0.1Hz正弦波不同载荷峰值砂岩位移速率和能量预测

Displacement rate and energy simulation of sandstone under different peak loadings of 0.1 Hz sine wave

在加载速率随时间变化规律已知的前提下,研究得出不同载荷峰值下,表观弹性模量和加载力之间均呈线性关系,并随峰值增大,一次项系数递减、常数项递增的变化规律,指出该规律主要由岩体的压密程度和原始碎屑胶结物的强度决定。给出砂岩毫秒级位移速率的预测公式,通过计算位移速率和实测位移速率的比较证明该预测公式的合理性。比较发现,各加载段峰值点变形速率的峰值点均出现在1 000和2 000 ms之间,超前于加载速率峰值时刻2 500 ms,而在卸载段的峰值均出现在8 000和9 000 ms之间,滞后于载荷变化速率峰值时刻7 000 ms,说明"错峰"现象在不同载荷峰值下均存在,预测公式也能很好地解释和预测变载荷峰值下的"错峰"现象。根据推导公式,进一步进行岩样能量吸收统计,结果显示不同加载峰值下的预测毫秒级能量吸收过程与实测过程吻合较好,进一步说明了不同加载峰值下位移速率预测公式的适用性和合理性。

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 de- clines and the constant term increases as the growth of peak loadings. This rule is determined by con- solidation 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 displacement 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 unload- ing 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 pre- dicted 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 fur-ther illustrated.