【作者】 张亮亮；

【导师】 顾金才； 夏元友；

【作者基本信息】 武汉理工大学 ， 岩土工程， 2009， 博士

【摘要】 为研究集中装药爆炸条件下抗爆洞室不同部位的3种结构形式(自由式、全长粘结式和半全长粘结式)预应力锚索受力特征,在“岩土工程抗爆结构模型试验装置”上进行了锚固洞室抗爆性能的地质力学模型试验。运用有限差分显式软件分析了预应力锚索抗爆加固效果,对抗爆洞室不同部位预应力锚索受力特征进行了深入地分析,针对预应力锚索加固设计参数进行了数值试验。最后给出了洞室锚固体动态响应解析解,并提出相应工程建议。主要工作内容如下：1.基于模型相似理论基本原理,以及抗爆结构锚固洞室模型试验研究内容、试验简化假设条件,确定了模拟岩体、锚索与注浆体材料力学参数以及模型洞室尺寸,简要说明了试验装置组成与功能指标,概述了模型岩体和模拟锚索的制作、安装工艺以及相关模型试验技术,着重从压力传感器、加速度传感器、相对位移传感器、锚索张力传感器、锚索体轴向变形测试方面说明了动力测试系统中传感器技术。从洞室拱部脱落面积统计、洞室破坏录像等观察角度更全面、更形象地描述锚固洞室抗常规武器加固效果。2.通过3组抗爆结构模型试验,分析了爆炸荷载作用下洞室围岩介质压力、洞室顶底相对位移、洞壁表面应变和顶底板加速度的时程曲线,研究了预应力锚索加固洞室的抗爆性能,拟合出自由场压应力峰值衰减公式以及地冲击波传播速度。记录了不同试验方案下的拱顶及边墙部位上预应力锚索索端张力及内锚固段轴应变时程,着重分析了顶爆条件下预应力锚索的动力响应和破坏机理。3.采用有限差分软件FLAC3D分别建立了自由式预应力锚索加固洞室的分析模型,探讨了爆腔-围岩-结构相互作用模型数值分析方法,并对比模型试验成果进行计算可靠性分析。结果表明：在动力分析模块模型中预留球形爆腔并施加初始法向应力方式可以模拟炸药爆炸效果；霍克-布朗模型可以用在动力模块分析素混凝土动力响应问题,且较符合实际；通过施加静态边界条件较符合抗爆结构洞室小型模型分析；单元网格长度选择最高频率对应的波长的1／10,尽量保证网格划分充分均匀；重力作用实现是按重力加速度以动力荷载方式加入到计算模型中的；采用瑞利阻尼可以考察爆炸波传播影响过程。4.利用数值试验研究了洞室不同部位上自由式锚索、全长粘结式锚索和半全长粘结式预应力锚索的受力特征。针对粘结式锚索加固参数(内锚固长度、注浆体与锚索弹性模量、锚索间距和布置方式)进行了多组数值试验,获得了半粘结式预应力锚索设计参数的合理值范围,为工程设计提供参考。5.简述了应力脉冲在两种介质传播以及自由分界面时反射与折射的基本概念。依据行波能量吸收方法推导出了锚杆受爆炸波冲击时所需张力增量计算公式。系统分析了模型试验中预应力锚索内锚固段上所受的“拖曳”作用,认为产生原因主要是爆炸成坑作用时产生抵抗岩体抛掷的惯性力引起的。更多还原

【Abstract】 To study force characteristics of pre-stressed anchor （freestyle, full-length bond-type and semi-full bond-type） in the antiknock chamber effected by concentrated explosive charge, the geo-mechanical model for researching antiknock properties of the anchor chamber in the "Test device of geotechnical engineering antiknock structure model" is tested. The numerical analysis model was established by the use of explicit finite difference algorithm for learning of the antiknock reinforced effect of prestressed cable, and the stress characteristic of prestressed cable in different site of antiknock chamber is analyzed. And the reinforced design factor is analyzed for the semi-full bond-type cable. Finally, the analytical solution of the dynamic response of anchorage chamber is shown to make appropriate project proposal. Main tasks are as follows:1. According to the similarity theory, the research contents and the assumptions of the antiknock model test, the mechanical parameters of rock mass, cables as well as grouting material, and the size of chamber model were determined. The equipment composition and the function index of "Test device of geotechnical engineering antiknock structure model" is described briefly. After blocking, the production of the simulated cable, the installation process and the associated model test technique were overviewed. The sensor technology in testing system was illustrated mainly from the aspects of the pressure sensors, acceleration sensors, the relative displacement sensors, cable tension sensor, and anchor body axial deformation tests. For describing the reinforcing effect of anti-conventional weapons anchored chamber more completely and vividly, the research was done from several observing angles such as the statistics of the shedding area of the anchorage, the failure video of the chamber and so on.2. Through 3 groups of antiknock structural model test, the wave curve of the wall-rock pressure of the anchorage chamber, the relative displacement from top to bottom, the surface strain of the tunnel wall, and the acceleration of roof and floor is gain to analysis. And then, the antiknock performance of the prestressed anchorage chamber was studied. And, the peak attenuation low of the free-field stress and the propagation velocity of wave were fitted. By analyzing the time history of the axis strain and the tension of the cable end in the vault and the side wall in different experiment plans, the dynamic response and the failure mechanism of the prestressed cable under the condition of the top explosion were researched.3. Useing the finite difference software FLAC^3D to building the analysis of freestyle prestressed cable reinforcement chamber model, the explosion cavity-rock-structure interaction model for numerical analysis methods were discussed, and the calculating reliability were contrasted to the model test results. The results show that:to reserve spherical explosion chamber and impose the initial normal stress method could realize the effect of explosive detonation in the dynamic analysis module; Hawk-Brown model can be used for dynamic response analysis of plain concrete; imposing the static boundary conditions could treat with a small model analysis such as antiknock structural model test; the element mesh is the highest frequency corresponds to the 1/10 length of the wavelength to ensure the full uniform mesh; the gravity acceleration is adopted to achieve dynamic load added to the calculation model; using of Rayleigh damping could realize the process of blast wave propagation effects.4. The anti-knock ability of chamber supported by freestyle anchor, full-length bond-type anchor and semi-full-length bond-type prestressed anchorage cable are examined by numerical analysis. Some sets of numerical experiment for the bond-type anchor reinforcement parameters including internal anchorage length, elastic modulus of anchor grouting, anchor spacing and layout were done, to obtain the reasonable value range design parameters of bonding prestressed anchorage cable, and refer to engineering design.5. The basic conception about the dissemination in two kinds of media and the reflection and refraction on the free sub-interface of stress pulse were described. Based on the basis of traveling wave energy absorption method, the formula of allow tension increment of anchorage cable under condition of the blast wave shock is derived. The "drag" role of prestressed anchor interior bond section in the model test is analyzed systematically, which is caused by resistance of rock thrown during exploding into a pit.更多还原