梯度应力路径下加—卸荷岩爆试验及颗粒流模拟研究

发布时间：2018-06-09 05:44

本文选题：岩爆 + 应力路径　；参考：《武汉理工大学》2014年硕士论文

【摘要】：随着我国社会经济的发展，人们对资源和生存空间的需求越来越大，大规模深部矿产资源的开采，超深隧道的开挖，以及国防防护工程对深部地下工程的要求，必将进一步加深地下工程深化。然而，岩爆是伴随着深部工程常见的一种灾害，随着工程埋深的增加或应力水平的增高，我国地下工程的岩爆呈频发趋势。越来越多的人开始对发生岩爆的机理进行研究，但由于岩爆发生环境的复杂性，对岩爆机理的研究还不够成熟，因而，对发生岩爆机理的研究具有重要的意义。论文在高等学校博士学科点专项科研基金（20110143110017）的支持下，通过室内自制岩爆模拟试验装置，对1000mm×400mm×600mm大尺寸高强度石膏试件进行梯度应力路径下不同围压卸载试验，以及PFC2D数值模拟，系统研究了梯度应力路径对岩爆的影响。论文主要工作与研究成果如下：（1）通过单轴与常规三轴试验，对不同配比石膏试件力学特性进行试验，选取了具有中等岩爆倾向的水膏比为0.7的配比试件作为岩爆试件。岩爆模拟试验结果表明：在梯度应力路径作用下，高围压卸载与低围压卸载试验在出现岩爆破坏时，卸载面附近的测点应变均出现突变，破坏主要发生在卸载面附近；但由于高围压卸载，在加载过程中，对能量有一个积蓄过程，在卸载前，裂纹扩展相当较慢，而低围压卸载由于初始阶段就开始卸载，随着加载，裂隙不断扩展，能量不断释放，最后破坏时高围压卸载出现的岩爆烈度要高于低围压卸载试验；低围压卸载由于裂隙不断的产生，最后破坏时相对高围压卸载试验提前，承载强度也有所降低。（2）通过PFC2D对数值模型材料细观参数进行反复调试，得到模型试件的宏观参数与室内模型宏观参数基本吻合。通过对室内模型试验两种加载方案进行数值模拟，并与室内试验结果对比，结果有较好的一致性。数值模拟结果表明：高围压卸载岩爆更具有突发性，烈度要高于低围压卸载；两方案发生岩爆部位主要集中在卸载面中下部，且高围压卸载出现岩爆破坏部位要低于低围压卸载。数值模拟结果还表明岩爆的发生是一个渐进破坏的过程，裂隙的产生以及贯通是岩爆的发生前提。（3）在PFC2D梯度应力路径对岩爆影响分析研究中，设计了7种应力路径进行加卸载分析研究，分析了梯度应力路径对岩爆烈度、岩爆破坏范围、以及发生岩爆最大切向应力等影响。结果表明：1）不同的梯度应力路径对应岩爆烈度有较大的影响，其中均布应力加载所表现出岩爆的烈度要远远超过梯度应力加载；2）隧道开挖半径越大，应力梯度范围也越大，此时对应发生岩爆的应力路径曲线坡率越小，发生初始岩爆所需岩爆最大切向应力会变小；3）应力梯度路径的变化对卸载面所发生岩爆的部位有一定的影响；应力梯度加载范围越大，，裂纹扩展路径范围越大，表现出破坏范围也越大；而且梯度范围较大时表现出破坏区域为楔形状，而梯度较小所表现出的形状为锅底状。
[Abstract]:With the development of China's social and economic development, the demand for resources and living space is increasing. The exploitation of deep mineral resources, the excavation of ultra deep tunnels, and the requirements of the defense engineering for deep underground engineering will deepen the deepening of the underground engineering. However, the rock burst is a common disaster accompanied by deep engineering. With the increase of the buried depth of the project or the increase of stress level, the rock burst of underground engineering in our country tends to be frequent. More and more people begin to study the mechanism of rock burst, but because of the complexity of the rock explosion environment, the study of the mechanism of rock burst is not mature enough, therefore, it is of great significance to study the mechanism of rock burst.
Under the support of the special scientific research fund (20110143110017) of the doctoral academic point of Higher Education (20110143110017), the paper carried out the different confining pressure unloading tests under the gradient stress path and the numerical simulation of the PFC2D number under the gradient stress path through the indoor self-made rock burst simulation test device. The gradient stress path was systematically studied for the rock burst. The main work and research results are as follows:
(1) through the uniaxial and conventional three axis tests, the mechanical characteristics of the gypsum specimens with different proportions are tested, and the ratio of the mixture of water paste with medium rock burst to 0.7 is selected as the rock burst test. The result of the rock burst simulation test shows that under the action of the gradient stress path, the high confining pressure unloading and the low confining pressure unloading test occur in the rock burst failure. The strain of the measuring point near the unloading surface is abrupt, and the damage mainly occurs near the unloading surface. However, due to the high confining pressure unloading, there is a accumulation process of energy in the loading process. The crack propagation is rather slow before unloading, and the low confining pressure unloading begins to unload due to the initial stage. With the loading, the crack expands and the energy is constant with the loading. The rock burst intensity of high confining pressure unloading is higher than that of low confining pressure unloading test, while low confining pressure unloading is produced by low confining pressure unloading, and the relative high confining pressure unloading test is ahead of time and the bearing strength decreases.
(2) the microscopic parameters of the material of the numerical model are repeatedly debugged through PFC2D, and the macroscopic parameters of the model specimen are basically consistent with the macro parameters of the indoor model. Through the numerical simulation of the indoor model test, two loading schemes are carried out, and the results are in good agreement with the laboratory test results. The results of the numerical simulation show that the high confining pressure is high. The unloading rock burst is more unexpected and the intensity is higher than the low confining pressure unloading; the rock burst part of the two scheme mainly concentrates on the middle and lower part of the unloading surface, and the rock burst damage location of the high confining pressure unloading is lower than the low confining pressure unloading. The numerical simulation results also indicate that the occurrence of rock burst is a progressive failure process, the formation of the crack and the penetration of rock are rock. The precondition of the explosion.
(3) in the analysis of the influence of PFC2D gradient stress path on rock burst, 7 stress paths are designed and unloaded analysis is designed. The effects of gradient stress path on rock burst intensity, rock burst damage range, and rock burst maximum tangential stress are analyzed. The results show that 1) the different gradient stress path has a larger shadow corresponding to the rock burst intensity. The intensity of the rock burst is far more than the gradient stress loading; 2) the greater the radius of the tunnel excavation, the greater the stress gradient range, the smaller the slope rate of the stress path curve of the rock burst, the smaller the maximum tangential stress of the initial rock burst, and 3) the variation of the stress gradient path is unloaded. There is a certain influence on the site of rock burst occurring on the surface. The larger the stress gradient, the larger the range of the crack propagation path, the larger the damage range, and the failure area is the wedge shape when the gradient range is larger, and the smaller the gradient is the bottom of the pot.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U451.2

【参考文献】