Digital representation of meso-geomaterial spatial distribution and associated numerical analysis of geomechanics: methods, applications and developments

Abstract

This paper presents the author's efforts over the past decade for the establishment of a workable approach for geomechanics by taking into account the actual spatial distribution of different minerals, particulars and components in geomaterials at the meso-scale range. The primary goal of the approach is to provide a possible solution to solve the two intrinsic problems associated with the current main-stream methods for geomechanics. The problems are: (1) the constitutive models and parameters for soils and rocks cannot be given accurately in geomechanical prediction; and (2) there are numerous constitutive models for soils and rocks in the literature. The problems are possibly caused by the homogenization or averaging method in analyzing laboratory test results for establishing the constitutive models and parameters. The averaging method employs an assumption that the test samples can be represented by a homogeneous medium. Such averaging method ignores the fact that the geomaterial samples are also composed of a number of materials and components whose properties may have significant differences. In the proposed approach, digital image processing methods are used as a measurement tool to construct a digital representation for the actual spatial distribution of the different materials and components in geomaterial samples. The digital data are further proceeded to automatically generate meshes or grids for numerical analysis. These meshes or grids can be easily incorporated into existing numerical software packages for further mechanical analysis and failure prediction of the geomaterials under external loadings. The paper presents case studies to illustrate the proposed approach. Further discussions are also made on how to use the proposed approach to develop the geomechanics by taking into account the geomaterial behavior at micro-scale, meso-scale and macro-scale levels. A literature review of the related developments is given by examining the Science Citation Index (SCI) papers in the database of Science Citation Index Expanded. The results of this review have shown that the proposed approach is one of the latest research and developments in geomechanics where actual spatial distribution and properties of materials and component at the meso-level are taken into account.

介紹和總結近十多年來研究實際巖土細觀介質空間分布的方法,以及基于實際細觀介質空間分布數學表述而建立的力學數值計算網格自動生成的方法和應用,該項研究可為解決巖土力學主流方法常遇到的巖土模型與參數給不準和本構關系模型種類繁多這兩個重要問題提供可行途徑。該可行途徑主要包括采用數字圖像技術來對巖土材料內部細觀不同介質的空間分布進行精確測量和數值表述以及采用相應的數值計算方法。研究結果表明,數字圖像技術可以用來準確量測和表述巖土內部各種介質的實際空間分布,這些空間分布數據可以用來建立巖土內部不同細觀介質的空間分布和相應數值計算網格,并通過與現有的數值計算方法如有限元法或有限差分法相結合來實現考慮真實巖土材料不同種細觀介質及其空間分布的力學數值分析和預測。進一步探討如何應用該方法來建立微觀–細觀–宏觀不同尺度耦合的真實巖土力學分析和預測方法與理論。SCI論文檢索結果表明,所提出的方法和途徑是巖土力學相關研究和探索的最新進展。