Back Analysis of Siah Bisheh Dam Powerhouse Cavern Using Instrumentation’s Results

Document Type : research - paper

Authors

1 Imam Khomeini International University, Qazvin

2 Imam Khomeini International University

Abstract

The estimation of in situ stresses and geomechanical properties of excavation surrounding rock masses is necessary for design purposes. Some of the field tests such as dilatometer and hydro-fracturing tests are usually conducted for such purposes. These tests are often costly and time consuming. Moreover,] because of heterogeneity, there is a wide dispersion of the results too. In order to solve these problems, back analysis is used to determine the in situ stresses and mechanical properties of rock masses by monitoring the data. Back analysis is generally defined as a technique that can provide the controlling system parameters by analyzing its output behavior. This technique has been constantly studied in rock engineering during the last decade. In back analysis problems, the main objective is to determine the initial stresses and material constants from the field measurement data. Back analysis problems may be solved in two different ways: inverse and direct. In this paper, a direct approach to back analysis was used based on univariate search technique for determining the rock mass modulus of elasticity (E) and the ratio of horizontal to vertical stress (K) of Siah Bisheh Dam Powerhouse Cavern. The numerical analyses were done by FLAC3D software. The results showed that the average values of the modulus of elasticity are 7.15 GPa in the bedding part (containing of quartzite sandstone and red shale), 15 GPa in the melaphyre part. Also the average value of horizontal to vertical stress is 1.325

Keywords

References

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History

  • Receive Date: 02 May 2010
  • Accept Date: 09 October 2011

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