首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 46 毫秒
1.
计算区段控制浓度的合理定量化模型研究   总被引:1,自引:0,他引:1  
李亚民  陈余道 《地下水》2003,25(4):279-282
对污染物实施总量控制已经成为我国防止水环境恶化、实现水资源可持续利用的主要战略手段之一。本文就总量控制工作进行了理论探讨,从理论上提出了控制平均浓度和最大浓度两种情况下的排污等效模型。同时对计算区段控制浓度的确定进行了定量化模型研究。该模型简便易操作、实用性强,具有一定的理论意义和实用价值。  相似文献   

2.
Do We Really Need Mantle Components to Define Mantle Composition?   总被引:2,自引:0,他引:2  
We discuss the concept of components in the Earth's mantle startingfrom a petrological and geochemical approach, but adopting anew method of projection of geochemical and isotopic data. Thisallows the compositional variability of magmatic associationsto be evaluated in multi-dimensional space, thus simultaneouslyaccounting for a large number of compositional variables. Wedemonstrate that ocean island basalts (OIB) and mid-ocean ridgebasalts (MORB) are derived from a marble-cake mantle, in whichdifferent degrees of partial melting of recycled lithosphere,which are heterogeneous in age and composition, contribute tothe magma genesis. This view is supported by the variabilityin the geochemical and isotopic signatures of OIB that are observedon the scale of a single ocean island as well as on that ofan ocean, mostly varying between two extreme compositions, thatare not strictly related to the commonly accepted mantle components(DMM, EMI, EMII, HIMU). Rather they are a distinctive featureof the mantle source sampled at each ocean island and are stronglydependent on the Pb isotope system. We recommend a change inperspective in studies of MORB–OIB geochemistry from onebased on physically distinct mantle components to a model basedon the existence of a marble-cake-like upper mantle. Althoughresembling the statistical upper mantle, this model impliesthat geochemical homogenization can be attained only withinthe limits of local mantle composition, so that a world-wideuniform depleted reservoir cannot be sampled by simply extendingthe volume of the region undergoing partial melting. KEY WORDS: geochemistry; isotope; mantle; OIB  相似文献   

3.
邓金枝 《吉林地质》2005,24(3):99-100
矿产资源是人类社会赖以生存和发展的物质基础。矿业是国民经济不可缺少的基础产业之一,也是地域经济发展的重要支柱。因此,矿业经济持续发展是经济社会长远发展的客观要求。“我国是人口众多,资源相对不足的国家,在现代化建设中,必须实施可持续发展战略”。因此,我们矿政管理工作的方向、目标和政策就是:“我们对国土资源的保护和管理必须严而又严,总的原则是在保护中开发,在开发中保护,资源开发和节约并举。  相似文献   

4.
李军  姚平均  陈道元  张相乾  曾艳军 《探矿工程》2015,42(3):76-79,84
井下巷道掘进仍然是地下煤炭开采的主要方式,在开采过程中必然要穿过一些断裂地层带以及无胶结的松软地层及煤层顶板上的含水层。在掘进过程中,如果处理不当,地层中的水将沿着裂缝和采空塌陷区大量进入巷道内,造成严重的透水事故,使掘进工作无法顺利进行,严重时将导致井巷的报废,甚至造成重大的人身伤亡事故。针对传统水泥浆经水侵后不凝固或被流动水稀释而完全漏失,起不到应有的封堵固化作用等问题,研制出一种防水侵水泥浆封堵材料。该水泥浆与水按1∶1的比例掺混后仍具有凝结时间快、凝结强度高等特点,可在25 ℃以上的温度条件下使用。在某煤矿840 m井深、120 m3/h出水量情况下进行堵水作业试验,堵水效果良好,可在类似的条件下推广应用。  相似文献   

5.
隔水帷幕渗漏是影响软土基坑稳定性的关键问题。针对隔水帷幕渗漏检测技术,开展了数值模拟和物理模型试验,深入研究了不同采集装置类型三维电阻率法和探地雷达法对渗漏异常的反映能力及在探测剖面上表现出来的异常特征,给出了判断帷幕是否渗漏和确定渗漏点位置的解释方法。结果表明:温纳装置、偶极装置和温纳-施龙贝格装置都能有效反映渗漏点的存在;降水后帷幕未发生渗漏时,与基坑外侧软土含水层相比,内侧软土层电阻率表现为高阻异常;帷幕渗漏后基坑内侧底部软土层电阻率降低,外侧电阻率升高,并呈现漏斗状异常,两侧低阻异常与帷幕的交叉点可正确指示渗漏点位置;帷幕发生渗漏后,基于基坑外侧的探地雷达探测剖面中会出现双曲型反射波同相轴,通过其顶点可确定渗漏点的位置。研究结果证实了两种地球物理手段开展软土基坑隔水帷幕渗漏检测的可行性。  相似文献   

6.
尹德战  余大有  胡曦 《探矿工程》2015,42(8):60-62,67
小口径地质勘探不断向深部发展,受地层条件、孔内事故和孔斜要求等因素影响,很多钻孔需要定向钻进施工。而小口径钻孔一般采用φ50、60 mm钻具无法满足随钻仪器的下入要求。通过技术攻关及数次现场试验和改进,研制成功了一套小直径电缆湿接头,较好地解决了小通孔钻杆随钻受控定向钻进的关键技术及难点。具体方案为:把测量探管和传输电缆分开,定向测量探管事先与钻具连接,随钻具下放到预定深度,电缆连接信号上接头由钻杆内腔下入,与探管顶部的信号下接头在钻井液中实现电气连接和信号传输,完成定向作业。该方法在国投新集杨村煤矿DF33断层地面探测及注浆工程和莲塘李井田煤炭勘探中进行了试验并成功应用。具有一定的推广应用价值。  相似文献   

7.
结合工程实践,阐述单排高压旋喷桩在基坑防渗、防流沙治理中的施工工艺,并详细介绍了基坑止水帷幕施工关键技术及可能出现的问题,提出了相应的解决方法和应急预案。  相似文献   

8.
郭盛 《福建地质》2004,23(2):97-99
通过福州三隆水泥厂散装库安全防护工程的例子,介绍高压喷射搅拌桩在防水帷幕加固工程中的应用。  相似文献   

9.
矿井防水煤柱稳定性的理论研究   总被引:1,自引:0,他引:1  
我国在地表水体及松散层水体下采煤的主要措施是留设与水体规模及煤层采动后覆岩破坏规律相适应的煤岩柱。  相似文献   

10.
Ismailia Canal is the principle source of drinking water supply to Suez Canal and Sinai governorates. However, Ismailia Canal is endangered from unwise activities in the surrounding environment. Drinking water resources protection can be implemented using land-use monitoring system or through land-use controls based on hydrogeologic mapping to study the impacts of development on water quality. Our approach is to protect the direct and indirect catchment areas for surface water supply, especially the sensitive areas, those that are more vulnerable to contamination than other areas. Remote sensing and geographic information system techniques are applied to construct and integrate the hydrogeological data, inventory for potential sources of contamination and mapping the sensitive areas in order to construct the a protected buffer zone for Ismailia Canal, and to constrain the development activities in all the surrounding areas of surface water supply. The sensitive areas are delineated, where extra protection is required, based on soils properties, geology, and specific hydrogeological criteria. Industrial areas, drains, and septic tanks in the surrounding villages are the common potential sources of contamination. The hydrologic relation between Ismailia Canal and groundwater has great variations. Comprehensive plan for water protection were composed. It includes maintaining three natural protection zones of at least 300-m width along the main course of the Canal and delineating vulnerable zones depending on the aerial extension of the sensitive areas within 10 km on both sides of the Canal. Specific protection measures are recommended over the sensitive areas. The natural ecosystems of swamps around Ismailia Canal should be conserved and the processes of continuous burial prevented.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号