Writers : Lashkaripour, Gh. R.; Ghafoori, M.; Ghalibaf, H.; Bagherpour Moghaddam, A.; Amini, S.
Refference : The Forth National Geological Conference of Payam Noor University(PNU)
Publishing Year : 1389

Abstract :

The diversion tunnel of Chah-chaheh Dam, located 70 km NE of the City of Mashad,is under construction.From the entrance portal up to a distance of 197m has a direction of NW-SE then N13E & at last gets a curve directing N08E,24m towards the exit portal.Since the most prevalent fracture encountered within the tunneling operation has been the falling of wedges off the ceiling or walls at rather shallow depths ,so that detection & orientation of wedges’ dimension & the related stability analysis are of high importance. In order to achieve the structural analysis & determination of the trajectory of stress in the area series of geological surveys were fulfilled & the joints crossing the tunnel section were detected.It,in practice ,appeared that the area’s joint system has the capability of forming wedges ,along which some cravings might be occurred on the ceiling & the walls of the tunnel.Therefore , the software UNWEDGE applied to analyze the cavings rocks & result,a system suggested to be taken two mentioned various methods proved that the. situation of the exit portal is supposed to be quite more critical than the entrance one.

Subject List : Dam