the supply of groundwater through the river sediments layer.