Spatial distribution and mechanism of geological hazards along the oil pipeline planned in western China

The oil pipeline planned in western China goes through the Northwest Loss Plateau, where geological hazards, mainly landslides and loess collapsibility, are extremely developed. After careful aerial photographic explorations, field investigations, in-situ tests and laboratory experiments, the following results are obtained concerning the spatial distribution and mechanism of the geological hazards. From the west to the east along the oil pipeline, the loess collapsibility becomes weaker and weaker, with the total collapse quantity decreasing from >200 cm in the west to several centimeters in the east, and with the dead weight collapse quantity from >150 cm in the west to zero in the east, while the landslide populations become more and more dense. Besides, the frequencies of landslides on each side of the valley are not the same though they often reoccurred in the same place. The spatial distributions of geological hazards are consistent with the climate, topography, seismic-geology and neotectonic movements. (C) 1999 Elsevier Science B.V. All rights reserved.