汽車制動系統(tǒng)英文文獻(xiàn)及翻譯

1、Brake systemsWe all know that pushing down on the brake pedal slows a car to a stop. But how does this happen? How does your car transmit the force from your leg to its wheels? How does it multiply the force so that it is enough to stop something as big as a car? HYPERLINK /enlarge-image.htm?terms=b

2、rakes&page=0 Brake Image GalleryLayout of typical brake system. See more HYPERLINK /enlarge-image.htm?terms=brakes&page=0 brake images.When you depress your brake pedal, your car transmits the force from your foot to its brakes through a fluid. Since the actual brakes require a much greater force th

3、an you could apply with your leg, your car must also multiply the force of your foot. It does this in two ways: Mechanical advantage (leverage) Hydraulic force multiplication The brakes transmit the force to the tires using friction, and the tires transmit that force to the road using friction also.

4、 Before we begin our discussion on the components of the brake system, well cover these three principles: Leverage Hydraulics Friction Leverage and HydraulicsIn the figure below, a force F is being applied to the left end of the lever. The left end of the lever is twice as long (2X) as the right end

5、 (X). Therefore, on the right end of the lever a force of 2F is available, but it acts through half of the distance (Y) that the left end moves (2Y). Changing the relative lengths of the left and right ends of the lever changes the multipliers. The pedal is designed in such a way that it can multipl

6、y the force from your leg several times before any force is even transmitted to the brake fluid. The basic idea behind any hydraulic system is very simple: Force applied at one point is transmitted to another point using an incompressible fluid, almost always an oil of some sort. Most brake systems

7、also multiply the force in the process. Here you can see the simplest possible hydraulic system: Your browser does not support JavaScript or it is disabled. Simple hydraulic system In the figure above, two pistons (shown in red) are fit into two glass cylinders filled with oil (shown in light blue)

8、and connected to one another with an oil-filled pipe. If you apply a downward force to one piston (the left one, in this drawing), then the force is transmitted to the second piston through the oil in the pipe. Since oil is incompressible, the efficiency is very good - almost all of the applied forc

9、e appears at the second piston. The great thing about hydraulic systems is that the pipe connecting the two cylinders can be any length and shape, allowing it to snake through all sorts of things separating the two pistons. The pipe can also fork, so that one HYPERLINK /master-brake.htm master cylin

10、der can drive more than one slave cylinder if desired, as shown in here: Your browser does not support JavaScript or it is disabled. Master cylinder with two slaves The other neat thing about a hydraulic system is that it makes force multiplication (or division) fairly easy. If you have read HYPERLI

11、NK /pulley.htm How a Block and Tackle Works or HYPERLINK /gears.htm How Gear Ratios Work, then you know that trading force for distance is very common in mechanical systems. In a hydraulic system, all you have to do is change the size of one piston and cylinder relative to the other, as shown here:

12、Your browser does not support JavaScript or it is disabled. Hydraulic multiplication To determine the multiplication factor in the figure above, start by looking at the size of the pistons. Assume that the piston on the left is 2 inches (5.08 cm) in diameter (1-inch / 2.54 cm radius), while the pist

13、on on the right is 6 inches (15.24 cm) in diameter (3-inch / 7.62 cm radius). The area of the two pistons is Pi * r2. The area of the left piston is therefore 3.14, while the area of the piston on the right is 28.26. The piston on the right is nine times larger than the piston on the left. This mean

14、s that any force applied to the left-hand piston will come out nine times greater on the right-hand piston. So, if you apply a 100-pound downward force to the left piston, a 900-pound upward force will appear on the right. The only catch is that you will have to depress the left piston 9 inches (22.

15、86 cm) to raise the right piston 1 inch (2.54 cm).A Simple Brake SystemBefore we get into all the parts of an actual car brake system, lets look at a simplified system:Your browser does not support JavaScript or it is disabled. A simple brake system You can see that the distance from the pedal to th

16、e pivot is four times the distance from the cylinder to the pivot, so the force at the pedal will be increased by a factor of four before it is transmitted to the cylinder. You can also see that the diameter of the brake cylinder is three times the diameter of the pedal cylinder. This further multip

17、lies the force by nine. All together, this system increases the force of your foot by a factor of 36. If you put 10 pounds of force on the pedal, 360 pounds (162 kg) will be generated at the wheel squeezing the brake pads. There are a couple of problems with this simple system. What if we have a lea

18、k? If it is a slow leak, eventually there will not be enough fluid left to fill the brake cylinder, and the brakes will not function. If it is a major leak, then the first time you apply the brakes all of the fluid will squirt out the leak and you will have complete brake failure. Drum brakes work o

19、n the same principle as disc brakes: Shoes press against a spinning surface. In this system, that surface is called a drum.Figure 1. Location of drum brakes. See more HYPERLINK /enlarge-image.htm?terms=Drum+Brakes&page=0 drum brake pictures.Many cars have drum brakes on the rear wheels and disc brak

20、es on the front. Drum brakes have more parts than disc brakes and are harder to service, but they are less expensive to manufacture, and they easily incorporate an emergency brake mechanism. In this edition of HYPERLINK /index.htm HowStuffWorks, we will learn exactly how a drum brake system works, e

21、xamine the emergency brake setup and find out what kind of servicing drum brakes need. Figure 2. Drum brake with drum in placeFigure 3. Drum brake without drum in placeLets start with the basics. The Drum BrakeThe drum brake may look complicated, and it can be pretty intimidating when you open one u

22、p. Lets break it down and explain what each piece does. Figure 4. Parts of a drum brakeLike the HYPERLINK /disc-brake.htm disc brake, the drum brake has two brake shoes and a piston. But the drum brake also has an adjuster mechanism, an emergency brake mechanism and lots of springs. First, the basic

23、s: Figure 5 shows only the parts that provide stopping power. Your browser does not support JavaScript or it is disabled. Figure 5. Drum brake in operation When you hit the brake pedal, the piston pushes the brake shoes against the drum. Thats pretty straightforward, but why do we need all of those

24、springs? This is where it gets a little more complicated. Many drum brakes are self-actuating. Figure 5 shows that as the brake shoes contact the drum, there is a kind of wedging action, which has the effect of pressing the shoes into the drum with more force. The extra braking force provided by the

25、 wedging action allows drum brakes to use a smaller piston than disc brakes. But, because of the wedging action, the shoes must be pulled away from the drum when the brakes are released. This is the reason for some of the springs. Other springs help hold the brake shoes in place and return the adjus

26、ter arm after it actuates. Brake AdjusterFor the drum brakes to function correctly, the brake shoes must remain close to the drum without touching it. If they get too far away from the drum (as the shoes wear down, for instance), the piston will require more fluid to travel that distance, and your b

27、rake pedal will sink closer to the floor when you apply the brakes. This is why most drum brakes have an automatic adjuster. Figure 6. Adjuster mechanismNow lets add in the parts of the adjuster mechanism. The adjuster uses the self-actuation principle we discussed above. Your browser does not suppo

28、rt JavaScript or it is disabled. Figure 7. Drum brake adjuster in operation In Figure 7, you can see that as the pad wears down, more space will form between the shoe and the drum. Each time the car stops while in reverse, the shoe is pulled tight against the drum. When the gap gets big enough, the

29、adjusting lever rocks enough to advance the adjuster HYPERLINK /gear.htm gear by one tooth. The adjuster has threads on it, like a bolt, so that it unscrews a little bit when it turns, lengthening to fill in the gap. When the brake shoes wear a little more, the adjuster can advance again, so it alwa

30、ys keeps the shoes close to the drum. Some cars have an adjuster that is actuated when the emergency brake is applied. This type of adjuster can come out of adjustment if the emergency brake is not used for long periods of time. So if you have this type of adjuster, you should apply your emergency b

31、rake at least once a week. ServicingThe most common service required for drum brakes is changing the brake shoes. Some drum brakes provide an inspection hole on the back side, where you can see how much material is left on the shoe. Brake shoes should be replaced when the friction material has worn

32、down to within 1/32 inch (0.8 mm) of the rivets. If the friction material is bonded to the backing plate (no rivets), then the shoes should be replaced when they have only 1/16 inch (1.6 mm) of material left. Photo courtesy of a local HYPERLINK /framed.htm?parent=drum-brake.htm&url= AutoZone storeFi

33、gure 9. Brake shoeJust as in disc brakes, deep scores sometimes get worn into brake drums. If a worn-out brake shoe is used for too long, the rivets that hold the friction material to the backing can wear grooves into the drum. A badly scored drum can sometimes be repaired by refinishing. Where disc

34、 brakes have a minimum allowable thickness, drum brakes have a maximum allowable diameter. Since the contact surface is the inside of the drum, as you remove material from the drum brake the diameter gets bigger. Figure 10. Brake drum 制動系統(tǒng)眾所周知，踩下制動踏板可以使汽車減速至停止。但這是如何產(chǎn)生的呢？汽車是如何將力從你的腿傳遞到車輪的呢？汽車是如何將力放大到

35、足夠大以致可以將像汽車一樣大的東西制動的呢？ 制動系統(tǒng)組件當(dāng)你踩下制動踏板的時(shí)候，汽車通過液體把力從腳傳遞到制動器。因?yàn)橹苿悠餍枰恼嬲α勘饶愕耐饶芴峁┑囊蟮亩?，所以汽車必須放大腳產(chǎn)生的力 有兩種方式：機(jī)械杠桿作用液力放大 制動器通過摩擦把力傳遞給輪胎，并且輪胎也是通過摩擦把力傳遞給路面的。 在我們討論制動系統(tǒng)的組成之前，先來介紹以下三條原則：杠桿液力摩擦力杠桿和液力在下面的圖中，一個(gè)力F加在杠桿的左端。左端的杠桿長度（2X）是右端（X）的兩倍。因此杠桿右端可施加的力為2F ，但是右端移動的距離(Y)是左端距離(2Y)的一半。改變杠桿的左端和右端的長度可以改變放大系數(shù)。 任何液壓系統(tǒng)背后的

36、基本原理都是非常簡單的：作用在某一點(diǎn)力通過通常是油一類的不可壓縮的液體傳遞到另一點(diǎn)。大多數(shù)的制動系統(tǒng)也在這個(gè)過程中放大力。下面的是最簡單的液壓系統(tǒng)： 簡單液壓系統(tǒng)在上圖中，兩個(gè)活塞放在兩個(gè)充滿油的玻璃液壓缸中并且由充滿油的管道相連。如果在一個(gè)活塞上施加一個(gè)向下的力，那么力將通過管道中的油傳遞到第二個(gè)活塞。因?yàn)橛鸵菏遣豢蓧嚎s的，所以傳遞效率很好，大部分的作用力都傳遞到了另一個(gè)活塞。液壓系統(tǒng)的好處連接兩液壓缸的管道可以是任何長度和形狀，這樣就可以使管道彎曲的通過兩活塞之間的各種部件。管道也可以是分叉的，如果有需要的話，這樣一個(gè)主缸可以驅(qū)動數(shù)個(gè)副缸。如下圖所示： 帶有兩個(gè)副缸的主缸 液壓系統(tǒng)的另一個(gè)

37、好處是產(chǎn)生放大（或者縮?。?力相當(dāng)?shù)厝菀?。如果你一讀過滑車設(shè)備工作原理或者齒輪齒數(shù)比原理，那么你就會知道在機(jī)械系統(tǒng)中把力轉(zhuǎn)化為距離處理是很常見的。在液壓系統(tǒng)中，我們所要做的就是相對地改變一組活塞和液壓缸的尺寸。如下圖所示： 液壓增力原理為了確定上圖中的放大因子，先由觀察活塞的尺寸開始。假設(shè)左邊活塞的直徑為2英尺（5.08cm而右邊的直徑為6英尺（15.24cm）。兩個(gè)活塞的面積是Pi * r2 。因此左面活塞的面積是3.14，而右面的面積是28.26。右面活塞的面積是左邊的九倍大。這就意味著無論在左面的活塞上施加多大的力，在右面的活塞上就會輸出九倍于左面的力。所以，如果在左邊活塞上施加100磅

38、向下的力，那么在右面活塞上將產(chǎn)生900磅向上的力。唯一的補(bǔ)償是左面的活塞要移動9英尺（22.86cm）來使右面提升1英尺（2.54cm）一個(gè)簡單的制動系統(tǒng)在我們深入了解一個(gè)真實(shí)的制動系統(tǒng)的各部分之前，讓我們先來看一個(gè)簡化的系統(tǒng)： 我們可以看到踏板到樞軸的距離是液壓缸到樞軸距離的4倍，所以施加在踏板上的力在傳遞到液壓缸之前將被增加4倍。我們還可以看到制動缸的直徑是踏板缸直徑的3倍。這就將力進(jìn)一步放大了九倍。最終這個(gè)系統(tǒng)將腿上的力增加了36倍。所以，如果在踏板上施加10磅的力，將在擠壓制動帶的輪上產(chǎn)生369磅（162kg）的力。下面是這種簡單系統(tǒng)所存在的問題。要是系統(tǒng)有泄漏該怎么辦呢？如果是輕微泄

39、漏，最終將會沒有足夠的油使制動缸充滿，并且制動器將停止工作。如果是嚴(yán)重泄漏，那么在你制動的第一時(shí)間，所有的油液將從泄露處噴射而出，并且制動系統(tǒng)將徹底地不起作用。鼓式制動器的工作原理和盤式制動器是一樣的：制動面接觸一個(gè)磨砂的表面。在這個(gè)系統(tǒng)中，那個(gè)表面稱作制動鼓 圖1.制動鼓的位置許多汽車的后輪安裝鼓式制動器，而盤式制動器安裝在前面。鼓式制動器比盤式制動器有更多的零件并且更難檢修。 但是制造成本相對便宜，還有鼓式制動器容易組裝一個(gè)緊急使用的制動裝置。在本版本的How StuffWorks中，我們將詳盡了解鼓式制動系統(tǒng)是如何工作的。考察緊急制動系統(tǒng)的組成，并且找到鼓式制動器需要何種檢修工作。圖2.

40、 有鼓的鼓式制動器 圖3.未安裝鼓的鼓式制動器讓我們基礎(chǔ)開始：鼓式制動器鼓式制動器可能看起來比較復(fù)雜，它可以是很復(fù)雜的，當(dāng)你打開一個(gè)的時(shí)候。讓我們拆開它，并解釋每一塊的作用。 圖4. 鼓式制動器的組成如盤式制動器，鼓式制動器有兩個(gè)制動蹄和一個(gè)活塞。 But the drum brake also has an adjuster mechanism, an emergency brake mechanism and lots of springs .但是鼓式制動器也有一個(gè)調(diào)節(jié)機(jī)制，緊急剎車機(jī)制和大量的彈簧 。首先，基礎(chǔ)知識： 圖5顯示只有部分提供的制動力。 圖5.工作狀態(tài)下的鼓式制動器當(dāng)你踩下剎

41、車踏板時(shí)，活塞推動緊靠著鼓的制動蹄。 Thats pretty straightforward, but why do we need all of those springs?這是很簡單的，但為什么我們需要所有這些彈簧呢？這使它變的有點(diǎn)復(fù)雜許多鼓式制動器是自增力式的。圖5表明，當(dāng)制動蹄與鼓相接觸的時(shí)候，兩者間有一個(gè)楔入運(yùn)動，這起到了產(chǎn)生更多的力量將制動蹄向鼓擠壓。由楔入運(yùn)動提供的額外制動力使得鼓式制動器可以使用比盤式制動器更小的活塞。但是由于這種楔入運(yùn)動，在制動釋放的時(shí)候制動蹄必須從鼓拉離開。這是使用其中部分彈簧的原因。其它彈簧的作用是將制動蹄固定并且驅(qū)動調(diào)節(jié)臂返回。制動調(diào)節(jié)器為了使鼓式制動

42、器正確的工作，制動蹄必須緊貼著鼓但是不碰到它。如果離鼓太遠(yuǎn)的話，活塞將需要更多的油液以通過那段距離，并且當(dāng)你制動時(shí)，制動踏板將下行而離地板更近。這就是為什么大多數(shù)的鼓式制動器有一個(gè)自動調(diào)節(jié)裝置的原因。 圖6.調(diào)節(jié)機(jī)構(gòu)現(xiàn)在讓我們在把調(diào)節(jié)機(jī)構(gòu)也加進(jìn)來，這個(gè)調(diào)節(jié)器使用的是上面討論過的自增力原理。圖7.工作狀態(tài)下的鼓式制動調(diào)節(jié)器在圖7中，我們可以看到由于摩擦片的磨損，這使得制動蹄和鼓之間形成更大的空間。每次車停下的時(shí)候，相反的是制動蹄被拉的和鼓更緊。當(dāng)間隙變的足夠大時(shí)，調(diào)節(jié)杠桿足夠擺動推進(jìn)調(diào)節(jié)齒輪先前轉(zhuǎn)動一個(gè)齒。調(diào)節(jié)裝置有一個(gè)行程，就像一個(gè)螺栓，以便當(dāng)它轉(zhuǎn)動時(shí)旋開一點(diǎn)點(diǎn)，延長以填補(bǔ)間隙。當(dāng)制動蹄進(jìn)一步

43、磨損，調(diào)節(jié)器又可以再向前。所以它總是保持制動蹄緊靠著鼓。有些汽車緊急剎車時(shí)有一個(gè)被驅(qū)動的調(diào)節(jié)器。如果緊急制動很長一段時(shí)間沒有使用，這種類型的調(diào)節(jié)器可以產(chǎn)生調(diào)節(jié)作用。所以如果你有這種類型的調(diào)節(jié)器，你應(yīng)該每周至少使用一次緊急制動裝置。檢修鼓式制動器最常見的檢修是更換制動蹄。一些鼓式制動器在背面設(shè)置了一個(gè)檢查孔，通過這個(gè)孔，你可以看到制動蹄上還剩余多少摩擦材料。當(dāng)摩擦材料磨損到鉚釘內(nèi)1/32英寸（0.8mm）時(shí)，必須更換制動蹄。如果摩擦材料和墊板直接連接（無鉚釘），那么當(dāng)摩擦材料只剩下1/16英寸（1.6mm）時(shí)，就該換制動蹄了。 圖9.制動蹄正如在盤式制動器中，深的刻痕可能會磨穿到制動鼓。如果一個(gè)

44、磨損的制動蹄使用過長的時(shí)間，把摩擦片固定到墊板上鉚釘可以將制動鼓摸出一條凹槽。一個(gè)嚴(yán)重磨損的制動鼓有時(shí)可以被修補(bǔ)修復(fù)。盤式制動器有最小允許厚度，鼓式制動器有一個(gè)最大允許直徑。因?yàn)榻佑|表面是鼓的內(nèi)側(cè)。當(dāng)你將材料從制動器中取出時(shí)，制動鼓的直徑變大了。 圖10.制動鼓 附錄資料：不需要的可以自行刪除超寬超深地下連續(xù)墻施工工藝一、概述武林廣場站位于杭州市中心廣場武林廣場東北角，是地鐵1號線與3號線的換乘車站，車站長161.75m，標(biāo)準(zhǔn)段寬36.6 m,底板埋深約26.4m, 車站為地下三層四柱五跨三層結(jié)構(gòu)，采用蓋挖逆作法施工。車站圍護(hù)結(jié)構(gòu)采用1200mm厚地下連續(xù)墻，墻幅寬度為6.0m，深度為48m左

45、右，十字鋼板接頭形式，單幅鋼筋籠重約70t，設(shè)計(jì)要求進(jìn)入中風(fēng)化巖0.5m。二、工法特點(diǎn)地下連續(xù)墻工法問世以來，迅速的占有了廣闊的市場，地下連續(xù)墻工法主要有以下幾方面的優(yōu)點(diǎn)。1、施工時(shí)振動小，噪聲低，非常適于在城市施工；2、墻體剛度大，用于基坑開挖時(shí)，極少發(fā)生地基沉降或塌方事故；3、防滲性能好；4、可以貼近施工，由于上述幾項(xiàng)優(yōu)點(diǎn)，我們可以緊貼原有建筑物施工；5、可用于逆作法施工；6、適用于多種地基條件；7、可用作剛性基礎(chǔ)；8、占地少，可以充分利用建筑紅線以內(nèi)有限的地面和空間，充分發(fā)揮投資效益；9、功效高、工期短，質(zhì)量可靠。當(dāng)然，所有的事物都有兩面性，地連墻工法也存在以下缺點(diǎn)：1、在一些特殊的地質(zhì)

46、條件下（如很軟的淤泥質(zhì)土，含漂石的沖積層和超硬巖石等），施工難度很大；2、如果施工方法不當(dāng)或地質(zhì)條件特殊，可能出現(xiàn)相鄰槽段不能對齊和漏水的問題。3、地下連續(xù)墻如果用作臨時(shí)的擋土結(jié)構(gòu)，比其他方法的費(fèi)用高；4、在城市施工時(shí)，廢棄泥漿的處理比較麻煩。三、施工方法及操作控制要點(diǎn)1、施工優(yōu)化控制的要點(diǎn)1.1 地下連續(xù)墻一般寬為6m，墻厚1.2m屬于超寬地連墻，在施工技術(shù)方面還不是很成熟，機(jī)械方面相應(yīng)的成槽機(jī)、反力箱、大型起重設(shè)備等的應(yīng)用都是經(jīng)過反復(fù)計(jì)算在經(jīng)濟(jì)安全的前提下確定的。1.2 在成槽過程中機(jī)械自身的垂直控制系統(tǒng)1.3 由于采用十字鋼板對刷壁造成一定難度，在經(jīng)過研究后采用在成槽機(jī)抓斗上安裝側(cè)鏟進(jìn)行

47、刷壁然后再用鋼刷刷壁器進(jìn)行刷壁。1.4 在地連墻施作過程中要穿越承壓水層，為防止開挖過程中承壓水繞流，在地連墻內(nèi)預(yù)埋注漿管，在地連墻全部達(dá)到強(qiáng)度后進(jìn)行墻趾注漿1.5 本工程反力箱放置深度達(dá)到4352m，混凝土澆筑時(shí)間也長達(dá)8小時(shí)左右，反力箱自重、混凝土的握裹力和土體的摩擦力極大，為順利拔出反力箱在混凝土澆筑完34小時(shí)后，先用液壓油頂對其進(jìn)行松動，在混凝土初凝后在進(jìn)行起拔。2、關(guān)鍵工序施工方法及控制要點(diǎn)2.1 道路硬化因地下連續(xù)墻施工過程中，成槽機(jī)械及吊運(yùn)鋼筋籠的大型履帶式起重機(jī)需要在場地內(nèi)來回行走，我單位根據(jù)以往的經(jīng)驗(yàn)并結(jié)合本工程的實(shí)際情況，對結(jié)構(gòu)內(nèi)側(cè)及導(dǎo)墻外側(cè)1m的范圍內(nèi)澆筑30cm厚C20

48、鋼筋混凝土路面，配筋采用16的螺紋鋼橫向間距200 mm、縱向200mm，雙層雙向布置，并與導(dǎo)墻筑成一體。2.2 導(dǎo)墻的施工導(dǎo)墻采用鋼筋混凝土結(jié)構(gòu)，壁厚20cm，配筋為單層雙向14200mm，導(dǎo)墻凈寬1250mm，導(dǎo)墻應(yīng)和附近路面一體澆搗.導(dǎo)墻溝（放坡比為1:0.5）采用挖掘機(jī)開挖，人工配合修整清底，導(dǎo)墻開挖好一段后，在溝槽底按地連墻尺寸制作木模，架立模板，經(jīng)測量檢查位置符合規(guī)范偏差要求后，進(jìn)行C20混凝土灌筑，泵送入倉。如果導(dǎo)墻施作過程中遇到障礙物、軟弱地層或其它廢棄管線導(dǎo)致開挖深度過大，則可把導(dǎo)墻加深以滿足施工要求。導(dǎo)墻施工工藝流程圖見下圖。平整場地測量定位挖 槽綁扎鋼筋澆 灌 砼支立模板

49、拆 模設(shè)橫支撐 導(dǎo)墻施工工藝流程圖導(dǎo)墻施工注意要點(diǎn)A. 在導(dǎo)墻施工全過程中，保持導(dǎo)墻溝內(nèi)不積水。B. 橫貫或靠近導(dǎo)墻溝的廢棄管道需封堵密實(shí)，以免成為漏漿通道。C. 導(dǎo)墻溝側(cè)壁土體是導(dǎo)墻澆搗混凝土?xí)r的外側(cè)土模，防止導(dǎo)墻溝寬度超挖或土壁坍塌。D. 現(xiàn)澆導(dǎo)墻分段施工，水平鋼筋應(yīng)預(yù)留連接鋼筋與鄰接段導(dǎo)墻的水平鋼筋相連接。E. 必須保證導(dǎo)墻的內(nèi)凈寬度尺寸與內(nèi)壁面的垂直精度達(dá)。F. 導(dǎo)墻立模結(jié)束之后，應(yīng)對導(dǎo)墻放樣成果進(jìn)行最終復(fù)核。G. 導(dǎo)墻混凝土強(qiáng)度達(dá)到50時(shí)，方可進(jìn)行成槽作業(yè)，在此之前禁止車輛和起重機(jī)等重型機(jī)械靠近導(dǎo)墻。2.3泥漿制備與管理泥漿在地下連續(xù)墻成槽過程中起到護(hù)壁作用，泥漿護(hù)壁是地下連續(xù)墻施工

50、的基礎(chǔ)，其質(zhì)量好壞直接影響到地下連續(xù)墻的質(zhì)量與施工安全，泥漿系統(tǒng)工藝流程見下圖。新鮮泥漿貯存施 工 槽 段新鮮泥漿配制加料拌制再生泥漿回收槽內(nèi)泥漿凈化泥漿劣化泥漿再生泥漿貯存振動篩分離泥漿沉淀池分離泥漿旋流器分離泥漿粗篩分離泥漿劣化泥漿廢棄處理凈化泥漿性能測試泥漿系統(tǒng)工藝流程圖A. 泥漿配合比根據(jù)地質(zhì)條件，泥漿采用膨潤土制備，泥漿配合比如下：（每立方米泥漿材料用量Kg）膨潤土:80 純堿:4 水:950 CMC:5上述配合比在施工中根據(jù)試驗(yàn)槽段及實(shí)際情況可進(jìn)行適當(dāng)調(diào)整。泥漿制備的性能指標(biāo)如下泥漿性能新配制循環(huán)泥漿廢棄泥漿檢驗(yàn)方法比重（g/cm3）1.06-1.081.151.35比重法粘度（s

51、）25-303560漏斗法含砂率（%）4711洗砂瓶PH值8-9814PH試紙泥漿配制的方法見下圖“泥漿配制流程圖”。原 料 試 驗(yàn)稱 量 投 料CMC和純堿加水?dāng)嚢?分鐘膨潤土加水沖拌5分鐘混合攪拌3分鐘泥漿性能指標(biāo)測定溶脹24小時(shí)后備用泥漿配制流程圖B. 泥漿儲存泥漿儲存采用半埋式磚砌泥漿池儲存。C. 泥漿循環(huán)泥漿循環(huán)采用3LM型泥漿泵輸送，4PL型泥漿泵回收，由泥漿泵和軟管組成泥漿循環(huán)管路。D. 泥漿的分離凈化在地下墻施工過程中，因?yàn)槟酀{要與地下水、泥土、砂石、混凝土接觸，其中難免會混入細(xì)微的泥沙顆粒、水泥成分與有害離子，必然會使泥漿受到污染而變質(zhì)。因此，泥漿使用一個(gè)循環(huán)之后，要對泥漿進(jìn)

52、行分離凈化，提高泥漿的重復(fù)使用率。槽內(nèi)回收泥漿的分離凈化過程是：先經(jīng)過土碴分離篩，把粒徑大于10mm的泥土顆粒分出來，防止其堵塞旋流除碴器下泄口，然后依次經(jīng)過沉淀池、旋流除碴器、雙層振動篩多級分離凈化，使泥漿的比重與含砂量減小，如經(jīng)第一循環(huán)分離后的泥漿比重仍大于1.15，含砂量仍大于4%，則用旋流除碴器和雙層振動篩作第二、第三循規(guī)蹈矩環(huán)分離，直至泥漿比重小于1.15，含砂量小于4%為止。E. 泥漿池設(shè)計(jì)泥漿池容量設(shè)計(jì)（以成槽開挖寬度6m計(jì)）地下墻的標(biāo)準(zhǔn)槽段挖土量：V1=長6m深47m厚1.2m=339m3新漿儲備量：V2=V180%=271m3泥漿循環(huán)再生處理池容量：V3=V11.5=509m

53、3砼灌筑產(chǎn)生廢漿量：V4=6m4m1.2m =29m3泥漿池總?cè)萘浚篤V3+V4=538m32.3 連續(xù)墻成槽施工成槽是地連續(xù)墻施工的關(guān)鍵工序，成槽約占地下連續(xù)墻工期的一半，因此提高成槽的效率是縮短工期的關(guān)鍵。同時(shí)，槽壁形狀決定墻體的外形，所以成槽的精度和質(zhì)量是保證地下連續(xù)墻質(zhì)量的關(guān)鍵，單元槽段之間的接頭盡量避免設(shè)在轉(zhuǎn)角處。A. 成槽施工連續(xù)墻施工采用跳槽法，施工根據(jù)槽段長度與成槽機(jī)的開口寬度，確定出首開幅和閉合幅，保證成槽機(jī)挖土?xí)r兩側(cè)鄰界條件的均衡性，以確保槽壁垂直，部分槽段采取兩鉆一抓。成槽后用超聲波檢測儀檢查成槽質(zhì)量。在成槽過程中，嚴(yán)格控制抓斗的垂直度和平面位置，在開挖槽段時(shí)，操作手要仔

54、細(xì)觀察成槽機(jī)的監(jiān)測系統(tǒng)，當(dāng)X，Y軸任一方向偏差超過允許值時(shí)，立即進(jìn)行糾偏，抓斗貼基坑側(cè)導(dǎo)墻入槽，機(jī)械操作要平穩(wěn),抓斗出入導(dǎo)墻口時(shí)要輕放慢提，防止泥漿掀起波浪，影響導(dǎo)墻下面和后面的土層穩(wěn)定,并及時(shí)補(bǔ)入泥漿，維持槽段中泥漿液面穩(wěn)定。成槽施工見下圖“成槽施工圖”。成槽施工圖： B. 成槽注意事項(xiàng)及操作要領(lǐng)a根據(jù)設(shè)計(jì)圖紙確定的地連墻位置，在導(dǎo)墻頂面上測量放線并按編號分段。b將抓斗就位，就位前要求場地平整堅(jiān)實(shí)，以滿足施工垂直度要求，吊車履帶與導(dǎo)墻垂直，抓斗要對準(zhǔn)導(dǎo)墻中心線,為減少抓斗施工的循環(huán)時(shí)間，提高功效，每臺成槽機(jī)配置2臺短駁車，將泥渣運(yùn)至堆料場暫存。c成槽垂直度控制是關(guān)鍵，成槽施工中注意觀察車載測

55、斜儀器圖形，發(fā)現(xiàn)偏斜隨時(shí)采用糾偏導(dǎo)板來糾偏，遇到嚴(yán)重不均勻的地層，或糾偏困難的地層時(shí)，回填槽孔，重新挖掘。d邊開挖邊向?qū)?nèi)泵送泥漿，保持液面在導(dǎo)墻頂面下30cm-50cm，挖槽過程中隨著孔深的向下延伸，要隨時(shí)向槽內(nèi)補(bǔ)漿，使泥漿面始終位于泥漿面標(biāo)高，直至成槽完成。e灌筑砼前，要測定泥漿面下1m及槽底以上1m處泥漿比重和含砂量，若比重大于1.20，則采取置換泥漿清孔，成槽后沉淀30分鐘，然后用抓斗直接撈渣清淤。f為避免對新澆槽段的混凝土產(chǎn)生擾動，開挖采取跳槽施工。g成槽過程中，導(dǎo)桿應(yīng)垂直槽段，抓斗張開，照準(zhǔn)標(biāo)志徐徐入槽抓土，嚴(yán)禁迅速下斗，快速提升，以防破壞槽壁和坍塌，垂直度應(yīng)控制在設(shè)計(jì)要求之內(nèi)，

56、抓斗挖出土直接卸到自卸車上，轉(zhuǎn)運(yùn)到堆土場。隨著開挖深度增加，連續(xù)不斷向槽內(nèi)供給新鮮泥漿，保證泥漿高度，各項(xiàng)泥漿指標(biāo)要符合技術(shù)要求，使泥漿起到良好的護(hù)壁作用，防止槽壁坍塌，在遇到含砂量較大的土層，槽壁易塌時(shí)，注意加大泥漿比重，適當(dāng)加入加重劑，當(dāng)接近槽底時(shí)，放慢開挖速度，仔細(xì)測量槽深，防止超挖和欠挖。h挖槽機(jī)操作要領(lǐng)抓斗出入導(dǎo)墻口時(shí)要輕放慢提，防止泥漿掀起波浪，影響導(dǎo)墻下面、后面的土層穩(wěn)定。不論使用何種機(jī)具挖槽，在挖槽機(jī)具挖土?xí)r，懸吊機(jī)具的鋼索不能松馳，定要使鋼索呈垂直張緊狀態(tài)，這是保證挖槽垂直精度必需做好的關(guān)鍵動作。挖槽作業(yè)中，要時(shí)刻關(guān)注測斜儀器的動向，及時(shí)糾正垂直偏差。單元槽段成槽完畢或暫停作

57、業(yè)時(shí)，即令挖槽機(jī)離開作業(yè)槽段。C. 成槽開挖精度槽段開挖精度表項(xiàng)目允許偏差檢驗(yàn)方法槽段厚度10mm5m精密鋼尺墻體垂直度L/300超聲波測斜儀槽段長度50mm超聲波測斜儀墻頂中心線允許偏差30mm全站儀2.5 刷壁施工成槽完成后在相鄰一幅已經(jīng)完成地下墻的接頭上必然有黏附的淤泥，如不及時(shí)清除會產(chǎn)生夾泥現(xiàn)象，造成基坑開挖過程中地下墻滲水，為此必須采取刷壁措施，首先采用成槽機(jī)上的側(cè)鏟進(jìn)行清除，然后采用刷壁器，用吊車吊入槽內(nèi)緊貼接頭混凝土面上下刷2-3遍，認(rèn)真仔細(xì)地清刷干凈，清刷應(yīng)在清槽換漿前進(jìn)行，使新老混凝土接合處干凈，確保砼密實(shí)。成槽完成后利用履帶吊，起吊專用的刷壁器，在接頭上上下反復(fù)清刷，確保接頭干凈，防止?jié)B漏水現(xiàn)象的發(fā)生。十字鋼板接頭刷壁器及施工2.4 清底換漿清槽先采用泵吸反循環(huán)法清底，而后采用導(dǎo)管吸泥漿，循環(huán)清底，確保清槽質(zhì)量，清底后槽底泥漿比重小應(yīng)于1.20，沉渣厚度不大于100mm。 清槽結(jié)束后1h，測定槽底沉淀物淤積厚度不大于10cm，槽底0.5-