Fluid pressure inside a borehole produces hydraulic fracture and damage zones in the vicinity of the borehole. These fractures result from stress concentrations around the borehole. The results of numerical simulation of a borehole subjected to fluid pressure using a micromechanical damage model [2] are presented in this paper. It is observed that tensional concentrated stresses are generated a...

The influx of roof water from exceptionally thick sandstone aquifers in northwestern China’s mining regions presents considerable challenges to the safety and productivity coal operations. However, a significant gap literature persists concerning underlying mechanisms. In this study, we investigated coal-seam beneath aquifer Zhiluo Formation at Lingxin Coal Mine, utilizing context as basis for ...

Abstract Rock bursts are one of the most common dynamic disasters in coal mines and seriously affect safety production. At present, there three types rock bursts: fault‐structure, fold‐structure, thick/hard‐roof bursts. First, paper proposed an innovative technology for mine ground fracturing to control those Then, new method, its devices, process, monitoring technique cracks were introduced. N...

To solve the problem of field application downhole hydraulic fracturing technology due to difficulty in sealing holes, this study analyzes influence special cement, expansion agents, stabilizers, and fiber material on basic properties, such as setting time, fluidity, compressive strength high-pressure materials through systematic tests based a summary conventional materials. It was determined t...

Recent years many authors reported thermal anomaly change around epicenter before earthquake. Some researchers tried to predict the earthquake based on the analysis on the temperature anomaly feature by using satellite thermal infrared data. However the infrared radiation can not pass through the thick-layer cloud, so as to hardly achieve the earthquake monitoring. Microwave is also a kind of t...

:‘)ii$ Machine piling of slash and brush after harvest is commonly practiced when establishing new conifer plantations. However, it can result in increased soil bulk density, decreased soil macroporosity, and increased soil strength, thus reducing conifer root development and above-ground growth (Froehlich 1979, Sands and Bowen 1978). Because natural recovery of soil from compaction is slow, wa...

To prevent outbursts and extract the gas, it is necessary to investigate structure of key layer evolution cracks during coal mining over a large height. A physical similarity model with geometric ratio 1:100 strike length 2 m was established on basis prevailing geological conditions. Stress sensors microseismic equipment were adopted monitor collapse characteristics different layers through var...

explosion has always been regarded as one of the most complicated engineering problems. as a result, many engineers have preferred rather simplified empirical approaches in comparison to extremely complex deterministic analyses. in this paper, however, a numerical simulation based on the combined finite/discrete element methodology is presented for analyzing the dynamic behavior of fracturing r...