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| Dynamic increasing factor model for strength and modulus of rock materials at different strain rates |
| ZHOU Yongqiang1，SHENG Qian1，2，LI Nana3，FU Xiaodong1 |
| (1. State key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China；2. University of Chinese Academy of Sciences，Beijing 100049，China；3. Wuhan Library，Chinese Academy of Sciences，Wuhan，Hubei 430071，China) |
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Abstract In order to determine the uniform dynamic increasing factor model for the strength and modulus of different rock materials at different strain rates，a large number of experimental data for the relationship between strength and modulus of different rock materials and strain rate are counted. The basic types of dynamic increasing factor models describing rock material strength and modulus at different strain rates are summarized. From the aspects of standard deviation，goodness of fit，experimental law and smoothness，a best suitable dynamic increasing factor model for reflecting the strength and modulus of different rock materials is comprehensively evaluated and then determined. The results show that the applicability of the evaluation of the dynamic increasing factor model can not only be determined by the standard deviation and the goodness of fit，but also by the experimental law and smoothness of rate effect of the rock strength and modulus. The rock strength and the logarithm of strain rate at medium and low strain rates is consistent with linear positive correlation. And the exponential function is most suitable for reflect the rate effect of different rock strength under medium and high strain rates. Further，the best uniform model for describing the strength of different rocks at full range strain rate is also determined. Compared with rate effect of the strength，the dynamic increasing factor model embodying rate effect of different types of rock modulus at different strain rates is almost the same. The difference is that the rock modulus at the medium and low strain rates is linearly positively correlated with the logarithm of the strain rate. Meanwhile，models suitable for describing the rate effect of different rock modulus at medium and high strain rates are not only exponential function but also power function.
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2020, Vol. 39 
