裂隙岩体泥浆流动细观分析与承压岩溶泥水突出试验研究

发布时间：2019-06-05 09:04

【摘要】：以我国南方普遍存在的红黏土为试验材料,从理论上分析泥浆在裂隙岩体中流动的影响因素,依托泥浆粘度试验和泥水突出物理试验为主要手段,结合数值分析探讨了颗粒大小以及含水率对泥浆粘度变化的影响、泥浆在水压作用下在过泥通道中流动规律、发生突泥后泥浆流量的特点以及在不同水压下发生涌突泥需要时间的规律等,对于深入认识岩溶地区突泥规律及机理、对预防与治理突泥灾害具有重要指导意义。得出主要结论如下:(1)泥浆粘度、裂隙粗糙程度、裂隙岩体所处应力状态以及渗透压等均会影响泥浆在裂隙岩体中流动特点。(2)采用PFC进行细观分析发现:刚施加水头时有极少部分颗粒进入裂隙,绝大部分颗粒是往模型中间移动,并在模型拐角处存在涡流现象;随着模型运行时间的增加,颗粒的流动方向会出现一定的变化,涡流消失,拐角处颗粒流动方向指向裂隙,其余颗粒沿垂直方向流动;研究还发现颗粒在裂隙中的流速与压力梯度并不是完全的正比例关系即与达西定律不吻合,而是近似一种“S”型曲线的关系。(3)运用NDJ-8S进行泥浆粘度试验发现:泥浆粘度的变化只与含水率有关而与颗粒粒径无关;随含水率的增加泥浆粘度变化规律分别是迅速下降、缓慢下降、趋于稳定三个阶段,在达到稳定阶段后泥浆的粘度约等于纯水的粘度5.46mpa·s;同时试验发现泥浆粘度与含水率近似呈指数函数的关系。(4)基于自行研发的“承压溶洞泥水突出试验仪器”进行一系列岩溶物理突泥试验发现:突泥一般可分为4个阶段,存在时滞突出现象,通过试验数据分析探讨了岩溶突泥后泥水压力梯度与流速的非线性关系。
[Abstract]:Taking red clay, which is common in southern China, as test material, the influencing factors of mud flow in fissured rock mass are analyzed theoretically, and the main means are mud viscosity test and mud water outburst physical test. Combined with numerical analysis, the effects of particle size and moisture content on the viscosity of mud are discussed, and the flow law of mud in mud passage under the action of water pressure is discussed. The characteristics of mud discharge after mud inrush and the law that it takes time to inrush mud under different water pressure are of great significance for deeply understanding the law and mechanism of mud inrush in Karst area and for preventing and controlling mud outburst disaster. The main conclusions are as follows: (1) mud viscosity, crack roughness, The stress state and osmotic pressure of the fracture rock mass will affect the flow characteristics of mud in the fracture rock mass. (2) it is found that very few particles enter the fracture when the water head is first applied. (2) using PFC to carry on the mesoscopic analysis, it is found that very few particles enter the fracture when the water head is first applied. Most of the particles move to the middle of the model, and there is a vortex phenomenon at the corner of the model. With the increase of the running time of the model, the flow direction of the particles will change to a certain extent, the vortex will disappear, the flow direction of the particles at the corner will point to the crack, and the other particles will flow along the vertical direction. It is also found that the velocity and pressure gradient of particles in cracks are not completely positive proportional, that is, they are not consistent with Darcy's law. It is similar to a kind of "S" curve. (3) the mud viscosity test with NDJ-8S shows that the change of mud viscosity is only related to moisture content and independent of particle size. With the increase of moisture content, the viscosity of mud decreases rapidly and slowly, and tends to be stable in three stages. After reaching the stable stage, the viscosity of mud is about equal to the viscosity of pure water 5.46mpa 路s. At the same time, it is found that the relationship between mud viscosity and water content is approximately exponential function. (4) based on the self-developed "pressure cave mud water outburst test instrument", a series of Karst physical mud outburst tests are carried out. It is found that the mud burst can generally be divided into four stages. There is a time delay outburst phenomenon. The nonlinear relationship between mud water pressure gradient and velocity after Karst mud outburst is discussed through the analysis of experimental data.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD315

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