Influence of Spatial Relationships between Key Strata on the Height of Mining-Induced Fracture Zone: A Case Study of Thick Coal Seam Mining

Abstract

Abstract:The behavior of the overburden of working face 20104 at the Wangjialing coal mine was investigated using borehole imaging. The measured height of the conductive fracture zone (CFZ) in the overburden, 148 m, is significantly different from the height that is predicted by an empirical formula. The spatial relationships between key strata (KS) required for their fracturing and their influence on the CFZ's height were analyzed. The results demonstrate that the spatial relationships between adjacent KS are a major factor behind the abnormal increase in the height of CFZ relative to the coal seam. The height of linkage (HoL) between KS was introduced and an equation for calculating this height was proposed. The study found that the fracturing of a KS could induce fracturing of the adjacent KS above it if their height difference was smaller than the HoL between them. Otherwise, the fractures resulting from the lower KS would terminate at the bottom of the higher KS. When the location of a high KS satisfies certain requirement, the spatial linkage between adjacent KS will allow for the conductive fractures arising in a lower KS to propagate through the high KS as well as the strata controlled by it, thus increasing the height of CFZ in overburden.

Porosity Distribution Law of Overlying Strata in the Goaf of the Adjacent Working Face: From the Perspective of Section Coal Pillar Types

“…This structure provides a large amount of storage space for oxygen and gas, which easily causes coal fire disasters, gas explosions and other accidents [2][3][4][5][6][7]. The pore and fissure structure of overlying strata can also serve as a water inrush channel to induce coal mine water inrush accidents [8][9][10]. Therefore, the study of the porosity distribution law of overlying strata in a goaf can provide theoretical and technical guidance for the identification of hidden disaster-causing factors and the reuse of gas and water resources in coal mines [11,12].…”

Assessment of stratification of the breeds of the underground cavity roof

“…Numerous works were performed within the creation of various models of the layered roof deformation [4][5][6][7], with the use of numerical models [8,9] which were used for the determination of the law of distribution of dynamic soil cracks under the influence of overlying bedded structures [10,11]. That should be noted that the considerable research is connected with the use of the frame models [12][13][14][15], based on the use of beam-and-hinge structures.…”

The Key Stratum Structure Morphology of Longwall Mechanized Top Coal Caving Mining in Extra‐Thick Coal Seams: A Typical Case Study

“…Based on the physical similarity simulation and field surveys, Zhou et al [20] and Yao et al [21] determined the distribution law of dynamic ground cracks under the influence of overlying strata structure. Li et al [22] indicated that spatial relationships between key strata have influence on the height of mining-induced fracture zone. Liang et al [23] discussed the influence of different key strata structure types on strata behavior with large mining height.…”