Estimating The Quality Of Grouted Rock Bolts Using Ultrasonic Waves In Rock Mass

Recently, the technology of metal bar bonding is used abroad in the engineering field. Especially in mining Engineering, the traditional passive methods like (brickwork, pigsty and steel stents and so on) not only expensive but also the results is not good, some accidents because of not effective support happen usually. As a way to prevent the active supporting in roadway and cavern roof fails and two across fall, anchor plays a very important role. The traditional passive support methods are not only expensive, and the effects are also unsatisfactory, often some due to adverse to support safety accident happens. With the invention of the anchor rod and the application of the subversion of the traditional passive support the idea, anchor reinforcement technique can not only reasonable transfer of the rock mass strength and bearing capacity from itself, but also can improve the stress state of rock mass, so as to improve the stability of rock mass structure, plus the construction is simple, low cost, safe, quickly etc and therefore caused the attention of mining engineering very rapidly, get a wide range of application. Due to the anchoring wall rock structure and spread the constraint of the field detection, this paper in ultrasonic guided wave propagation theory research, and on the basis of a large number of anchorage wall rock director of propagation and anchor of the quality detection of experimental research, for ultrasonic guided wave method used in the anchor the mental rod anchor quality engineering field testing laid a foundation.Contents show below:Firstly, in this thesis,a new approach for field monitoring grouted rock bolts using guided ultrasonic waves is proposed with the input transducer on the rebar, the receiving transducer on the grout surface near the exposed end of the bolt.The effects of the installation location of the receiving transducer are studied with numerical modeling. It is practically possible to receive meaningful signals with the receiving transducer installed on the grout surface. So this can be used in field test more accurately.Secondly, in this thesis, use the method above, the group velocity of guided ultrasonic waves in field rock mass bolt is studied.Finally, on the basic of above research, according to the group velocity and the amplitude attenuation of the guided ultrasonic waves, the quality of the grouted bolt in rock mass can be tested.