Mahdi Jalili Ghazizade, Mohammad Ali Abduli, Edwin Safari, Behrouz Gatmiri,
Volume 5, Issue 1 (9-2011)
Abstract
Desiccation cracking commonly occurring in compacted clayey soils typically used as landfill liners can result in poor hydraulic performance of the liner. In this research, a simplified image processing technique was developed in order to characterize desiccation cracking intensity in compacted clayey soils. Three pairs of compacted clayey soils were studied in a relatively large scale experiment to evaluate the effect of geotextile cover on desiccation cracking under real-time atmospheric conditions. Digital images were taken from the surface of soils at certain time intervals for 10 months and were analyzed to determine crack intensity factor (CIF). The key parameter in identification of cracks as accurately as possible was found to be sensitivity. Calibration process was based on using %20 of the images with different crack intensities whose crack dimensions and therefore CIF values have been already measured to compare to program output. A calibration coefficient for sensitivity was accordingly determined based on the average difference between the sensitivity introduced by the program and the actual sensitivity calculated based on an overlaying process. Result of verification of this methodology indicated that it can be reliably used to determine CIF of compacted clay soils in a simple yet accurate manner.
Ar Yarahmad, S Kakamami, J Gholamnejad, Mt Ssadeghi, Majid Mobini,
Volume 8, Issue 3 (12-2014)
Abstract
The in situ measurement of discontinuity geometry of rock mass exposures is a time consuming and sometimes hazardous process. Moreover, a large proportion of the exposure is often inaccessible. Thus, a fast and safe tool is required in order to acquire the information which characterizes the geological/structural regime. Digital image processing techniques provide the necessary tools for realizing this goal. This paper presents a methodology for automated discontinuity trace detection in digital images of rock mass exposures. In this study at first based on difference in gray level discontinuities with the face, fracture traces detected in images of rock face. Then some parameters of discontinuities geometry such as spacing, linear joint density, persistence, trace angle of joints and value of RQD are obtained. The Automated discontinuity geometry analysis system including: 1- Providing a digital image from rock face 2- The pre-processing on the images 3- Detection of edge or joint traces by the canny detector 4- Description of the edges using line detector by the Hough transform 5- The joint sets estimation using fuzzy methods and 6- Description the rock mass geometry properties.
