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Subba Rao C.,Central Water and Power Research Station CWPRS
Indian Geotechnical Journal | Year: 2013

Information on shear wave velocities (Vs) of soil deposits is required for solution of design earthquake motions, soil-structure interaction and wave amplification. Cross-hole logging technique gives reliable measure of in situ shear wave velocity. However, this test is expensive, requiring two closely spaced boreholes, special recording equipment and skill in identifying shear wave arrivals on a seismic record. Many empirical relations were proposed connecting Vs and soil indices. Most of these equations are based on the relation between Vs and N-value. Empirical relations for estimating the low-strain Vs using different combinations of soil indices such as N-value, depth, geological age and soil type are available. Of these, the relationship connecting Vs and all soil indices having highest correlation coefficient of 0.86 was tested for six sites with varied soil types. At these sites, in situ shear wave velocities using cross-hole technique have also been measured and SPT conducted. A modified relationship is proposed to predict Vs from soil indices and is found to give better estimates of shear wave velocity. © 2013 Indian Geotechnical Society.

Venugopal K.,Central Water and Power Research Station CWPRS | Dhawan K.R.,Central Water and Power Research Station CWPRS | Pangavhane S.M.,Central Water and Power Research Station CWPRS
Indian Concrete Journal | Year: 2011

Studies for ascertaining the resistance of rock aggregates to "Alkali Aggregate Reaction (AAR)" and checking the associated rock-engineering properties are necessary in the construction of a concrete dam, since reactive aggregates may lead to the deterioration of concrete, and poor rock-engineering properties may hamper the uprightness of the structure of the dam. Keeping this in view, several tests were performed on basalt and quartzite rock aggregates for the Bellary Nala Dam, Karnataka State, India, by following Bureau of Indian Standards (BIS) guidelines for selection of the better rock aggregate, enabling its use in concrete construction work. The results indicated that the basalt rock present in the area satisfied most of the tested parameters and that those of the quartzite rock exceeded the admissible limits set in BIS code. Hence, of the two discrete rock types, only basaltic rock was found suitable.

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