【作者】 王红胜；

【导师】 张东升；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2011， 博士

【摘要】 沿空巷道窄帮的长期稳定特性将直接影响沿空巷道围岩结构的整体稳定性,其有效控制也是成功开发该项技术的关键。论文基于沿空巷道基本顶四种断裂结构形式,以沿空巷道窄帮稳定性的时间效应研究为切入点,综合采用理论分析、物理模拟、数值模拟、实验室岩块实验、工业性试验等研究方法,对窄帮应力变形规律、窄帮蠕变特性、窄帮破坏准则及稳定性控制技术进行了较系统的分析,取得了以下主要研究成果:(1)基于沿空巷道基本顶四种断裂结构形式,建立了相应的窄帮稳定性分析的结构力学模型,推导出窄帮上的静载荷计算公式,并明确了窄帮应力与变形规律。(2)动载效应数值分析表明,基本顶断裂回转产生动载效应对窄帮的稳定性影响最大,且不论断裂线位于窄帮的内侧还是外侧,窄帮上部应力与横向变形都最大,极易在该部位先发生破坏。(3)建立了混凝土人造帮蠕变模型与本构关系方程。基于最小势能原理稳定性分析得出混凝土人造帮蠕变失稳最短时间;混凝土人造帮蠕变极限载荷及其破坏载荷与其配比强度成正比关系;基于蠕变特性及尺寸效应确定了人造帮强度须提高20%~30%左右、高宽比宜为1:1<H:B<2:1。(4)采用正交八面体对混凝土人造帮进行受力分析,得到双剪应力函数和双剪强度理论,并通过实验验证了混凝土人造帮破坏形态是受两组剪应力共同作用的结果,最大剪应力“X”形分布特征与其“X”形破坏断面是一致的。(5)研制出10,000 kN大尺寸蠕变试验系统。对大尺寸人造帮蠕变特性、锚栓强化人造帮蠕变特性、不同构筑方式人造帮蠕变特性的实验分析表明,人造帮蠕变极限载荷及其破坏载荷与水灰比成反比关系;锚栓(杆、筋)能有效约束人造帮横向变形,扩大人造帮承压区面积,提高人造帮整体承载性能和稳定性;人造帮的稳定性与其构筑方式关系密切,整体构筑比分块构筑稳定性强,采用“软+硬”结构比常规“全硬”结构的稳定性强。(6)建立了“软+硬”窄帮结构效应力学模型,解释了该结构与顶底板之间的协调变形机理。上部“软”结构通过大变形吸收顶板能量,有效改善窄帮应力分布特征,能适应基本顶断裂回转下沉给定变形的要求;下部“硬”结构能提供足够的支护阻力,从而确保了人造帮的整体稳定性。上述研究成果在4个典型试验地点进行了工程应用,取得了满意的技术经济效果,可指导该项技术在类似条件下的推广应用。该论文有图228幅,表40个,参考文献162篇。更多还原

【Abstract】 The long-term stability feature of the gob-side entry’s narrow side directly affects its overall stability and it is also difficult to successfully develop the pillarless mining technology. Taking the time effect research of stability of the gob-side entry’s narrow side as a pointcut, law of the stress and deformation, creep property, failure criterion and stability control technology of the narrow side based on four species main roof’s fracture forms, have been systematically analyzed by theoretical analysis, physical simulation, numerical simulation, laboratory rock block experiment, and industrial experiment methods etc. Innovative achievements of this dissertation have been displayed as follows:(1) Based on the main roof’s four species fracture structure form, the corresponding mechanical model of the stability analysis of the narrow side is established, and the calculation formula of the static load on the narrow side is derived, and the law between stress and deformation is clarified.(2) The numerical analysis of the dynamical effect shows that the dynamical effect produced by the main roof’s fracture and rotation mostly affects the stability of the narrow side. Whether the fracture line of the main roof located inside or outside of the narrow side, the stress and lateral deformation are the largest of its upper part, and this part is most likely to be destroyed firstly.(3) The self-defining nonlinear creep model and the constitutive equations of concrete artificial side are built. The concrete artificial side’shortest time of the creep failure was obtained based on the minimum potential energy principle. The creep limit load and creep failure load of concrete artificial side are proportional to its strength ratio. The strength of the artificial side should be increased 20%~30% and its appropriate aspect ratio should be in between 1 and 2 based on the creep property and size effect.(4) Twin shear stress function and twin shear strength theories were obtained after the orthogonal octahedron was adopted to analyze the stress of the concrete artificial side. Experiments verified that two sets of the shear stress together resulted in the failure modes of the concrete artificial side, and the distribution pattern of the maximum shear stress in the concrete artificial side accorded with its failure pattern appeared“X”shape.(5) Large-size creep experimental system with 10,000 kN was independently developed. The creep property experimental analysis on the Large-size artificial sides, Large-size artificial sides with anchor bolts strengthen, and Large-size artificial sides with different building ways, was carried out. The results show that the creep limit load and creep failure load of artificial side are inverse proportional to water-cement ratio. After being strengthened by the anchor bolts, the anchor bolts effectively constrained the progress of artificial side’s lateral deformation, and expanded the artificial side’s pressure district area, and improved the artificial side’s overall bearing capacity and its stability. The stability of artificial side was closely related to its building ways, and the stability of integral building artificial side was stronger than that of blocking piled artificial side, and the stability of the soft-hard structure artificial side was stronger than that of hard structure artificial side.(6) The soft-hard structure effect mechanical model of narrow side was built, and the compatible deformation mechanism that the structure was coordinated with the roof and floor is explained. The upper soft structure can absorb the energy in the roof by its large deformation, and the artificial side’s stress distribution characteristics is improved, and can adapt to the given deformation caused by the fracture and rotation and subsidence of main roof. The hard structure at the bottom of the backfill wall can afford the adequate supporting resistance, and the stability of the entire backfill wall is insured.The above research results were successfully carried out by the engineering application research at four typically experimental sites, and the satisfactory economic and social benefits were obtained, and can promote the use of the technology under the similar conditions.228 pieces of figures, 40 pieces of tables and 162 pieces of consult documents have been quoted in this dissertation.更多还原