采动裂隙岩体渗流试验与计算模型的开发应用

Due to the formation and development of the mining-induced fractures network in watery surrounding rockmass, underground water brings great risk and threat of water inrush to the mining activities in the practice of engineering. It is meaningful to investigate the development characteristics of mining-induced fractures network in surrounding rockmass, as well as the nonlinear seepage flow under high pressure gradient in the mining-induced fractures network in underwater mining projects. It is also meaningful to develop computational models for Hydro-Mechanical coupling behavior of fractured rockmass, and for evaluating the quantity of water intake into roadway. In this proposal, 3D printing technique is used to print the transparent rock specimens in which the fractures network is artificially designed taking the photosensitive resin material as the printing material. The nonlinear seepage flow characteristics in large-opening fractures in studied and observed adopting Particles Image Velocity (PIV) technique. Additionally, an integrated computational model linking the Finite-Discrete Element Method (FDEM, controlling the generation and development of fractures) and Computational Fluid Dynamics (CFD, based on Navier-Stokes equations) together is proposed. The Hydro-Mechanical interaction in small dimension fractured rockmass will be comprehensively studied using this proposed integrated model FDEM-CFD. Finally, based on the concept of equivalent seepage flow in fractured rockmass, another integrated model coupling with FDEM modulus for evaluating the water intake quantity of seepage flow into roadway is further proposed. Its reliability and suitability will be verified by taking a true practice mining engineering located at Shizuishan, Ningxia Province.

富含水条件下矿山地下开采时，开采扰动岩层内原生裂隙与采动裂隙共同组成地下水流通的通道，对水体下矿山开采带来极大的突水威胁。因此研究富含水条件下地下开采引起的采动裂隙发育特征及裂隙内部的渗流演化规律，并开发相应的水-力耦合模型，和开发能够评估开采巷道进水量的计算模型具有重要的科学研究意义。本项目拟利用3D打印技术，采用光敏树脂材料打印裂隙网络可控的透明岩体试件，使用粒子成像测速PIV技术，试验研究大开度裂隙网络内的非线性渗流特征；并研发有限-离散元FDEM（计算裂隙生成、扩展的数值方法）和计算流体动力学CFD（基于Navier-Stokes方程）的联合计算模块，精细研究小尺寸裂隙岩体水-力相互作用的演化特征。针对大尺度工程实际案例，基于等效渗流的理念开发出与有限-离散元FDEM计算模块相联合的渗流量评估模型，并以宁夏石嘴山某矿的地质条件和开采方案为工程背景，验证其可靠性和适用性。

地层岩体天然地包含大量的各种尺度的裂隙，而且在各种矿产地下开采过程中会在地下巷道围岩内形成大量的采动裂隙。当天然裂隙或采动裂隙成为高压地下水的通道后，可能对工程活动形成致命的威胁。所以研究裂隙的渗透特征具有重要的工程意义。本基金课题紧紧围绕裂隙渗流这一科学问题，开展了以下两个方面的研究工作：（1）成功研发了一套开展岩体裂隙渗流研究工作的新型试验设备；基于3D打印技术，依托自我研发的试验设备，系统深入研究了不同粗糙度的单裂隙的渗流特征，建立了裂隙渗流的渗透阻力的数学描述公式；（2）采用流体动力学计算仿真技术，深入研究岩体复杂裂隙网络内的水渗流过程和特征，论证了采用Navier-Stokes方程为控制方程的流体动力学数值计算仿真方法科研可以较为真实地研究裂隙水的渗流过程。本课题的研究工作为将来进一步深入研究复杂裂隙网络内的渗流奠定了坚实的基础。