【作者】 宋良；

【导师】 刘卫群；

【作者基本信息】 中国矿业大学 ， 工程力学， 2013， 博士

【摘要】 天然裂隙中一般含有泥沙等沉积物，沉积物随水流运移和对裂隙的填堵作用可以显著改变裂隙岩体的渗透性，进而影响地下水位和地层孔隙压力分布。地下水位改变会影响地下水的供给和油、气等资源的生产。水位变化导致的地层孔隙压力上升会使砂土产生大面积液化，从而引起地表位移或沉降，并造成一系列地质灾害。本文综合运用试验测试、理论分析和数值模拟等方法，研究了颗粒在岩体裂隙中的动力学行为以及对裂隙渗透性的影响规律，并从泥沙颗粒作用的角度探讨了地震引起的远场地下水位响应模式和变化幅度，取得了如下研究成果：(1)自行设计了一种岩体裂隙渗流试验系统，有效测试了非接触型单裂隙含沙渗流特性；建立了基于颗粒碰撞和能量损失的裂隙渗透系数计算模型，得到了颗粒运移条件下裂隙渗透特性与颗粒体积分数、颗粒粒径和渗流速度的关系；(2)完成了接触型单裂隙含沙渗流试验，以试验现象和结果为依据，建立了考虑颗粒填堵作用的裂隙渗透率计算模型，得到了颗粒在裂隙中的填堵分布规律，研究了颗粒填堵作用对裂隙渗透率和裂隙空间水压分布的影响；(3)自行设计并组建了一种可加载的裂隙岩体渗流试验系统，测试了不同法向应力条件下接触型单裂隙的含沙渗流特性，得到了裂隙填堵颗粒分布和渗透率随法向应力的变化趋势；(4)试验研究了“人”字型裂隙偏流规律及流量分配特征，建立了考虑局部压力损失的交叉裂隙偏流计算模型；从试验和理论方面分析了交叉角度、渗流速度和隙宽组合对裂隙系统渗透特性和流量分配的影响；(5)采用数值模拟的方法分析了“人”字型裂隙交叉区域的水流运动特征，提出了交叉区域平均水速分布假设；建立了交叉裂隙含沙渗流泥沙分配动力学模型，探讨了裂隙系统水、沙偏流的不均等性；结合“人”字型裂隙含沙渗流测试，研究了水流分配比、颗粒体积分数、渗流速度和颗粒粒径对泥沙分配的作用规律；(6)试验分析了地震波造成的远场地下水流量波动对含沉积物裂隙渗透特性的影响，建立了考虑泥沙颗粒作用的地震远场井水位阶变和缓变响应模型，研究了震后远场井水位阶变响应形式及水位变化幅度与沉积物作用和观测井位置之间的关系，分析了震后井水位随时间的变化趋势，说明了模型的有效性。本文研究成果可为工程岩体渗流计算、地震水力响应机理以及地震地下监测、预报等方面的研究提供重要参考。更多还原

【Abstract】 Large quantities of soils and sediments are distributed widely in natural faults. Inrock fractures sediments also often get mobilized and clogged, changing thepermeability of underground fractured rock significantly. The changed permeabilitycan lead to the variation of groundwater level, which can affect the production of oil,gas and other resources. The rise of the pore pressure caused by the changed ofgroundwater level often makes liquefaction massively, and then, surface subsidenceand a series of geological disasters will break out. In this paper, the dynamic behaviorof particles and its influence on permeability of fractured rock are studied by testing,theoretical analysis and numerical simulation comprehensively. Considering thesediment effect, response model and variation range of the underground water levelcaused by the earthquake in the far field is discussed. The main research achievementsare as follows:(1) A system for testing flow in rock fracture is designed which effectively teststhe characteristics of flow in a non-contact single fracture with sand. Calculationmodel of the fracture permeability coefficient is established based on particle collisionand energy loss, and the relationship of particle volume concentration, particle sizeand flow velocity with the flow characteristic in non-contact fractures under thecondition of particle migration is obtained;(2) The test for flow in contact single fractures with sand is accomplished. Basedon the phenomena and results of the experiment, calculation model of permeabilityconsidering the particles clogging effect is set up. The particle clog distribution infracture space is obtained, and the influence of particles clog on permeability and thewater pressure distribution in fractures are researched;(3) A system for testing flow in fractured rock under normal and shear stress isdesigned, by which we effectively test the flow characteristics in a contact singlefracture with sand under different normal stress. The influence of normal stress onparticles clog distribution in fracture space and induced changes of permeability forfractured rock is established;(4) The permeability characteristic and flow distribution in herringbone fractureis researched by experiments. The calculation model for deflection flow in theherringbone fracture considering the local pressure loss is built. The effects ofcrossing angle, flow velocity and fracture aperture combination on permeability characteristic and flow distribution are analyzed by both experiment and theory;(5) Through numerical simulation method, we analyze the flow motion feature inintersection region of the herringbone fracture. Assumption of the average flowvelocity distribution in intersection region is put forward and verified. We build thesediment distribution dynamic model for flow in the herringbone fracture with sandand discuss the inequality between water and sand distribution. Combined with theexperiments of flow in herringbone intersection fracture with sand, we also discussthe relationship of flow distribution ratio, particle volume concentration, flow velocityand particle size with particle distribution;(6) Experimental Analyzing the underground water flow fluctuation in the farfield caused by seismic wave，the response model of step-like change and slowlyvarying change of well water level in the far field considering particles effect is built.The relationships of the response form and magnitude for step-like changes of wellwater level after earthquake with sediment effect and observation wells location isresearched. We also verified the availability of the model by analyzing the law ofslowly varying change for the well water level after earthquake.The research achievements in this paper can provide important references for theresearch of calculation for seepage in engineering rock mass, earthquake hydraulicresponse mechanism, earthquake underground monitoring and forecasting and so on.更多还原