Numerical modeling is a useful tool to design underground openings. Masjed E Soleyman Power House Cavern is one of the largest caverns in the Middle East. Ramamurthy introduced an empirical equivalent media in 1994. Ramamurthy Equivalent media was applied to a Finite element analysis. Phase2D software was used to analyze continuum media. The displacements obtained from Equivalent continuum analysis were compared to those measured by MultiPoint Borehole Extensometers (MPBX).
Many uncertainties are involved in determination of rock mass characteristics. Ramamurthy introduced an empirical equivalent media to determine the rock mass modulus and strength. On the other hand, numerical simulation of the underground openings is performed to predict rock mass behavior during and after the construction. Among different numerical methods, Finite Element Method (FEM) is very common. Ramamurthy equivalent media has been applied to a FEM model of Masjed E Soleyman Power Plant Project (MESPP). MESPP has been constructed on the Karun River, Iran. The full capacity of MESPP is 2000 Mega Watt (MW), which is through 8 units of 250 MW each. Two main openings in this project are power house and transformer caverns. The dimensions of the power house and transformer caverns of MESPP are 30×51× 154.5 meters (m) (width, height and length) and 13.6×21×100 m respectively. Phase2 software was used to analyze Equivalent Continuum Media of Ramamurthy. The displacements predicted by Equivalent continuum analysis were compared to the actual measured displacements by Multiple Borehole Extensometers (MPBX).
REGIONAL GEOLOGY OF MASJED
The dam site contains the upper most portion of the Aghajari and outcrops of Bakhtiyari Formations which are from Pliocene era. The Aghajari Formation is composed of interbeds of moderately strong sandstones and low strength clay stones, marlstones and siltstones. The Bakhtiyari Formation dominantly consists of coarse grain conglomerates with sandstones, clay stones and some lenses of clay in the upper portion. The Bakhtiyari Formation is subdivided into several units; each unit can be representative of a distinct period of sedimentation. Most of the rock units, excluding units II, IV and VI, start with conglomerates in lower portion and end with 5 to 10 m thick beds of siltstones on the top most portions. The powerhouse and transformer caverns are located in Unit V of the Bakhtiyari Formation. Caverns longitudinal axes are parallel to the strike