【作者】 刘建庄；

【导师】 张农；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2013， 博士

【摘要】 U型钢支架参与的联合支护，是解决高压力软碎围岩巷道支护难题的重要途径之一。支架受力承载的变形特征，既有平面内的折弯和错断，也有平面外的翻转扭曲，其中不乏由于结构失稳、纵向受力、偏载侧倾造成的低阻折损现象。现有的面内弹性线单元力学模型，较难解释其力学机理，面对更为复杂的约束状况和受载条件，则难以给出理论解析解。探究支架的三维受力计算和屈曲机理分析，可更准确的评定支架的承载能力，预判薄弱点位置和变形发展趋势，为屈曲控制指明方向，具有较高的研究价值和指导意义。基于上述背景，深入调研了两淮矿区和开滦矿区的支架变形折损状况，根据变形特征和力学原因归纳了平面内结构性受载折损、搭接部位撕裂型破损、卡缆失效与破坏、拉杆和背板失效与破坏、轴力错断型折损、纵向扭曲破坏、综合性破坏等7种型式，提出了屈曲概念和内涵，其中平面内结构性受载折损、纵向扭曲破坏和轴力错断型折损均有屈曲破坏现象的发生。以ANSYS中的BEAM189结构单元建模支架，通过变换约束类型、断面积、跨高比和加载方式，研究了包括弯矩、剪力和轴力的在支架棚梁和棚腿各部位的分布变化规律，查明了内力极值点的大体位置包括棚脚、起拱线、拱顶以及两个肩窝，条件变换会造成内力方向、薄弱点数目和位置的变化。设计了U型钢钢梁加载试验，进行了试验模型的理论分析，选取位移、加载力和3个关键点位的挠度和横纵应变重要指标，试算反演了包括泊松比、屈曲强度、抗拉强度和强化阶段的切线模量等重要参数，解释了局部受载中25UY支架强于29U支架的原因。通过FLAC3D中BEAM单元的模拟计算，对比了碎矸充填和浆液充填下支架与围岩的作用关系。以常用29U型钢直腿拱形支架为原型，实现了支架、拉条和约束类型的三维ANSYS建模，开展了面内失稳和空间失稳、支架的特征值与屈曲模拟对比计算，分析了不同条件的等效载荷集度和薄弱点分布状况，进行了不同条件的支架承载能力评定，从面外失稳、纵向受力和偏载受力三方面的力学机制方面和力学来源方面，阐明了支架的屈曲机理。系统分析了架型优化、壁后充填、锚杆（索）强化以及滞后注浆在控制屈曲及提升支架承载效能方面的重要作用，提出了开展屈曲控制的一般过程与方法。采用壁后充填、锚杆锁腿、帮部锚索补强、滞后注浆等屈曲控制对策，成功开展了两类典型条件的软岩巷道支护治理，进行了浅拱底梁、锚杆（索）锁腿、滞后注浆等施工方法的有益尝试。该论文有图109幅，表22个，参考文献149篇。更多还原

【Abstract】 Combined support with U-steel beam is the main supporting mean in softfragmentized surrounding rock roadway with high in-situ stress. The frame deformingfeatures include2D bending and breaking in the frame plane, also twisting in space. Thereare many breaking beams phenomenons induced by structural instability, longitudinalloading, or eccentric loading. However, the existing2D model is incapable of explaingU-steel beam longitudinal deforming. Constructing3D beam model and analyzing itsmechanism is the requirements of deepening the research on beam, especially for bucklingbeam. The buckling mechanism is of significant value for buckling controlling measures,and for its support capability assessment.After investigating most beam breaking situation in Huainan, Huaibei, and Kailuanmining areas, the article sums up and classifys it to7types:2D Structural overloadingbending breaking, axial fracture induced by big axial force, longitudinal twisting, tearingdamage on lap point, cable band failure, and integrated breaking. The fore4types are allbuckling types. The frame internal forces distribution law is researched by ANSYS12.13D model with BEAM189. The results of the modeling indicate that internal force extremepoint position on frame and its value are all greatly influenced by constraint types, framearea, span-to-height ratio, and loading method.A U-steel beam loading test is designed to check its main elastic and plastic mainphysical parametrics including Poisson’s ratio, stress limit and tangent modulus. FLAC3Dis applied in this article to study the mechanical function of support and surrounding rock.A new3D model is constructed by SOLID45in ANSYS in order to simulating the frameistability and exploring beam buckling mechanism. In conclusion, the mechanism is putforward from mechanical properties and mechanical sources in the article.The main measures are analyzed in Capter5, which consist of optimization of U-steelframe specification, backfilling behind support, structural reinforcement with bolt andcable on weakness, lag grouting. According to the research results, the appropriatemeasures for frame buckling are practiced in two representative condition soft roadways.There are109figures,22tables and149references in the articale.更多还原