## 7 Conclusions  
To study the time-dependent deformation of deep-buried tunnels in soft rocks, the host rocks of the Weilai Tunnel in China's Guangxi province have been taken as the main research substance. A novel visco-elasto-plastic creep constitutive model with two variants are designed. Moreover, two closed-form solutions are proposed to properly forecast the convergence deformation of the tunnel. To effectively guarantee the long-term safety and stability of the tunnel, a robust support structure is proposed, and long-term monitoring with appropriate remote sensors is offered. The main conclusions drawn from this article are as follows:  
1. Typical load-unload cycles of rock excavation are employed to design the novel creep constitutive model. Major factors such as damage and the time-to-failure are accounted in the first variant of the proposed creep model, and additionally to these, pore water pressure is considered in the second variant of the model. Suitable experimental data are employed to validate the creep constitutive model, and good agreements are found. 2. The second variant of the proposed creep constitutive model shows that pore water pressure has an enormous influence on the development of creep in soft rocks. It better captures the actual relevant conditions of the deep-buried tunnels located in complex soft rock environments. 3. The conversion of the novel creep constitutive model into the two closed-form solutions is mainly based on the Hoek-Brown criterion. Comprehensive parametric investigations show that the geological strength index of the rocky media and creep parameters deeply influence the deformation comportment of deep-buried tunnels. 4. Comparisons between the calculated convergence deformations and the on-site monitoring data are adequately made, and good conformity is found. It is revealed that in only 27 days, the Weilai Tunnel suffered large convergence deformation which was greater than 400 mm. This deformation greatly exceeds the established deformation limit in the entire alignment of the tunnel. As suitable measures, a robust support scheme and adequate long-term monitoring with appropriate remote sensors are strongly suggested to effectively ensure the long-term safety and stability of the studied tunnel. 5. To better describe the time-dependent behavior of deep soft rock tunnels, it is suggested to design creep constitutive models with variants. Comparisons between the behavior of the variants and the experimental or field data can provide clear indications on the analytical solutions, which can really represent the time-varying deformations of deep soft rock tunnels. * 6. The convergence deformation of deep soft rock tunnels is remarkably influenced by the creep parameters and the geological strength index (GSI) of the medium. The lower the creep parameters and the GSI values, the greater the convergence deformation. Accordingly, the requirements for support structures of deep-buried tunnels in complex soft rocks are very significant, and the difficulty in ensuring their long-term safety and stability is considerable. * 7. It can be concluded that effectively guaranteeing the long-term stability of deep-buried tunnels in complex soft rock environments is a very major task, which implies integrated research studies. Firstly, it requires the design and establishment of an accurate creep constitutive model to capture the time-dependent behavior of the host rocks, which is not sufficient. Secondly, to properly calculate the convergence deformation of the tunnel, closed-form solutions must be appropriately conceived. Even though the support scheme can withstand the tunnel deformation, long-term monitoring with suitable remote sensors is needed to effectively guarantee the safety and stability of the tunnel at all times. Conceptualization, W.F. ; methodology, W.F. ; software, W.F. ; validation, H.P. ; formal analysis, H.P. ; investigation, W.F. ; resources, W.F. ; data curation, W.F. ; writing--original draft preparation, W.F. ; writing--review and editing, W.F.