声发射测量地应力方法中Kaiser点确定方法的优选与分析

Optimization and Analysis of the Method to Determine Kaiser Point of the Method to Measurement to Stress by Acoustic Emission

准确确定Kaiser点是研究声发射测量地应力的关键。通过对模拟岩心的水泥块进行单轴受压破坏过程的声发射试验,得到了试件在试验过程中的应力-应变曲线、应力、声发射强度、声发射累积数与时间的关系图。分别对试样用突变点法、最大曲率法、双切线法、重加载法(抹录不尽现象、两次加载相减法)、多方面综合判定法以及声发射强度信号的统计分析法进行了分析。从不同的方面认识了试样的Kaiser点的特性,总结并分析了确定Kaiser点的方法以及各自的适应性,并进行了优选。研究表明,试验确定了试样的物理特性,各种方法都能从不同角度和机理上解释Kaiser点现象,综合判定法能相对更加全面、准确地确定Kaiser点。

The key of the study of acoustic emission measurement of in-situ stresses is to properly determine the Kaiser point. Through the simulation of core concrete in uniaxial compression failure process of acoustic emission test, the stress-strain curve,the relationships between stress, intensity and cumulant of acoustic emission with time of the specimens in the test process are obtained. The specimens are analyzed respectively with mutation point, maximum curvature method, double tangent method,again loading method （incomplete erasion phenomenon, two loading phase subtraction） various comprehensive judgement method and statistical analysis method of acoustic emission signal intensity. Understands the characteristics of Kaiser point of the specimens, summarizes and analyzes the methods to determine the Kaiser point and their adaptability, and was optimized. Research shows that the test can determine the sample physical properties,various methods can explain the phenomenon of Kaiser point from different angle, various comprehensive analysis will be more comprehensive to determine Kaiser point.