本文選題：層狀頂板 + 變形失穩(wěn)��； 參考：《中國礦業(yè)大學(xué)(北京)》2017年博士論文

【摘要】：巷道頂板穩(wěn)定性控制是實現(xiàn)礦井安全高效生產(chǎn)的基礎(chǔ)。隨著煤炭開采規(guī)模和開采強度的增加,礦井向大型化、集約化、機械化發(fā)展,掘進(jìn)大斷面巷道成為煤炭行業(yè)發(fā)展的必然趨勢。對于在煤層中掘進(jìn)的大斷面巷道由于煤層強度一般較低,且頂板具有典型的層狀特征,當(dāng)頂板層理、裂隙發(fā)育,分層厚度小,層間黏結(jié)程度低,煤幫完整性差時,巷道冒頂和片幫等安全問題較為突出,使巷道頂板維護(hù)變得更加困難。本文以趙莊礦布置在煤層中的開拓大巷為工程背景,綜合采用現(xiàn)場調(diào)研、理論分析、數(shù)值模擬和現(xiàn)場工程試驗等方法,系統(tǒng)研究了弱黏結(jié)、薄分層、含多層軟弱夾層頂板的變形破壞規(guī)律,揭示了典型條件下大斷面煤巷層狀頂板變形失穩(wěn)機理和錨索破斷失效原因,基于上述研究成果提出了以保證頂板巖梁連續(xù)性和抑制巷道頂角破壞為核心,以長錨桿、短錨索、長錨索為主導(dǎo)的多層次頂板控制技術(shù),主要取得以下結(jié)論:大斷面煤巷典型變形破壞特征為:頂板下沉劇烈、冒頂事故頻發(fā);煤壁極易片幫、內(nèi)擠顯著;錨索破斷率高,支護(hù)結(jié)構(gòu)損壞嚴(yán)重;巷道返修量大、維護(hù)成本高;局部存在底鼓現(xiàn)象。大斷面煤巷頂板內(nèi)部層理、裂隙發(fā)育,層間黏結(jié)程度低,自身穩(wěn)定性差,頂板跳躍性、非連續(xù)性破壞現(xiàn)象較多,離層較明顯,內(nèi)部含多層泥頁巖夾層或煤線。頂板泥巖粘土礦物含量高,遇水易碎裂軟化;煤幫松軟,破壞范圍大。煤巷頂板具有典型的層狀特征,巖體力學(xué)性質(zhì)受到巖性與結(jié)構(gòu)面的聯(lián)合制約。以頂板巖梁理論為基礎(chǔ),根據(jù)層狀頂板特征,考慮層理面和軟弱夾層的影響,闡明了層狀頂板離層的形成及擴展過程;頂板離層的形式可分為三種:連續(xù)離層、間隔離層以及無離層;并指出采用合理的支護(hù)方式阻止層間剪切作用,能夠抑制頂板離層、減小頂板下沉量。根據(jù)頂板層理發(fā)育程度,將層狀頂板分為兩類,揭示了大斷面煤巷層狀頂板重力驅(qū)動型失穩(wěn)和離層撓曲型失穩(wěn)機理;并指出層狀頂板離層、撓曲,導(dǎo)致巷道頂角處易產(chǎn)生剪應(yīng)力集中,并在該處產(chǎn)生剪切破碎帶,隨著頂板撓曲的發(fā)展,剪切破碎帶以一定角度向上擴展,直至達(dá)到較堅硬巖層,圍巖變形加劇,錨索承受載荷增加,發(fā)生破斷,支護(hù)強度不足,誘發(fā)頂板切落式失穩(wěn)冒落。煤幫作為巷道頂板巖梁的載體,煤幫不同的破壞程度和破壞范圍將對頂板巖梁提供不同的支撐方式。合理地增大煤幫的支護(hù)強度,減小煤幫塑性區(qū)范圍,使煤幫為頂板提供可靠的支撐,可抑制頂板有害變形的產(chǎn)生,有利于煤幫的維護(hù)。對于大跨度頂板、超高松軟煤幫巷道應(yīng)堅持“頂幫協(xié)同控制”的原則,保證圍巖的長期穩(wěn)定。軟弱夾層極易導(dǎo)致頂板的沿層破壞,使頂板出現(xiàn)大范圍的離層;軟弱夾層位置距離巷道頂板越遠(yuǎn)到對頂板變形的影響越小,但巷道頂板具有穿層破壞特性,當(dāng)軟弱夾層在其開挖影響范圍內(nèi)時,之間即使具有相對堅硬的巖層阻隔,軟弱夾層也會破壞。軟弱夾層數(shù)量增加后,層狀頂板被切割成的分層頂板數(shù)量越多,抵抗變形的能力越低,頂板破壞范圍增大,使冒頂高度和冒頂風(fēng)險增加。煤巷頂板裂隙水的存在和空氣濕度的季節(jié)循環(huán),加劇頂板風(fēng)化碎裂,造成錨索托板錨空,預(yù)應(yīng)力損失,加劇頂板下沉變形,錨索破斷失效,支護(hù)強度降低極易引發(fā)頂板失穩(wěn)。此類巷道掘出后必須及時噴射混凝土層,密閉圍巖隔絕空氣和水,防止圍巖風(fēng)化、潮解剝落,降低工程巖體強度劣化。錨索預(yù)應(yīng)力損失、破斷失效導(dǎo)致其工作狀態(tài)發(fā)生改變,是引發(fā)頂板變形失穩(wěn)的主要因素,對于大變形巷道圍巖控制時必須使支護(hù)結(jié)構(gòu)的力學(xué)性能與圍巖的大變形相匹配。大斷面煤巷層狀頂板錨索失效主要是索體破斷,索體破斷位置主要發(fā)生在托板孔口處和頂板2m范圍內(nèi),其中發(fā)生在托板孔口處的破斷主要是由于頂板非均勻變形使托板翻轉(zhuǎn),造成錨索彎折剪切破斷。錨索拉伸試驗斷口多為杯錐狀,具有明顯的頸縮,斷口基本平齊,斷裂位置較為集中,為典型的韌性斷裂;錨桿軸向承載能力一般低于錨索,但其具有較高的延伸率,適應(yīng)圍巖大變形的能力強。對比分析了不同類型錨索以及錨桿的剪切力學(xué)性能,錨索剪切過程中受力較為復(fù)雜,錨索剪切試驗中鋼絲斷口以斜切斷口為主,同時含有頸縮拉伸斷口、旋渦狀扭轉(zhuǎn)斷口,以及拉剪復(fù)合斷口。錨索剪切破斷時砂漿試塊接觸面錯動位移受索體類型、預(yù)應(yīng)力、錨固方式和砂漿試塊強度的制約;全長錨固錨索支護(hù)系統(tǒng)的剪切剛度優(yōu)于未錨固錨索;錨桿支護(hù)系統(tǒng)具有較高的初期剪切剛度,有利于增大頂板層間剪切阻抗,抑制頂板離層。采用FLAC3D軟件和改進(jìn)的pile單元模擬錨索(可承受彎矩和施加預(yù)緊力)分析層狀頂板與錨索的相互作用關(guān)系,得出布置在頂板不同位置的錨索其受力狀態(tài)存在差異:頂板錨索越靠近幫部,受到的層間剪力越大,軸向拉力越小;而越靠近巷道頂板中部,錨索受到的軸向拉力越大,層間剪力越小;錨索破斷是頂板層間剪切錯動與豎直下沉共同作用的結(jié)果,靠近巷道幫部的頂板錨索主要是剪切破斷,而靠近頂板中部的錨索以拉伸破斷為主。長時間服務(wù)的巷道錨索受局部腐蝕影響時,易產(chǎn)生應(yīng)力腐蝕斷裂和腐蝕疲勞斷裂。根據(jù)錨索不同的破斷原因,提出了相應(yīng)的控制對策。分析了目前巷道支護(hù)存在的主要問題:主觀臆斷性強,對頂板變形失穩(wěn)機理認(rèn)識不清,支護(hù)對策針對性差;對巷道圍巖地質(zhì)條件和應(yīng)力環(huán)境認(rèn)識不充分,巷道支護(hù)方式“一刀切”,造成區(qū)域支護(hù)強度不足冒頂隱患大和過度支護(hù)材料浪費嚴(yán)重;對巷道礦壓監(jiān)測重視不夠,對圍巖局部大變形處理不及時;錨桿與錨索協(xié)調(diào)支護(hù)理論缺乏深入、系統(tǒng)的研究,錨桿與錨索不能協(xié)同承載;缺乏對巷道服務(wù)時間因素的考慮,對時間因素影響下工程巖體強度劣化和支護(hù)結(jié)構(gòu)力學(xué)性能劣化考慮不足。并提出大斷面煤巷層狀頂板控制思路。分析了錨桿錨索預(yù)應(yīng)力、錨固長度、桿體長度和索體長度對圍巖控制效果的影響規(guī)律,其中預(yù)應(yīng)力對圍巖主動支護(hù)效果起重要作用;錨桿極限錨固力隨著錨固長度的增加成指數(shù)關(guān)系增加;合理地增加錨桿的長度有利于控制下位頂板巖層的離層錯動;錨索長度增加后不利于對其中部圍巖的控制,適當(dāng)降低錨索的長度有利于預(yù)應(yīng)力在圍巖中疊加擴散,增加圍巖控制效果。根據(jù)大斷面煤巷層狀頂板不同區(qū)域巖體冒頂風(fēng)險以及承載特性,劃分為非穩(wěn)定層、亞穩(wěn)定層和穩(wěn)定層,同時根據(jù)不同區(qū)域巖體變形特征,提出了以保證頂板巖梁連續(xù)性、抑制巷道頂角破壞為核心的多層次支護(hù)技術(shù)。多層次支護(hù)技術(shù)以“長短結(jié)合、強弱結(jié)合、疏密結(jié)合”的支護(hù)系統(tǒng)為依托,選取典型的巷道,根據(jù)工程地質(zhì)條件選擇3.2m的長錨桿、5.4m的短錨索、7.4m的長錨索聯(lián)合支護(hù)頂板,形成連續(xù)的預(yù)應(yīng)力承載結(jié)構(gòu),并使護(hù)表構(gòu)件與之相配套,加強煤幫的控制,支護(hù)完成后及時噴射混凝土層抑制圍巖強度劣化�，F(xiàn)場監(jiān)測表明,新支護(hù)方案實現(xiàn)了圍巖的長期穩(wěn)定,取得了較好的支護(hù)效果。
[Abstract]:The roadway roof stability control is the basis for safe and efficient production of coal mine. With the increase of coal mining scale and strength of mining, mine to large-scale, intensive, mechanization, large section roadway has become the inevitable trend of the development of the coal industry. For large section roadway in coal seam excavation of the coal seam because of low strength, and has the typical characteristics of the layered roof, when the roof bedding, fissures, layer thickness, interlayer bonding degree is low, coal poor integrity, roadway caving and sloughing and other security problems are more prominent, the roof of the tunnel maintenance becomes more difficult. In this paper, Zhaozhuang Mine layout in Coal Exploration Major lane as the engineering background, combined with field survey, theoretical analysis, numerical simulation and field engineering test method, system of weak bonding, thin layered, the deformation failure law of soft interlayer containing multilayer roof, exposing the The mechanism of instability and failure of cable breaking deformation under typical conditions of large section roadway roof, based on the above research results to ensure the continuity of the roof and roadway damage suppression as the core put forward angle, with long bolt, short anchor, anchor for multi-level roof dominant control technology, mainly made the following conclusion: large section roadway deformation and failure characteristics of typical roof subsidence: severe, frequent accidents easily; the coal wall spalling, squeeze significantly; anchor breaking rate is high, the supporting structure was damaged; roadway repair capacity, the maintenance cost is high; the drum phenomenon exists in the local bottom coal roadway roof inside. Bedding, fracture, interlayer bonding degree is low, its poor stability, roof jumping, non continuity damage phenomenon more obvious internal separation, with multiple layers of mudstone and shale or coal line. Clay mineral content of roof high, the water easily broken Softening; coal soft, damage range. Roof of coal roadway with layered typical characteristics, mechanical properties of rock mass by lithology and structure of the joint constraints. In roof rock beam theory, according to the characteristics of layered roof, considering the influence of bedding surface and soft interlayer, expounds the formation and propagation process of layered roof separation; the roof separation form can be divided into three types: continuous separation, isolation layer and separation layer; and points out that the reasonable support means to prevent the interlaminar shear effect, can inhibit the roof separation, reduce roof subsidence of roof layer. According to the barber education, the layered roof is divided into two categories, reveals the large cross section coal Xiang bedded roof of gravity driven instability and flexible separation mechanism of instability; and pointed out that the layered roof separation, deflection, roadway leading vertex is easy to produce stress concentration, and shear fracture zone in the area, with the roof deflection The development of shear fracture zone at a certain angle extended upward until it reaches the hard rock, the surrounding rock deformation intensifies, anchor load increase, break and support strength is insufficient, cutting down type instability induced by roof caving coal. As a carrier of roadway roof rock beam, destruction degree and range of different coalside will provide support for different roof beam. The increase of coal for supporting strength, reduce coal for the plastic zone, which help to provide reliable support for the coal roof, can inhibit the harmful deformation of roof coal, to help the maintenance. For the long-span roof, super high soft coal roadway help should adhere to the "hangwall cooperative control" principle, to ensure the long-term stability of the surrounding rock. The weak interlayer can easily lead to the destruction of the roof layer along the roof, the large scale separation; weak interlayer distance between the roadway roof and roof deformation of far more. Ring is small, but has the failure characteristics of roadway roof wear layer, when the influence of excavation in soft interlayer between range, even with a relatively hard rock barrier, soft interlayer will be destroyed. The increase in the number of weak interlayer, layered roof number of layered roof was cut into more and more low ability to resist deformation. The roof damage range increased, the height of caving and caving risk. The seasonal cycle of coal roadway roof crevice water and air humidity, intensified roof weathering fragmentation caused by cable anchor plate, prestress loss, intensified roof subsidence deformation, cable breaking failure, supporting strength reduction can easily lead to instability. This kind of roadway roof to must be timely shotcrete, rock closed isolated from the air and water, to prevent rock weathering, deliquescence spalling, reduce the engineering rock strength deterioration. Prestress loss, breaking failure leads to the work. State change, is a major factor for instability of the roof deformation, for large deformation and mechanical properties of surrounding rock control of large deformation of surrounding rock roadway supporting structure must be matched. Large section roadway roof anchor failure is mainly cable breaking, cable breaking occurs mainly in the orifice plate and the roof in the range of 2M, which occurs when the broken plate orifice is mainly due to the inhomogeneous deformation of roof plate turning, bending shearing break caused by cable. Cable tensile test fracture is cup cone, with obvious necking, fracture basic flush, fracture location is more concentrated, is typical ductile fracture bolt; the axial load capacity is generally lower than the anchor, but extends its high rate, ability to adapt to the large deformation of surrounding rock. The comparative analysis of different types of anchor bolt, shear mechanical properties, shear stress of anchor cable Complex fracture shear test with anchor wire oblique fracture, with necking tensile fracture, spiral torsion fracture and tensile shear fracture. Anchor shear rupture mortar block contact surface displacement by the cable body type, prestress, anchorage and mortar control block strength; anchoring cable supporting system of shear stiffness better than the anchor cable; initial shear bolting system has high rigidity, can increase the roof shear resistance, inhibition of roof separation. Using pile FLAC3D software unit and improved analog cable (which can be subjected to bending and preload) analysis of the interaction between the layered roof with the anchor, the anchor roof arranged in different positions of the stress state are different: the roof cable is close to the part by the interlayer shear increases, axial tension is smaller and closer to the roof; In the middle, the axial force of anchor has a larger interlayer shear is smaller; anchor is broken roof interlayer shear interaction and vertical sinking the roof cable near the sidewall is mainly shear fracture, while near the roof of central cable tensile breaking. Cable tunnel long time service local corrosion effect, easy to produce stress corrosion cracking and corrosion fatigue fracture. According to different break reason, put forward the corresponding countermeasures. The article analyzed the current problem of roadway support are: the subjective nature of the instability mechanism of strong, clear understanding of the deformation of roof, supporting measures for poor; geological conditions of surrounding rock and the stress of environmental awareness is not sufficient, roadway "caused by regional support strength is insufficient and the hidden dangers of excessive waste of roof supporting materials is serious; for rock pressure monitoring does not pay attention to Enough, on the rock of local large deformation processing is not timely; bolt and cable supporting coordination theory lack of in-depth, systematic study of bolt and cable cannot load; lack of roadway Business Hours factors, the factor of time under the influence of rock strength deterioration and supporting structure mechanical property deterioration and lack of consideration. The coal roadway roof control method. The analysis of layered prestressed anchor rod, anchor length, body length and body length of cable influence on control effect of surrounding rock, the prestressed plays an important role in the active supporting effect of rock bolt; anchoring force with the increase of anchorage length exponentially increase; reasonable increase of bolt the length of the roof strata is helpful to control the separation fault; cable length increase is not conducive to the control of the surrounding rock, appropriate to reduce the length of the anchor to pre stress in The superposition of diffusion in the surrounding rock, increase the control effect of surrounding rock. According to the large section roadway roof in different areas of layered rock mass caving risk and bearing characteristics, divided into non stable layer, sub stable layer and stable layer, and according to the different regional characteristics of rock deformation, put forward to ensure the continuity of the roof beam, vertex damage is the core of the inhibition of roadway multi level support technology. Multi level support technology in "combined with the length, strength, density combination supporting system based on typical roadway, according to the engineering geological conditions of long anchor 3.2m, short cable 5.4m, 7.4M long cable anchor supporting the roof, forming a continuous prestressed load-bearing structure and, the surface protecting component matching, strengthening the control of coal, after supporting timely shotcrete inhibit the rock strength deterioration. The monitoring results indicate that the new scheme can support the long-term stability of surrounding rock It has achieved good support effect.

【學(xué)位授予單位】：中國礦業(yè)大學(xué)(北京)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TD322.4;TD353

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