共查询到20条相似文献，搜索用时 109 毫秒
1.
2.
3.
针对在卵石及基岩地层中桩孔施工时成孔难、渗漏大的问题，以液压抓斗为成孔设备，采用合理的机械结构、钻进方法、泥浆配方进行矩形截面桩的施工。 相似文献
4.
中宁县地处黄河中游,黄河滩地地下水受黄河补给,是具有巨大开采潜力的水源地。针对中宁黄河滩地第四系含粘粒土砂卵石地层的傍河水源地,选择辐射井作为取水建筑物,完成5眼辐射井。集水井成孔采用反循环方法,并配有专用钻头打捞含水层中粒径＞200 mm的漂石,用具有扭力、推力、拉力和振冲力的全液压水平钻机进行水平辐射管施工。采用“等效大口井法”计算辐射井抽水量。对抽水试验的数据及相关资料进行分析,比较辐射井、管井和大口井的稳定出水量和降深,结果表明采用辐射井开采类似水源地是有效的取水方式。 相似文献
5.
在新近杂填土上建厂，因杂填土松散、厚度大、基岩埋深大，若采用基岩作天然地基即用人工挖孔桩或机械成孔灌注桩，则很不经济，施工也存在安全隐患，易坍孔，且工期长。经过比较，采用灰土碎石挤密桩对杂填土进行处理后，作复合地基，施工易于操作并极大的缩短了工期，取得了良好的效果。 相似文献
6.
7.
8.
砂卵石含水层的辐射井成井技术较复杂,施工条件高,难度大,而打成的辐射井比一般含水层的辐射井出水量多,调控浅层地下水时,地下水位降深大,稳定的快,单井效益高。1 砂卵石含水层的辐射井成井技术 砂卵石含水层的辐射井主要由竖井和集水管两部分组成。1.1 竖井的成井技术 竖井是辐射井的主体部分,采用反循环回转式钻井成孔,漂浮下管法成井。这种方法较沉井法投资少、速度快。竖井井壁是由不透水的钢筋混凝土构成,井座外径一般为2.8m,内径为2.5m,井筒的外径一般为1.86m,内径为1.60m。用反循环钻机成孔,然后将事先预制好的井座、井管一节接一节吊装到井孔中,漂浮下管,直到井座下到预定深度为止,并确保井筒直立。井筒接头采用“三油两毡”封闭接口,最后在井筒周围均匀回填好土。这种建造大口径竖井的方法,既简便,又稳妥。钻竖井时锥形钻头要有足够的重量,方能破碎土层。钻头刮刀的角度要合理,泥浆泵量与钻孔成比例,才能取得好的钻井效果。 相似文献
9.
近年来在新疆伊犁盆地施工的砂岩型铀矿钻孔孔深大多在600~1000 m之间,钻孔终孔测井平均偏斜距在28 m左右,孔斜控制是影响伊犁矿区钻孔成孔质量的主要技术难题。伊犁盆地钻探施工多采用普通取心钻进工艺,成孔的钻杆与孔壁间的环状空间大,盆地内复杂地层引起的钻孔扩径现象普遍。普通取心钻进钻杆刚度小,钻杆在孔内转动时甩动弯曲幅度大,是导致孔斜控制困难的主要影响因素。中深孔钻孔偏斜距较大,影响地质成果质量和钻探经济效益。通过设计适合在伊犁盆地复杂地层内使用的扶正器并优化钻具组合,使伊犁盆地试验区内施工的中深孔平均偏斜距得到了大幅度的下降,该技术方案对同类型钻孔施工具有一定的借鉴性。 相似文献
10.
11.
12.
Babar Ali Shah 《Arabian Journal of Geosciences》2014,7(9):3525-3536
A groundwater arsenic (As) survey in Mirzapur, Varanasi, Ghazipur, Ballia, Buxar, Ara, Patna, and Vaishali districts of UP and Bihar shows that people from these districts are drinking As-contaminated groundwater (max. 1,300 μg/l). About 66 % of tubewells from Buxar to Mirzapur areas and 89 % of tubewells from Patna to Ballia areas have As?>?10 μg/l (WHO guideline). Moreover, 36 % of tubewells from Buxar to Mirzapur areas and 50 % of tubewells from Patna to Ballia areas have As above 50 μg/l. Most of the As-affected villages are located close to abandoned or present meander channels of the Ganga River. In contrast, tubewells located in Mirzapur, Chunar, Varanasi, Saidpur, Ghazipur, Muhammadabad, Ballia, Buxar, Ara, Chhapra, Patna, and Hazipur towns are As-safe in groundwater because of their positions on the Pleistocene Older Alluvium upland surfaces. The iron (Fe) content in tubewell water samples varies from 0.1 to 12.93 mg/l. About 77 % As-contaminated tubewells are located within the depth of 21 to 40 m in the Holocene Newer Alluvium aquifers. The potential source of As in sediments carried through the rivers from the Himalayas. Maximum As concentrations in the Older and Newer Alluvium sediments are 13.73 and 30.91 mg/kg, respectively. The Himalayas rivers, i.e. Yamuna, Ganga, Gomati, Ghaghara, Gondak, Buri Gandak, and Kosi rivers carrying suspended sediments have high content of As (max. 10.59 mg/kg). 相似文献
13.
Babar Ali Shah 《Environmental Earth Sciences》2012,66(8):2491-2501
Groundwater arsenic survey in Cachar and Karimganj districts of Barak Valley, Assam shows that people in these two districts are drinking arsenic-contaminated (max. 350 μg/l) groundwater. 66% of tubewells in these two districts have arsenic concentration above the WHO guideline value of 10 μg/l and 26% tubewells have arsenic above 50 μg/l, the Indian standards for arsenic in drinking water. 90% of installed tubewells in these two districts are shallow depth (14–40 m). Shallow tubewells were installed in Holocene Newer Alluvium aquifers are characterised by grey to black coloured fine grained organic rich argillaceous sediments and are mostly arsenic contamination in groundwater. Plio-Pleistocene Older Alluvium aquifers composed of shale, ferruginous sandstone, mottle clay, pebble and boulder beds, which at higher location or with thin cover of Newer Alluvium sediments are safe in arsenic contamination in groundwater. 91% of tubewell water samples show significantly higher concentrations of iron beyond its permissible limit of 1 mg/l. The iron content in these two districts varies from 0.5 to as much as 48 mg/l. Most of the arsenic contaminated villages of Cachar and Karimganj districts are located in entrenched channels and flood plains of Newer Alluvium sediments in Barak-Surma-Langai Rivers system. However, deeper tubewells (>60 m) in Plio-Pleistocene Older Alluvium aquifers would be a better option for arsenic-safe groundwater. The arsenic in groundwater is getting released from associated Holocene sediments which were likely deposited from the surrounding Tertiary Barail hill range. 相似文献
14.
Groundwater arsenic contamination in Manipur,one of the seven North-Eastern Hill states of India: a future danger 总被引：1，自引：0，他引：1
Dipankar Chakraborti E. Jayantakumar Singh Bhaskar Das Babar Ali Shah M. Amir Hossain Bishwajit Nayak Sad Ahamed N. Rajmuhon Singh 《Environmental Geology》2008,56(2):381-390
Manipur State, with a population of 2.29 million, is one of the seven North-Eastern Hill states in India, and is severely
affected by groundwater arsenic contamination. Manipur has nine districts out of which four are in Manipur Valley where 59%
of the people live on 10% of the land. These four districts are all arsenic contaminated. We analysed water samples from 628
tubewells for arsenic out of an expected total 2,014 tubewells in the Manipur Valley. Analyzed samples, 63.3%, contained >10 μg/l
of arsenic, 23.2% between 10 and 50 μg/l, and 40% >50 μg/l. The percentages of contaminated wells above 10 and 50 μg/l are
higher than in other arsenic affected states and countries of the Ganga–Meghna–Brahmaputra (GMB) Plain. Unlike on the GMB
plains, in Manipur there is no systematic relation between arsenic concentration and the depth of tubewells. The source of
arsenic in GMB Plain is sediments derived from the Himalaya and surrounding mountains. North-Eastern Hill states were formed
at late phase of Himalaya orogeny, and so it will be found in the future that groundwater arsenic contamination in the valleys
of other North-Eastern Hill states. Arsenic contaminated aquifers in Manipur Valley are mainly located within the Newer Alluvium.
In Manipur, the high rainfall and abundant surface water resources can be exploited to avoid repeating the mass arsenic poisoning
that has occurred on the GMB plains. 相似文献
15.
为了研究油页岩的地下原位开采技术,设计施工了FK-1井。该井地处吉林省松原市扶余县,完钻井深500 m,完钻层为嫩江组地层。该井设计施工中主要需克服大口径钻井的保直钻进、软塑性地层的裸眼钻进、水敏性地层中钻井液的应用、泥页岩层中发生钻头泥包现象及原位开采井的特殊成井、固井等问题。通过对钻井设备的优选,钻井液性能和井身结构的相应优化,钻头和钻具组合的选择等措施来解决钻井过程中的施工难题。设计结果在施工过程中进行了应用,施工效果良好,缩短了钻井时间,减少了钻井投入,解决了施工难题,为同类钻井的施工提供了借鉴和指导依据。 相似文献
16.
17.
在找矿突破战略行动逐步推开实施的今天,钻探工作量大幅度增加,施工的深孔特深孔数量急剧增长,对钻探技术和装备提出了前所未有的挑战。就钻探技术的新进展、深孔钻探存在的问题及解决对策进行了初步探讨。 相似文献
18.
Privatization of tubewells in North China: Determinants and impacts on irrigated area, productivity and the water table 总被引：3，自引：0，他引：3
Despite the rise in importance of the private sector in the expansion of the use of groundwater in China and the potential implications this might have for production and poverty, little has been written about the effect of these phenomena on northern China’s economy. In examining determinants of tubewell privatization and its impact on producers in northern China, data were collected using a community leader survey, carried out in 448 villages in six provinces in northern China. The results show that since 1990 collective ownership of tubewells has largely been replaced by private ownership. Increasing water scarcity, government grants and bank loans for tubewell investment and the declining investment capacity of China’s local communities have led to the observed change in tubewell ownership patterns. By far, the most important positive effect on income appears to be due to the expansion of newly irrigated area that has been fueled by the rise of private tubewells. Many newly private tubewells also have begun to replace irrigation from surface water sources. While helping increase income and productivity, the rise of private tubewells also has contributed to the fall in groundwater levels.
相似文献
| Jinxia WangEmail: Phone: 86-10-64889841Fax: 86-10-64856533 |
19.