Development of AE counting system and it's application to monitoring of ground behavior

研究人员开发了一种简单的声发射监测系统，它只记录与超过阈值的声发射波相对应的率计数。这是能够自动记录长期（即超过400天）的电池电源，没有电脑。该系统制作经济，可在现场多种系统配套使用。一个系统由两个放大器和声发射传感器组成。也就是说，该系统的特点点是对声发射信号的噪声采用主动-虚拟方法。在声发射测量中，特别是在野外，从记录的信号中区分噪声是不容易的。因此，主动声发射传感器直接附着在岩石或波导上，而虚拟传感器则不附着在岩石或波导上。如果一个声发射计数同时记录在活动和虚拟传感器中，活动计数在给定的时间间隔内从记录中取消。这些声发射计数系统在日本、土耳其和埃及的许多油田和地下结构中得到了应用。例如，大约60年来，土耳其一个叫巴巴达格的小镇一直遭受山体滑坡的困扰。巴巴达格距离代尼兹利市约60公里。这个城镇的主要部分坐落在一个象马一样的小山上。位于东部和西部的两条小溪限制了城镇的面积。这个城镇的海拔高度约为700米。在本实验中，我们安装了声发射系统、地面变形手持式激光测距仪、管道应变仪、地下水位、降雨量、温度和湿度。通过对这些综合监测系统所获得参数的比较，表明声发射活动与滑坡的地表运动和降雨量有较好的对应关系。特别是，AE活动与降水之间存在明显的时间差。在日本的许多领域都观察到这种时间滞后现象。本项目开发的声发射监测系统具有一定的实际应用价值。

The researchers developed a simple AE monitoring system which records only rate count corresponded with AE wave over a threshold. This is to be able to automatically record for a long term (i.e. more than 400 days) by battery power without a computer.This system is made economically and so we can use many systems in field. One system is composed of two amplifiers and AE sensors. That is, the characteristic point of the system is to adopt an active-dummy method for a noise of AE signal. In AE measurements, especially in the field, it is not so easy to distinguish any noise from recorded signals. Therefore, an active AE sensor is directly attached onto a rock or a wave-guide while a dummy sensor is not attached onto them. If an AE count is recorded at the same time in active and dummy sensors simultaneously, the active count is cancelled from the record for a given time interval. These AE counting systems were applied to many fields and underground structures in Japan, Turkey and Egypt.For example, for about sixty years, a town called Babadag in Turkey has been suffering from a landslide. Babadag is located about sixty kilometers far from Denizli City. The main part of this town is located on a horst-like hill. Two small creeks situated on the east and west limit the area of the town. The elevation of the town is about 700 meters. In this twon, we installed the AE system, ground surface deformation through hand-held laser distancemeter, pipestrainmeter, ground water level, rainfall, temperature and humidity.According to comparison with each other's parameters obtained by these integrated monitoring systems, it is shown that AE activities well corresponded to the surface movement of the landslide and the amount of rainfall. Especially, it is obvious that there a time lag between the AE activities and the rainfall. These time lag were observed in many Japanese fields.This AE monitoring system developed by the project has enough practicality in field.