failure mechanism of tunneling in sand; solution by macro-synthetic fibers

a successful tunnel design must fulfill basic requirements for soil structural stability, durability and cost effectiveness with reasonable accuracy. the use of fiber reinforced concrete in tunnel linings, with or without conventional rebars, has increased in the two last decades, especially with regard to precast tunnel segmental linings. in addition, there is a general growing interest in the scientific community on macro-synthetic fibers for use in underground structures. in the presented research, there’s a brief reference of the mechanism of sand tunnel’s failure and precast pp fibers only (pfrc specimens); combination of pp fibers and conventional reinforcement (rc + pfrc segments). based on the loading configurations considered, analytical results showed that pp fibers represent an efficient reinforcement for precast tunnel segments