王守光, 穆鹏宇, 王嘉敏, 李海涛, 齐庆新. CT扫描的煤岩面裂隙椭球模型重构与张量表征及其应用[J]. 煤炭学报, 2022, 47(7): 2593-2608.
引用本文: 王守光, 穆鹏宇, 王嘉敏, 李海涛, 齐庆新. CT扫描的煤岩面裂隙椭球模型重构与张量表征及其应用[J]. 煤炭学报, 2022, 47(7): 2593-2608.
WANG Shouguang, MU Pengyu, WANG Jiamin, LI Haitao, QI Qingxin. Ellipsoid reconstruction and tensor characterization of planar fractures incoal obtained by CT scanning and the applications[J]. Journal of China Coal Society, 2022, 47(7): 2593-2608.
Citation: WANG Shouguang, MU Pengyu, WANG Jiamin, LI Haitao, QI Qingxin. Ellipsoid reconstruction and tensor characterization of planar fractures incoal obtained by CT scanning and the applications[J]. Journal of China Coal Society, 2022, 47(7): 2593-2608.

CT扫描的煤岩面裂隙椭球模型重构与张量表征及其应用

Ellipsoid reconstruction and tensor characterization of planar fractures incoal obtained by CT scanning and the applications

  • 摘要: CT 扫描技术为观测煤岩内部裂隙提供了重要手段,然而由于煤岩 CT 扫描裂隙场的高度 复杂性,对其精确定量描述一直是行业内十分困难的问题。 通过 CT 扫描发现,煤岩内部裂隙结构 以面裂隙为主,因此针对 CT 扫描获得的煤岩面裂隙结构,提出了一种基于椭球模型的解决方案: 首先将煤岩 CT 扫描获得的面裂隙结构离散为三角形面网格,在 Geomagic Wrap 软件中对三角形面 网格进行简化和修复,得到一系列三角形裂隙面代替原有的裂隙结构;然后采用一种特殊的面椭 球,即旋转扁椭球,拟合每一个三角形面裂隙,据此实现对整个裂隙结构的椭球模型重构,详细给出 了二维空间和三维空间中面椭球重构的控制方程及求解策略,并验证了求解策略的可行性,给出了 椭球模型重构 CT 扫描裂隙场的精度分析;最后利用重构的椭球形裂隙场,分别设计面裂隙方向张 量与面裂隙组构张量,定量表征煤岩 CT 扫描面裂隙结构,同时给出了针对面裂隙方向张量与组构 张量的简便计算方法。 对于裂隙张量表征理论的应用,选取了简单面裂隙结构、CT 扫描获得的真 实复杂裂隙结构、真实裂隙场的演化过程等 3 个具体案例,验证了裂隙张量理论对煤岩复杂裂隙结 构的描述能力,并阐明了其与孔隙率、分形维数描述方法之间的异同。 关于椭球模型重构方法的应 用,除了有助于裂隙结构的定量表征,还介绍了其在裂隙煤岩等效弹性模量预测理论方面的应用前 景,并通过数值模拟分析初步验证了理论公式的适用性。

     

    Abstract: CT scanning technique provides an important means to observe the internal fractures of coal. However,due to the high complexity of the CTscanned fracture field in coal,the accurate and quantitative description for the fracture field remains tough and unsolved in our field. Through CT scanning,it was found that the mesofractures in coal mainly consist of planar fractures. Herein,a solution based on ellipsoid model was proposed for quantitatively describing the planar fractures in coal obtained by CT scanning. Firstly,the CTscanned planar fracture structures in coal were discretized into triangular meshes which were simplified and repaired afterwards by using Geomagic Wrap software,and multiple triangular fracture surfaces were obtained and used to replace the original fracture structure. Then,a special ellipsoid,namely rotary oblate ellipsoid,was used to fit each triangular planar fracture,and thus the ellipsoid model reconstruction for the entire fracture structure was accomplished. The governing equations and solving strategies of the reconstruction for the planar ellipsoid in twodimensional and threedimensional spaces were given in detail,which was verified by a specific case,and its reconstruction accuracy analysis was given. Further,by using the reconstructed ellipsoidal fracture field,the planar fracture orientation tensor and fabric tensor were coined respectively to quantitatively characterize the CTscanned planar fractures in coal,and a simplified calculation method for the planar fracture orientation tensor and fabric tensor was provided. As for the application of fracture tensor theory,we selected three specific cases,such as simple planar fractures,real complex fracture structure obtained by CTscanning,and evolution process of the real fracture structure,which verified the effectiveness of fracture tensor theory to describe the complex fracture structures in coal. The differences between fracture tensor theory and porosity,fractal dimension description methods were clarified as well. As for the application of ellipsoid reconstruction method,we introduced its application prospect in theoretically prediction of the equivalent elastic modulus of fractured coal,verifying its applicability through numerical simulation analysis.

     

/

返回文章
返回