Case Study: Raison Foster Associates achieves rigorous cut and cover tunnel stress analysis with Oasys SAFEt

Raison Foster Associates - Customer Case Study

Raison Foster Associates was asked by the contractor to investigate stresses in the base slab of a cut and cover tunnel after concerns were raised about drainage pipes cast into the slab. To better understand pipe loading and slab behavior, the firm turned to Oasys software, using Oasys SAFE (Version 19.0) for a more rigorous finite element analysis.

Oasys used staged FEA modelling to represent excavation, dewatering, tunnelling, backfilling, and long-term service and ultimate conditions, with soil and structural elements modeled using appropriate elastic and Mohr-Coulomb assumptions. The analysis showed that bending moments in the diaphragm walls stayed within capacity with sufficient durability margin, and that bearing pressures remained below available bearing capacity. It also provided bending, shear, and thrust results for the embedded drainage pipe, helping confirm the tunnel base slab and surrounding support system were adequate for long-term performance.

Raison Foster Associates