This paper deals with the relations between the distribution of soil liquation and topographic unit,stratigraphic age,and strata association ,based on the data of Tangshan earthquake in 1976.

topographic unit,stratigraphic age,and strata association as the most important elements for controlling the soil engineering geological conditions.

According to the analysis of regional geological structure,engineering geology and hydrogeology of the of rail traffic first stage construction in Harbin city,this paper points out the construction method of rail traffic and the base content and method of geotechnical engineering reconnaissance under the conditions of different landform unit and geological.

DEM based auto-extraction of geomorphic units;

By dividing the geological and physiognomic units along the project highway, the work related to spotting, pit detecting, describing, sampling, testing and data collecting was completed, the type of soil cause and shape for each unit were analyzed, the sections of expansive soil and bad soil were marked off, and finally the recommendation on treatment was brought forward.