Improving Technical and Environmental Safety of the Gas Pipelines Operation Crossing under Large Rivers with Destructive Spring Flood Using Ground Penetrating Radar on the Lena River Example

摘要

Gas pipeline transportation crossings (trench method) under the large rivers with destructive spring flood and intensive ice jams involves very different safety hydro-technical issues of operation. Such as changing the riverbed, the banks destruction, the new channels formation, erosion, and formation of alluvial sedimentation. For the effective application of the remote control method of underwater gas pipelines for the purpose of operational inspection of its technical condition it is necessary to improve the methodical of GPR application. Low-frequency linear GPR with a frequency of 50 MHz and 100 MHz (OKO-2, Logis-GEOTECH Company) to study the water surface of the Lena River depth up to 20 meters are applied. A special device for waterproof of antennas is developed. And also, if it necessary, a special equipment to submersibility the antennas to a depth of 1 meter is constructed. The paper presents the results of the survey of the operated main gas pipeline in the period 2014 to 2017, including monitoring of changes in the conditions of occurrence, as well as determining the exposure of the pipeline due to the erosion of the banks after the destructive spring flood. For the first time, the technology of changing the orientation of the receiving and transmitting antenna are applied to increase the search area of the pipeline in the bottom sediments at a depth of more than 8 meters, which is also disclosed and described in the paper. Experimentally proved the effectiveness of the GPR using in the inspection of gas pipelines at river crossings with a depth of more than 10 meters, buried in the sediments with a capacity of more than 6 meters. The method of increasing the search area of pipelines is developed.