利用声发射和波速变化判定岩石损伤状态

Evaluation of rock damage state with acoustic emission and velocity variation

摘要:

对岩石受单轴压缩损伤过程中的声发射和超声波波速进行了同步测量,对比分析了声发射和波速随损伤过程的变化规律。研究表明,岩石损伤过程可分成几个阶段,不同阶段声发射和声波波速变化呈现不同特征;利用超声波波速的相对变化能够稳定可靠地鉴别岩石的＂加载强化＂与＂加载弱化＂;声发射b值对裂隙的非稳定扩展更加敏感,可以作为岩石失稳预警参数;岩石声发射和波速都对损伤具有记忆性,重复加载下的声发射和超声波波速变化可提供更丰富的岩石损伤状态信息。

Abstract:

Rock damage and evolution is the basic reason for rock material failure; it is significant to determine the damage state for the security of the rock engineering. The rock will damage under external load, accompanied by a series of changes in physical and mechanical properties. By testing the changes, we can determine the damage state of rock and evaluate the damage degree. In this paper, we use uniaxial monotonous loading to detect the acoustic emission and ultrasonic wave velocity synchronously in the process of rock damage, and make comparative analysis on the variation law of acoustic emission and velocity with damage. It shows that rock damage process can be divided into several stages, and the acoustic emission and ultrasonic velocity variations exhibit different characteristics in different stages. The relative changes of ultrasonic velocity can be used to make stable and reliable identification of the rocks＇ ＂strengthening loading＂ and ＂weakening loading＂ ; the b-value during acoustic emission is more sensitive to the non-stable expansion of the fractures and can be considered as a warning parameter of rocks＇ instability; both the acoustic emission and the velocity have a memory in rock damage, and the acoustic emission and velocity variation under cycle loading can provide richer information on rock damage. These results can be used to guide the quantitative evaluation for rock or concrete damage and safety evaluation in rock engineering.[著者文摘]