1, acoustic tube selection
Acoustic pipe material selection, to sound transmission rate, convenient installation and low cost principle.
Acoustic pulse from the transmitter transducer sends, through the coupling water to reach the water and measurement of pipe wall of the interface, and then through the wall of the tube to the sound test tube wall and concrete interface, through the concrete and then through another acoustic pipe two interface to the receiving transducer.
The current commonly used pipe steel pipe, plastic pipe.
Steel pipe has the advantages of convenient installation, available welding welding in steel skeleton Bob, can replace part of the bar section, and because the steel pipe with large rigidity. Embedded can basically keep the parallel straightness, at present a lot of large diameter bored piles are used as acoustic pipe steel. But steel prices more expensive:
Plastic pipe acoustic impedance rate is low, with a sound test tube having a larger sound transmission rate, usually used in small piles, in a large pile should be cautious when using - because large diameter pile filled with massive concrete, hydration heat of cement not easy divergence: in view of the thermal expansion coefficient of plastics and concrete the disparity, the concrete is solidified plastic pipe when the temperature drops to produce a radial and longitudinal contraction, it is possible to and from concrete caused by air or water in the acoustic path, and added more intense reflection interface, easy to cause the mistaken judgment.
Acoustic pipe diameter, usually smaller than the large diameter radial transducer can be l0mm, common specifications are50-60mm diameter. Pipe wall thickness on sound transmission and effects is very small, so, in principle, the wall thickness of the tube is not limited, but the savings from the amount of steel angle pipe wall can bear, as long as the concrete lateral pressure, the thinner more province.
2, acoustic pipe buried number and arrangement
Arrangement of acoustic pipe buried in the pile quantity and its cross section layout should be considered for the detection of control area.
General pile diameter is less than 0.6~1m, along the diameter arranged two; pile diameter is 1~2.5m, the arrangement of 3root, a equilateral triangle; pile diameter greater than 2.5m, the arrangement of 4root, a square.
3, acoustic pipe installation method
Acoustic tube can be directly fixed in reinforcing cage inner fixation methods can be used: welding or binding, between the tubes should basically remain parallel - if the detection result of the strength of concrete is evaluated, not parallel degree should be controlled below 1 per thousand. Pile reinforcement cage into the hole should be to prevent distortion.
The tubes are generally installed with the reinforcement cage section, each section between the joint can adopt reverse threaded sleeve interface or casing welding scheme. No matter what the joint scheme must be guaranteed at high hydrostatic pressure without leakage, interface wall should be smooth, without welding slag, burr of projection, so as not to hinder the probe freely mobile, acoustic pipe bottom also should be sealed, after installation should be catchy with a cork plug, so as not to pour concrete falling objects, resulting in pore blockage.
In 4, the other uses of acoustic pipe
Acoustic pipe in addition to a detection channel and replacing a part of steel, also can be used as a pile bottom grouting pipe. Test shows that, the pile bottom grouting of bored pile, can greatly improve the bearing capacity of. At the same time acoustic tube can also be used as a pile accident defect flush with the grouting pipe, it is necessary to take measures to require grouting defects in pipe penetrated.
Ultrasonic transmission method, the acoustic pipe General requirements are: joint firm not off, sealing without leakage; the tube wall is smooth and not discounted, smooth without distortion; the tube body vertical not skewed; tube unblocked without foreign body.
When the acoustic pipe material or installation process poorer, may cause a leak slurry, plugging, fracture, bending, subsidence, deformation of accidents, of ultrasonic transmission method for integrity testing of pile foundation have a greater impact, even can't carry on the ultrasonic transmission method.
Based on the above situation, we through the corresponding theoretical calculation and a large number of engineering practice and reference of other product form, by the Cangzhou City Tai Yu Feng Steel Pipe limited company introduced the clipper acoustic pipe
Sealing clamp pressure acoustic pipe in the socket end designed two convex groove, a convex slot with sealing ring, when installing this product the spigot end is inserted into the socket of the 8cm, and then use the special hydraulic clamp of two convex groove for extrusion, is extruded parts of the pipe under stress shrinkage deformation, two convex groove between the outer pipe deep into the inner tube, thereby effectively to achieve the product reliable connection; at the same time of rubber sealing ring in extrusion deformation after pasted on a two layer between pipes, played a very good sealing effect.
High strength double seal hydraulic acoustic pipe major is the advantages of fully considering the acoustic pipe in use is involved in a variety of factors, from various aspects to the domestic and the world's leading performance.