1、爆破在巖巷掘進(jìn)中的應(yīng)用及井巷支護(hù)作者：J.Tronvoll;A.Skjarstenin;E.Papamichos摘要：本文主要研究爆破技術(shù)在巖巷掘進(jìn)中如何破巖及其應(yīng)用問(wèn)題，根據(jù)破巖理論和炮眼裝藥的方法，進(jìn)而研究如何控制爆破技術(shù)，達(dá)到光面爆破要求。在爆破掘進(jìn)后如何進(jìn)行井巷支護(hù)，各種先進(jìn)的支護(hù)材料被廣泛應(yīng)用于支護(hù)作業(yè)當(dāng)中，從而大大提高掘砌速度，保證施工質(zhì)量，縮短井巷施工工期。關(guān)鍵詞：破巖理論 光面爆破 井巷支護(hù) 噴射混凝土1爆破在巖巷掘進(jìn)中的應(yīng)用1.1 破巖理論破巖是用爆破的方法把煤、礦石或巖石破碎，以便于大部分物料的塊度小到便于裝載、處理和運(yùn)輸。碎塊不要小到不便于裝運(yùn)，也不要大到需要手工破碎或二

2、次爆破。這樣的破巖才算最佳。為了破巖，必須用直接或間接的方式向巖石施加能量。能量的大小取決于巖石的性質(zhì)和裝藥系統(tǒng)的類(lèi)型。破巖的能量在以下三個(gè)主要機(jī)理內(nèi)被消耗掉：(1)形成新的表面(破巖能量)，(2)摩擦(塑性)，(3)傳播彈性波能。裝藥的方法決定破碎某種已知巖石時(shí)上述三方面的相對(duì)比例和所消耗的能量。無(wú)約束時(shí)巖石拉伸破壞所消耗的能量最少，在破巖過(guò)程中如巖石受到較高的壓應(yīng)力場(chǎng)的約束時(shí)，破巖能量需要有所增加。用機(jī)具傳遞能量使巖石或礦石破碎的方法，對(duì)于決定破巖效率至為重要。為了設(shè)計(jì)出最好的破巖機(jī)具和最佳的破巖系統(tǒng)，需要盡可能地弄清楚巖石性質(zhì)是如何影響破巖的。巖石的強(qiáng)度受到周?chē)h(huán)境的影響。其中最重要的因

3、素是：(1)約束力，(2)空隙中的流體壓力，(3)溫度，(4)加壓的速度，約束力的增加(如隨著高地表深度的增加或在破巖機(jī)具的作用下而使其增加)，使嚴(yán)石的強(qiáng)度增加。隨著孔隙流體壓力增加，巖石的視強(qiáng)度就降低 因?yàn)樗鼫p弱了約束力的作用。雖然孔隙流體的化學(xué)作用對(duì)巖石的強(qiáng)度有影響，僅和約束力作用比較，除少數(shù)幾種巖石外，一般都比較小。巖石溫度的增加使巖石的強(qiáng)度降低。但這種效應(yīng)非常小，因?yàn)椴傻V的時(shí)候周?chē)鷾囟茸兓　＜訅旱乃俣仍黾?，使巖石強(qiáng)度顯著增加。巖石具有影響其破碎方式的方向性。這體現(xiàn)在巖石的結(jié)構(gòu)上，包括集合巖石組分的結(jié)構(gòu)或形狀以及巖石的物理特性或機(jī)械特性巖石的結(jié)構(gòu)不僅與礦物組分的方向及其薄弱面有關(guān)，而且

4、與其非連續(xù)性、微觀裂隙和孔隙的構(gòu)造有關(guān)。在現(xiàn)場(chǎng)，節(jié)理和層理對(duì)破巖有很大影響。人們經(jīng)常綜合利用巖石的物理性質(zhì)(密度、壓痕，硬度、磨蝕硬度、孔隙度)和機(jī)械性質(zhì)，來(lái)謀取更好的破巖效果。1.2 炮眼裝藥方法炮眼裝藥的方式可根據(jù)所采用的炸藥是藥卷或散裝而有所不同。最古老的裝藥方法是用炮棍裝藥，這種方法至今仍廣泛使用。在過(guò)去二十年中，壓風(fēng)裝藥器已被采用，這些裝藥器既提高裝藥效率，同時(shí)又改進(jìn)裝藥密度，因此炮眼的利用率較高。近幾年來(lái)采用了半自動(dòng)裝藥器，主要用于井下作業(yè)。裝填散裝藥的壓風(fēng)裝藥器也已大規(guī)模地投入使用。就漿狀炸藥而論，已發(fā)明了一些專(zhuān)用的泵送方法，這種方法對(duì)于大孔徑炮眼的裝藥能力實(shí)際上是很高的。炮棍必

5、須用木或塑料做成。但炮棍與鉆孔相比不能做得太粗，因?yàn)檫@在裝藥作業(yè)中有可能捅壞和損壞導(dǎo)火索或電雷管腳線。用炮棍裝藥時(shí)，若想裝填得好，那么一次只能裝填并搗實(shí)一個(gè)藥卷。裝藥時(shí)雷管必須送到炮眼中的準(zhǔn)確位置。壓風(fēng)裝藥器在瑞典已使用了大約二十年。第一種裝藥器由幾節(jié)鋁管連接而成并用42磅英寸2的壓風(fēng)把藥卷吹入炮眼。后來(lái)這種裝藥管由專(zhuān)門(mén)設(shè)計(jì)的經(jīng)抗靜電處理的塑料軟管所代替。一臺(tái)裝藥器包括腳踏閥，帶風(fēng)管的減壓閥、分風(fēng)管、連接管和裝藥軟管。半自動(dòng)裝藥器可連續(xù)裝填藥卷，其裝藥速度與軟管裝藥速度相同。這種半自動(dòng)裝藥器不用閥門(mén)，而是讓藥卷通過(guò)一個(gè)位于兩個(gè)閘門(mén)之間的氣室。裝藥時(shí)裝藥欽管中的風(fēng)壓不變。半自動(dòng)裝藥器的裝藥能力比

6、普通的裝藥器高得多。散裝炸藥一般為硝銨炸藥(銨油炸藥)，需要專(zhuān)用裝藥器。有兩種不同的裝藥器：壓力罐式裝藥器和注藥器。壓力罐式裝藥器特別適用裝填結(jié)晶的銷(xiāo)銨炸藥，其裝藥能力較高。注藥器的操作是用一個(gè)噴射器經(jīng)很軟管把炸藥吸出，然后再通過(guò)這根裝藥軟管將炸藥吹入炮眼入。還有一些由壓力罐和注藥器組合的裝藥器。裝填銨油炸藥的裝藥軟管必須能導(dǎo)電，其電阻最小為1千歐米。最大為30千歐米。奈特羅諾貝爾(硝化諾貝爾)公司曾創(chuàng)造一項(xiàng)專(zhuān)用泵送炸藥的工藝，它包括一臺(tái)直接把炸藥泵入炮眼的槽車(chē)。向大直徑炮眼裝藥時(shí)其裝藥能力極高。1.3 控制爆破控制爆破用于減少巷道超挖和使圍巖震裂減至最小程度。摔制爆破的四種基本方法是：輪廓線

7、鉆眼法、預(yù)裂爆破法、緩沖爆破法和光面爆破法。 輪廓線鉆眼法，是最早的控制爆破法，這種方法是沿巷道(最終)輪廓線打一排緊密相鄰的鉆眼，形成一個(gè)有利于破碎的薄弱面。布在輪廓線上的鉆眼直徑為2英寸或3英寸。眼距通常相當(dāng)于24個(gè)炮眼直徑，不裝藥。靠近輪廓線鉆眼的炮眼，起裝藥量及眼距均比其他炮眼小。輪廓線眼的最大深度大約為30英尺。由于輪廓線鉆眼法的最后一排眼不爆破，因而對(duì)巖壁的破壞最輕。預(yù)裂爆破，有時(shí)又稱(chēng)為預(yù)剪切爆破，是在巷道的輪廓線上鉆一排炮眼，其直徑一般為2至4英寸眼距為炮眼直徑的612倍，顯然市場(chǎng)上可買(mǎi)到柱狀裝藥所需的小直徑藥卷和專(zhuān)用的連接器，但一般仍采用直徑為l11，英寸的代那買(mǎi)特藥卷，間隔裝

8、藥，藥卷間隔為12英尺，以導(dǎo)爆線串系起來(lái)。在松軟巖層中，要求眼距小些，裝藥量少一些。眼底23英尺處的裝藥量略比其余部分要多一些。單個(gè)藥卷之間及其周?chē)欠癯涮钆谀嗫呻S意確定?？卓?3英尺處不裝藥，但要充填炮泥。預(yù)裂爆破的深度受炮眼排列的限制，最大深度約為50英尺。預(yù)裂炮眼比鄰近主炮眼先起爆，以形成有利于主炮眼爆破的裂面。預(yù)裂爆破中在鄰近主炮眼爆破之前很難判斷其效果。因此建議預(yù)裂的超前距離不要太大。預(yù)裂爆破很少在井下使用。緩沖爆破法是沿巖道輪廓線鉆一排直徑為26英寸的炮眼，眼中裝入均勻分布的小藥卷，完全堵滿(mǎn)炮泥，起爆順序與預(yù)裂爆破不同，要在主炮眼起瀑之后周邊眼才爆破。炮眼的最小抵抗線(光爆層厚度)

9、略大于眼距?？衫眯ㄗ影阉幘砉潭ㄔ谘壑锌拷谱杂擅嬉粋?cè)，以減少爆破對(duì)巖壁的損壞。這種方法的裝藥方式與預(yù)裂爆破法相似。因?yàn)殂@大直徑炮眼容易準(zhǔn)直，所以緩沖爆破法采用大直徑炮眼時(shí)一次爆破深度以達(dá)一百英尺。但緩沖爆破在井下很少使用。光面爆破法就是井下的緩沖爆破法。巷道周邊的密集炮眼的光爆層厚度(周邊眼的抵抗值)與眼距之比L接近1.5：1。周邊眼中裝上分布均勻的小藥卷。光面爆破與緩沖爆破的區(qū)別在于：(1)除炮眼口外，藥卷不用充填炮泥；(2)周邊眼在一茬炮眼中最后一段起爆。雖然藥往中也可采用間隔物(間隔裝藥)，但最常用的是柱狀裝藥。孔底裝藥量稍多一些。炮眼均填以炮泥，以防止(在延期爆破中)光爆炮眼爆轟時(shí)

10、將藥包帶出。光面爆破減少巷道的超挖，增強(qiáng)圍巖穩(wěn)定性并減少支護(hù)量。但比普通方法需要多鉆一些周邊眼。各種控制爆破方法可結(jié)合使用。在松軟巖石中，有時(shí)需要輪廓線鉆眼方法與預(yù)裂法或緩沖爆破法結(jié)合使用。當(dāng)采用緩沖爆破法時(shí)，有時(shí)需要在轉(zhuǎn)角處用預(yù)裂法爆破。1.4 巖巷爆破最常用的巖巷掘進(jìn)方法是三個(gè)工序的循環(huán)作業(yè)： (1)鉆炮眼、裝炸藥和爆破。 (2)裝巖(將爆破的巖堆裝運(yùn)出去)。 (3)安裝支架，支護(hù)剛掘出的巷道，敷設(shè)接長(zhǎng)軌道、風(fēng)管和電纜，為下個(gè)循環(huán)作好準(zhǔn)備工作。簡(jiǎn)而言之，巖巷爆破的基本原則是，把巖體上一部分巖石破碎下來(lái)，當(dāng)裝走爆落的巖石后，巷道按正確的方向前進(jìn)，其斷面盡可能地接近設(shè)計(jì)斷面。炮眼布置設(shè)計(jì)要做到

11、：便于鉆跟，耗用炸藥最少，爆破后所形成的巷道斷面盡可能接近設(shè)計(jì)要求。一組炮眼由掏槽眼、擴(kuò)槽眼、輔助眼和周邊眼組成。掏槽眼最重要。掏槽眼的作用是為炮眼組的其他炮眼提供一個(gè)自由面，便于爆破。常用的兩種掏槽方式是斜角眼掏槽和直眼掏槽。這兩種掏槽方式可以聯(lián)合組成其他各種掏槽方式。在較大斷面巷道中，斜角眼掏槽比直眼掏槽優(yōu)越，因?yàn)榕谘蹟?shù)目少掏，每掘進(jìn)一英尺巷道所需炸藥量少。其缺點(diǎn)是“v”形掏槽有可能拋出大塊巖塊。 楔形掏槽或v型掏槽內(nèi)成對(duì)的斜角炮眼在底部相遇或接近相遇組成。楔形掏糟可由一個(gè)或幾個(gè)v型槽構(gòu)成垂直或水平楔形掏槽。對(duì)于深度較大的炮眼或難于爆破的巖石，可采用復(fù)式楔形掏槽。較小的掏槽稱(chēng)為小槽。它適用

12、于小斷面巷道。 大直徑掏槽直眼在大斷面巷道中可為良好的擴(kuò)槽創(chuàng)造條件。采用直眼掏槽，炮眼組的深度可比斜眼掏槽大一些，因?yàn)槊坎缗诘倪M(jìn)度增加了，證明其更為經(jīng)濟(jì)。直眼掏槽的槽眼要平行，眼距要適當(dāng)，其深度要比其他炮眼深121英尺。一般有一個(gè)或一個(gè)以上槽眼(大直徑眼)不裝藥、為其他裝藥槽眼提供自由面。槽眼間距，布置及裝藥槽眼可采用各種組合形式。井下巷道掘進(jìn)中炮眼布置有無(wú)數(shù)種。甚至在同一巷道中，隨著巖石性質(zhì)的變化也要改變炮眼布置。對(duì)任何一組炮眼來(lái)說(shuō)，重要的因素是爆破順序。一般來(lái)說(shuō)，炮眼引爆的順序應(yīng)使每個(gè)炮眼或一組炮眼隨前一響炮眼所形成的自由面爆破。每茬炮的深度取決于整個(gè)掘進(jìn)循環(huán)和巷道的斷面尺寸。一般規(guī)律是，

13、一茬炮的深度不要超過(guò)巷道最小斷面尺寸太多。炮眼布置要使爆破下來(lái)的巖石堆的形狀及位置有利于更有效地裝運(yùn)和循環(huán)作業(yè)。對(duì)用需用密集支架的巷道，炮眼布置要能夠預(yù)防破壞。2 井筒及巷道的支護(hù)2.1井筒的支護(hù)在國(guó)外，很少使用磚、料石和鑄鐵井壁， 從前，幾乎全用木支架，但現(xiàn)在混凝土和金屬井壁使用量日增。 井壁的選擇決定于圍巖和水的條件，井筒的形式和材料的費(fèi)用。 (1)木支架直到最近，大多數(shù)方形的井筒還在用框形木支架支護(hù)井幫和分成隔間。.所用木料的尺寸和框距取決于所遇到的巖層情況。. 木支架缺點(diǎn)是費(fèi)用高，強(qiáng)度低、壽命短，易引起火災(zāi)。在膨脹性巖層中，木支架損壞得慢，警告時(shí)間長(zhǎng)。在大多數(shù)情況下，開(kāi)始鑿井時(shí)澆灌一個(gè)

14、混凝土鎖口以固定支架，為井筒木支架提供良好的基礎(chǔ)。木框架一般用掛鉤掛在上面的框架上，框架就位后插入支柱，拉緊掛鉤，在井筒周?chē)伾媳嘲濉?2)金屬支護(hù)有時(shí)用金屬支架代替木支架。 通常與木背板配合使用。木背板可快速而高效地插入金屬支架的翼緣中。金屬支架若設(shè)計(jì)恰當(dāng)其安裝的速度和準(zhǔn)確度均比木支架高，因?yàn)榘惭b時(shí)金屬支架可能螺栓連接，并且排列很整齊。(3)混凝土井壁現(xiàn)在，原形混凝土井壁使用日益廣泛。 例如，在南非幾乎100%的井筒采用圓形混凝土井壁。而且?guī)缀跛芯埠翢o(wú)例外地達(dá)到最高的鑿井速度。 除了鑿井速度快外，還有許多其它優(yōu)勢(shì)。 圓形混凝土井壁做井筒指甲其強(qiáng)度系數(shù)最高，風(fēng)流特性最好，與任何井壁形式相比

15、其維護(hù)量最小?；炷辆谌菀撞鸪⒏难b成另一種提升布置方式，或改為風(fēng)井而不影響圍巖狀態(tài)。這類(lèi)井筒對(duì)涌水的控制或封堵容易的多。與大多數(shù)其他類(lèi)型相比，這種井筒的事故較少，萬(wàn)一發(fā)生事故，修復(fù)也容易得多。在某些特殊的情況下，也采用方形或橢圓形混凝土做井壁的井筒。盡管方形井筒的成本與圓形或橢圓形相仿，但其強(qiáng)度不如圓形或橢圓形井筒。橢圓形井筒具有良好的強(qiáng)度系數(shù)，需要分開(kāi)風(fēng)流時(shí)采用這種形狀。但起鑿井費(fèi)用比圓形的高。 (4 )噴漿或噴射混凝土井壁有一些井壁采用噴漿或噴射混凝土井壁。這類(lèi)井筒的罐道一般用錨桿固定。如果井筒完成后并能不需要罐道，那么鑿井時(shí)可采用鋼絲繩罐道。2.2巷道支護(hù) 過(guò)去，框形或多節(jié)木支架是大

16、家熟悉的唯一支護(hù)井下巷道的方法。隨著坑木的減少，寬翼緣型的出現(xiàn)，鋼材，作為一種結(jié)構(gòu)支護(hù)材料，迅速的取代了坑木。最近錨噴支護(hù)也列入礦山實(shí)用支護(hù)方式。不論錨桿還是噴射混凝土（包括噴漿及噴混凝土在內(nèi)）一英尺巷道的支護(hù)費(fèi)用一般比金屬支架要低。有時(shí)兩者同時(shí)采用，其費(fèi)用也比金屬支架省。(1)金屬支架金屬支架通常由兩節(jié)組成，每節(jié)包括一條棚腿和半截拱。同樣兩節(jié)相對(duì)立好之后，在拱頂用螺栓對(duì)接。金屬支架的尺寸取決于巖石的性質(zhì)和地壓。一般地說(shuō)，小斷面巷道采用4英寸或5英寸金屬支架，間距為1.54英尺；中斷面巷道采用56 英寸金屬支架，間距為1.54英尺；大斷面巷道采用68英寸金屬支架，間距25英尺。對(duì)于全部采用錨噴

17、支架的工程，只是在斷層和嚴(yán)重破碎或軟巖地帶才需用金屬支架。根據(jù)需要，金屬棚子還必須鋪以木檔塊及木背板。一個(gè)標(biāo)準(zhǔn)掘進(jìn)班組架設(shè)一架金屬棚子，需時(shí)2040分鐘。 (2 )錨桿支架現(xiàn)在通用的能張緊的錨桿有許多多種，其主要區(qū)別在于，擰緊螺帽使錨桿張緊之前，在孔內(nèi)固定錨頭的脹圈結(jié)構(gòu)的不同。最適合某種巖石的錨頭形式要經(jīng)常做試驗(yàn)來(lái)確定。軟鋼金屬錨桿的直徑至少應(yīng)為1英寸，長(zhǎng)度應(yīng)為10英尺（巷道斷面要足以允許使用這樣長(zhǎng)的錨桿）。安裝錨桿時(shí)應(yīng)認(rèn)真研究巖石節(jié)理的規(guī)律。錨桿的布置要大致均勻有規(guī)律，使錨桿張緊之后能與圍巖構(gòu)成一個(gè)相似的拱形結(jié)構(gòu)，以承受作用在巷道上的外部壓力。在起拱線以上整個(gè)巷道頂板錨桿的平均間距在最小約1

18、2平方英尺/根，最大25或25以上平方英尺/根之間變化。由普通掘進(jìn)班組安裝錨桿時(shí)，一個(gè)標(biāo)準(zhǔn)掘進(jìn)班組通常在30至40分鐘內(nèi)可安裝錨桿，一個(gè)小時(shí)也許只能平均安裝兩根。(3 )噴射混凝土噴射混凝土或噴漿，這種把混凝土或砂漿直接噴到拱形巷道頂板巖石表面的方法正迅速地被公認(rèn)是一種效率高而又經(jīng)濟(jì)的巷道支護(hù)方式。只要噴上的混凝土能附著相當(dāng)時(shí)間達(dá)到初凝強(qiáng)度而不陷落，此方法在各類(lèi)軟、硬巖石或硬土上均可用。有許多促凝劑可到初凝。混凝土的噴射厚度為26英尺。干法噴射的效果通常比濕法好，因?yàn)榭梢試?、得厚一些，可以采用較大粒度的骨料（最大為0.75英寸），每臺(tái)噴嘴的小時(shí)生產(chǎn)率較高（一個(gè)小時(shí)達(dá)5立方碼）。噴射混凝土在經(jīng)濟(jì)

19、上常具備的優(yōu)點(diǎn)之一是可在裝巖的同時(shí)，向巷道頂板噴混凝土，從而縮短完成整個(gè)“循環(huán)”所需用的時(shí)間。木支架掘進(jìn)中也許需要支護(hù)巷道頂板和兩幫的支架。傳統(tǒng)的方法通常是掘進(jìn)時(shí)先架設(shè)臨時(shí)木支架，然后換成永久支架或襯砌。永久支架也可用坑木。坑木作永久支架時(shí)應(yīng)該很好地晾干并用防腐蝕劑處理。木支架不用專(zhuān)用的工具或設(shè)備就能方便地就地加工很快地架好，通過(guò)局部不良地層掘進(jìn)時(shí)，用木材作臨時(shí)支架，容易截割和加工，適應(yīng)各種需要。木棚是由幾根坑木構(gòu)成、橫截巷道斷面的支架。小斷面巷道最常用的是三個(gè)構(gòu)件組成的棚子，由一根頂梁（橫梁或棚梁）架在兩個(gè)棚腿上組成。棚腿傾斜度是每英尺11.5英寸，這樣的斜度除非側(cè)壓力太大及底板松軟，一般能

20、防止棚腿底部向里推移。棚腿一般為硬木，圓形，小頭的最小直徑為5英寸。頂梁最小厚度一般為5英寸，寬度68英寸。背板一般厚2英寸，兩幫和頂板上可鋪也可不鋪背板。在膨脹巖層中兩棚腿底部一般有“偏坡底撐”以防止棚腿移動(dòng)，底板易隆起的地方，可采用反拱支架。巷道的懸頂（或頂板）如果做成拱形往往比較穩(wěn)定，特別是在寬巷道中更是如此。只有頂板需要支護(hù)而兩幫堅(jiān)硬的地方，可以省去棚腿，拱梁則固定在起拱線處的梁窩中。支架木料的尺寸和棚架間距取決于巷道的斷面和所需承受的壓力。在膨脹巖層中，背板不要鋪得太密，相鄰背板之間應(yīng)留一定間距，以釋放低壓。裝設(shè)木支架的常規(guī)工序和速度主要取決于支架在工作面后面應(yīng)保持多近的距離。如果每

21、進(jìn)一個(gè)循環(huán)需要立即支護(hù)，那么架設(shè)支架就成為掘進(jìn)循環(huán)的一部分。爆破后的第一道工序是撬落頂板上的浮石；在松軟的地層中，利用前探梁、滑梁或類(lèi)似的裝置以支護(hù)最后一架棚子前面的頂板，以便裝巖時(shí)保護(hù)工人。一個(gè)循環(huán)的矸石裝完后，就架設(shè)新棚子，必要時(shí)用楔子固定并裝上背板，并為新的循環(huán)安裝好鑿巖機(jī)。這種工序顯然會(huì)減慢掘進(jìn)速度，但是除非巖層條件太差需要才用前探板樁法或其他方法，一般坑木可標(biāo)準(zhǔn)化，并采用常規(guī)作業(yè)。作業(yè)開(kāi)始之前，將所有材料和器材運(yùn)到工作面，可加快速度；工人應(yīng)攜帶整架棚子、角楔、木楔、背板和工具進(jìn)入工作面。支護(hù)工作落后于工作面過(guò)遠(yuǎn)的地方，一般需要專(zhuān)業(yè)支架隊(duì)。利用適當(dāng)?shù)墓ぷ髋_(tái)進(jìn)行支架工作，可不影響掘進(jìn)工作

22、。如果采用移動(dòng)式工作臺(tái)，其臺(tái)面有幾架棚子長(zhǎng)，其高度又能讓礦車(chē)從底下通過(guò)，則對(duì)掘進(jìn)工作會(huì)有好處的。設(shè)計(jì)巷道支護(hù)一直被視為一個(gè)非常復(fù)雜的事情，從的角度來(lái)看，工程，并已在很大程度上已淪為實(shí)證配方（ 巴頓等人， 1974年和 bieniawski ， 1974年 ）表示，已提供了良好的效果下類(lèi)似的地質(zhì)條件。 許多工地工程師認(rèn)為，實(shí)證分析的收斂性是足夠的管理挖掘一條隧道，不那么在意更精密的分析方法（ aftes ， 2002年和 graziani等人， 2005年 ） 。不過(guò)，模型，可證明是非常有用的，在取得更深入的了解的互動(dòng)關(guān)系巖體和支持，以?xún)?yōu)化設(shè)計(jì)。 難度設(shè)計(jì)的支持隧道是一個(gè)后果是以下幾個(gè)方面： 知

23、識(shí)不足的行為，在地面條件下與開(kāi)挖隧道。 數(shù)據(jù)不足，對(duì)自然應(yīng)力狀態(tài)的地面。 它是一個(gè)三維問(wèn)題。 它是有必要予以分析的互動(dòng)關(guān)系，支持和地面附近向前進(jìn)面子。 時(shí)間依賴(lài)的反應(yīng)，由于流變學(xué)特性的地面必須加以考慮。SHAFT AND DRIFT EXCAVATION BY BLASTING AND SHAFT SUPPORTJ.Tronvoll;A.Skjarstenin;E.PapamichosIKU Petroleum Research, N-7034 Trondheim, NorwayABSTARACT: This paper makes a study of the blasting techno

24、logy in rock heading to the rocks and their application in question，according to the theory of rock and borehole charging method，and then we study how to control the blasting technology，To achieve smooth blasting requirements. How after sinking support In blasting tunneling，various kinds of advanced

25、 supporting materials are widely used in support of homework，Which greatly improve dug build by laying bricks or stones speed to ensure construction quality, shorten the construction period alley.KEYWORDS: Broken rock theory smooth blasting Alley of supporting sprayed concrete1 APPLICATION OF BLASTI

26、NG IN SHAFT AND DRIFT EXCAVATION1.1 FRAGMENTATIONFragmentation is the breaking of coal, ore,or rock by blasting so that the bulk of the material is small enough to load, handle and transport.Fragmentation would be at its best when the debris is not smaller than necessary for handling and not so larg

27、e as to require hand breaking or secondary blasting .Energy must be supplied to rock by direct or indirect means to fragment that rock and the type of loading system.Fragmentation energy is consumed by the main mechanisms: (1) creation of new surface area (fracture energy), (2)friction (plasticity)

28、and (3)elastic wave enegy dispersion.The loading method determines the relative proportions and the amount of energy consumed in fragmenting a given rock type. Unonfined tensile failure consumes the least energy with an increasing a,mount of energy required as the rock is more highly confined within

29、 a compressive stress field during fragmentation The way energy is applied by tools to cause rock or mineral fragmentation is important in determining fragmentation efficiency. To best design fragmentation tools and optimize fragmentation systems it would be desirable to know how rock properties inf

30、luence breakage.The strength of rock is influenced by the environmental conditions imposed on the rock.Those of most importance in rock are (1)confining pressure ,(2)pore fluid pressure, (3)temperature and (4)rate of load application .Increase in confining pressure, as with increasing depth beneath

31、th earths surface or under the action of a fragmentation tool, causes an increase in rock strength .Apparent rock strength decreases as porc fluid pressure increases, since it decreases the effect of confining pressure. Although chemical effects of pore fluids influence rock strength, they generally

32、 are small compared to the confining pressure effect, except for a small minority of rock types .Increase in rock temperature causes a decrease in rock strength.This effect is very small because of the small ambient temperature changes found during mining. An increase in rate of load application cau

33、ses an apparent increase in rock strength.Rock exhibits directional properties that in fluence the way it breaks. These are embodied in the concept of rock fabric ,which connotes the structure or configuration of the aggregate components as well as the physical or mechanical property manifestations.

34、 Rock fabric ont only relates to the preferred orientation of mineral constituents and their planes of weakness, but also to the configuration of discontinuities, microcracks and pores.Joints and bedding planes have great influence on fragmentation at field scale.Physical properties of rock (density

35、,indentation,hardness,abrasivehardness and porosity ,)are frequently used in conjunction with mechanical properties to develop better empirical esti mations of rock fragmentation.1.2 BLASTHOLE CHARGING METHODSDrill hole charging can be carried out in different ways depending on whether the explosive

36、 used is in cartridges or in the form of loose material. The oldest charging method implies the use of a tamping rod and this system is still used to a very great extent .During the last 20years, compressed air chargers have been used and these machines provide both good capacity and also an improve

37、d level of charge concentration so that the drill holes are utilized to a higher degree. During the last few years semi-automatic chargers have been taken into use, primarily in underground work. Compressed air chargers for blasting powder in the form of loose material have also come into use on a l

38、arge scale. As far as slurry blasting is concerned, special pumping methods have been developed through which charging capacity in the case of large diameter drill holes is practically good.A tamping rod must be made of wood or plastic. It must not be too thick in relation to the drill hole diameter

39、 since this can crush and damage fuse or electric detonator cables during charging work. If a good degree of packing is to be obtained during charging with a tamping rod then only one cartridge at a time should be charged and tamped. The detonator must be correctly fed into the drill hole during cha

40、rging work.Compressed air chargers have been in use is Sweden for about 20 years. The first type consisted of aluminum pipes connected together and the cartridges were blown into the hole with an air pressure of 42 pounds per square inch .since that time the charging tube has been replaced by anti-s

41、tatic treated plastic hose of a special design. A charger includes a foot-operated valve, reduction vavle with air hose, breech, connecting tube and charging hose.The semi-automatic charger permits the continuous insertion of explosive cartridge at the same rate as they are charged in the hole by th

42、e hose .Instead of a valve being used ,the cartridges pass through an air lock between two flaps. The air pressure in the charging hose is retained while cartridges are pressure in the charging hose is retained while cartridges are beins inserted .The semi-automatic charger permits considerably high

43、er charging capacity than the normal type of charger.Explosives in the form of the form of loose material, usually ammonium nitrate explosives(ANFO), require special chargers. Two types can be differentiated: pressrure vessel machines and ejector units. Pressure vessel machines are particularly suit

44、able for crystalline An explosives with good charging capacity. Ejector units are operate by an ejector sucking up explosive from a container through a charging hose. The explosive is then blown through the charging hose into the drill hole .There are, also combined pressure ejector machines. The ch

45、arging hose used for ANFO charging operations must conduct electricity and have a resistance of at least 1K/m and max.30K/M.Nitro Nobel has developed a special pumping procedure which consists of a tanker vehicle which is used to pump explosive directly the drill holes. The charging capacity is very

46、 high in the case of large diameter drill holes.1.3 CONTROLLED BLASTING TECHNIQUTES Controlled blasting is used to reduce overbreak and minimize fracturing of the rock at the boundary of an excavation. The four basic controlled blasting techniques are: line drilling, presplitting, cushion blasting a

47、nd smooth blasting.Line drilling, the earliest controlled blasting technique, involves drilling a row of closely spaced holes along the final excavation line, providing a plane of weakness to which to break. Line drill holes, 2or 4 diameters apart and contain no explosive. The blastholes adjacent to

48、 the line drillholes normally are loaded lighter and are on closer spacing than the other blastholes. The maximum depth for line drilling is about 30 ft .Line drilling involves no blasting in the final row of holes, and thus minimizes damage to the final wall.Presplitting, sometimes called presheari

49、ng ,involves a single row of boreholes ,usually 2 to 4 in .in diameter ,drilled along the final excavation at a spacing of 6 to 12 borehole diameters .Dynamite cartridges 1to 1.5 in . in size on 1 to 2 ft .centers usually are string-loadde on detonating cord ,although special small-diameter cartridg

50、es with special couplers are available for total column loading .In unconsolidated formations ,closer spacings with lighter powder loads are required .The bottom 2 to 3 ft .of borehole usually is loaded somewhat heavier than the remainder .Stemming between and around the individual charges is option

51、al .The top 2 to 3 ft . of borehole is not loaded ,but is stemmed. The depth that can bu presplit is limited by hole alignment ,with 50 ft .being about maximum .The presplit holes are fired before before the adjacent primary holes to provide a fracture plane to which the primary blast can break .In

52、presplitting it is difficult to determine the results until the adjacent primary blast is shot .For this reason ,presplitting too far in advance is not recommended .Presplitting seldom is done underground.Cushion blasting involves drilling a row of 2 to 6-in .diameter boreholes along the final excav

53、ation line ,loading with a light well-distributed charge ,completely stemmed and firing after the main excavation is removed rather than before ,as in presplitting. The burden on the holes is slightly larger than the spacing .Wedges may be used to abut the charges to the excavation side of the boreh

54、ole and minimize damage to the final wall .Eeplosive loading is similar to that in presplitting .Cushion blasting has been done to depths near 100 ft .in a single lift with the larger-diameter boreholes because alignment is more easily retained .Cushion blasting seldom is done underground.Smooth bla

55、sting is the underground counterpart of cushion blasting .At the perimeter of the tunnel or drift ,closely spaced holes with a burden-to-spacing ratio near 1.5:1 are loaded with light well-distributed charges .Smooth blasting differs from cushion blasting in that (1) except at the collar ,the charge

56、s are not stemmed and (2) the perimeter holes are fired on the last delay in the same round as the primary blast .Total column loading is most common ,although spacers may be used .The holes are stemmed to prevent the charges from being pulled out by the detonation of the previous delayed holes .Smo

57、oth blasting reduces overbreak in a drift and also provides a more competent back requiring less support .It involves more perimeter holes than does normal blasting.Combinations of controlled blasting techniques are used .In unconsolidated rock,line drilling sometimes is desirable between presplit o

58、r cushion boreholes . Corners sometimes are presplit when cushion blasting is used.1.4 TUNNEL BLASTINGThe most common methed of driving a mining tunnel is a cyclic operation in three sequences:(1) Drilling shot holes ;charging them with explosives and blasting.(2) Removing the resulting muck pile.(3) Inserting the tunnel linings into the newly excaved area; and advancing the ralls. ventilation arrangements, and power supplies ready for the next cycle of operations.The basic principle of tunnel blasting ,in its simplest term, is to loosen a volume of the virgin rock in such a