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，只记录超过阈值的声发射波对应的比率计数。这是为了能够在没有计算机的情况下通过电池供电自动记录长期(即超过400天)。该系统制造经济，因此我们可以在现场使用许多系统。其中一个系统由两个放大器和声发射传感器组成。也就是说，该系统的特点是对声发射信号的噪声采用有源-虚拟的方法。在声发射测量中，特别是在野外，很难从记录的信号中区分出任何噪声。因此，有源声发射传感器直接连接到岩石或波导上，而不是虚拟传感器连接到它们上。如果同时在活动传感器和虚拟传感器中同时记录声发射计数，则在给定时间间隔内从记录中取消活动计数。这些声发射计数系统被应用于日本、土耳其和埃及的许多田野和地下建筑。例如，大约60年来，土耳其一个名叫Babadag的小镇一直在遭受山体滑坡的折磨。巴巴达格距离德尼兹利市约60公里。这个小镇的主要部分位于一座地垒状的小山上。位于东面和西面的两条小溪限制了该镇的面积。这个小镇的海拔约为700米。安装了声发射系统，通过手持式激光测距仪、管道应变计、地下水位、降雨量、温湿度等综合监测系统获得的参数进行对比，结果表明，声发射活动与滑坡地表移动和降雨量有很好的对应关系。尤其是声发射活动与降雨量之间存在明显的时滞。该项目开发的声发射监测系统在现场有足够的实用性。

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.