Investigation of Energy Transformation and Dissipation in Soft Rock Tunnels with Yielding Support Under Large Deformation.

Energy drives the large deformation of soft rock tunnels, which is a nonlinear mechanical behavior of surrounding rock. This study aims to develop an analytical model for analyzing the energy conversion and absorption processes involved in tunneling. First, an analytical approach is presented for analyzing the energy conversion of the surrounding rock and energy absorption properties of the yielding support system during tunnel excavation. Subsequently, a comprehensive parametric investigation is conducted using the analytical model to investigate the impact of support pressure, tunnel radius, and initial stress on the energy conversion and dissipation of the surrounding rock. Similarly, the effect of support installation time, tunnel radius, and initial stress on the energy absorption properties of the yielding support system is explored. The results reveal that energy is input into the surrounding rock at the outer boundary through radial stress work. A portion of the energy is converted into elastic strain energy of the surrounding rock. Simultaneously, the plastic deformation of the surrounding rock consumes some of the input energy. Subsequently, the remaining energy flows from the excavation boundary as rock pressure work. Installing yielding components in the support system significantly enhances its maximum energy absorption capacity, which may be raised by up to 30 times. Moreover, the earlier the support installation time, the larger the tunnel radius, and the higher the initial stress, the more energy the yielding elements of the support system absorb. Highlights: Proposed an analytical model to characterize energy conversion in large deformation tunnels with yielding support. Quantitatively analyzed the energy conversion and dissipation properties in the surrounding rock. Explored the energy absorption characteristics of yielding support in large deformation tunnels. [ABSTRACT FROM AUTHOR]