Fuzzy Evaluation And Application Research On Ultrasonic Transmission Method To Detecting The Quality Evaluation System Of Foundation Pile

As a kind of very significant foundation forms,pile foundation belongs to the concealed work in most cases,and his quality is hard to control because of the engineering geological conditions and construction technology and other influencing factors.When the pile foundation accidentally has quality problems,on the one hand,the repair and reinforcement is very difficult,on the other hand,it will cause a huge accident.Therefore,the pile testing is a very important tache in pile foundation engineering.Starting from the theory of ultrasonic wave,the acquisition and processing of acoustic parameters and fuzzy comprehensive evaluation method,this paper studies the improvement of evaluation and applicability in engineering problems,the main content is divided into four parts:Firstly,starting from the basic theory of ultrasonic detection technology,including the acoustic theory of ultrasonic waves,the detection principle and method,the ultrasonic detection device and the layout of Acoustic Pipe and so on,understand the actual use of the ultrasonic testing device,and how to detect the quality of the pile.Secondly,A series of acoustic parameters,such as sound velocity,amplitude,frequency,etc.,can be obtained from ultrasonic testing,and these parameters are the main factors to judge the quality of the pile.These parameters cannot be used unless processed.For example,the real time of ultrasonic wave in pile foundation is that the time of detecting should subtract the time of the system and the time from the transducer to the wall.Thirdly,the integrity of the pile can be evaluated by the collected acoustic parameters.There are many methods for evaluating the integrity of piles,such as probability method,amplitude,PSD method and NFP that is a comprehensive analysis method,and then the fuzzy comprehensive judgment model is proposed from the advantages and disadvantages of these methods.Based on the fuzzy comprehensive analysis of the parameters of wave velocity,amplitude,frequency and waveform,the quality of pile concrete is determined.Finally,based on the pile foundation testing in one project,the result is obtained by comparison of conventional pile quality criterion and fuzzy comprehensive criterion,when the parameters of the measuring points are not abnormal,fuzzy comprehensive evaluation is consistent with conventional criteria,when the abnormal points that is judged by conventional criterion are mutual contradiction,fuzzy comprehensive criterion can accurately discriminate the defects of pile quality.