New research on a case of Linear Discontinuous Ground Deformation (LDGD)

LDGD is defined as surface fissures, steps as well as structures formed by them in the form of several steps, thresholds, ditches, and flexure. The paper presents a case study of formed LDGD - the origin, and possible methods to assess its occurrence on the basis of the research carried out in the Central Mining Institute (Poland). The authors showed that the presence of LDGD leads not only to the horizontal strain but also contributes to the formation of vertical curvatures of terrain that cause fissures in the near-surface layer of the rock mass in the areas with a thick layer of tertiary claystones and a thin layer of Quaternary strata. The accumulated experience also indicates that there is an influence of other mining factors, such as the interval between operations, face advance, and direction of operation, which may contribute to the occurrence of LDGD. Moreover, the authors pointed to the fact that predicting of LDGD is problematic and complex and is subject to uncertainty. The authors showed that both of LDGD methods prediction, when first of them is based on horizontal strains index and second one is points method, have good verifiability in practice.