Probabilistic Assessment of a Circular Tunnel in the Non-rotated and Rotated Anisotropic Random Fields

The spatial variability of soil properties is common in geotechnical engineering projects due to the complex geological and deposition processes.Spatial variation of soil property with rotational anisotropy is simulated, and its impact on tunnel convergence has been studied. This study employs the random finite difference method (RFDM) to assess the tunnel convergence influenced by both the soil property's transverse (non-rotated) anisotropy and rotated anisotropy. In the present study, Young's modulus of soil is considered as a spatially variable random parameter which is modelled using a rotated random field. Moreover, comprehensive parametric studies were also conducted regarding the effect of coefficient of variation (COV), the effect of different scales of fluctuations and rotation angles of the random fields on the stability of tunnel support. The results highlight the significance of accounting for rotational anisotropy of soil while assessing the mean of tunnel convergence and the probability of exceeding certain thresholds of deformation.

Keywords: Spatial variability, Tunnel convergence, Random Finite Difference Method (RFDM), Rotational anisotropy, Random fields.