Acta Geodyn. Geomater., Vol. 14, No. 4 (188), 445–462, 2017 DOI: 10.13168/AGG.2017.0025 journal homepage: https://www.irsm.cas.cz/acta ORIGINAL PAPER CLUSTER BEHAVIOR OF THE GROUND DURING ITS IRREVERSIBLE MOVEMENT Victor NAZIMKO * and Ludmila ZAKHAROVA Institute for Physics of Mining Processes NAS, Ukraine,2A, Simferopol St., Dnieper, Ukraine, 49005 *Corresponding author‘s e-mail: victor.nazimko@gmail.com ABSTRACT Irreversible behavior of the ground or a rock mass encompasses both the transition of the ground over a peak strength and further development of the nonreversible movement and deformation. The irreversible ground movement is traditionally considered as the transition to chaos. However the moving ground passes through itself the energy of ground pressure, thermal energy, and exchanges by substances with surrounding rock mass. According to thermodynamics of irreversible processes, such a non-equilibrium ground behavior may create dissipative structures that are the embodiment of self-organization. The paper describes the results of the structures investigation, which have been unveiled with incremental fields of the irreversible ground movement during a landslide development and underground roadway maintenance. These structures were evolving from close interaction of the separate blocks or fragments of the ground and distant cooperation of the short-lived clusters that were periodically rearranging in time and space as the irreversible ground movement started and progressed. Extant techniques restrain basically one prevalent component of the irreversible ground movement. The other two collateral transversal components were usually ignored. However, blocking of these transverse components can prevent the development of a dangerous irreversible movement of the ground and a rock mass. ARTICLE INFO Article history: Received 25 June 2017 Accepted 9 October 2017 Available online 26 October 2017 Keywords: Irreversible ground movement Cluster Structure pattern Vortex Close and distant interaction demonstrated by Grenon et al., (2017) despite the generally accepted theory separates process to elastic (Devies and Selvadurai, 1996) and post-peak stages (Jaeger and Cook, 1969). Therefore the irreversible ground movement is inherent in many geomechanic and geologic processes and plays the important role in safety maintenance and formation of the complex structures and their evolution. That is why the irreversible behavior of the ground and rock masses is of constant interest for researches. Any irreversible process reflects a specific behavior of a thermodynamic system (Kondepudi and Prigogin, 2015). The irreversibility involves the accumulation of the entropy. If a thermodynamic system is open – namely exchanges by energy and substance with its surrounding – it becomes dissipative and tends to form a structure or to transfer to the self-organized state. According to Kondepudi et al. (2015), certain structure might emerge as the dissipative system when the excess of entropy production is negative. The ground and a rock mass are the typical thermodynamic systems. Their structure might appear in different patterns: the seismic waves during an earthquake, specifically oriented fracture systems (Jaeger et al., 1969), the folds as a result of the Earth crust flow (Bigoni and Gourgiotis, 2016), and thin details of the strain facies, which Tikoff and Fossen (1999) demonstrated. Seismologists developed a set of experimental and numerical methods to visualize the seismic waves that 1. INTRODUCTION Investigation of irreversible behavior of the ground and rock masses is an important part of geomechanics (Kumsar et al., 2016), civil engineering (Bloodworth, 2002) and structural geology (Wilson et al., 2016). In contrast to elastic behavior, the nonreversible movement and deformation may cause disintegration of a rock mass (Malinowska and Hejmanowski, 2016), damage of a support and even failure of an underground or a civil structure, and trigger landslides. For instance, a roof fall in an underground opening is preceded with the irreversible movement of the roof rock layers. Nonreversible deformation of a dam foundation after its consolidation deteriorates stability of the dam eventually. A dangerous landslide evolves after the accumulation of irreversible ground deformations. On the other hand, the irreversible rock mass movement is the natural process that follows roof weighting in an advancing longwall face. Garvey and Ozbay (2013) illustrate that delay of the roof caving causes a danger of a catastrophic roof bump. Therefore a rock irreversible movement may be desirable in this case. Also, the irreversible flow of the Earth crust was the main process which has formed the modern rock mass structure during certain geological periods (e.g. Wallis et al., 2015), so geologists use this structure to investigate geological processes. Furthermore, the irreversible deformation of a rock mass accumulates long before its collapse as Cite this article as: Nazimko V, Zakharova L: Cluster behavior of the ground during its irreversible movement. Acta Geodyn. Geomater., 14, No. 4 (188), 445-462, 2017. DOI: 10.13168/AGG.2017.0025