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基于格子Boltzmann方法的地下突水数值模拟
Simulation of Underground Water Inrush Based on Lattice Boltzmann Method
【作者】 王伟;
【导师】 黄光球;
【作者基本信息】 西安建筑科技大学 , 采矿工程, 2011, 硕士
【摘要】 巷道突水是指开采矿层时,在水压和矿压等因素综合作用下,底板含水层内的地下水突破矿层或含水层间的相对隔水层,沿断层、节理等结构面突然涌入矿井的现象。巷道突水是一种与工程和采矿活动有关的诱发性地质灾害,是工程地质问题。大量突水,不仅淹没巷道和井巷,还能导致塌方和围岩失稳,甚至造成人身伤亡、工程报废的灾难性结果。因此选择科学的方法,研究地下突水在巷道内的变化情况和运行规律,对于我们提高矿山生产安全,保障人员财产有重要的指导意义。通过阅读大量的文献资料,了解了目前国内外学者在地下突水方面的研究的现状,发现学者在突水数值模拟方面所做的研究相对来说少一些,其中以东北大学和中国矿业大学为主,且采用有限元方法结合FLAC软件进行模拟,解决方法较为单一。所以本文选择在诸多领域已经有很好研究成果的格子Boltzmann来对地下突水情况进行研究。首先研究了一个二维巷道的突水过程。通过介绍D2Q9模型来向大家介绍格子Boltzmann的方法原理。为了提高模拟的可靠性和精度,我们选择了Guo等人提出的针对类似于水一样的不可压缩流体的G2Q9模型。在进行边界处理的时候,根据不同的边界情况,我们选择了不同的解决方法。对于平直边界来说,我们选用了修正的反弹格式进行处理,对于那些不规则的边界来说,我们选用BFL进行曲面边界的处理。同时由于巷道结构的复杂,为了降低运算量,提高运算的效率,我们使用分块耦合的方法对巷道进行了相应的处理。最后通过一个实例模拟来验证我们的理论。其次针对突水抢救的两种方式进行了数值模拟,提出堵式模拟和疏式模拟模型。对于堵式模拟,我们建立了相应的突水阻滞模型,使用BFL进行边界的处理。通过模拟挡水墙的完成情况,我们得到了不同时刻的巷道内的压力、速度、流向等结果,分析这些结果,我们可以比较清楚的看到这种方法对于巷道内压力,速度,水流方向的改变都有一定的作用,符合我们的预期情况。对于疏式模拟,我们建立了相应的抽放模型,并使用作用力的方式来模拟抽水机的原理,最后通过对比有压力和无压力下的两种状况,得到的各种压力图,速度图,流线图等结果满足了我们的期望值。最后为了直观清楚的了解LBM方法在巷道突水方面的模拟作用,我们在前两章的基础上,我们选用D3Q15模型来对三维巷道的突水情况进行模拟。最后也通过一个实例模拟来验证了我们的理论。如何简化处理复杂的巷道问题,如何选用合适的Boltzmann模型,如何进行网格边界的处理,如何提高程序的运行效率,如何得到满意的仿真结果,这些都是本文的研究重点。本文的研究对于矿山开发,综合治理,以及相关技术的研究提供了方法参考和研究依据。
【Abstract】 ?Tunnel water-inrush in tunnel is a phenomenon that means groundwater in the bottom aquifer breaks mine seam or relatively impermeable layer between aquifers along faults, joints and other structural plane inrush mine suddenly, under the combined effects of factors such as the water pressure and rock pressure, when the mine was exploited Tunnel water-inrush is a induced geological disasters which related with engineering and mining activities. It is engineering geological problems. Large inrush of water is not only flooded mine tunnel , but also can cause collapse and rock unstable, or even result in disastrous results like personal injury and construction scrapped. So it has important guiding significance in improve mine safety and guarantee officers and properties for us selecting scientific method to study the water-inrush changes and movement law in tunnel.I understand the research status in water-inrush from domestic and foreign scholars after reading large amount of literatures. And find that there is a relatively small number scholar to study water-inrush simulation, in which Northeastern University and China University of Mining and Technology are stay on top. They simulate the water-inrush combined the finite element method and FLAC software, the solution is relatively homogeneous. So the paper adapts Lattice Boltzmann Method to simulate tunnel water-inrush, which has a lot of great research result in many fields.We study a two-dimensional tunnel water inrush process at first. The principle of lattice Boltzmann method was introduced by introducing D2Q9 model. In order to improve the reliability and accuracy of simulation, we choose the G2Q9 model is to handle incompressible fluid like water, which was proposed by Guo. We choose different solutions to deal with boundary treatment according different boundary conditions. The bounce-back scheme on a straight boundary and the BFL scheme on a curved boundary were adopted respectively. Because of the complex of tunnel structure, we use separated-coupled algorithm to handle the corresponding boundary in order to reduce computation and improve the efficiency of operations. Finally an example simulation was to verify our theory.Then we simulate two methods that rescue the water inrush and proposed block-style simulation model and emission-style simulation model. For block-style simulation, we established a corresponding inrush block model, using the BFL to process the border. We get the press, speed, flow and other result of tunnel at different time according to the completion of retaining wall. After analysis these results, we think that the results is in line with our expectations. We also established the corresponding drainage model for emission-style simulation and use force to simulate the principles of pumps. And finally the results that instruct the press graph, speed chart ,flow charts and others was got by comparing the two conditions that are under the pressure and stress-free. The results meet our expectation.Finally, in order to understanding about the role that simulate water inrush based on LBM method more clearly, we select D3Q15 model for three-dimensional water inrush simulation which based on the first and second chapters. A simulation case is also verifies our theory at last.How to simplify the complex tunnel, how to select the appropriate Boltzmann models, how to deal with the grid boundaries, how to improve the efficiency of the program, how to get a satisfactory simulation results, all are the focus of the study. This study has also provided the reference and research basis for mine development, comprehensive management and related technology research.
【Key words】 tunnel water-inrush; lattice Boltzmann method; boundary treatment; meshing; computer numeric simulation;