花岗岩动态压缩力学特性研究

由于岩石材料动态破坏的复杂性,理论分析和实验研究都还很不充分,岩石的动力特性越来越受到重视。本文采用霍普金森压杆对花岗岩圆柱试样进行了动态压缩试验,建立了加载速率与花岗岩冲击破坏时的弹性应变能、结构破坏能及岩石破坏形态之间的关系。试验结果表明:甘肃地区弹模在17~21 GPa的花岗岩在瞬时加载条件下,强度随着加载速率的增加而提高;动态压缩强度平均强度为240 MPa,动态模量为31.5 GPa;应变率的变化范围在81~210 s^-1,动态压缩强度随着应变率的增加有明显增大的趋势;当冲击速度增加时,岩石破坏后释放的能量显著增长,应变率越大,岩石破碎块越小。该试验结果能够评价动态荷载作用下花岗岩的强度参数,为类似区域的工程设计与施工提供依据。

Study on Dynamic Compression Mechanical Properties of Granite

Due to the complexity of dynamic damage, the theoretical analysis and experimental research on the dynamic damage of rock materials are still insufficient. Therefore, the study of the dynamic characteristics of rock under dynamic loading has been paid more and more attention. In this paper, the dynamic compression test of granite cylindrical specimens was carried out by Hopkinson pressure bar, and the relationship between the loading rate and the elastic strain energy, structural failure energy and rock failure morphology of granite impact failure was established. The experimental results show that the strength of the 17~21 GPa granite in the Gansu area is increased with the loading rate under the transient loading conditions; the average compressive strength is 240 MPa, the dynamic modulus is 31.5 GPa, and the strain rate varies from 81~210 s^-1. The increase of strain rate increases the dynamic compressive strength. The energy released after rock failure increases with the increase of impact velocity. The larger the strain rate, the smaller the rock fragmentation. The experimental results can evaluate the strength parameters of granite under dynamic loading, and provide a basis for engineering design and construction of similar areas.