Non-destructive Detection Methods And Experimental Study Of Expressway Barrier Post Embedded Length In Soil

The Wave-beam barrier posts were used which are the most commonly and safety devices in expressways. The barrier posts are the main carrying parts in barriers. The length of barrier post partly embedded in soil whether can achieve the design requirements which directly determine if the barrier could play a security role when the accident occurred .The post is partly embedded in the highway soil, It is often occurred the quality problems in the construction process, so it is necessary to inspect the length partly embedded in soil. At present, the inspection of length partly embedded in soil only by pulling piles manual inspection. This method will undermine the integrity of soil when the barrier part is pulled, and it is need to re-lay a solid foundation as it is completed, when the barrier part is drive into soil once again, the length of the guardrail part need to re-inspect, these bring about certain difficulties at quality supervision and management, so it needs a fast and non-destructive testing methods and equipment to solve the current problems.Non-destructive testing methods were analysised and researched in other fields , and explore the use of elastic waves to inspect the feasibility of the length of barrier post embedded in soil .According to knowledge of elastodynamics, the characteristics of elastic-wave spreading in the post at different frequencies were studied, the theory of elastic waves and non-destructive testing methods about inspection of length partly embedded in soil were proposaled, and have a large number of tests research. However, due to the differences of the standard and batch of steel columns,there were certain differences of wave transmitting velocity in the post between the actual value and the theoretical value. After construction, if velocity can be corrected, it will improve precision. The results show that the maximum absolute error is less than 21 mm and the maximum relative error is less than 1.1%. This method can meet the requirements of engineering testing. If velocity can't be corrected, using 5160 m/s as detection of velocity. The results show that the maximum absolute error is less than 31 mm and the maximum relative error is less than 1.6 %. This method can meet the requirements of engineering testing too.