Software Evaluation of In-situ Shear Test - Case Study: Narmab Dam Site

Category Engineering Geology
Group GSI.IR
Location 3rd Iranian rock mechanics conference
Holding Date 10 March 2008
      Results obtained from in situ tests play critical role in the design of any foundation. On the other hand, carrying out in situ tests requires high costs. Therefore, high precision is required in the design, measurement and interpretation of the tests. Due to their capability in engineering analysis and simulation, numerical methods can be applied to better control and use the results of in situ tests. Having applied in situ shear tests on similar blocks in the gallery through right abutment of Narmab dam, FLAC software was used to simulate tests trend. The principles of this research are based on the recommended method of the International Society of Rock Mechanics (ISRM). Shear strength parameters were determined by Coulomb criteria. These tests showed that block preparation as well as testing methods can significantly affect interpretation of results. Thus, selecting in situ shear strength values is based on engineering judgments. Back analysis was applied for software evaluation of shear strength parameters. Consequently, in situ shear strength parameters were evaluated using updated empirical method of geological strength index (GSI) and numerical model of FLAC. The results showed good agreement of the values estimated from numerical method with those obtained from in situ shear tests.
   Key words: In situ shear stress, Narmab dam, rock mass, FLAC, GSI.