Abstract The micro-scale gas adsorption–desorption characteristics determine the macro-scale transport and production behavior. To reveal three-dimensional stress state-induced in coal-bearing shale reservoirs from a perspective, samples Dongbaowei Coal Mine Shuangyashan Basin were chosen as research subject. Isothermal experiments under state conducted using low field nuclear magnetic resonance (L-NMR) T 2 spectrum method to simulate in-situ process. average effective was used equivalent...

This study proposes a new fractal permeability model for fractured rocks that comprehensively accounts the geometric fracture characteristics and fluid transport mechanism. Then, changes of are analyzed using discrete networks (DFNs) with or without roughness different geometry parameters in DFN modeling finite element simulation. The results show proposed well agrees experimental data, established numerical more realistically reflects network rocks. Fluctuation tortuous lines (rough...

Abstract As mines become deeper, the potential for coal and gas outbursts in deep rock cross-cut uncovering is enhanced. The outburst precursors are unclear, which restricts effectiveness reliability of warning systems. To reveal evolution characteristics precursor information uncovering, briquette specimens constructed experiments conducted using a self-developed true triaxial test system. Using acoustic emission monitoring technology, dynamic failure monitored, variations root mean square...

Abstract Groundwater has a significant influence on the mechanical properties of surrounding rock. Aiming at large deformation rock red layer soft tunnel affected by groundwater, uniaxial graded loading tests were carried out beds with different water content. The failure process specimen was monitored acoustic emission (AE) and crack evolution law analyzed, scanning electron microscopy (SEM) used to compare microstructure specimens before after immersion. Combined fractal theory,...

To reveal the influence mechanism of different fracture parameters on permeability characteristics hot dry rock after hydraulic shear. The self-made high temperature true triaxial shear test device and roughness profile tester were used. granite in Daqing area Songliao Basin is taken as research object. prefabricated fractured subjected to high-temperature treatment. geological geothermal reservoirs are simulated by changing three-dimensional stress. coefficient surface used characterize...

Massive quantities of NH3 generated after blasting in underground coal mines are believed to enhance the adsorption O2 by and accelerate rate coal's spontaneous combustion oxidation. The behavior for provides critical insights into mechanisms combustion. This research was conducted on Xiaolongtan lignite, examining characteristic NH3/O2 binary gas mixtures single-component lignite at 278.15-323.15 K 0-500 kPa using Grand Canonical Monte Carlo simulations. Additionally, kinetic properties...

Rock creep is essentially a process of damage accumulation. According to the evolution rock under conditions, TAW2000 triaxial test system used carry out on red layer soft taken from Yibo Tunnel in Leshan, Sichuan Province, China, and analyzed deformation rule different confining pressures. Meanwhile, based Nishihara model Weibull distribution function Perzyna viscoplastic theory, an improved viscoelastic-plastic which can describe whole failure was established. The critical point variable...

In order to investigate the impact mechanism of branch slope on fire smoke in underground bifurcation spaces, a series small-scale experiments were conducted. This study measured relevant data under natural ventilation conditions for four different slopes and six power levels, focusing highest ceiling temperature tunnel attenuation pattern temperatures along longitudinal direction both main tunnels. It also analyzed field, velocity pressure field at bifurcation. The results indicate that...

Abstract Coal and gas outburst is one of the geological disasters that seriously threaten safety coal mines production. In recent years, with increase mining depth, outbursts become frequent. To further explore occurrence mechanism deep outburst, a self-developed true triaxial simulation device was used to simulate at different depths. The results show critical pressure gradually decreases, unit intensity increases sharply. threshold lower. During incubation excitation, has three special...

Coal shale gas is an important type of gas. The microscopic pore size distribution and structure characteristics coal determine the macroscopic storage transportation In order to quantitatively characterize properties from a multiscale perspective, specimens with different grain sizes were characterized using low-temperature N

To investigate the effects of different conditions water cooling at high temperature on tensile strength and split surface roughness characteristics hot dry rock in Songliao Basin, physical characteristics, strength, granite under were studied. In addition, relationship between was established. The results showed following: (1) as increased, number injection cycles increased or decreased, mechanical properties specimen weakened, increased. threshold for effect 300°C. At 400°C, greatly...

The hysteretic behavior of square concrete-filled steel tube (CFST) stub columns subjected to sulfate corrosion and freeze-thaw cycle is examined by numerical investigation. constitutive model considered the Bauschinger effect, compression (tension) damage coefficient was also adopted for core concrete. experimental results are used verify finite element (FE) model, which could accurately predict behaviors CFST piers. Then, effects yield strength steel, compressive concrete, ratio, axial...

With the increase of mining depth and intensity, coal gas outburst dynamic disasters occur frequently. In order to deeply study macroscopic fracture mechanism body evolution characteristics analysis impact force, taking seam Pingmei No. 11 Coal Mine Sunjiawan Hengda as research objects, simulation roadway test system self-developed true triaxial is applied carry out deep with buried depths 1000 m, 1200 1400 m 1600 m. During test, overlying strata stress simulated by axial compression,...

Coal and gas outburst is the most serious dynamic disasters in coal mining. The essence of mechanics instability destruction process rock caused by energy accumulation release. With mining depth increase, complex geological stress conditions make present new characteristics, which severely restricts reliability effectiveness disaster warning. Using self-developed true triaxial roadway simulation test system, tests at different depths were carried out. Meanwhile, acoustic emission technology...

According to the instability failure of deep rock mass, a superposition block model anomalously low‐friction effect was established. The numerical results were compared with previous experiment, which verifies feasibility and effectiveness simulation. A vertical impact confining pressure applied superimposed model, horizontal static force working (the third block). This study aimed determine influence rules energy, pressure, lithology on displacement normal contact surface. show that,...