Scientific Quarterly Journal of Iranian Association of Engineering Geology

Scientific Quarterly Journal of Iranian Association of Engineering Geology

Impact of strike-slip and reverse faulting on volume proportion and uniaxial strength of fault rock blocks across the Purkan and Namrak faults in south Alborz range

Document Type : Original Article

Authors
Marzieh Davarpanah 1
Ali yasaghi 2
Shahriar Sadeghi 3
1 M.Sc. Student, Tectonics Group, Department of Geology, Tarbiat Modares University, Tehran - Iran
2 Associate Propfessor, Tectonics Group, Department of Geology, Tarbiat Modares University, Tehran - Iran Yassaghi@modares.ac.ir
3 Ph.D. Student, Tectonics Group, Department of Geology, Tarbiat Modares University, Tehran - Iran
Abstract
Evaluation of rock strength is key information on design and construction of infrastructures such as tunnels and dams. Brittle fault zones in which mechanical properties of rocks reduces can be considered as bimrock. The bimrocks consists of large rock fragments with greater strength within fine grained texture with lesser strength. The volume proportion of the fragments with respect to texture affects the strength of bimrocks within the fault zones. In this paper, fault rocks from the Purkan and Namrak faults with different reverse and strike-slip mechanisms, respectively, located in south Alborz range are studied in detail. The volume proportion and uniaxial strength of fault rocks across these fault zones are investigated.  The results showed that the volume proportion and distribution of fragment block sizes vary across the fault zone. The volume proportion and uniaxial strength of fault rocks blocks across the Purkan fault zone doesn’t show regular changes while in the Namrak Fault zone these changes have a specific order from inside to outside of the fault zone. This is interpreted to indicate that is related mainly with the amount of fault displacement, width of the fault zone and the presence of micro faults as well as different rock units across the fault zones.
Keywords
Fault rock strength
Bimrock (large rock fragments in fine grained matrix)
Brittle fault zone
Subjects
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Scientific Quarterly Journal of Iranian Association of Engineering Geology
Volume 7, Number 1 & 2
September 2014
Pages 57-70

  • Receive Date 28 December 2011
  • Revise Date 20 March 2014
  • Accept Date 29 October 2014