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传统人工钻井

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修建、运作和维护
'''关于水泥的建议''':建筑和隔板(例如水箱、大坝、水道和水井)出现裂缝的常见原因是在混合和使用水泥时出错。首先,很重要的一点是使用的成分一定要纯:干净的水、沙子和岩石,这些成分必须充分混合。第二,混合时使用的水尽量少:混凝土或水泥成形即可,宁可干点,也不要成为液体。第三,在固化过程中混凝土或水泥需要保持一定的水分,至少维持一周。同时,在固化过程中应该用塑料、大树叶或其他材料覆盖在引水建筑物上以保持水分。
'''Specific advice具体建议''':[[Image:telescopic lining.jpg|thumb|right|200px|Hand-dug well with telescopic lining有伸缩衬砌的人工井. Diagram图示: Watt, S.B.; Wood, W.E. (1979) Hand Dug Wells and their Construction人工钻井及修建. IT, London, UK英国伦敦.]][[Image:HandDugWellConstruction.jpg|thumb|right|200px|Construction of hand dug well at 在埃塞俄比亚阿姆哈拉州(Amhara)的 Kulala Kebele, Dera Woreda, Amhara Region, Ethiopia地区进行人工钻井. Photo图片来源: [http://www.flickr.com/photos/waterdotorg/4923124025/ Water.org]]]The basic elements of a hand-dug well are illustrated in Figure 5人工井的基本要素,详情请见图示5.3. The three main elements are3,三个要素分别是: <br>A. '''The Well Head井口装置''' - this is the part of the well which is visible above the ground. It generally consists of a protective apron and a superstructure which depends on the type of extraction system in use. 这个部分在地表以上,它通常由防护板和上部结构(由使用的抽水系统决定)组成。<br>B. '''The Well Shaft井身''' <br>C. '''The Intake取水口''' - this is the part of the well in contact with the aquifer. It is constructed in such a way that water flows from the aquifer into the well, from where it can be extracted using a bucket, a pump or another method.这个部分与含水层相接。因此水从含水层流进水井,然后使用水桶、水泵或其他方法将水抽出。
Hand-dug wells have a tendency to have very little water or even dry up in the dry season. This is largely to do with the factthat the intake area is not deep enough inside the dry season water table. Shallow aquifers tend to reflect recharge more sharply than deeper aquifers, resulting in water table fluctuations of several metres between seasons – these fluctuations need to be accounted for in the construction method. Several techniques can ensure that wells are sunk deep enough人工井在旱季时很可能干涸或水量极少,主要原因是取水口深度不够。浅层含水层比深层含水层更能反映补给情况,地下水位在不同季节可相差几米。在选用修建方式时应该考虑这个变化。有几种方法可保证水井的深度:* Construct wells using a telescopic system, where an a permanent lining is created above the water table, together with a smaller diameter telescopic lining that enters the water table. The advantage of this system is that the smaller lining can be deepened at a later date without affecting the permanent lining and slab, e.g. in case the well was not sunk deep enough the first time. Another advantage is that the shaft has less chance to go out of vertical alignment during caissoning (where a shaft is sunk by digging). 使用伸缩系统修井,在地下水位之上修建永久衬砌,以及进入地下水位的小型伸缩衬砌。该系统的优势是即使日后加深小型伸缩衬砌也不会影响永久衬砌和厚板,例如第一次水井深度不够。另一个优势是井身在凿井沉箱(通过挖掘将井身放入地下)的过程中不会倾斜。 * Use an effective method of de-watering during caissoning within the water table. Many hand-dug wells are dug without using a de-watering pump – consequently, the limit of penetration into the water table is about only 1 metre. Providing a de-watering pump will allow the shaft to be sunk deeper into the water table, but note在地下水位中,凿井沉箱时使用有效的排水方法。许多人工井在修建时没有使用排水泵,因此只能深入地下水位约1米。使用排水泵可以使得井身在地下水位中下沉得更深,但是请注意:# Type of pump depends on the height from ground level to water table – for a suction pump, the limit will be 6水泵的类型取决于地表到地下水位的距离,对于真空泵,最多可达6-7 metres, after which a submersible pump and generator needs to be considered. The type of pump should allow a certain amount of solid particles to be pumped.7米,如果多于这个距离就需要使用潜水泵和发电机。水泵应该允许抽取一些固体颗粒。# Attention needs to be given to safety considerations when using a motorized pump with someone digging in the well – engines should be located downwind so fumes do not enter the well, a 100 – 150mm vent pipe can be temporarily tied to the crossbeam to ventilate the well (in similar way to a VIP latrine), submersible pumps should be fitted with circuit breakers in case of electrical shortcuts to avoid electrocution, digger should be wearing construction harness attached to rope, and rescue & recovery action should be in place and practised regularly. 如果在有人挖井时使用水泵,需要额外注意安全问题。引擎应该位于顺风处,烟气才不会进入井中,可以在横梁上临时绑一个100-150毫米的排气管用来通风(与通风厕所原理相似),潜水泵应配备断路器避免在短路时发生触电致死事故。施工工人应该穿上工作服并绑上绳子,并且应该定期进行应急与恢复系统演习。 * Where using a de-watering pump results in subsidence around the well (in the case of flowing sands), another idea is to use a bailer instead of a pump. A bailer is normally used in percussion drilling, and consists of a heavy hollow metal tube with a valve on the bottom. When the bailer is dropped, sediment enters which does not come out when the bailer is removed. This method takes longer, but can be performed at ground level without a de-watering pump – since the water is not being pumped, flowing sand has less incentive to enter and the well shaft can sink slowly.使用排水泵造成水井周围下陷时(在有流砂的情况下),另一个办法是使用抽泥筒。抽泥筒通常在冲击钻井时使用,它由底部有阀门的重型空心金属管组成。将抽泥筒放入井中时,沉淀物将进入井中,并且在移除抽泥筒时也不会出来。这个方法耗时更久,但是可以不使用排水泵并在地面上进行操作。既然没有抽出水,流砂就不会进入水井,井身也可以慢慢下降。* Aim to dig wells during the latter half of the dry season when water table will be at their lowest. 应该在旱季的后半段(地下水位最低时)挖井。
Where deepening the well further is not possible due to water/sand ingress, jetting in the bottom of the well can provide a means of faster recharge into the well from deeper in the aquifer, meaning the well dries up less quickly. In this case a larger diameter screen (can be wrapped with geotextile) is jetted into the well base with the end protruding above the bottom of the well, after which it is plugged using a small bag of gravel.
Where wells still dry up in the dry season, recharge techniques could be used upstream of the well. 如果水井在旱季仍持续干涸,应在水井的上游进行补给。
The use of porous concrete in part of the section of the well shaft which is underwater can help increase flow velocity into the well. Porous concrete is made using a of 1 在位于地下的井身部分中使用透水混凝土可帮助加快流入水井的水流速度。透水混凝土中水泥、沙子和碎石的比例为1: 1 : 4 (cement : sand : aggregate) and can be used for curved blocks or also for a central portion of any pre-cast concrete ring. Also perforated pointed steel pipes can be driven horizontally into the aquifer using a jack – this can also increase flow velocity into the well.4,并可用作弯道砖或混凝土环的中间部分。也可以使用千斤顶将多孔尖头钢管钻入含水层,这也能提高流入水井的水流速度。
Simplify construction methods while getting a more robust end product in a safer fashion. Using lining & telescopic lining has the advantage that heavy lifting equipment for pre-cast rings is obsolete while procedures are inherently safer. Lining is made using one-skin moulds that hold concrete against the dug wall of the hole, while the telescopic shaft can be made from curved blocks built onto a foundation cutting ring – the blocks can be extended as and when necessary.简化修建方法,得到更优质成品的同时达到更安全的效果。使用衬砌或伸缩衬砌更加安全,并无需再使用重型起重设备吊起预制混凝土。衬砌使用一体式模具制成,模具中装满混凝土并靠在井身,而伸缩井身可以由弯道砖砌成地基环刀,必要时可加长。
===Costs===
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