Prediction of grout take using rock mass properties
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Seepage through foundation and abutments of a dam can potentially result in waste of the water stored in the dam reservoir, erosion of foundation materials, and development of uplift pressure in the dam foundation which, consequently, threatens the long-term stability of dam. A grouting process, which is carried out based on the results of the Lugeon test, is among the techniques applied for seepage control. In this paper, factors affecting the grouting process were assessed in the Bazoft dam site. Bazoft dam is a hydroelectric supply and double-curvature arch dam with a height of 211 m located in Chaharmahal and Bakhtiari Province of Iran. The bedrock of the dam site consists of Asemari formation (limy marl and marly limestone), in the middle and upper parts of left abutment, and Jahrom formation (limestone and dolomite) in the right abutment, river bed, and lower part of left abutment. As test grouting, two trial grouting programs were applied in the right and left abutment of this dam site. At a first step, using the existing relations and engineering geology reports, Q system, SPI, grouting pressure, joint aperture and grout take were determined for 5 m segments of the trial grouting boreholes. Then, using SPSS software (version 21) the grout take was estimated based on the parameters noted. According to the results, grout take showed good correlation with Q system, grouting pressure and joint aperture. There was no correlation between SPI and grout take. Examination of the necessary assumptions of the model, such as normality, multicollinearity (eigenvalues, condition index, tolerance and VIF), and independence of errors revealed the moderate accuracy of the model obtained.
KeywordsTrial grouting boreholes SPI Q system Grouting pressure Joint aperture
It is our pleasure to offer our sincere regards to staffs of “Qods Niru Engineering Company” (QNEC) for their cooperation with the work presented in this paper.
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