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针对在实际应用中非开挖钻机液压系统出现气蚀现象而造成液压系统失效的问题，分析了气蚀产生的原因，提出了预防措施。 相似文献
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根据墙体的厚度与破碎力的大小，利用优化设计与等强度原理，设计了钳体与钳口韵合理结构，计算了液压系统的流量与压力；通过计算机模拟，确定了液压系统执行机构的结构与性能参数。设计的TGY系列液压破碎钳在钢筋混凝土结构改造与拆除工程中应用取得了较好效果。 相似文献
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介绍了ＭＤ－５０型钻机液压系统的设计原理和主要液压元件的选择依据，并通过对设计和实践的总结，谈了作者在全液压钻机液压系统设计中的一些体会。 相似文献
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我厂生产的300米岩心钻机是一种机械传动、液压给进和操纵的立轴式钻机。它的代表产品先后有XU300-2型、XU300-2A型和XY-2型钻机。它们的液压系统的主要区别在于：XU300-2型和XU300-2A型钻机的液压系统，是由定量的齿轮油泵供油，采用了调压溢流阀的旁路调压回路和多路换向阀（13—0）操纵的方向控制回路。它所采用的大部分液压元件与五十年代的产品基本一样，一直未加以改造。这种液压系统也是一直沿用下来，它存在着许多不合理的部分。XY-2型钻机，则是1982年底经部级鉴定，并于1984年起形成了 相似文献
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一、问题的提出目前在我国巷道掘进中使用的各种小型双机液压凿岩台车，大部分采用单泵定量供油多液动机并联的开式液压回路。这种回路的特点是：液压系统简单、元件少、功率小，为整个台车紧凑结构、降低造价提供了有利条件。但是，由于油泵的流量是固定的，油缸的运动速度就与油缸内径平方成反比，并与系统中同时开动的油缸数目成反比。当油泵的流量保证了最大的油缸和开动数目最多时的速度，就不能保证最小油缸和开动数目最少时的速度要求。今以SYT-18型双机凿岩台车的液压系统为例分析如下： 相似文献
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钻机提升系统在开启和关闭时存在着严重的液压冲击现象,因而会造成钻机运行的不平稳。产生液压冲击主要是由换向阀开启和关闭时液压油和负载的动能瞬时转化为压力能而造成的。本文结合DGZ-150B型多管全方位旋喷钻机,主要介绍了通过改进提升液压系统回路和选择合理的提升速度来降低液压冲击的影响。通过利用AMESim 软件对改进前后的提升液压系统建模仿真,可以看出改进后的液压系统对液压冲击有明显的控制,系统稳定性大大提高。按照改进后的提升液压系统对钻机的提升系统进行改造,钻机在步进提升时基本感觉不到液压冲击,钻机的震动大大减轻,稳定性增强。 相似文献
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常用的煤矿瓦斯抽采分体履带式钻机需用油管将两个履带车体的液压系统连接,在井下行走和在钻场进行移位时操作不方便。为了提高履带行走的便利性,设计了ZDY6500LF型分体履带钻机的液压系统,分析了钻机液压系统的组成和原理。该液压系统具有2个履带车体不需要管路连接而独立行走的特性,到达钻场调整好两履带车体位置,再连接管路进行钻探施工,实现了履带式钻机的分体化液压传动及履带行走的独立控制。通过测试试验验证了液压系统的可靠性,表明该液压系统具备很好的应用价值。 相似文献
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大庆市地下水石油类污染系统形成机制研究 总被引：7，自引：0，他引：7
本文以大庆市具有代表性的纳污湖泡—— 贴不贴泡区地下水石油类污染系统为研究对象,通过对其进行成因分析,提出地下水石油类污染系统是石油污染质以地下水循环系统为载体,在水动力场、水化学场的共同作用下形成的。其中,水动力场对地下水污染系统的形成起着主导作用。因此,通过控制水动力场来防治大庆市地下水污染将是一条行之有效的途径。 相似文献
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As a systematic approach to waste disposal site screening for groundwater pollution protection, the DRASTIC system developed by the US Environmental Protection Agency (USEPA), was introduced at Younggwang County in Korea. Hydrogeological spatial databases for the system include information on depth to water, net recharge, aquifer media, soil media, topographic slope, hydraulic conductivity and lineament. Using the databases, the DRASTIC system and a GIS, the regional groundwater pollution vulnerability of the study area was assessed. The fracture density extracted from lineament maps was added to the DRASTIC system to take into account the preferential migration of contaminants through fractures. From the results of the study, a degree of groundwater pollution vulnerability through the study area was easily interpreted, and waste disposal sites could be screened for groundwater protection. 相似文献
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陕北能源化工基地潜水易污性评价 总被引：4，自引：0，他引：4
随着陕北能源化工基地的建设和发展,地下水污染问题日益突出。为了预防基地地下水的污染,保护水资源,依据陕北能源化工基地地下水勘查、地下水污染调查、野外包气带原位污水垂直入渗、水平运移试验等基础资料,选取潜水位埋深（D）、降雨入渗补给量（R）、含水层岩性（A）、土壤类型（S）、地形坡度（T）、包气带介质（I）和含水层渗透系数（C）7个指标,运用DRASTIC指标叠加法,建立了陕北能源化工基地潜水易污性评价指标体系,对陕北能源化工基地潜水进行了易污性评。依据评价结果,将研究区潜水区划分为易污性高、中、低3个区,并针对3个区提出了相应的防污建议。 相似文献
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为了研究压裂曲线与储层污染程度的响应关系,以沁水盆地柿庄区块为例,在区块内选取储层敏感性强弱不同的井,通过比较各井压裂施工曲线中油压曲线到达破裂压力后下降行迹特征的差异,总结出油压曲线下降行迹与储层敏感性的响应规律。然后在同一区块内根据油压曲线下降行迹判定几口井的储层敏感性,根据储层渗透率损害比模型计算出几口井开发煤层段的储层渗透率损害比。结果发现,预测出的储层敏感性强井具有较高的储层渗透率损害比,储层受到严重污染;储层敏感性弱井储层受到轻度污染。研究表明油压曲线到达破裂压力点后的下降行迹能够反映储层污染程度,可以为后期工程开发提供依据。 相似文献
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污泥屏障渗透性及重金属阻截效果试验研究 总被引：1，自引：0，他引：1
目前,废弃物处置场渗滤液中的重金属污染物只能依靠极低渗透性的水力屏障来控制,还不存在利用化学场专门拦截重金属污染物的反应型屏障。在有机结合生活污泥的低渗透性与丰富的有机质和厌氧微生物特性的基础上,提出“污泥屏障”的构想。研究利用柔性壁渗透仪测量不同有效应力作用下生活污泥试样的渗透系数,并对渗出液的化学性质进行了监测,验证污泥屏障的可行性。试验结果表明：随着有效应力的增大,污泥试样干密度提高,渗透系数的对数值随孔隙比的减小线性降低。试样内部微生物厌氧呼吸形成的生物膜和无机物沉淀以及黏土颗粒双电层厚度的增大,也是污泥渗透系数降低的原因,污泥渗透系数仅为 数量级。另外,污泥强烈吸附能力及厌氧微生物呼吸作用形成的中-弱碱性还原环境,对渗透液中的Zn和Cd都起到了很好的拦截作用。 相似文献
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Aquifer vulnerability assessment using the DRASTIC model at Russeifa landfill,northeast Jordan 总被引：1，自引：0，他引：1
Groundwater is inherently susceptible to contamination from anthropogenic activities and remediation is very difficult and expensive. Prevention of contamination is hence critical in effective groundwater management. In this paper an attempt has been made to assess aquifer vulnerability at the Russeifa solid waste landfill. This disposal site is placed at the most important aquifer in Jordan, which is known as Amman-Wadi Sir (B2/A7). The daily-generated leachate within the landfill is about 160 m3/day and there is no system for collecting and treating this leachate. Therefore, the leachate infiltrates to groundwater and degrades the quality of the groundwater. The area is strongly vulnerable to pollution due to the presence of intensive agricultural activity, the solid waste disposal site and industries. Increasing groundwater demand makes the protection of the aquifer from pollution crucial. Physical and hydrogeological characteristics make the aquifer susceptible to pollution. The vulnerability of groundwater to contamination in the study area was quantified using the DRASTIC model. The DRASTIC model uses the following seven parameters: depth to water, recharge, aquifer media, soil media, topography, impact on vadose zone and hydraulic conductivity. The water level data were measured in the observation wells within the disposal site. The recharge is derived based on precipitation, land use and soil characteristics. The aquifer media was obtained from a geological map of the area. The topography is obtained from the Natural Resources Authority of Jordan, 1:50,000 scale topographic map. The impact on the vadose zone is defined by the soil permeability and depth to water. The hydraulic conductivity was obtained from the field pumping tests. The calculated DRASTIC index number indicates a moderate pollution potential for the study area. 相似文献
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X. Zhang Q. Y. Wu J. T. Cui Y. Q. Liu W. S. Wang 《International Journal of Environmental Science and Technology》2018,15(10):2253-2268
Research on the “source–sink” landscape pattern of nonpoint source pollution is of great significance to natural resource management, environmental protection, water quality improvement, nonpoint source pollution prevention and control, and ecological security pattern construction. Remote sensing has proven by many scholars as a practical and effective technique to study landscape patterns and nonpoint source pollution. However, there are still many obstacles to the application of remote sensing technology, such as classification errors, scale effects and the issue, whereby landscape metrics cannot describe the landscape information comprehensively. In view of the characteristics of the macroscale and multi-scale of remote sensing, the analysis of landscape patterns is the basis for the study of the relationship research between patterns and ecological processes, and it is also the key to the study of landscape dynamics and functions. This paper attempts to summarize the representative results and the challenges of remote sensing in the study of the source and sink landscape of the nonpoint source pollution landscape and provide corresponding solutions as a reference for future research. 相似文献
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桂江流域地下水污染途径及防控措施研究 总被引：1，自引：1，他引：0
对桂江流域开展岩溶地下水污染调查发现:流域内地下水污染源分为“三氮”污染源、重金属污染源、有机污染源三类;“三氮”污染源主要包括工业、养殖和生活三类污水、生活垃圾渗滤液、农业施用氮肥等;重金属污染主要来自工矿企业;有机污染来自工业、养殖业。污染途径主要有孤峰平原的分散入渗式、孤峰平原的脚洞灌入式、峰丛洼地的消水洞灌入式、溶丘谷地的入渗式和峰丛峰林谷地的天窗灌入式等五类。并对88组地下水样品测试结果进行多指标地下水污染综合评价,结果表明36.5%的水点为“三氮”污染,多以分散入渗进入地下水,其污染形态呈面状分布;15.3%的水点为重金属污染,主要通过峰丛洼地消水洞灌入式补给和溶丘谷地入渗补给两种途径,呈点状分布于污染场地附近;3.49%的水点为有机污染,主要为分散入渗补给途径,污染呈短线状或点状分布。 相似文献
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Alessandro Chelli Andrea Zanini Emma Petrella Alessandra Feo Fulvio Celico 《Environmental Earth Sciences》2018,77(6):246
In the last decades, hydraulic barriers have been activated in a large number of polluted sites with the aim of preventing groundwater pollution outside the contaminated area. From a regulatory point of view, there is the need of evaluating the efficacy of these barriers. For this reason, the goal of the present study is to apply a coupled experimental modelling approach aimed at evaluating the efficacy of the barrier and providing management strategies. In particular, a case study in Italy is investigated. The study case is of main interest because of its complexity due to a heterogeneous aquifer and the presence of surface water that interacts with the below aquifer. The study has been carried out through the experimental characterization of the aquifer system (coupling the classic stratigraphic techniques with the results of radiocarbon dating, as well as through pumping and injection tests) and its hydrogeological behaviour (by means of hydraulic- and the stream-head measurements, as well as some isotopic investigations), and the implementation of a numerical model (through MODFLOW 2005). The results show the effectiveness of the coupled experimental modelling approach to analyse and simulate the hydrodynamics within the test aquifer system, as well as to evaluate the efficacy of the hydraulic barrier. Based on the results of the numerical model, easy solutions were designed to manage the barrier. 相似文献