1、附录 1: 题目: 土方工程 由于土方挖远的施工方法与费用,比起土木工程中任何其它工种的施工方法与费用都变化的快,因此对于有事业心的人来说,土方工程是一个大有作为的领域。在 1935 年,目前采用的用轮胎式机械设备进行土方挖运的方法大多还未出现。大部分土方是采用窄轨铁路运输,这在目前来说是很少采用的,主要的开挖方法是使用正铲、反铲、垃 铲或抓斗等挖土机,尽管这些机械现在仍在广泛的使用,但只不过是目前许多方法中的一小部分。那时,挖土机的主要动力是自烧煤锅炉的蒸汽,而目前连盛产煤矿的英国也不用这种动力了,除有电力施工的工地外,目前各地都用内燃机。因此,一个工程师为使自己在土方搬运设备方面的知识跟的
2、上时代的需要,他应当花时间去研究现代的机械,并且要重心认真考率任何已使用了数年的陈旧方法。一般说来,有关挖土机、装载机和运输机械的唯一可靠而又最新的资料可从制造厂商处取得。 土方工程或土方挖运工程指的是把地表面过高处的土壤挖去(挖方),并把它倾 卸到地面过低的其它地方,(填方)。为了降低土方工程的费用,填方量应等于挖方量,而且挖方地点应尽可能靠近土方量相等的填方地点,以减少运输和三次搬运。土方设计这项工作落到了从事道路设计工程师的身上,因为土方工程的设计比任何其它项目更能决定工程造价是否低廉。根据现有的地图和标高,道路工程师应在设计绘图室中画出土方工程的横断面图并可能制定出尽可能多的方案。在现
3、场若取得更确切的资料,他可以变动他所做的断面图和设计图,但设计制图室的工作并非徒劳。它将帮助他在最短的时间内得到最优的方案。 费用最低的运土方法是用同一台机械 直接挖方取土并卸土为填方。这一点并非总是能够做到的。但如果能做到,则就十分理想,因为这样即快又省。拉铲挖土机、推土机和正铲都能做道这点。拉铲挖土机的工作半径最大,推土机所推土的数量也最多,只是运距很短,拉铲挖土机的缺点是只能挖本身比它低的土,不能施加压力挖入压实的土壤内,不能在陡坡上 挖土,而且挖卸都不准确。 正铲介于推土机和拉铲挖土机之间,其作用半径大于推土机,但小于推铲挖土机,正铲能挖取竖直陡峭的工作面,其操作方式对推土机司机来说是
4、危险的,而对拉铲挖土机则是不可能的。每种机械设备的作业应最适合它的性能 ,正铲不能挖比其停机平面底很多的土,而深挖竖直土壤时,反铲挖土机最合用,但其卸料半径比其装有正铲的同一挖土机的卸土半径却小的很多。 在比较平坦的场地开挖,如用拉铲或正铲挖土机运距太大时,则装有轮胎的斗式铲运机就是必不可少的,它能在相当平的地面上挖较深的土(但只能挖机械本身下的土),需要时可将土运到几百米远,然后卸土并在卸土的过程中将土初步摊平。挖掘硬土时,人们发现这样的施工方法是经济的,即在开挖场地经常保持一台助推拖拉机(轮式或履带式)对返回挖土的铲运机进行助推。一但铲运机装满,助推拖拉机就回到开挖的起点去 帮助下一台铲运
5、机。 斗式铲运机通常是功率非常大的机械,不少厂家制造的铲运机铲斗容量为 8立方米,满载时可达 10 立方米。最大的自行式铲运机铲斗为 19 立方米(满载时25 立方米),用 430 马力的牵引擎驱动。 在土坝工地,大多数开挖面都底于四周的地面,一种缆索式铲运机往来于装在河两岸高处的两个塔架之间,可以经济而又迅速的进行大部分的开挖和填筑作业;其跨度之大是拉铲挖土机所远远不能达到的。一个塔架是尾塔,仅装有缆索回程滑轮。另一个塔架是主塔,在塔架底座附近没有卷扬机及两个卷筒,在塔顶装有一个缆索滑轮。尾塔是可以移动的, 而且通常把它装设在轨距很宽的轮子上。轨距应有足够的宽度以保持稳定,以便能抵抗正在牵引
6、满载土斗的缆索的张力,以及在持续挖土时所能容许的最强风力。如果塔顶很高或施工工地易遭强风,那么最好规定在发生最不利的大风时停止开挖,以免尾塔为保持稳定性而需要做的过宽过重。过重就的需要很多的轮子和钢轨,从而使得轨道成本太高。一台索道可容易跨越峡谷进行施工,即可以浇注混凝土,也可以开挖土方,但用抓斗时,只能是向挖土。现在未考虑费用较高的土方挖运方法,挖土机挖土可将土装入轮胎式卡车或采用其它运输方法。例如皮带运输机就非常经济而且 能够运输大量的物料,但是很难找到一个土木工程工地能长期使用皮带运输机以补偿其它大的初次投资。 翻斗车可能是使用最为普遍的轮胎式运输设备,因为它们还适于运输混凝土或其它建筑
7、材料。翻斗车的车斗位于大橡胶轮胎车轮前轴的上方,尽管铰接式翻斗车的卸料方向有很多种,但大多数土斗是向前倾翻的,在最小型的翻斗车中,步行控制型翻斗车的车斗容量约为 200 升,司机是在车旁边步行,最小型翻斗车的容量约为 500升,司机是在车上驾驶,而最大的翻斗车的容量约为 4.5立方米。特殊型的翻斗车包括容量达 4立方米的自装式翻斗车和容量约为 500升 的铰接式翻斗车。翻斗车和自卸式卡车之间的区别必须记住。翻斗车车斗向前倾翻而司机生在所装物料的后方。自卸卡车是经过加固的重型翻斗车,司机在物料的前方驾驶,物料在司机的后方卸载,因此有时称它 为后翻卡车,这个名称倒更为切合实际。 附录 2: 英文翻
8、译 Earthwork Because earthmoving methods and costs change more quickly than those in any other branch of civil engineering ,this is a field where there are real opportunities for the enthusiast. In 1995 most of the methods now in use for carrying and excavating earth with rubber-typed equipment did n
9、ot exist .Most earth was moved by marrow rail track, now relative rare ,and the main methods of excavation, with face shove backward, or dragline or grab, though they are still widely used, are only a few of the many current methods. At that time, the main power for excavation was steam from the coa
10、l-fired boiler ,now out of use even in Britain where coal is plentiful. Internal-combustion engines are now used everywhere except on sites where electricity is available. To keep his kNowledge of earthmoving equipment up to date an engineer must seriously reconsider any methods more than a few year
11、s old, generally the only reliable up-to-date information on excavators, loaders and transport is obtainable from the makers. Earthwork or earthmoving means cutting into ground where its surface is too high(cuts), and dumping the earth in other places where the surface is too low(fills). To reduce e
12、arthwork costs, the volume of the fills should be equal to the volume of the cuts and wherever possible the cuts should be place near to fills of equal volume so as to reduce transport and double handling of the till. This work of earthwork design falls on the engineer who lays out the road since it
13、 is the layout of the earthwork more than anything else which decides its cheapness .Form the available maps and levels, the engineer drawing cross sections of the earthwork. On the site when further information becomes available he can make changes in his sections and layout, but the drawing office
14、 work will not have been lost. It will have him to reach the best solution in the shortest time. The cheapest way of moving earth is to take it directly out of the cut and drop it as fill with the same machine. This is most always possible, but when it can be done it is ideal ,being both quick and c
15、heap, draglines, bull dozers and the largest tonnage of earth is moved by the bulldozer, though only over short distances. The disadvantages of the dragline are that it must dig below itself, it cannot dig with force into compacted material, it cannot dig on steep slopes, and its dumping and digging
16、 are not accurate. Face shovels are between bulldozers, and draglines, having a larger radius of action than bulldozers but less than draglines, they are able to dig into a vertical cliff face in a way which would be dangerous for a bulldozer operator and impossible for a dragline. Each piece of equipment should be given the work for which it is best suited. Face shovels cannot dig much below the level of their tracks and for deep digs in compact material a backward is most useful, but its dumping radius is considerably