Abstract
1- Introduction
One of the conventional field methods for determine permeability of rock masses is lugeon test. The absorption is specific with division water permeability test (lugeon) on the number of joints. The Secondary Permeability Index (SPI) relative to the specific joint that included the degree of joints, consistency joints, and void filling. The secondary permeability index obtained based on dams foundation classification for improvement dams foundation and rock masses classification. The secondary permeability index relative to rock mass permeability. The lugeon test is a way for determination secondary permeability index in dams foundation. The geological strength index that the results of this test were used for evaluation groutability of rock masses. In the classification of rock masses, geological strength index is better than other classification of rock masses because geological strength index noticed the roughness of surface joint in rock masses and structure rock masses with interlocking components. The roughness has a direct relation with hydrology parameters in rock masses — the geological strength index preference for groutability. The geological strength index is not noticing to the in situ stress and underground water — the estimation efficiency joints by log excavation and outcrops.
The surface condition rating concluded: roughness, weathering and filling. This parameters collection thogether and determination of SCR. The structure rating determination by rock quality designation (RQD( equations (3,4). The geological strength index classification of rock masses can be used for evaluation the permeability and groutability. The groutability determination by absorption specific. This estimation is easy, rapid and without additional cost to the project and provide an estimation will be important role in allocation cost exploration, project management and programming.
2- Methodology
In this paper, permeability and groutability are evaluated by Lugeon and geological strength index in several dams. In this regard the groutability estimations are more or less in this relation, it is possible to zone the GSI chart based on lugeon number. In this research used of 200 lugeon test and geological strength index classifications. Their projects selected for estimation. These projects include Karun 2 dam, Jamishan reservoir dam, and Veniar reservoir dam. The 120 data used for the main chart and 80 data for validation. The structure rating (SR), surface condition rating (SCR), and lugeon determination in geological strength index chart. The permeability zones determined and the groutability zones evaluated. The zonation in the chart has a suitable correlation.
3-Findings
In the chart of Figure 1, for GSI more than 55, the Lugeon between 1 to 3 or impermeable, the range of GSI between 45 to 55 equal to Lugeon 3 to 10 or low permeability, the range of GSI between 35 to 45 equal to Lugeon10 to 30 or medium permeability. Also, GSI less than 35 is Lugeon between 30 to100 or high permeability. The three boundary zone determination on geological strength index. The boundary one zone is SR=30 or Blocky/Disturbed/Seamy to Blocky middle boundary in the vertical axis, and horizontal axis included total SCR. The two-zone is disintegrated to middle very blocky in the vertical axis, and horizontal axis included total SCR. The three-zone is boundary Laminated/Sheared to middle boundary Blocky/Disturbed/Seamy in the vertical axis and boundary Good to Very poor in the horizontal axis.
After the zoning in geological strength index chart, groutability and ground treatment of rock masses estimated. The first zone is without groutability (None groutable), the second zone has the local groutability (Local groutable, the third zone has the medium groutability (Medium groutable) and the fourth zone has the high groutability (High groutable). This chart application in sedimentary and igneous rocks. This rocks include: limestone, sandstone, gabbro and diabase. This chart not application for fragmentation and impermeability rocks. For example shale and schist. The boundary of zonation has some vacillation it can improve in research future.
Figure 1. Zonation in chart of geological strength index with groutability and ground improvement
4-Conclusion
In this chart, for GSI more than 55, the Lugeon between 1 to 3 or impermeable, the range of GSI between 45 to 55 equal to Lugeon 3 to 10 or low permeability, the range of GSI between 35 to 45 equal to Lugeon10 to 30 or medium permeability. Also GSI less than 35 is Lugeon between 30 to100 or high permeability. Based on the zonation in the chart, four zones namely none groutable, locally groutability, medium groutable and high groutable were identified. The zonation in chart also have a suitable correlation. This estimation is easy, rapid and without additional cost to the project and provide an estimation that will decrease exploration cost, project management and programming. In this paper, permeability and groutability are evaluated by Lugeon and geological strength index for sealing and consolidation rock masses.
The recommended that examination accomplished in zonation of geological strength index and groutability for more exactly boundary zonation.
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