Highway Guardrail Column Depth Of Ndt Technology And Influencing Factors

Expressway guardrail post embedded depth which directly related to the driver's life and property security, but due to the lack of effective detection measures, resulting in serious quality problems when construction . At present, the inspection of post embedded depth widely by pulling piles manual inspection. But this method needed special tension piles machinery and to be buried the foundation once again after each inspection which brought a lot of trouble to inspectors. Therefore, we needed a kind of rapid and reliable detection method and a type of portable equipment to settle the matter that the depth of guardrail post embedded.In this paper, the elastic wave propagation was researched on the basis of one-dimensional rods and the different conditions of guardrail post device were analyzed, Such as whether or not to connect with guardrail plate and install rubber cap, the relative position between guardrail and post, sensor types and its installation locations, vibration hammers and the stations for exciting vibration etc. which influenced the test results that the length of half- buried post by the detection method of elastic wave. The change of detection frequencies and the influence of the detection results were analyzed preliminarily on different states. The range of correction factors were obtained in various states by experiments when post connected with guardrail plate.The preliminary test results demonstrated that when the post at the non-lap position the detection frequency mostly were from 950 to 1000 Hz and the correction factorsψ1were from 1.25 to 1.22, when the post at the lap position the detection frequency mostly were from 875 to 925 Hz and the correction factorsψ2were from 1.32 to 1.25. It not only provided references for detection persons in engineering field which inspected the depth of post embedded in soil but also provided the theoretical and experimental proof for engineering test and developing portable inspection equipment. But it remained to be further verified the accurate value of correction factor through the experiment.