【摘要】：復(fù)合頂板巷道在煤礦中分布廣泛,各巖層之間黏結(jié)力較弱甚至無(wú)黏結(jié)力,復(fù)合巖層易離層、下沉甚至破壞,導(dǎo)致由下至上的分層冒落,復(fù)合頂板的支護(hù)是國(guó)內(nèi)外巷道支護(hù)的難題之一。復(fù)合頂板層理面是巖體中的薄弱部分,是影響巖體穩(wěn)定的重要因素之一。層理面抗剪強(qiáng)度參數(shù)的確定是復(fù)合頂板、巖質(zhì)邊坡穩(wěn)定等問(wèn)題分析關(guān)鍵問(wèn)題。因此,研究復(fù)合頂板層間剪切特性及考慮層間剪切特性的復(fù)合頂板控制有重要意義。論文綜合利用實(shí)驗(yàn)室實(shí)驗(yàn)、理論分析、數(shù)值計(jì)算等相結(jié)合的研究方法,考慮層間剪切特性對(duì)復(fù)合頂板穩(wěn)定性及其控制機(jī)理進(jìn)行研究。首先,對(duì)節(jié)理面的粗糙度JRC進(jìn)行了測(cè)定,并將節(jié)理面輪廓導(dǎo)入PFC,在不同法向正應(yīng)力作用下進(jìn)行剪切實(shí)驗(yàn),利用最小二乘法線性回歸求出節(jié)理面的內(nèi)摩擦角。對(duì)復(fù)合頂板的穩(wěn)定性進(jìn)行了力學(xué)分析,根據(jù)組合梁分析得出通過(guò)增加層間剪切強(qiáng)度,可提高復(fù)合頂板的抗變形及破壞能力,在層狀復(fù)合頂板中引入了復(fù)合頂板關(guān)鍵層進(jìn)行力學(xué)分析,并在考慮層間剪應(yīng)力的基礎(chǔ)上對(duì)推導(dǎo)出復(fù)合頂板關(guān)鍵層破斷距,提出復(fù)合頂板柔性控制層的概念并對(duì)其判定及對(duì)頂板控制的作用進(jìn)行了分析,最后利用C#語(yǔ)言在Visual Studio 2005平臺(tái)進(jìn)行了復(fù)合頂板柔性控制層判別軟件實(shí)現(xiàn)。利用UDEC數(shù)值計(jì)算軟件,對(duì)復(fù)合頂板中層理面參數(shù)(內(nèi)摩擦角、內(nèi)聚力、抗拉強(qiáng)度等)對(duì)復(fù)合頂板的穩(wěn)定性影響進(jìn)行了研究:隨層理面內(nèi)摩擦角和內(nèi)聚力的增大,巷道變形、裂隙發(fā)育、破壞范圍逐漸變小;隨內(nèi)摩擦角和內(nèi)聚力的增大,巷道變形對(duì)兩參數(shù)敏感性降低,改變頂板層理面抗拉強(qiáng)度對(duì)幫部和底板破壞范圍影響不明顯;巷道頂板圍巖的破壞形式主要以剪切破壞和拉破壞為主,且兩種破壞多同時(shí)出現(xiàn),巷道幫部的破壞形式仍主要為剪切破壞和拉破壞,幫部圍巖的破壞形態(tài)呈現(xiàn)倒三角形分布,底板破壞以拉破壞為主。頂板裂隙的發(fā)育總體規(guī)律為:頂板裂隙發(fā)育可分為快速增長(zhǎng)階段和平穩(wěn)階段,煤壁裂隙的生成過(guò)程中,存在明顯的裂隙產(chǎn)生-裂隙閉合-裂隙持續(xù)增長(zhǎng)的三個(gè)階段。以老石旦煤礦為背景,對(duì)復(fù)合頂板支護(hù)機(jī)理和支護(hù)對(duì)策進(jìn)行了研究分析。利用UDEC數(shù)值計(jì)算軟件研究了錨桿的抗剪切作用效果,錨桿的整體作用效果和錨索加強(qiáng)支護(hù)效果。將圍巖破壞演化規(guī)律總結(jié)為四個(gè)階段,第一階段為起始階段,第二階段破壞往頂板深部發(fā)育,第三階段幫部在頂板擠壓作用下發(fā)生大量剪切和拉伸破壞,最后一階段頂?shù)装迤茐陌l(fā)育進(jìn)入穩(wěn)定階段。通過(guò)統(tǒng)計(jì)不同形式破壞的接觸長(zhǎng)度(contact length)和總接觸長(zhǎng)度的比值比較巷道圍巖不同區(qū)域的破壞形式。提出針對(duì)不同區(qū)域頂板的破壞形式不同,應(yīng)進(jìn)行不同區(qū)域分區(qū)支護(hù)的策略。
[Abstract]:The composite roof roadway is widely distributed in the coal mine, and the bonding force between each rock layer is weak or even no bonding force. The composite rock strata are easy to separate, sink or even destroy, resulting in the falling of the layers from the bottom to the top. The support of composite roof is one of the difficult problems in roadway support at home and abroad. Composite roof bedding plane is a weak part of rock mass and one of the important factors affecting rock mass stability. The determination of shear strength parameters of bedding plane is a key problem in the analysis of composite roof and rock slope stability. Therefore, it is of great significance to study the interlaminar shear characteristics of composite roof and the control of composite roof considering interlaminar shear characteristics. In this paper, the stability and control mechanism of composite roof are studied by means of laboratory experiment, theoretical analysis and numerical calculation. Firstly, the roughness of joint surface JRC is measured, and the joint surface profile is introduced into the shear experiment of PFC, under different normal stresses, and the internal friction angle of joint surface is obtained by least square linear regression. The stability of composite roof is analyzed by mechanics. According to the analysis of composite beam, it is concluded that the deformation resistance and failure resistance of composite roof can be improved by increasing the interlaminar shear strength. The key layer of composite roof is introduced into the layered composite roof for mechanical analysis, and the breaking distance of the key layer of composite roof is deduced on the basis of considering the interlaminar shear stress. This paper puts forward the concept of flexible control layer of composite roof and analyzes its judgment and function to roof control. Finally, the discriminant software of flexible control layer of composite roof is implemented by using C # language in Visual Studio 2005 platform. By using UDEC software, the influence of the parameters of the middle layer of composite roof (internal friction angle, cohesive force, tensile strength, etc.) on the stability of composite roof is studied: with the increase of the friction angle and cohesion of the bedding plane, the roadway deformation is studied. With the increase of internal friction angle and cohesion, the sensitivity of roadway deformation to two parameters is decreased, and the influence of changing tensile strength of roof bedding surface on the failure range of roof and floor is not obvious. The main failure forms of roadway roof surrounding rock are shear failure and tensile failure, and the two kinds of destruction occur at the same time. The failure form of roadway wall rock is still shear failure and tensile failure, and the failure form of wall rock of roadway is inverted triangle distribution. The main failure of the bottom plate is tensile failure. The general law of roof crack development is as follows: roof crack development can be divided into rapid growth stage and stable stage. In the process of coal wall crack formation, there are three stages of obvious crack generation, crack closure and continuous growth. Taking Laoshidan coal mine as the background, the mechanism of composite roof support and supporting countermeasures are studied and analyzed. The anti-shear effect of bolt, the whole effect of bolt and the effect of strengthening support of anchor cable are studied by using UDEC numerical calculation software. The evolution law of surrounding rock failure is summarized into four stages, the first stage is the initial stage, the second stage is the deep development of the roof, and the third stage is the large amount of shear and tensile failure of the wall under the action of roof extrusion. In the last stage, the top and bottom plate damage and development entered a stable stage. By calculating the ratio of contact length (contact length) and total contact length (contact length) of different failure forms, the failure patterns of different surrounding rock of roadway are compared. In view of the different failure form of roof in different area, the strategy of different area partition support should be carried out.
【學(xué)位授予單位】：中國(guó)礦業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TD353

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