Comparison of the evaluated rock mass properties from the TSP system and the RMR classification (Semnan tunnel, Iran)

摘要

In order to design the excavation method and the tunnel support requirements, the prediction of the geomechanical properties of the rock masses is the main concern. One of the techniques recently used for this aim is the TSP method, which is based on the analysis of the S and P waves reflected from the major discontinuities ahead of the excavation face. Semnan water supply project is to covey water from Roozieh spring, located at 46 km north of Semnan city, to its urban area. The water with a flow rate of 650 lit/s is pumped through 16 km of a steel pipeline from the spring, with an altitude of 1840 m, to the altitude of 2335 m. From this point on water is transferred gravitationally through a G.R.P. pipeline (diameter = 1000 mm) in a tunnel of 3.2 m diameter and 3200 m length. From the tunnel outlet, water is conveyed through 27 km of a steel pipeline to Semnan city. The water supply tunnel, having two construction portals, is being excavated through mount Bashm, located in the Alborz range with an east-west trend.