CURRENT STATUS OF DIGITAL IMAGE BASED QUANTITATIVE ANALYSIS OF INTERNAL STRUCTURES OF SOILS,ROCKS AND CONCRETES AND ASSOCIATED NUMERICAL SIMULATION

The internal structures of geomaterials including soil,rock,asphalt concrete and cement concrete are complicated.The internal constitutions and structure of a geomaterial determine the stress and strain distribution and control the failure mechanism and process of that geomaterial when it is subject to loading.As a tool of precise measurement and digital representation for the actual spatial distribution of the different materials and components in geomaterials,digital images have been gaining more and more applications in the internal structural analysis of geomaterials at the micro and meso-levels since 1995.This paper gives a literature review of 175 papers published in the relevant literatures on the subject.Based on the literature review,this paper analyzes and investigates the development and status of digital image processing techniques(DIP) in quantitative analysis and associated numerical simulation of the geomaterials.It includes(a) quantitative analysis of particle shapes,(b) quantitative analysis of internal structures of soil,rock,asphalt concretes and cement concrete,(c) quantitative analysis of macro-structures of rock mass in the ground,and(d) numerical modeling and simulation of geomaterials by taking into account their actual internal structures.Based on the review results,the paper discusses the development history and future trend of the utilization of the digital images and associated techniques in soil and rock.Due to the facts that they are a measuring tool of spatial distributions and a digital representation way,the digital images have a great potential for further developments and utilizations.They can be used to realize the establishment of new theories and methods for analyzing geomaterial internal structures and for taking them into account in the numerical prediction of the geomaterials under external loading.