外文翻譯---關(guān)于二柱掩護(hù)式支架與頂板之間相互作用的研究

1、<p><b>　　翻譯部分</b></p><p><b>　　英文原文</b></p><p>　　A STUDY OF THE INTERACTION</p><p>　　BETWEEN THE 2-LEG SHIELD SUPPORT</p><p>　　AND THE ROOF

2、STRATA</p><p>　　INTRODUCTION</p><p>　　The 2-leg shield powered support is shown in Fig.1.</p><p>　　It is known that in order to asses the adaptability of a powered support normally

3、there are two principles to be considered:</p><p>　　Fig.1 2-leg shield support </p><p>　　EFFECTIVENESS OF ROOF CONTROL </p><p>　　Obviously, shield support is much easier to prevent

4、the broken rocks from falling into the working space, but it is much harder to prevent the broken rocks from falling into the face-to-canopy area. On the basis of the statistical data obtained from the Collieries Yang-Qu

5、an and Zhai-Li, the down-time leads to stop production due to falling roof in the face-to-canopy area is about 40-60% of the total down-time in the working face. Collapse of roof strata along the faceline is shown in Fig

6、.2. That</p><p>　　EFFECT ON SUPPORT STRUCTURE UNDER THE ACTION OF ROOF PRESSURE </p><p>　　Recent reports from some collieries reveal that 2-leg shield support has been broken under the action of

7、 roof pressure, especially at the joint of the canopy and the stabilizing cylinder as shown in Fig.3. It is evident that the supporting capacity of this type of support could not be considered as adequate to some such ki

8、nd of roof conditions and must be improved.</p><p>　　Fig.2 Collapse of a longwall face at the faceline</p><p>　　Fig.3 Damage at the joint of the stabilizing cylinder and the canopy </p>&

9、lt;p>　　ANALYSIS OF LOADING CONDITION OF 2-LEG SHIELD SUPPOIRT </p><p>　　The forces acting on the canopy of 2-leg shield support are: the roof pressure, the forces from the support legs, ram, hinge pin of

10、the canopy and the caving shield, the surface friction between the canopy and the roof strata.</p><p>　　Assuming that the surface friction and the force acting on the caving shield are not taken into account

11、, the following formula can be obtained:</p><p>　　The meanings of all the symbols used in this formula are illustrated in Fig.4a.</p><p>　　Assuming that </p><p>　　then we can obtain

12、 the following formula.</p><p>　　It can be seen that When P is increased to the yield load P+, the force thus in the ram would be distributed as shown in curve Z in the Fig.4b. In fact the ram has a yield lo

13、ad in push and pull. For example, for the shield support W.S.1.7,the yield load in push is equal to 67.7t and in pull 62.4t. So the curve of the force from the ram would be redistributed in the face as curve Z+, and the

14、curve of force for the support legs would be redistributed as carve P shown in Fig.4b. Then the total load</p><p>　　, Assuming that W=0, then:</p><p>　　Thus, according to the position where the

15、roof pressure acts on the canopy and refer the support performance to the load of the ram Z is equal to +Z, (the yield load of the leg ) and Ⅲ-CD zone, on which the load of ram is equal to –Z (the yield load of the ram i

16、n pull ).</p><p>　　The load bearing characteristics of the support legs and the each zone of the canopy are shown as follows:</p><p>　　Fig.4 Three working zones of support canopy </p><

17、;p>　?、?zone Z=Z+.</p><p><b>　　.</b></p><p>　?、?zone P=P+</p><p><b>　　.</b></p><p>　?、?zone

18、 Z=-Z-</p><p>　　Obviously, the resistances of Ⅰ zone and Ⅲ zone on the canopy are produced by the yield load of the ram. For example, if Z is equal to zero, the resistance of the support itself in zo

19、nes Ⅰ and Ⅲ would loss and the resistance can be produced only when there exists some additional forces from the corresponding zones. In zone Ⅲ or Ⅰ. There exists a balance force produced by the roof strata. If the yield

20、 load of the ram is increased, obviously, the interval of the Ⅱ zone would become much wider, and</p><p>　　Fig.5 Resistance Curve of different yield load of ram</p><p>　　INTERACTION BETWEEN ROOF

21、 PRESSURE AND SUPPORT RESISTANCE</p><p>　　It is well- known that the roof pressure acting on the canopy of the support can be divided into two components, they are: Q1 produced by the immediate roof and Q2 b

22、y the main roof, as shown in Fig.6.</p><p>　　As a general rule, the immediate roof can be considered as a discontinuous media (like a loose body) and there is a free face along the caving line. Load Q1 acts

23、steadily on the supports. Load distribution on the canopy may be considered as uniform. Load Q2 from the main roof may be considered as a concentrated</p><p>　　load which acts on the immediate roof and then

24、acts on the canopy of the support. Based on the displacement measurement of roof strata it has been found that the main roof of the overlying strata can be considered as a structure formed by layers of rock blocks interl

25、ocking with one another, when the coal face advances, each block becomes to move forming a turning block. The displacement of the main roof is shown in Fig.7.</p><p>　　Obviously, the acting position of the l

26、oad from the main roof firstly depends on the stability condition of the blocks in the main roof. Q2 can act either in front or in the rear of the canopy. Secondly, it depends on the position where the immediate roof fal

27、ls. If the front section of the immediate roof is fractured and falls into the working space, then the force from the main roof would act on the canopy. If the condition is opposite to this, then the force would act on t

28、he position in front </p><p>　　Consequently, the roof pressure Q acting on the canopy can thus can be combined from those of Q1 and Q2.</p><p>　　Fig.6 Roof Pressure Produced by the main roof and

29、 the immediate roof </p><p>　　Fig.7 Displacement of the main roof </p><p>　　When the pressure Q acts on zone Ⅰ and Q>Ps, the relief valve of the ram would firstly open ,then the front part of

30、 the canopy would turn downwards and the balance force Q3 would be produced in the rear part of the canopy must be kept intact or must not cave equal to the resistance force (Ps) of the support. In the opposite condition

31、 the balance force Q3 would be produced in zone Ⅰ.</p><p>　　From this we can see that the resistance of this type support can thus be formed in the condition when the balance force Q3 occurs on the canopy. T

32、hat is to say, the immediate roof must not cave at all.</p><p>　　According to the analysis mentioned above, now consider that is under the different conditions: The roof is unbroken and the resistance of the

33、 support Ps is equal to P+ (the yield load of the legs). Then the resistance of the support can be expressed as follows:</p><p><b>　　Q＋Q3＝Ps</b></p><p>　　Assume Ps＝P+, so that </p

34、><p>　　Then the acting position where the roof pressure Q acts would become </p><p>　　x＝P＋（1－A）·z/B</p><p>　　Assume that the acting position where the roof pressure Q acts is at x

35、1, and the balance force Q3 is x3 (the origin is in the hinge pin point), then the following formula is obtained:</p><p>　　Q·x1＋Q3·x3＝（Q＋Q3）·（p＋（1－A）·z/B）</p><p>　　The roof p

36、ressure Q which the support can resist is equal to:</p><p>　　The roof pressure Q which the support can resist is equal to:</p><p>　　Take to stand for the efficiency of the support, obviously, t

37、his has relation with the following factors: the geometrical parameters of the support, i.e. parameters of the balance force (reaction) of the immediate roof x3. It is obvious that the nearer the value x1 approaches to z

38、one Ⅱ, the higher the efficiency of the support would be. Something the value x3 can be represented as an index to stand for the interactive relation between the canopy and the immediate roof. When Q acts in the positi&l

39、t;/p><p>　　Fig.8 shows that when a variable roof pressure (Q) acts in three different positions (x1) in the zone Ⅰ of the canopy and with different index x3 in zone Ⅲ, in order to resist the roof pressure (Q),

40、a corresponding balance reaction force Q3 with different values must be given in zone Ⅲ. For example, when the roof pressure is acting on the tip of the canopy and is equal to 80t if x3>37cm. then there would be no su

41、ch balance force formed in the rear part of the canopy.</p><p>　　Because roof fall occurs in the face-to-canopy area where the roof would become irregular, thus the canopy would have three kinds of operating

42、 condition for the canopy to swing: downwards (<0○) upwards (>10○) and at an angle from 0○ to 10○. According to statistical data collected from Zhai-Li Colliery, the percentage of the operating of the operating con

43、ditions of the canopy swinging canopy in <0○ accounts for 3.5% and that of in >15○, for 11%.</p><p>　　Due to the fact that the acting position of the roof pressure on the canopy is different, the angle

44、 between the canopy and the caving shield may be variable. Table1 shows the variation accounts for 44.8%, which means that the canopy and the caving shield may be variable. Table1 shows the variation of this angle in eac

45、h operation cycle.</p><p>　　From Table1, we can see that the percentage of positive variation accounts for 44.8%, which means that the roof pressure (Q) firstly acts on zone Ⅰ and than the balance force (rea

46、ction) (Q3) is formed on zone Ⅲ;finally, the acting position of the combined force (Q+Q3) would move towards zone Ⅱ. In Table1 the percentage of negative variation accounts for 19.4%.</p><p>　　Similar result

47、s have also been obtained from field measurements in working face No.332 of Zhai-Li Colliery as shown in Table2 and Fig.9.</p><p>　　Obviously, whether the roof pressure acts on zone Ⅰ or Ⅲ of the canopy, if

48、the acting position of the combined force (Q+Q3) moves towards zone Ⅱ,the operating condition of the support would be normal. But if the acting position of the combined force moves over zone Ⅱ and continuously moves forw

49、ards or backwards, the support would then work in abnormal conditions.</p><p>　　Fig.8 Balance force Curves for different index X3 in zone Ⅲ</p><p><b>　　中文譯文</b></p><p>　

50、　關(guān)于二柱掩護(hù)式支架與頂板之間相互作用的研究</p><p>　　二柱掩護(hù)式支架如圖1所示。為了評(píng)定支架的適應(yīng)性，通常有兩個(gè)特性要考慮：</p><p><b>　　頂板控制影響</b></p><p>　　顯然，掩護(hù)式支架更容易阻止冒落矸石掉在工作面上，但是它更難阻止冒落矸石掉在遮蓬區(qū)。根據(jù)來(lái)自陽(yáng)泉和翟梨的資料顯示,下落時(shí)間導(dǎo)致停止生產(chǎn)，歸因

51、于下落頂板在遮蓬區(qū)大約是40％～60％的下落時(shí)間在工作區(qū)。頂板沿著朝向倒塌。就是說(shuō)，在一個(gè)裝有二柱掩護(hù)式支架的面上更多關(guān)注的是頂板及時(shí)控制問(wèn)題，特別是面向遮蓬區(qū)。</p><p>　　在頂板壓力作用下對(duì)支護(hù)結(jié)構(gòu)的作用</p><p>　　近期來(lái)自煤礦的報(bào)道證明，二柱掩護(hù)式支架已經(jīng)在頂板壓力作用下破壞，特別是遮蓬和穩(wěn)定柱面連接處。明顯的是這種支架的支護(hù)空間被認(rèn)為對(duì)一些頂板條件不夠，并且必須改

52、進(jìn)。</p><p>　　二柱掩護(hù)式支架加載條件分析</p><p>　　作用在二柱掩護(hù)式遮蓬上的壓力：頂板壓力，來(lái)自立柱的力，撞擊，遮蓬和洞穴保護(hù)的銷軸，頂梁和頂板的破碎表面。</p><p>　　假設(shè)表面破碎和作用在掩護(hù)梁上的力不考慮，可以得到下面的公式：</p><p>　　上式中符號(hào)的意思表達(dá)在圖4a中。</p><

53、;p>　　假設(shè) </p><p>　　然后我們可以得到下面的公式。</p><p>　　可以看出，當(dāng)P增大到屈服載荷P+，力因此在撞擊中形成象在圖4b中曲線Z所描述的。事實(shí)上撞擊的推拉力有一個(gè)屈服載荷。例如，對(duì)于掩護(hù)式支架W.S.1.7，屈服力是推力67.7t和拉力62.4t。因此，撞擊力的曲線如圖4b所示。那么總的載荷Ps整個(gè)的支架給出如下：</

54、p><p><b>　　假設(shè)W=0,那么</b></p><p>　　因此，根據(jù)頂板作用在頂梁上的壓力的位置和支架支護(hù)的表現(xiàn)，我們可以遮蓬劃分為3個(gè)工作區(qū)，即，II－BC區(qū)，立柱的載荷P等于P+，Ⅱ－BC區(qū)，立柱載荷P等于P+和Ⅲ-CD區(qū)，和撞擊的載荷力等于－Z（撞擊的屈服力是拉力）。</p><p>　　支撐立柱承受力的特性和每個(gè)遮蓬區(qū)上的沖擊顯

55、示如下：</p><p>　?、駞^(qū) Z＝＋Z</p><p><b>　　；</b></p><p>　　Ⅱ區(qū) P＝P+</p><p>　?、髤^(qū) Z＝－Z-</p><p&

56、gt;　　顯然，作用在Ⅰ和Ⅲ區(qū)遮蓬上的反作用力是由沖擊的屈服載荷產(chǎn)生的。例如，如果Z等于0，在Ⅰ和Ⅲ區(qū)支護(hù)本身的反作用力將失去和反作用力丟失和只有當(dāng)來(lái)自相應(yīng)區(qū)域的一些附加力存在時(shí)反作用力將產(chǎn)生。在Ⅰ或Ⅲ區(qū)，存在由頂板產(chǎn)生的平衡力。如果沖擊的屈服載荷產(chǎn)生了，顯然，Ⅱ區(qū)的距離將變的更寬，并且Ⅰ或Ⅲ區(qū)上的反作用力將由此增加。這些如圖5所示。</p><p>　　頂板壓力和支護(hù)反作用力的相互作用</p>&

57、lt;p>　　眾所周知，作用在支護(hù)頂梁上的頂板壓力可以分成兩個(gè)部分，它們是：由及時(shí)頂梁產(chǎn)生的Q1，由主頂梁產(chǎn)生的Q2，顯示在圖6中。</p><p>　　作為通用法則，作為一個(gè)不連續(xù)的媒體被考慮和存在一個(gè)沿著洞穴的自由面。載荷Q1固定作用在支護(hù)上，載荷分布在遮蓬區(qū)可以認(rèn)為是均布的。來(lái)自主頂梁的載荷Q2被作為一個(gè)集中載荷考慮，作用在及時(shí)頂梁和支護(hù)保護(hù)?；陧敯鍦y(cè)量顯示，發(fā)現(xiàn)主頂梁過(guò)度層可以作為由大量的巖石連續(xù)

58、互鎖形成的一種結(jié)構(gòu)。當(dāng)煤高度提高，每一石塊滑向另一石塊。主頂梁在圖7中顯示。</p><p>　　顯然，來(lái)自主頂梁的載荷作用位置首先依靠石塊在主頂梁上的穩(wěn)定條件。Q2可以作用在掩護(hù)區(qū)的前部和尾部。其次，依靠及時(shí)頂梁下落的位置。Q2。如果條件反向，那么力作用在前部遮蓬的位置。</p><p>　　結(jié)果，頂梁壓力Q作用在遮蓬上因此可以從Q1和Q2連接起來(lái)。</p><p&g

59、t;　　當(dāng)頂梁壓力Q作用在I區(qū)和Q>Ps，將首先減輕沖擊的影響。那么遮蓬前部將向下轉(zhuǎn)和平衡力Q3將在遮蓬尾部產(chǎn)生。顯然，在這種情況下，在遮蓬尾部以上的頂板保持完整或者不能剪斷。聯(lián)合作用（Q+Q3）的作用點(diǎn)移向Ⅱ區(qū)直到聯(lián)合作用（Q+Q3）等于支護(hù)的反作用力Ps。在相反條件下，平衡作用Q3將在Ⅰ區(qū)產(chǎn)生。</p><p>　　從這我們能看出這類支架的反作用力因此能形成在當(dāng)平衡力Q3產(chǎn)生和作用在遮蓬的條件下。就是說(shuō)

60、，及時(shí)頂梁不能完全剪斷。</p><p>　　根據(jù)以上提到的分析，現(xiàn)在考慮在下列不同的條件下：頂梁未知和支護(hù)阻力Ps的反作用力等于P+（立柱的屈服載荷）。那么支護(hù)的反作用力可以按下式表達(dá)：</p><p><b>　　Q＋Q3＝Ps</b></p><p>　　假設(shè)Ps＝P+，那么</p><p>　　那么X在連接作用的

61、位置（Q＋Q3）的作用將變?yōu)?lt;/p><p>　　x＝P＋（1－A）·z/B</p><p>　　假設(shè)頂板作用力Q作用在x1的位置，平衡作用力x3（原因是在于連接點(diǎn)），然后可以得到下式：</p><p>　　Q·x1＋Q3·x3＝（Q＋Q3）·（p＋（1－A）·z/B）</p><p><

62、;b>　　和Q3等于：</b></p><p>　　頂板壓力Q的支護(hù)反作用力等于：</p><p>　　采用來(lái)代表支護(hù)作用，這有下面因素的聯(lián)系：幾何參數(shù)的支持，也就是參數(shù)p，A，B，和z；頂板壓力的作用位置x1；及時(shí)支護(hù)的平衡力作用位置x3。很明顯，越近，x1的值靠近Ⅱ區(qū)，支護(hù)效率就越高。有時(shí)，x3的值作為遮蓬和及時(shí)頂梁之間相互關(guān)系的順序。當(dāng)Q作用位置平衡力Q3等于0，支

63、護(hù)效率，等于1。</p><p>　　圖8顯示，當(dāng)變量頂板壓力Q作用在3個(gè)不同的位置，遮蓬Ⅰ區(qū)的位置x1和Ⅲ區(qū)不同順序x3，為了反抗頂梁壓力（Q），相應(yīng)的平衡力Q3，和在Ⅲ區(qū)必須給出的不同的值。例如，當(dāng)頂板壓力作用在遮蓬尖端和等于80t如果x3>37cm,那么沒(méi)有遮蓬作用力在遮蓬尾部形成。</p><p>　　因?yàn)轫敯逑侣浒l(fā)生在面向遮蓬區(qū)變得不規(guī)則，因此為了遮蓬轉(zhuǎn)動(dòng)遮蓬有3種操作條件

64、：向下（<0○）向上（>10○）和從0○到10○不同的角度。根據(jù)翟梨煤礦收集的統(tǒng)計(jì)數(shù)據(jù)，遮蓬旋轉(zhuǎn)的操作條件，<0○說(shuō)明3.5％和>15○，對(duì)應(yīng)11％。</p><p>　　由于，頂板對(duì)頂板的作用位置是不同的，頂梁和掩護(hù)梁的角度是變化的。通過(guò)表1，我們可以看到方向變化的百分?jǐn)?shù)占44.8％，意味著頂板壓力Q首先作用在Ⅰ區(qū)和平衡力Q3形成在Ⅲ區(qū)；最后，合力（Q＋Q3）作用位置將轉(zhuǎn)向Ⅱ區(qū)。在表1中