Acoustic Pipe Qujing, Yunnan acoustic tube Acoustic Pipe is the definition of the probe into the interior of the channel when the pile piles ultrasonic testing method. It is a pile of ultrasonic detection system is an important part of it in a pile embedded manner and arrangement of the cross section of the pile, will directly affect the test results. Therefore, a test is required in the design of the pile should be arranged and embedded standard way acoustic tube into the drawings, the construction should strictly control the quality of embedded, in order to ensure the smooth progress of inspection work. Acoustic Pipe choose acoustic tube material selection to sound transmission rate is high, ease of installation and low cost principle. Acoustic pulse from the transmitting transducer issued by coupling the water reaches the water acoustic test tube wall interface, and then through the wall to reach the interface acoustic tube wall and concrete through the concrete and then need to pass through another acoustic tube The two interfaces reach the receiving transducer. Thus, the formation of four acoustic tube interface, the acoustic energy at each interface permeability coefficient can be calculated: (1) where: - an interface acoustic energy transmission coefficient; - boundary acoustic media on both sides impedance ratio () transmitting and receiving between the transducer 4 interface overall sound transmission coefficient (2) currently used has a steel tube, steel bellows, three kinds of plastic pipe. Advantages of steel is easy to install, can be welded welded steel skeleton BU, can replace part of steel section, and because after a large pipe stiffness. Embedment may be substantially parallel to maintain its flatness, many large diameter piles are used As the acoustic steel pipe. But the price of steel is more expensive: steel bellows is a good acoustic tube material, it has a thin wall steel provincial and impermeability, pressure, high strength, flexibility and good features, typically used for prestressing post-tensioned structures reserved channels: make a sound when using the test tube. Direct lashing steel skeleton in the soil, the joint socket available at a bigger ripple. Because the bellows is very light, so the operation is very convenient, but should pay attention to keep it straight when installing its axis. Low acoustic impedance of plastic pipe, with make a sound test tube with a larger sound transmission rate, typically used for smaller piles, should be used in a large pile of caution - because a lot of large diameter concrete piles need perfusion, heat of hydration of cement is not easy to diverge: Since the thermal expansion coefficient differences between plastic and concrete, plastic pipe due to temperature drop in radial and longitudinal shrinkage after the concrete has set, it is possible to make a partial disengagement of the concrete caused by air or water cracks in the sound path has added more highly reflective screen, likely to cause false positives. Acoustic tube diameter, and is usually higher than the radial transducer diameter l0mm to common specifications is the inner diameter of 50-60mm. Impact on the abundance of sound through the pipe wall thickness is small, so, in principle, no restrictions on the wall thicknesses, but save steel consumption point of view, as long as the wall can withstand the lateral pressure of fresh concrete, the thinner the province. Acoustic tube embedded layout arrangement and the number of cross-section embedded in the pile layout BU controlled area should consider testing. Usually arrangement shown in Figure 7, the shaded area in FIG control area detection. Generally when the pile diameter less than 0.6 to 1m, two diametrically arranged; pile diameter when 1 ~ 2.5m, arranged in three, equilateral triangle; when the pile diameter greater than 2.5m, arranged in four, square. Acoustic Pipe installation method can be directly mounted on the inside of the steel cage, shown in Figure 8-8: Fixed mode can be welded or banding should remain substantially parallel between the pipes - If necessary strength test results for each measuring point Concrete assess, no parallelism should be controlled below 1 ‰. Steel cage into the pile hole should be to prevent distortion. General segmented pipe with steel cage installation, joints can be counter-threaded sleeve or sleeve welded interface between each program, shown in Figure 8: The use of bellows may favor a bigger bellows socket, Wells set to take over at both ends sealed with tape wrapped. Whether ah Bu kinds joint program must ensure that at high hydrostatic pressure does not leak slurry wall should be kept flat interface, there should be no welding slag, burrs and other projections, so as not to hinder the probe to move freely, the bottom of the acoustic tube it should be sealed after installation should be catchy with cork block, in order to avoid falling into foreign body poured concrete, resulting in clogged pores. Other 5- sealing tape 4, acoustic tube; Edit this section to install a) steel pipe socket; b) 1- reinforced bellows sockets; 2- acoustic tube; 3- set to take over; 4- stirrups Uses Acoustic Pipe is used in addition to the detection channel and replace part of the steel section, but also as a post grouting pipes. Tests show that pile after pile bottom pulp processing can greatly improve its carrying capacity. Meanwhile acoustic tube defects but also as accidents pile grouting flush the pipeline and processing, then the need to take measures to require grouting pipes penetrated defective parts. Ultrasonic transmission method of acoustic tube general requirements are: joint firm does not disengage, slurry seal does not leak; do not discount the wall smooth, smooth without distortion; vertical tube is not skewed; no foreign body within the flow tube. When the acoustic tube materials or poor installation process, it may cause leakage of plasma, blocked tubes, broken, bent, sink, deformed and other accidents, ultrasonic transmission method pile integrity testing have a significant impact, even can not be detected by ultrasonic transmission. Based on the above, we passed the corresponding theoretical calculations and a large number of engineering practice, from Zhejiang Hongchang Technology Development Co., Ltd. launched our patent products: high-strength double-sealed hydraulic acoustic tube (patent number: 200720112817.3). High-strength double-sealed hydraulic acoustic tube in socket terminal end design of the two convex groove, groove with a convex ring, the end of the product insert jack socket end when installing 10cm, then use special hydraulic clamp while two convex groove extrusion, extruded parts shrink tubing force after deformation between two convex outer groove deep into the inner pipe tubing, thus effectively achieve a reliable connection of the product; the same rubber material seal Circle in the service posted by compressional deformation between two pipes, played a very good seal double insurance. The advantages of high strength dual seal hydraulic acoustic tube is fully taken into account mainly the various elements in the use of acoustic tube involved in all aspects of the domestic and world leading performance.