Research On The Detecting Of Dam Hidden Danger By Microtrmors

With the country pay attention to the disease of water conservancy projects,the technology of disease exploration has been greatly developed,the geophysical exploration,as a new method of exploration,has made breakthrough progress.In recent years,the physical methods,such as DC electrical method,electromagnetic method,elastic wave method,radioactive method,have been applied on the detection of dam diseases.The micromotion is a kind of "passive source" method,It's signal source comes from a variety of natural phenomena caused by the weak vibration of the earth's surface,These complex signals contain some useful signals,We can extract the surface wave information from it,and obtain the subsurface velocity structure by inverting the wave dispersion cur ve.It has many advantages,such as simple method,low cost,small site and friendly environment.As a new survey method,microtremor is applied in the field of dam hidden danger detection The following studies are carried out for microtremor:(1)The basic principle of microtremor and the form o f traditional array are studied.meanwhile,the extended form is also studied.(2)Through the microtremor testing of the Yellow River model dam,several types of hidden dangers are detected,so as to find the advantages and disadvantages of this method.(3)Through the actual microtremor testing of the Yangtze River dam,the validity of this method is verified.Through the above research,it is found that the microtremor method is better for the detection of holes and weak layers,and it is not good for crack detection.Most of the microtremor methods are based on the fundamental surface wave,and it is suggested that the combination of the base surface wave and the high-order surface wave is better.