Research methods: The paper carries on the research combining distribution of collapsibility loess with construction drawing design of Shengchi-Lingbao section of Zhengxi PDL.
Research results: The line will pass through loess tableland, strath terrace, gentle slope and relatively stable ravine zone, avoiding through sink hole, gully side and slope zone where the gully is developed as possible. If passing through the collapsed loess regions, the line will pass through the regions where there is light collapsibility and good drainage condition on the ground surface. If the line passes across the deep loess gutter, in combination with landform the designed height will be lowered. When selecting the route, the subgrade-bridge proposal and subgrade-tunnel proposal will be alternated comprehensively.
Research conclusions: The route in loess regions with deep collapsibility will try to avoid passing through embankment. The section concentrated with the culverts will be considered to pass with bridges. And long cutting engineering will be avoided. The concave slope will not be designed where the entrance and exit of the tunnel as well as the underpass of the highway have already been set as possible.
2006, Vol. 23 
