Analyse der Sprengergebnisse mit der Software BMX Fragmenter
摘要
In this contribution, which is based on the bachelor’s thesis of the first author, five sample arrangements were produced on a laboratory scale (1:25) and analysed under varying conditions to determine whether significant deviations between the grain size distribution from the sieve analysis and the software BMX Fragmenter can be detected after rearranging the sample. The series of images for the photogrammetric analysis of the sample were taken with a digital camera from a bird’s eye view and with a smartphone camera from terrestrial positions. As the software identified the surface of the test setup as a fine component, the analyses were carried out without a fine component. The results show that the grain size distributions from the software show similar curves under the same conditions but tend towards smaller grain sizes as the mass throughput of the sieve curve increases. Arrangements without a point light source tend towards smaller grain sizes compared to analyses with a point light source. A series of images with a moistened sample was taken, analysed, and compared with the results of the dry sample. This comparison shows that the results of the moistened structure tend towards smaller grain sizes. The evaluation of the terrestrial recording positions without fines provides sufficient information to create a grain size distribution that corresponds to the grain size distribution from a bird’s eye view. As the software splits individual grains into several fragments, combines several grains into one fragment, or identifies grains that are larger than the ground sample distance as a fine fraction, manual post-processing of the fragment analysis is necessary, especially for boulders. To summarise, the software BMX Fragmenter provides the basis for the rapid creation of a grain size distribution, but a critical examination and manual post-processing of the fragment analysis is recommended.