【作者】 史海明；

【导师】 徐曾和；

【作者基本信息】 东北大学 ， 采矿工程， 2005， 硕士

【摘要】 考虑到颗粒堆积的多孔介质是可变形的，在外载荷作用下其孔隙结构、孔隙率将会发生改变，导致其渗透率不再是常数而是随着孔隙率变化的函数，因此对其渗流场进行研究时，不能再采用线性的Darcy定律应该对其做出修正。 本文首先通过颗粒堆积的人工多孔介质试样在常规三轴应力作用下的定水头渗透试验测得了不同水头H下的水的渗透速度v，同时由Darcy公式算出了不同水头H下的渗透系数K，得到了渗透速度v和水力坡度J的关系曲线及渗透系数K和水力坡度J的关系曲线；然后改变试样的轴向和侧向压力得到了一系列的v及算出一系列的K，最后通过拟合曲线得到了渗透系数K和体积应力σ_v，的关系，它们之间为负幂函数关系；渗透速度v和水力坡度J之间在水力坡度较低时不再是线性关系，当水力坡度逐渐变大时线性关系才逐渐明显了。 本文还对试样进行了常规三轴压力下的不排水固结试验，测得了试样在不同孔隙水压作用时的固结变形，通过整理与分析试验数据发现固结变形与孔隙压力之间不是线性的关系，有效应力定律中的孔隙压力系数应该是孔隙压力和体积应力的函数。 最后本文研究了双重孔隙介质的孔隙压力耦合渗流问题，建立了双重孔隙介质的物理模型和数学模型，得出了求解渗流场的控制方程和边界条件，形成了定解问题，然后通过有效容积法求解定解问题，得到了双重孔隙介质中小颗粒间的孔隙压力P₁和大颗粒间的孔隙压力P₂的分布曲线关系；最后通过改变参数得到了不同颗粒粒径、不同孔隙率以及不同时间的孔隙压力分布曲线，发现大颗粒参数的变化对P₁和P₂的大小及分布规律影响显著，小颗粒参数的变化对P₁影响明显而对P₂影响不是太明显；颗粒粒径影响孔隙压力之间的相对大小关系，小颗粒间的孔隙压力P₁明显小于大颗粒间的孔隙压力P₂；孔隙率的大小会影响孔隙压力的绝对大小关系，大颗粒堆积体的孔隙率越大P₁和P₂的值相对就越大；当时间足够大时，孔隙压力P₁和P₂将会相等，且它们的压力梯度为常数。更多还原

【Abstract】 Considering the porous media is deformable, so the pore structure and the pore volume will change under the outer stress. It leads to a changeful permeability according to pore volume. Under this condition ,the linear Darcy Law is not valid when the seepage profile is studied. We must retrofit the linear Darcy Law.In this paper, the manual porous test piece is studied under the conventional three triaxial pressure. Through the experiment, the seepage velocity is obtained with the varied pressure head. Then the permeability can be derived from the Darcy Law. At the same time, the curve about velocity, permeability and hydraulic gradient could be received. After that, a serial of velocities and permeability can be met by changing axial and side stress. At last the curve about permeability and volume stress can be get through fitting. The fitting function is a negative power function. This shows that the seepage velocity and the hydraulic gradient is not satisfied the linear relation when then hydraulic gradient is very small. The linear relation will be more obvious with the heighten of the hydraulic gradient.The consolidation test without draining under normal three axial stress is also studied in this paper. The sample clotted deformation is recorded with different pore hydraulic pressure. It is found that the clotted deformation and the pore pressure is not fitting linear relation, and the pore pressure coefficient should be the function of pore pressure and volume stress in the law of effective stress.At last, the pore pressure in the double porous media coupled with pore deformation is studied. The physical model and physical model are both founded, also the control equations and boundary conditions, the solvable problem is formed. On this ground, the small pellets pore pressure P₁ and the bigger pellets pore pressure P₂ can be got in the double pore media by volume control numerical technique. Then through changing parameters, the pore pressure profile had been received under different pellet diameter pore volume and time. It has been found that the parameters about bigger pellets have more obvious influence on the profile of P₁ and P₂ than that of small pellets. It is just contrary when it comes to the pore pressure. The pore volume will effect the pore pressure and the bigger the pore volume, the bigger the pressure P₁ to P₂. When the time is long enough, the pressure P₁ and P₂ will be equal, also their pressure gradient will be constant.更多还原