应力作用下破碎岩体变形与水沙渗流特性试验研究

发布时间：2018-03-15 12:51

本文选题：破碎岩体　切入点：突水溃沙　出处：《中国矿业大学》2016年博士论文　论文类型：学位论文

【摘要】：采动岩体水沙渗流特性研究是关系煤矿安全的一项重要课题。岩体由于采动引起结构破坏,产生的破碎岩体往往处于围压之下。本文自行研制了一套加载设备相配套的渗透试验设备对应力作用下破碎岩体变形与水沙渗流特性进行研究,取得了如下创新性成果:(1)为了研究应力作用下破碎岩体变形与水沙渗流特性,自行研制了一套与加载设备相匹配的渗流试验设备。使破碎岩体能够在应力下发生流变,研究流变后的破碎岩体的水沙渗流特性。该渗流设备能模拟围压下破碎岩体的流变变形;破碎岩体与沙粒分层,沙粒受水流搅动后形成水沙混合物流入破碎岩体的情况。可为同类试验以及相关后续的扩展研究提供参考方法。(2)利用自行研制的应力作用下破碎岩体水沙渗流试验系统,研究了不同应力水平、不同粒径级配对破碎岩体流变特性与水沙渗流特性的影响。破碎岩体压实流变过程中,流变模型的弹模、粘度等参数是不停的随时间变化的。根据破碎岩体流变试验结果,基于分数阶微积分理论与三参量流变模型,引入分数阶Abel粘壶替代牛顿粘壶,获得了一个新的分数阶流变模型,并推导了岩石在恒应力条件下的三维蠕变本构方程;分析了破碎岩体流变对水沙渗流特性的影响。(3)破碎岩体水沙渗流过程中,一部分沙粒流入破碎岩体后被截留,占据了部分空隙,改变了破碎岩体的孔隙率。拟合了不同粒径级配的破碎岩体在两种渗流组合的情况下,初始孔隙率与渗透率的关系式;拟合了不同粒径级配的破碎岩体的溃沙、滤沙能力与破碎岩体初始孔隙率的关系曲线。对破碎岩体进行应力加载(流变变形)与位移加载两种方式使破碎岩体发生压缩变形以研究不同的加载方式对破碎岩体水沙渗流特性的影响。(4)当破碎岩体中发生水沙渗流情况时,在一定情况下,沙粒不能够完全通过破碎岩体,破碎岩体对沙粒的过滤作用进而导致破碎岩体骨架属性变化,破碎岩体的对沙粒的过滤能力是对其渗流特性影响的一项重要因素。根据试验结果提出了考虑渗流长度的破碎岩体筛层模型,并对破碎岩体等效厚度与破碎岩体初始孔隙率的关系进行了研究,给出了建议的计算公式,基于颗粒离散元软件(PFC)进行了破碎岩体水沙渗流数值模拟。可为破碎岩体水沙渗流灾害的预测提供参考。
[Abstract]:The study on seepage characteristics of mining rock mass is an important subject related to coal mine safety. The broken rock mass is often under confining pressure. In this paper, a set of osmotic test equipment with loading equipment is developed to study the deformation of broken rock mass and seepage characteristics of water and sediment under stress. In order to study the deformation of broken rock mass and the seepage characteristics of water and sediment under stress, a set of seepage test equipment matching the loading equipment was developed to make the broken rock mass rheological under stress. The characteristics of water and sediment seepage in fractured rock mass after rheology are studied. The seepage equipment can simulate the rheological deformation of broken rock mass under confining pressure. Sand particles are agitated by water and sand to form a mixture of water and sediment flowing into broken rock mass. It can provide a reference method for the similar test and related extended research. 2) using the self-developed water and sediment seepage test system of broken rock mass under the action of stress. The effects of different stress levels and particle size gradation on the rheological characteristics and seepage characteristics of fractured rock mass are studied. The elastic modulus of rheological model during compaction rheological process of broken rock mass is studied. According to the rheological test results of broken rock mass, based on fractional calculus theory and three-parameter rheological model, fractional Abel clay pot is introduced to replace Newtonian viscosity pot. A new fractional order rheological model is obtained, and the three-dimensional creep constitutive equation of rock under constant stress is derived, and the influence of the rheology of broken rock mass on the seepage characteristics of water and sediment is analyzed. Some of the sand particles were cut off after flowing into the broken rock mass, which occupied part of the void and changed the porosity of the broken rock mass. The relationship between the initial porosity and the permeability of the broken rock mass with different particle size gradation in the case of two kinds of seepage combinations was fitted. The sand collapse of broken rock mass with different particle size gradation is fitted. The relation curve between sand filtration capacity and initial porosity of broken rock mass. Stress loading (rheological deformation) and displacement loading on broken rock mass make the fractured rock mass compress and deform in order to study the different loading ways to break the rock mass. The influence of seepage characteristics of rock mass water and sediment. (4) when water and sediment seepage occurs in broken rock mass, Under certain circumstances, sand particles can not completely pass through the broken rock mass, and the filtration effect of broken rock mass on the sand grain will lead to the change of the property of the broken rock mass skeleton. The filtration ability of broken rock mass to sand particles is an important factor affecting its seepage characteristics. Based on the experimental results, a model of sieve layer of broken rock mass considering seepage length is proposed. The relationship between the equivalent thickness of broken rock mass and the initial porosity of broken rock mass is studied, and the suggested calculation formula is given. Based on the particle discrete element software (PFC), the numerical simulation of water and sediment seepage in broken rock mass is carried out, which can provide a reference for prediction of water and sediment seepage disaster in broken rock mass.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TU45

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