To accurately correct wind resistance acquisition problems during the ventilation reconstruction and then calculate the air quantity in various roadways, taking the reconstruction of ventilation system in Shaqu Coal Mine of China as an example, the "calculation-feedback-correction" mechanism for adjusting roadway wind resistance was proposed based on the Ventsim simulation technique. Wind resistance was calculated and the change of air supply-demand after the reconstruction of the ventilation system was analysed using the proposed mechanism. The reasonable isolation reconstruction program was verified. Finally, the relationship between opening area of air window and wind resistance after the isolation reconstruction was fitted by the Fluent technology and the optimal opening area of air window was calculated. Results show that: (1) the ventilator area of the south upcast inclined shaft 1# operates unstably after the isolation reconstruction; (2) when the opening area of air window reaches at least 3.28 m 2 , the ventilator works normally and steadily. The results also demonstrate that good ventilation effect can be achieved by adjusting resistance reduction and setting the optimal opening area of air window which conforms to the actual status of ventilation systems.

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The exits and entrances of the multi arch tunnel are often located in unfavorable geological sections, such as shallow buried, bias, high weathering degree, rock breaking and so on. In addition, the existence of the side slope makes the force more complicated after the tunnel excavation. When exits and entrances of tunnels are excavated, there are often large deformation of surrounding rock, initial deformation and two lining cracks. Serious accidents may lead to collapse and instability. Based on the geological conditions and the mechanical characteristics of the surrounding rock, the influence of the bias angle of the biased multi arch tunnel on the mechanical properties of the surrounding rock after excavation is studied by the theoretical analysis and numerical simulation. It is said that with the increase of the bias angle; the influence of the deep buried side of the bias tunnel is more obvious than that of the shallow buried side. Numerical simulation of excavation of a multi arch tunnel under different bias angles is carried out. According to the analysis of the critical point displacement, the influence of the tunnel under the bias pressure intensified as the slope go steeper. And when the thickness of the earth beside is over 15 meters, the influence of it would get rids of the change of different bias angle. These results can provide some reference and guidance for similar arch tunnel design, construction and research.

During tunnel construction, the stability of tunnel surrounding rock caused by excavation of water-rich section has always been a major problem in the project. In this paper, the influx of water in the face of the excavation of the water-rich section of the Junmachang tunnel caused a large amount of water to be unable to be constructed. The on-site sampling was carried out to test the natural and saturated water conditions and the rock mass of the excavation section under the water-rich effect was determined. The characteristics of softening of body mechanics, in view of the lithology of the surrounding rocks of the tunnel and the water inrush of groundwater in the tunnels in the water-rich section of the tunnel, a combination of the grouting reinforcement of the advancement of the small face of the tunnel face, the radial grouting reinforcement around the tunnel, and the combination of a reasonable anti-drainage system were proposed to close the groundwater treatment. The results show that the deformation of the surrounding rock in the water-rich section of the tunnel after treatment is controlled within a reasonable deformation range, and the accumulative total settlement of the dome settlement and the cumulative convergence of the clearance are less than 1/3 of the reserved deformation. The water-rich section of the Junmachang has achieved good results in the combination of advanced small-vessel grouting reinforcement, peripheral radial grouting reinforcement, and the installation of a reasonable anti-drainage system, which has certain engineering application value.

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