岩石试样凯塞效应的实验研究

EXPERIMENTAL STUDY ON KAISER EFFECT IN ROCK

本文结合白云质大理岩试样先存应力的凯塞效应测定法进行实验研究,指出:试样的外加最大应力在142天之内仍能被记忆,且误差小于4%;对以声发射技术求取岩石先存最大应力的不同方法进行比较,并讨论了每种方法的精度;认为应仔细准备试样,按特定要求加载,以便获取可靠的实验结果;此外还提出了“抹录不净”的见解。

The concept ot Kaiser Effect states that no acoustic emission(AE)is generated when loading a rock specimen to a lower load than had perivous- ly been applied.This phenomenon has recently been investigated by a num- ber of workers for its potential application to in-situ stress measurement. In this paper,laboratory study of Kaiser Effect on dolomitic marble speci- mens is presented.The maximum stress recorded lasts as long as 142 days and the error is less than 4%.Estimations of the pre-existing maximum stress by different methods of the AE technique are compared and the accuracy for each method is discussed.From the test results the authors call for special caution in specimen preparation and loading. Besides,authors find out that during the third loading period of rock sample,an apparent AE signal seems to be observed at the peak stress level in first loading process.