## 2 Methodology  
### Design Concept of Energy-Dissipation Support  
When constructing tunnels in soft surrounding rock, if the initial support of the tunnel should crack, the existing countermeasures primarily consist of installing an arch frame at the site of the support failure, removing the original support, and adopting the strengthening method. However, engineering practice has proved that the problem of cracking the supporting structure cannot be effectively solved by strengthening, which often involves multiple cycles of demolition and support measures. For example, in the cases of the Muzhailing Highway tunnel and Xinchengzi tunnel in China, it was necessary to adopt multiple arch modifications and to raise the support parameters to manage significant deformation. It nonetheless remained difficult to effectively solve the problem of damage to the supporting structure caused by large-scale deformation [21]. The objective of the repeated process of excavation and demolition cycles during construction is essentially to release the pressure of surrounding rock. This, however, also means being forced to accept the inevitability of the deformation of the surrounding rock. The stability of the supporting structure of the surrounding rock is dependent on the coordination between these two components, as shown in Figure 2 below. For this reason, merely relying on improving the strength of the supporting structure of tunnels in a high-energy geological environment is inadequate; hence, a new approach, method, and design are called for to achieve successful short- and long-term outcomes. In a high in situ stress environment, significant levels of strain energy are stored in the surrounding rock, and the elastic strain energy stored in the soft surrounding rock is dissipated via the plastic deformation of a large stroke [19]. According to the law of mutual transmutation of energy, energy conversion in the broadest sense occurs via the coordinated combination of force and displacement. In the context of current tunnel design concepts, when dealing with large-scale soft rock deformation, the type of strengthening support often adopted consists of attempting to suppress the deformation of surrounding rock. In cases of small displacements, because the energy dissipation within the support structure and surrounding rock is very small, the energy accumulation process can only be expressed in the form of a \"force\", and the supporting structure needs to provide a high resistance at that time. Therefore, when designing tunnels in soft surrounding rock, a change in thought processes is in the present authors' view called for to realize that \"force\" is not the only means of addressing large-scale soft rock deformation and that the problem of large-scale deformation can be solved by rationally applying a method that capitalizes on the \"displacement\" of the surrounding rock. To reasonably use the \"displacement\" of the surrounding rock to reduce the pressure within it, deformable tunnel ring supporting members were selected for the present study. Designing deformable elements within the steel frame transformed the original rigid support into an energy-dissipation support [22], as shown in Figure 3. According to the  
Figure 2: Respective characteristic curves of surrounding rock and support structure. study [2], the energy transformation of the perimeter rock system is only related to the final equilibrium point of the perimeter rock-support characteristic curve, independent of the support path.