Pavement distortions, such as rutting and shoving, are the common pavement distress problems that need to be inspected and repaired in a timely manner to ensure ride quality and traffic safety. This paper introduces a real-time, low-cost inspection system devoted to detecting these distress features using high-speed 3D transverse scanning techniques. The detection principle is the dynamic generation and characterization of the 3D pavement profile based on structured light triangulation. To improve the accuracy of the system, a multi-view coplanar scheme is employed in the calibration procedure so that more feature points can be used and distributed across the field of view of the camera. A sub-pixel line extraction method is applied for the laser stripe location, which includes filtering, edge detection and spline interpolation. The pavement transverse profile is then generated from the laser stripe curve and approximated by line segments. The second-order derivatives of the segment endpoints are used to identify the feature points of possible distortions. The system can output the real-time measurements and 3D visualization of rutting and shoving distress in a scanned pavement.
This study researched the geochemical origin of coalbed methane (CBM) in three mining areas of the Huaibei coalfield and the distribution of different origin gases. The Rock-Eval data indicate that coal and coaly mudstone in this coalfield are both good gas-source rocks and are within the gas generation window. The large ranges of isotope data (δ 13 C CH 4 = −42.8‰ to −75.5‰; δD CH 4 = −153.2‰ to −228.1‰; δ 13 C CO 2 = +8.2‰ to −24.3‰) reflect the complicated formation mechanism and evolutionary process of CBM. Both thermogenic and biogenic gas are present within the mining areas to varying degrees, with the biogenic gas being predominately generated via the CO 2 reduction pathway. Gas migration was most prevalent in the Suixiao mining area, low in the Linhuan mining area, and not identified in the Suzhou mining area. An appropriate distribution model for the gases of different origin is, from bottom to top, a thermogenic gas zone, a mixture zone, a secondary biogenic gas zone, and a gas-weathered zone. Spatially, secondary biogenic gas was in the basin margins, thermogenic gas in the central part, and the mixed gas in the transitional zone. The CBM prospectivity is greatest in the Suzhou mining area, moderate in the Linhuan mining area, and worst in the Suixiao mining area.
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