A Novel Damage Model for Strata Layers and Coal Mass

Abstract

Coal burst occurrences are affected by a range of mining and geological factors. Excessive slipping between the strata layers may release a considerable amount of strain energy, which can be destructive. A competent strata is also more vulnerable to riveting a large amount of strain energy. If the stored energy in the rigid roof reaches a certain level, it will be released suddenly which can create a serious dynamic reaction leading to coal burst incidents. In this paper, a new damage model based on the modified thermomechanical continuum constitutive model in coal mass and the contact layers between the rock and coal mass is proposed. The original continuum constitutive model was initially developed for the cemented granular materials. The application of the modified continuum constitutive model is the key aspect to understand the momentum energy between the coal–rock interactions. The transformed energy between the coal mass and different strata layers will be analytically demonstrated as a function of the rock/joint quality interaction conditions. The failure and post failure in the coal mass and coal–rock joint interaction will be classified by the coal mass crushing, coal–rock interaction damage and fragment reorganisation. The outcomes of this paper will help to forecast the possibility of the coal burst occurrence based on the interaction between the coal mass and the strata layers in a coal mine.

Study on the Co-Evolution Mechanism of Key Strata and Mining Fissure in Shallow Coal Seam Mining

“…where b is the length of 1/2 of the minor axis of the fissure, m. By substituting Formulas (37) and (38) into Formula ( 35), the evolution height of upward type I mining fissures under polar coordinate conditions can be obtained. By transforming it into rectangular coordinates, the evolution height H st of upward mining fissures can be obtained as…”

“…When the elongation deformation value is higher, mining fissures are formed [33][34][35][36]. From the above analysis, it can be seen that mining fissures play a vital role in the mining process, and an accurate grasp of the failure form of mining fissures has a positive effect on coal mining operations and surface damage mining [37][38][39][40]. The formation of mining fissures is difficult to avoid.…”

Study on the Mechanism and Response Law of Fracture Movement on the Super-High Position Hard-thick Strata

“…In the process of coal mining, these thick and hard rock strata are not easy to break. However, as the mining space increases, the overhanging roof area of the hard-thick strata keeps increasing and begins to accumulate a large amount of elastic energy, and when the breaking limit is reached, the hardthick strata will break and release the accumulated energy [1][2][3] , thus inducing many strong dynamic disaster phenomena such as strong mine earthquake, mine water burst, and roof falling [4][5][6][7][8] . Take Ordos area in China as an example, there are thick and hard rock strata mainly medium and fine grained sandstone in the Cretaceous strata, which have high strength, large thickness and distance from coal seams.…”

A Case Study of the Water Abundance Evaluation of Roof Aquifer Based on the Development Height of Water-Conducting Fracture Zone

“…The strain energy accumulated in the places where rock deformation, caused by mining activities, occurs. When the stored energy reaches a certain level, a large amount of energy will be released, leading to cracks in overburden layers [4]. Those longitudinal fractures gradually develop to water-conducting pathways and connect overburden aquifers and mining space, resulting in the water inrush from aquifers into the mine [5,6].…”