Abstract: In this paper, under the premise that the rule of loading rate varying with time has been known, the research results show that there presents a linear relationship between the apparent elastic modulus and the loading force under different peak loadings, in which the first-order coefficient declines and the constant term increases as the growth of peak loadings. This rule is determined by consolidation degree and original clastic cement strength of rock mass. Meanwhile, the predictor formula of displacement rate in millisecond level was put forward, its rationality was confirmed by comparing the calculated dis-placement rate and the observed values. After comparison, it suggests that the peak points of displacement rate in loading areas all appear between 1 000 ms and 2 000 ms, which is 2 500 ms ahead of the peak time of the loading rate, while the peak points of displacement rate in unloading areas appear between 8 000 ms and 9 000 ms, which is 7 000 ms lagging behind the peak time of the unloading rate. It explains that the ‘peak shifting’ phenomenon exists under different peak loadings and the predictor formula can well explain and predict this phenomenon. According to the derivation formula, the energy absorption statistics of rock samples were further carried out, which suggests that the predicted millisecond level energy absorption process under different peak loadings agrees well with the measured process, and the applicability and rationality of the displacement rate predictor formula is further illustrated.

Key words: load peak value；apparent elastic modulus；millisecond level；displacement rate；&ldquo, peak shifting&rdquo, phenomenon