【作者】 陈红江；

【导师】 李夕兵；

【作者基本信息】 中南大学 ， 采矿工程， 2010， 博士

【摘要】 裂隙岩体内部富含各种缺陷,包括微裂纹、孔隙以及节理裂隙等宏观非连续面,这些存在的缺陷不但大大地改变了岩体的力学性质,而且也严重影响着岩体的渗透特性,因而裂隙岩体具有复杂的力学特性和渗透特性。应力-损伤-渗流耦合是指裂隙中的渗流水压力加剧岩体裂隙的起裂、扩展、贯通,导致岩体中应力场和损伤场的改变；而岩体应力的改变和岩体裂隙的损伤扩展,又导致裂隙岩体渗透特性变化,进而改变渗流场的分布。本文重点研究了裂隙岩体的应力-损伤-渗流耦合过程,揭示了岩体裂隙在应力-损伤-渗流耦合状态下裂隙的起裂、扩展、贯通规律,探求了裂隙岩体在应力-损伤-渗流耦合状态下由于其裂隙的扩展贯通而导致破坏的机理,进而揭示了含水裂隙岩体失稳破坏的原因。该耦合理论在预防采矿工程中的矿井突水、水利水电工程中的大坝失稳破坏以及水下隧道工程突(涌)水等方面有着广泛的应用前景。本文结合国家重点基础研究发展973计划项目(2007CB209402：矿井突水的动力学特征及控制因素)和山东省黄金集团相关科研项目的共同资助下开展理论和应用研究,主要开展的研究工作如下：(1)理论分析研究：将断裂力学和损伤力学相结合,对渗透水压作用下裂隙岩体的损伤断裂力学性质进行研究；探讨压剪、拉剪应力状态下及渗透水压力作用下裂隙岩体中张开型裂纹闭合、起裂、分支裂纹扩展、相邻裂纹间岩桥断裂破坏及贯穿等的规律；给出渗透水压力-压(拉)剪应力共同作用下岩石裂隙变化发展规律。(2)力学试验研究：设计制作含预置裂纹圆柱体岩石试样(φ50mm×100mm)的模具,可根据需要制作单、双预置裂纹的类岩石试件；在原有2000KN伺服试验机设备的基础上,设计开发三轴室、水压加载系统和围压加载系统,改进后的试验装置可完成完整类岩石试件应力应变-渗透率试验和渗透水压-应力耦合作用下含预置裂隙岩石试件破坏过程的试验；进行含预置裂隙类岩石试件的常规单轴试验并使用声发射仪对试验过程进行监测,并用离散元软件PFC对单轴试验过程进行数值模拟；运用RFPA-flow模拟分析在渗透水压力作用下,含预置裂隙岩石的破坏过程,并与试验结果进行了对比,通过应力场和渗流场的图形显示观察到岩石试件中裂纹的萌生、扩展、贯通直至整个结构破裂的全过程。(3)本构推导研究：研究拉、压剪应力及渗透水压力共同作用下,裂隙岩体的损伤演化特性；推导考虑渗透水压力作用的裂隙岩体弹塑性断裂损伤本构关系方程和裂隙岩体损伤演化方程；建立应力-渗流-耦合作用下裂隙岩体渗透张量演化方程。(4)物理模拟研究：以海下开采矿井突水灾害为研究目标,开发设计“矿山突水机理及渗流特性研究试验机”。采用重晶石粉、液体石蜡、固体石蜡和河沙等材料配置用于模拟流固耦合相似物理模型试验的非亲水性相似材料；以三山岛海下开采为工程实例,针对海下矿山开采的最小顶板安全厚度问题进行相似物理模拟试验研究；试验结果证明该试验系统的研制对于考虑渗流-应力耦合作用的深部开采承压突水的宏细观机制试验和理论研究具有重要的理论意义和实用价值。(5)数值分析研究：推导出包含离散介质和拟连续介质的双重介质渗流应力耦合模型；详细介绍了有限元程序自动生成系统FEPG的原理、文件组成以及使用方法等。根据裂隙节理调查数据,利用Monte-Carlo模拟技术生成岩体裂隙网络,通过VB编写程序将裂隙面控制点坐标导出,再用Ansys调用裂隙面控制点坐标文件,使用Ansys对整体裂隙岩体进行网格划分,然后将所建数值模型导入FLAC3D,运用FISH编写孔隙-裂隙岩体介质流固耦合分析计算程序,数值模拟的最终结果通过Tecplot软件输出。(6)工程应用研究：编写SURPAC三维地质模型转化为FLAC3D数值计算模型的接口程序,实现SURPAC三维地质模型与数值模拟的耦合,使快速、便捷地建立较复杂的FLAC3D计算模型成为现实；然后运用FISH扩展建立了基于FLAC3D的裂隙岩体渗流应力耦合计算程序。后处理在TECPLOT和SURFER中完成,通过接口程序FLACTOTECPLOT.dat将FLAC3D计算结果导入TECPLOT软件进行后处理。此外,用FISH编制小程序实现数据的倒换至SURFER中,绘制孔隙水压力的等高线图形。更多还原

【Abstract】 Jointed rock mass is rich in a variety of internal defects such as micro-cracks, pores, fissures and other discontinuous macro-joints etc. The jointed rock mass usually possesses very complex mechanical properties and permeability characteristics because the existence of those defects will not only dramatically change the mechanical properties of the rock mass, but also seriously affect its permeability. On the one hand, fracture seepage water pressure will intensify the crack’s opening, extension and the linking between each other, resulting in the change of stress field and damage field of rock mass; on the other hand, the stress level and the extension of rock mass fractures will lead the change of fractured rock permeability and the distribution of seepage field in rock mass. This kind of interaction described above is called the stress-damage-seepage coupling.In this paper, the process of the seepage in the stress-damage-seepage coupling state has been strongly researched. The studies reveal the law of fracture’s initiation, extension and the linking of rock fissures, and explore the damage mechanism of the fractured rock in the stress-damage-seepage coupling state. The reasons of in-stabilized destruction of water-bearing fractured rock mass are explained as well. The proposed coupling theory has a great application prospect in the mining engineering, the dam construction and underwater tunnel project to prevent from water inrush.The achieved researches in this paper have been supported financially by the National Key Basic Research and Development 973 project (No.2007CB209402:Dynamic characteristics and controlling factors of the water-inrush in mine) and the related research project with SHAN DONG Gold Group CO LTD. This paper mainly includes the following research contents:(1) Research on theoretical analysis:The fracture mechanical properties of jointed rock mass under the seepage water pressure is studied by the combination of fracture mechanics and damage mechanics. For the open type of cracks, the law of crack’s closure or initiation, the law of branch crack’s propagation, and the penetration and fracture laws of rock bridges between the adjacent cracks are discussed under the pressure-shear stress and the presentation of water pressure. The theoretical basics on the rock fracture and damage under the coupling action of seepage water pressure and pressure-shear stress are established.(2) Research on mechanics test:A model is studied and designed to make the pre-crack cylindrical rock samples ((?)50mm×100mm) with a single crack or with a pair of cracks according to the real needs. A high-precision universal seepage experimental device is developed on the basis of 2000KN servo testing machine. The modified equipment can help to measure the rock permeability by using fixed-level method or flow method at high confining pressure and high pore water pressure conditions. The software PFC is used to simulate and analyze the failure process under pore water pressure of non-uniform medium such as rock mass containing holes, cracks and grain, etc. The accordance between the numerical results and the test results is studied. The full process of the crack’s initiation, expansion, linking up and even the breakdown of the entire structure are displayed and observed graphically in the stress field and seepage field.(3) Research on constitutive relation:The damage evolution of fractured rock under the coupling effect of tensile, compressive and shear stress and seepage water pressure is studied. The damage constitutive equations of elasto-plastic fracture and the damage evolution equations for the jointed rock mass under the consideration of the osmotic water pressure are derived. The damage constitutive tensor equations of elasto-plastic fracture are established under the coupling action of seepage and stress.(4) Research on physical simulation:A test system to study mine water inrush mechanism and seepage characteristics in mining engineering is developed and designed. Based on the above derived constitutive equations, a three-dimensional fluid-structure interaction model for Shandong Sanshandao Gold Mine is constructed. Theoretical calculation and numerical simulation analysis of mine water inrush caused by under seabed mining-induced seepage in jointed rock mass. Barite powder, liquid paraffin, solid paraffin, sand and other materials are selected and mixed up with proper proportion to make a non-hydrophilic material, which is used to build the fluid-structure coupling similar physical model. The minimum safe mining roof thickness for Shandong Sanshandao Gold Mine is studied by the similar physical model test under the consideration of seepage-stress coupling. The results show that the developed test system has important theoretical significance and practical value both in micro-macro tests and theoretical studies of deep mining water inrush mechanism.(5) Research on numerical analysis:The seepage stress dual-medium coupling model is derived with both discrete medium and quasi-continuous medium. The theory, source files and application methods of Finite Element Program Generator (FEPG) are introduced in detail.According to the survey data of fractured joints, the Monte-Carlo simulation technique is used to generate fracture network, then the coordinates of control points for the crack plane are derived through the VB programming. The file of the coordinates is directly called by ANSYS. The whole fractured rock mass is divided into grids with ANSYS, then the meshed numerical model is imported into FLAC3D. The numerical procedures of the fluid-structure interaction analysis and calculation are developed by using FISH. The final numerical results are pulled out by TECPLOT software.(6) Research on engineering application:The interface program that transits SURPAC three-dimensional geological model into FLAC3D numerical model is developed, which makes the coupling of the SURPAC three-dimensional geological model and numerical simulation to be possible and help to build complex computational FLAC3D model quickly and easily. The use of FISH is then extended to stress-coupling calculations based on FLAC3D seepage in fractured rock. Post-processing is completed in the TECPLOT and SURFER, e.g. the FLAC3D results are input into TECPLOT software through the interface program FLACTOTECPLOT.dat. Moreover, the data can be switched to SURFER by small program developed in FISH, the visual contours of pore water pressure can be draw.更多还原