## 1 Introduction  
The large water sealing cavern is an underground space system for storing crude oil, gasoline, diesel and other energy sources under the stable groundwater level [1]. Compared with the traditional way of storing crude oil, the underground water sealing cavern has the advantages of less investment, less land occupation, minor pollution, little wastage, high safety performance, low cost of operation and management, fast loading and unloading. It has been widely used to store petroleum and petrochemical products [2]. The drilling and blasting method, a traditional and cost-effective construction method, has been widely used in the excavation of underground caverns [3]. Ventilation is the only means of air exchange inside and outside the cavern, and it is an indispensable key technology during the construction process [4]. Ventilation effect not only restricts the whole construction process, but also relates to the quality of construction and the efficiency of mechanical equipment and affects the health of the construction workers [5; 6]. However, the construction ventilation of large-scale underground engineering is often characterized by large sections, variable cross-sections,multiple caverns, internal combustion operations, trackless transportation, and a large amount of pollution, and there is no systematic method to solve these construction ventilation problems [7]. Forced ventilation or new-built vertical shafts are mainly used to solve ventilation problems in large underground cavern groups. However, it is impossible to increase the air supply due to the size restrictions of the construction channel, resulting in ventilation deterioration [8; 9]. The design of the shaft is not scientific, it relies on experience or site conditions to set up in a shallow depth of the underground cavern, and also, the ventilation path is difficult. With the rapid development of computational fluid dynamics (CFD) and computing technology, the CFD technique is used to simulate the ventilation of underground engineering during the construction period [10; 11; 12; 13]. The air flow organization and the change characteristics of harmful gas in the underground cavern group are studied to solve the ventilation problems in the construction process and to optimize the ventilation scheme. [PERSON] et al. [14] proposed 3D unsteady quasi-single-phase models to optimize the ventilation time with different tunneling lengths. The effect of buoyancy is considered in the momentum equation of the CO transport model while the effects of inter-phase drag, lift force, and virtual mass force are considered in the momentum source of the dust transport model. [PERSON] et al. [15] developed a model of gas dilution after blasting and the conditions in which workers can return to the blasted area based on CFD. They validated the correctness of the \(k\)-\(\varepsilon\) turbulence model based on Reynolds-Averaged Navier-Stokes (RANS) equations by experimental measurements and found that the CFD results were in satisfactory agreement with the experimental data. [PERSON] et al. [16] used the RANS approach and the standard \(k\)-\(\varepsilon\) turbulence model to simulate the fluid dynamics in tunnel groups when different ventilation schemes are employed. The study revealed that flow vortices appear in the tunnels with a long axis length ranging from 5 m to 20 m. [PERSON] et al. [17] adopted a RANS approach to study the characteristics of the ventilation and dust suppression system for open-type TBM tunneling work area in a \(\mathcal{O}\)8.53 m diversion project. When the main vent was located 70-80 m away from the working face, the ventilation in the TBM tunneling work area was optimal; when the air baffle is as long as the main beam, the dust collection efficiency was highest. [PERSON] et al. [18] employed RANS approach and the RNG \(k\)-\(\varepsilon\) turbulence model to investigate the flow pattern of air backflow in ventilated tunnels.