The different lithological combinations of the surrounding rock of coal seams play a key role in controlling the enrichment and migration of coalbed methane (gas), and their permeability and stress sensitivity have important theoretical guiding significance for the regional election and evaluation of coalbed methane development. In this paper, the HB-2 type coal rock sample pore permeability adsorption simulation measurement device is used to carry out the sensitivity experiment of the permeability of different surrounding rock combinations on the effective stress of the No. 3 coal seam roof in the Daping coal mine area, Luan, Shanxi. The sensitivity coefficient of permeability to effective stress, the maximum damage rate of permeability, and other parameters are defined to characterize the response mode of permeability to effective stress and the dynamic change rule of permeability, and reveal the control mechanism of effective stress on permeability change of different surrounding rock combinations. The results show that the permeability of the roof of No. 3 coal seam is highly sensitive to the effective stress, and the permeability of different surrounding rock combinations decreases with the increase of the effective stress, and there is a strong negative exponential correlation between the permeability and the effective stress; the stress sensitivity coefficients of different surrounding rock combinations under unloading stress are higher than those under loading; the permeability changes of specimens with different combinations of surrounding rock under the same experimental conditions are varied and the differentiation phenomenon is significant; the permeability is affected by lithology, pore fissure degree, and different combinations of surrounding rock, among which different combinations of surrounding rock are the main controlling factors for the dynamic change of permeability.

The paper applies fractal theory to the structure of fractal coal pores and calculates the fractal dimension and integrated fractal dimension for each pore section >100 nm, 100 nm > d > 5.25 nm, and <2 nm. In the experiment, we performed the full stress–strain-seepage experiment of methane-bearing coal, revealed the deformation–seepage characteristics of methane-bearing coal under load, and deduced the dynamic prediction mechanical model of methane-bearing coal permeability based on pore heterogeneity, followed by practical verification. The results show that the permeability change in methane-bearing coal is an external manifestation of coal pore deformation, and the two are closely related and affected by changes in the effective stress coefficient. The derived fractal-deformation-coupled methane permeability mechanics model based on coal pore heterogeneity has high accuracy, a general expression for the stress–strain-permeability model based on coal heterogeneity is given, and the fractal Langmuir model is verified to be highly accurate (>0.9) and can be used for coal reservoir permeability prediction.

Fatigue is a complex physiological phenomenon that reflects worsening physical function and can lead to poor work performance, safety and health conditions. The research targets to obtain the degree of eye fatigue of college students in fixed sitting posture. An eye movement detection method was proposed in this paper. Using the wireless transmission eye tracker and its supporting software from the American Laboratory of Applied Sciences (ASL), three basic types of eye movements were examined, including blink, gaze, and saccade. The results show that with the increase of fatigue, participants’ blink time increased first and then decreased. During fatigue, the pupil diameter increased by about 91% and the percentage of fixation time decreased by about 31.31%. Compared with waking state, the average fixation time increased by about 9%, saccade distance decreased by about 40%. The research results can provide reference for fatigue monitoring and accident prevention.