【作者】 苏学贵；

【导师】 宋选民；

【作者基本信息】 太原理工大学 ， 采矿工程， 2013， 博士

【摘要】 特厚复合顶板为大厚度不稳定层状围岩,依据传统的支护理论难以诠释锚索的作用机理与巷道支护结构,要科学合理地确定支护参数较为困难。本论文在总结分析现有巷道支护理论基础上,结合国家自然科学基金项目(51274145)“涵盖峰后大变形过程的巷道围岩与支护平衡规律及控制机理研究”和煤气化专项基金项目“神州煤业4#煤层巷道联合支护技术研究”,采用理论分析、试验模拟、数值模拟及工程实践应用等方法,对特厚复合顶板巷道支护结构与围岩稳定控制技术进行了研究,得出以下结论：(1)在总结分析现有支护理论的基础上,提出特厚复合顶板巷道拱梁耦合支护新理论：特厚复合顶板破坏主要包括弯曲断裂离层和层间错动离层；在锚杆作用下浅部岩层形成组合梁,深部复合顶板在锚索高预应力作用下形成压缩承载拱,“拱”与“梁”耦合作用形成特厚复合顶板巷道支护承载结构主体；建立巷道拱-梁结构体系力学模型,提出支护结构稳定性力学计算与支护参数设计方法。(2)利用大尺度二维相似模拟试验系统,以神州煤业4#煤层特厚复合顶板为原型,试验模拟不同支护条件巷道分级加载(0～40MPa)过程中巷道围岩应力、围岩位移变化等规律。试验结论为：①无支护巷道：顶板浅部岩层位移呈μ=aln (p)+b对数曲线变化特征,顶板岩层弯曲破坏从中间开始向两侧扩展,呈拱形冒落。顶板围岩垂直应力随该岩层离层破坏逐步使两侧垂直应力升高,增压系数1.12～1.60；围岩水平应力随该岩层破坏逐步使上部岩层水平应力升高,增压系数1.12-1.18；水平应力是复合顶板产生挤压弯曲、剪切错动破坏的主要因素。②顶帮锚杆支护巷道：顶板围岩位移呈μ=kp+b线性变化规律,锚杆锚固层中部位移速率大于两侧,岩层整体性提高,呈组合梁弯曲变形特征；当锚杆组合梁弯曲破断后,上部围岩应力明显下降,岩层破坏向两侧及上部扩展,仍然形成冒落拱。锚杆组合梁中水平应力较高,侧压系数达1.45,表明水平应力是组合梁弯曲变形的主要因素；组合梁两端垂直应力高于水平应力,表明垂直应力是巷道肩部剪切破坏的主要因素；锚杆组合梁形成后,使巷道顶板水平承载力提高49%,垂直承载力提高30%,综合承载能力提高75%。③锚索+顶帮锚杆联合支护巷道：锚索减跨作用下锚杆组合梁抗弯强度增加,组合梁上部围岩应力上升、位移减小；顶板岩层中部与两侧位移速率差值由浅到深递减,顶板深部基本接近,表明顶板较大范围内围岩整体性提高,显现锚索压缩拱特征；拱-梁组合结构形成后与锚杆支护巷道相比顶板下沉量减少43%。④锚索+全断面锚杆支护巷道：在斜跨锚索作用下围岩压缩拱范围有所扩大,锚杆组合梁最大水平承载力比锚索垂直布置提高35%；顶板下沉量比锚索垂直布置减少16%,比顶帮锚杆支护减少52.3%；巷道底板在采用锚杆支护后承载能力增大,底鼓量减小77.4%。(3)采用RFPA2D数值模拟试验,以神州煤业4#煤层特厚复合顶板为模拟对象,对不同支条件巷道分级加载时围岩破坏过程进行模拟。计算分析围岩应力场特征与围岩裂隙演化规律。分别研究不同围岩应力对巷道围岩稳定性的影响规律以及支护结构不同对巷道围岩变形破坏的影响规律。数值模拟表明随锚索密度增加特厚复合顶板中形成的“拱-梁组合”结构特征越加明显,支护强度越高。(4)基于本文的特厚复合顶板巷道支护理论与围岩稳定控制技术,合理优化设计巷道支护参数,并在神州煤业4303工作面顺槽巷道及切眼中实际应用。经过监测分析与生产应用验证了巷道支护结构的稳定性,取得良好的支护效果。更多还原

【Abstract】 Extra-thick compound roof is unstable layered strata. It is difficult to interpret anchor mechanism and roadway support structure in traditional support theory, even more difficult to reasonably determine the parameters of the support. On the basis of summing up the theory and technology of the existing roadway support, combined with the project of National Foundation of China (51274145) named "covers peak after large deformation process of surrounding rock and support balance of law and control mechanism" and gasification project with special fund called "SHENZHOU Coal4#coal seam Combined Support Technology", this paper studies the extra-thick roof roadway support structure and rock stability control technology by using theoretical analysis, similar physical simulation, numerical simulation and practical application.The following are conclusions:(1) On the basis of summing up the existing support theory, this paper put forward a new theory of extra-thick roof roadway support, including:The damage of extra-thick roof mainly include bending fracture departure layer and ionospheric of layer shear dislocation; In the bolt role, low layered strata form a composite beam, extra-thick roof compression bearing arch formed in the role of anchor high prestressed,"arch" and "beam" coupling to form extra-thick roof roadway support structure; To establish roadway arch beam combination structural mechanics model proposed supporting structure stability mechanics checking analytic method.(2) The use of large-scale two-dimensional similar material simulation test system, taking the extra-thick roof of SHENZHOU Coal4#seam as a prototype, testing and simulating the displacement law of surrounding rock stress, change of surrounding rock under the different support conditions of roadway grading load (0～40MPa).The following are conclusions:①No support roadway:Displacement of the roof in shallow strata is μ=aln(p)+b logarithmic curve characteristics displacement in deep surrounding rock is μ=kp+b linear characteristic; the roof strata curved destruction from the middle to extend to both sides, with vaulted failure characteristics. Vertical stress with roof rock strata ionospheric destruction gradually leads both sides of the vertical stress increased the boost coefficient of1.12 to1.60; the rock horizontal stress increased gradually with the destruction of the rock formations of the upper strata level, boost coefficient of1.12to1.18; horizontal stress are the composite roof produce extrusion bending, shear dislocation destruction of the main reasons.②Bolting roadway:Displacement of the roof rock is μ=kp+b linear variation, displacement rate of anchor layer is greater than both sides, with characteristics of a combination beam bending deformation; when the bolt combined beam bending breaking up the rear, upper surrounding rock stress decreased strata destruction to both sides and the upper extension, and the last is still formed arch caving. The lateral pressure coefficient of anchor composite beam is1.45, indicating that the level of stress composite beam bending deformation; roof on both sides of the vertical stress is higher than the level of stress, indicating that the vertical stress is the main factors of the roadway shoulder shear failure.③Bolting and Anchor roadway:The bolt combined beam bending strength to be increased by the effect of anchor, stress of the upper surrounding rock of roof is rising, displacement of roof is decreasing. The displacement rate between the middle of the roof strata and both sides is descending from shallow to deep, indicating that the integrity of the surrounding rock of roof to be improved widely, with features of the anchor compression arch; the roof subsidence quantity has43%reduction.④Full-face support roadway:Under the diagonal anchor cable (compared with the vertical arrangement), the range of the surrounding rock compression arch is expanded, sinking declined by16%. The lateral pressure coefficient of roof bolt anchoring layer is increased to3.3, show that the horizontal stress is the main factor of combination of beam bending deformation. The bearing capacity of floor is increased and floor heave is decreased by employing bolts in the roadway floor.(3) By using of the RFPA numerical simulation test, taking extra-thick roof of SHENZHOU Coal4#seam as mock object, simulating the process stage loading in surrounding rock under the different support conditions. Computational analysis of the evolution of the characteristics of surrounding rock stress and rock crack. Respectively, studying the impact of different vertical stress and horizontal stress on the roadway stability law, and various supporting structure of the surrounding rock deformation damage were studied. Focus numerical computation on the structure features and supporting functions of anchor support roadway.(4) Combination of the above extra-thick roof roadway support theory and surrounding rock stability control technology, it is reasonable to optimize the design of roadway support parameters, and taking the practical application in the SHENZHOU Coal4303working face roadway and open-off cut. After monitoring, analysis and production application to verify the stability of the roadway support structure, and achieving a good supporting effect.更多还原