岩土工程中的水岩相互作用实验及数值模拟研究

发布时间：2018-02-27 20:13

本文关键词： 水岩相互作用岩石气态水吸附流固耦合换热多相流模型自激振荡射流亥姆霍兹谐振器固有频率　出处：《中国矿业大学(北京)》2017年博士论文　论文类型：学位论文

【摘要】：本文充分利用岩土工程、岩土力学、流体力学和计算流体力学等相关知识,对岩土工程中若干水与岩石之间相互作用的问题进行了研究。以敦煌莫高窟围岩在当地环境下由于气态水引起风化与盐分运移的问题为背景,针对岩石与气态水的静态吸附作用进行了实验和数值模拟研究。敦煌莫高窟所处环境常年干燥,四季分明,作为人类珍贵的物质文化遗产长期受到诸多病害和风化侵蚀的威胁。目前,利用了自主研发的岩石气态水吸附试验系统,对试样的气态水吸附特性进行了研究。同时结合SEM扫描实验和X射线衍射实验,分析黏土矿物和空隙、裂隙对气态水吸附的影响。为了分离黏土矿物的作用对气态水吸附的影响,利用CFD软件对概化的不同角度裂隙的试样和随机裂隙试样中气态水的运移情况进行了模拟研究,并与实验得到岩石与气态水吸附在时间序列上的规律进行对比验证。在动态的水与岩石相互作用时,除了水分吸附,换热过程也是岩土工程中不可避免的重要课题。研究以煤矿开采中深井热害控制问题为背景,针对张集矿深井HEMS降温系统中浅层冷能提取部分的换热过程进行研究。本文讨论了巷道中流固耦合换热的问题,考虑了岩石表面粗糙度在水岩换热中的作用,同时以边界层换热取代传统设置壁函数的方法,模拟了系统浅层漫流段的低温乏风回风、系统热水媒介和浅层低温围岩的三相热流固耦合的问题。利用已有的深井热害控制现场实验系统原有参数,对本模型进行了验证,误差在5%以内,进而利用本模型对张集矿降温系统进行了数值模拟,通过控制壁面粗糙程度或是现场巷道的倾角,可以对降温系统的冷能提取进行调控,获得浅层漫流设计的一般性方法。利用本模型的模拟结果,对张集煤矿的浅层冷能提取部分的参数设计进行了优化,期望为今后降温系统的设计提供方法和思路。针对更加强烈的动态水与岩石相互作用,即高压水射流产生高能和岩石破坏的问题。结合岩土工程中对于更高速、高压和高效水射流工具的需求,以及另一方面在采矿科技革命的进行中,寻求新的高能防爆、防尘破碎和钻凿工具,例如110和N00采煤工法中的切顶需求,对自激振荡射流这一特别的水射流的能量,和其产生的震荡频率规律进行研究。通过理论模型推导,建立自激振荡射流核心元件——亥姆霍兹谐振器的固有频率计算方程。结合数值模拟的方法,对自激振荡射流喷嘴尺寸进行设计,将数值模拟得到的喷嘴震荡频率结果同公式计算结果进行比对,以期对模型进行验证和参数修正。
[Abstract]:This paper makes full use of the relevant knowledge of geotechnical engineering, geotechnical mechanics, hydrodynamics and computational fluid mechanics. The interaction between water and rock in geotechnical engineering is studied. In the context of weathering and salt migration caused by gaseous water in the surrounding rock of Dunhuang Mogao Grottoes in the local environment, The static adsorption of rock and gaseous water is studied experimentally and numerically. The environment of Dunhuang Mogao Grottoes is dry all year round with four distinct seasons. As a precious material and cultural heritage of mankind, it has been threatened by many diseases and weathering for a long time. The adsorption characteristics of gaseous water on the sample were studied, and the clay mineral and voids were analyzed by SEM scanning and X-ray diffraction. In order to separate the effect of clay minerals on the adsorption of gaseous water, the migration of gaseous water in samples with different angles and random fissures was simulated by CFD software. And compared with the experimental results, the law of adsorption of rock and gaseous water on time series is verified. In the dynamic interaction of water and rock, except water adsorption, The heat transfer process is also an inevitable and important subject in geotechnical engineering. The heat transfer process of shallow layer cold energy extraction from HEMS cooling system in deep well of Zhangji Mine is studied. The problem of fluid-solid coupling heat transfer in roadway is discussed in this paper, and the effect of rock surface roughness on water rock heat transfer is considered. At the same time, the boundary layer heat transfer is used instead of the traditional method of setting wall function to simulate the low temperature air return air in the shallow overflowing section of the system. This model is verified by using the original parameters of the existing deep well thermal hazard control field experiment system, and the error is less than 5%, which is the problem of the coupling between the hot water medium of the system and the low-temperature surrounding rock of shallow layer. Furthermore, the model is used to simulate the cooling system of Zhangji Mine. By controlling the roughness of the wall or the inclination of the roadway, the cold energy extraction of the cooling system can be controlled. The general method of shallow overflowing design is obtained. Using the simulation results of this model, the parameter design of the shallow cold energy extraction part of Zhangji Coal Mine is optimized. It is expected to provide methods and ideas for the design of cooling system in the future. In view of the more intense dynamic interaction between water and rock, that is, the high energy and rock damage caused by high pressure water jet, combined with the higher speed in geotechnical engineering, The demand for high-pressure and high-efficiency water-jet tools, and, on the other hand, the need for new high-energy explosion-proof, dust-proof and drilling tools, such as the top cutting requirements in 110 and N00 coal mining methods, in the context of the technological revolution in mining, In this paper, the energy of self-excited oscillating jet, a special water jet, and its oscillation frequency are studied. The natural frequency calculation equation of Helmholtz resonator, the core element of self-excited oscillating jet, is established. The size of self-excited oscillating jet nozzle is designed by numerical simulation. The numerical simulation results of the nozzle oscillation frequency are compared with the calculated results of the formula in order to verify the model and modify the parameters.
【学位授予单位】：中国矿业大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TU45

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