Recently, it has become necessary to evaluate the resistance properties of rock structures based on dynamic properties. This is due to the Japanese guidelines for seismic evaluation and the design of civil structures have been reviewed in response to the frequent occurrence of large earthquakes in the country. However, few studies have been performed on the dynamic-deformation and damping characteristics of rocks. To clarify the dynamic-deformation characteristics of granite, we performed cyclic uniaxial tests using "JGS0542-2009 Method". The experimental results are as follows: (1) the measured equivalent Young's modulus increases along with strain in the small- (<10 micro-strain) to medium- (10 to 1,000 micro-strain)-strain range; however, the modulus decreases abruptly at the large (>1,000 micro-strain) strain range where the specimen is broken and (2) the evaluated damping ratio is 0% in the small- to medium-strain range; however, it increases abruptly at the medium- to large-strain range.
Previously, rock structures were believed to be resistant to earthquakes; therefore, seismic evaluations were implemented only for critical rock structures. However, recently, the Japanese guidelines for seismic evaluation and the design of civil structures have been reviewed in response to the frequent occurrence of large earthquakes in the country. Hence, seismic evaluation of rock structures has become necessary.
A dynamic-response analysis of the rock structure requires the dynamic-deformation and damping properties of the rock mass. The testing method used to determine the dynamic-deformation properties of soils has been standardized since the 1960s and has been the subject of many reports. However, the test method for rock is not yet standard. Therefore, there have been few reports about the dynamic-deformation and damping properties of intact rock and rock mass that are unclear (Ochi et al. 1993, Ochi et al. 1995, Fukumto et al. 2009).
we discuss the effects of number of cycles and loading rate on the dynamic-deformation properties of a hard rock under uniaxial compressive stress.
