充填型断层破碎岩体锚固力学特性研究

发布时间：2018-08-26 08:35

【摘要】：断层是一类在地层中常见的地质构造体,其断裂面附近往往存在一个整体强度较低、稳定性较差的软弱破碎带,严重威胁工程施工安全。本文以淮南矿区顾北煤矿断层破碎带为研究背景,采用不同胶结料、不同粒径骨料、不同预紧力及不同锚固方式物理模型试验及数值模拟计算研究了锚固体强度及其变形特征的演化规律。并进一步分析了矩形、拱形巷道组合拱(梁)的形成条件,建立了巷道失稳判别依据。主要研究成果如下:(1)随着模型骨料粒径或胶结材料强度的增大,断层破碎岩体的力学参数均呈现出逐渐增大的趋势。对比完整岩体,其弹性模量的劣化程度最为显著(78.82%),内摩擦角的劣化程度最弱(25.21%)。(2)随着锚固预紧力、骨料级配或胶结强度的逐渐增大,断层岩体的峰值强度及弹性模量均呈现出逐渐增大的趋势;模型按无锚→端锚→全锚锚固顺序变化时,岩体的峰值强度及弹性模量均逐渐增大。(3)各影响因素对岩体强度影响的主次顺序为:胶结强度骨料粒径锚固预紧力锚固方式。锚固模型内锚杆轴力随时间的变化曲线主要包括稳定阶段、增长阶段、屈服阶段及峰后阶段。(4)采用数值软件扩展研究了锚杆密度及侧向围压对岩体强度的影响规律,从模型内部空间应力分布特征切入分析了锚杆的作用机制。距锚杆较近时,锚固应力值从两端向中间呈现出对称减小的变化规律;而距锚杆较远时,锚固应力值从两端向中间呈现出对称增大的变化规律。(5)随着锚杆密度的减小、锚杆预紧力的增大或托盘尺寸的增大,锚杆作用组合拱的厚度呈现出逐渐增大的趋势。非线性拟合得到各控制因素对组合拱厚度的影响系数,从而对锚固组合拱几何关系式进行修正。(6)基于结构力学理论,探讨分析了矩形、拱形巷道破坏围岩锚固组合拱(梁)的承载能力,确定了巷道围岩失稳的判别依据,并成功应用于现场工程算例分析。
[Abstract]:Fault is a kind of common geological structure in strata. There is a weak fracture zone near its fault surface which has low overall strength and poor stability, which seriously threatens the safety of engineering construction. Taking the fault fracture zone of Gubei coal mine in Huainan mining area as the research background, different cementing materials and different particle size aggregates are used in this paper. Physical model tests and numerical simulation of different pretightening forces and different anchoring modes are carried out to study the evolution of the strength and deformation characteristics of anchors. Furthermore, the forming conditions of rectangular and arch roadway combined arch (beam) are analyzed, and the criterion of roadway instability is established. The main results are as follows: (1) with the increase of the size of the model aggregate or the strength of the cemented rock mass, the mechanical parameters of the fractured rock show a trend of increasing gradually. Compared with the intact rock mass, the degradation degree of elastic modulus is the most obvious (78.82%), and the deterioration degree of internal friction angle is the weakest (25.21%). (_ 2). With anchoring pretightening force, aggregate gradation or cementing strength increases gradually. The peak strength and elastic modulus of faulted rock show a trend of increasing gradually, and the model changes according to the order of anchoring without anchor and full anchor. The peak strength and elastic modulus of rock mass increase gradually. (3) the primary and secondary order of the influence factors on rock mass strength is as follows: the anchoring mode of pretightening force with aggregate particle size of cemented strength. The variation curves of anchor axial force with time in the Anchorage model mainly include stable stage, growth stage, yield stage and post-peak stage. (4) the influence of anchor rod density and lateral confining pressure on rock mass strength is studied by numerical software expansion. The mechanism of bolt action is analyzed from the characteristics of spatial stress distribution in the model. When the anchor rod is near, the anchor stress value decreases symmetrically from the two ends to the middle, while the anchor stress value increases symmetrically from the two ends to the middle when the anchor rod is farther away. (5) with the decrease of the bolt density, With the increase of the pre-tightening force or the size of the tray, the thickness of the combined arch increases gradually. The influence coefficient of various control factors on the thickness of composite arch is obtained by nonlinear fitting, and the geometric relationship of Anchorage composite arch is modified. (6) based on the theory of structural mechanics, the rectangle is discussed and analyzed. The bearing capacity of surrounding rock anchoring combined arch (beam) is destroyed in arch roadway, and the criterion of surrounding rock instability is determined, which is successfully applied to field engineering example analysis.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD353

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