AN AUTOMATIC PROCEDURE TO DETERMINE MAGNITUDE AND LOCATION OF ERODED SOIL VOLUMES FROM A PIPELINE TRACK

摘要

A procedure is described, which constitutes a first step in the direction of automatizing the determination of location, size, and strength of soil retention structures for pipeline tracks, for a first stage design. Based on topographic data, and using RUSLE for a design event, the procedure provides a series of eroded soil volumes, and identifies the locations at which sedimentation of each one of them will take place. The procedure is programmed within a GIS environment. A Digital Elevation Model (DEM), such as SRTM, is used as the basic topographic data. The trace of the track is introduced, as a series of x, y coordinates. As a result of crossing the DEM and the trace, the software generates, by interpolation, new points (nodes) to define the trace, coincident with the DEM grid sides. Additional nodes are also introduced to avoid lengths between nodes larger than the maximum slope length (taken as 130 m). Elevation values are next assigned to the trace nodes, by interpolating within the DEM. After that, each segment is characterized as an erosion or sedimentation segment, depending on its steepness being above or below a critical value (taken as 5%). Each erosion segment is interpreted as a slope, and the corresponding eroded volume for the design event calculated using RUSLE. Consecutive erosion segments are grouped, and the corresponding sedimentation segments, where the eroded soil will move, identified. In this way, the total eroded volume that reaches each sedimentation segment group is obtained. As an illustration, the developed software, named DUCTO, is applied to the Macueta-Piquirenda gas pipeline track, where INMAC participated as the Contractor to open the track for pipeline construction, and closing it for restoration.