An Analysis of the Design of Holding System in Rocks Containing Esfahan Metro Tunnel-Southern Segment (Sofeh-Azadi)

摘要

Esfahan metro with 12745 m length is being constructed in north-south direction as two parallel tunnels. This tunnel has 3737m length in southern segment and is constructed as horseshoe form with 6.5m height and 7m width.To determine the type of holding system regarding pressure entering to system various methods were used such as 1- Experimentalmethod that includes RMR geomechanic classification, Qualitative index of tunneling in Q rock and geological strength index GSI, 2- GSIA method; at the end on the basis of achieved data from sampling during excavation the most proper holding system was estimated. By considering conditions of holding system that are offered by two experimental methods, it can be inferred that the suggested system of experimental method is conservative. But sand rocks don't need holding system according to analytical methods. If wedges are created by collision of joint sets, holding system may become necessary.DOI: http://dx.doi.org/10.3126/ijls.v9i4.12639