Research On The Monitoring Method Of The Abrasion Of Concrete Based On A Chirped Fiber Optic Bragg Grating(CFBG)

In water resources and hydropower engineering,it's very common that the surfaces of diversion structures and release works are subjected to the abrasion damage caused by the sediment flow.With the rapid development of hydropower cause in our country,many high-head,large-flow,high-flow-rate water conservancy and hydropower projects are being constructed in the southwest and northwest area.Under this circumstance,one of the important subjects that engineers have to face in the hydropower projects' design,construction,operation,and management is how to solve the abrasion of hydraulic structures under the action of high-speed flow(especially high-speed sediment flow).For this,focusing on the abrasion monitoring of diversion structures and release works is a good research direction.The abrasion monitoring of hydraulic structures is to master the concrete properties of diversion structures and release works' surface timely,in order to detect the abrasion damage's occur as early as possible,track the development of abrasion,and provide the basis for the safety scheduling to avoid the danger of the buildings' safety.At present,the means of monitoring the hydraulic concrete abrasion depth are mainly visual surveillance and instrumental surveillance both at home and abroad.The instrumental surveillance is using echo detection,sonar instrument and other nonsynchronous monitoring means.But duo to noise interference and unable to achieve continuous and real-time monitoring,this method isn't widely used.Nowadays in our country,a kind of concrete abrasion sensor invented by Dai Xiaobing who works in Zhongnan Engineering Corporation Limited is being used,but this sensor's precision and measuring range are not good enough.So conducting a research and presenting a new method of the concrete abrasion's monitoring is very necessary.The chirped fiber Bragg grating(CFBG)is introduced into the field of abrasion's monitoring and related research has been carried out in this paper.Basing on the consulting lots of correlative papers,a series of theoretical and experimental work of abrasion's monitoring method based on a chirped fiber Bragg grating has been put in practice.The main work of this paper is:1)The monitoring technology of hydraulic structure's concrete abrasion and the fiber Bragg grating sensing technology were reviewed;2)Research on the sensing technology of a chirp fiber Bragg grating;3)Design the concrete abrasion's monitoring method based on a chirp fiber Bragg grating and put the design into practice;4)Carry out the indoor experiments to check the feasibility and the precision of monitoring method proposed in this paper which is based on the chirp of fiber Bragg grating;5)Carry out the model experiments to preliminarily probe into the development process and regularity of the concrete's abrasion depth,under a certain water condition.Compared with the existing methods of concrete abrasion's monitoring method,this new monitoring method has the characteristics of high precision and strong anti-interference ability.It's reasonable to say this method has a broad application prospect in the field of the monitoring of concrete abrasion.