Study of the Key Technology about Low Embankment of Freeway in Plain Areas of North China

In the plain areas of China, in order to avoid freeway transverse traffic disturbance, when design passages or culverts, it usually designs high embankment for passages or culverts. If embankment is low, it is difficulty for passages or culverts to drain water. Hengshui to Daming freeway in Hebei Provence (Heng-Da freeway) is one section of Daqing to Guangzhou freeway. This paper studies the key technology of low embankment drainage of Heng-Da freeway based on the analysis of the characteristic of climate, geology, hydrology and low underground water table, good permeability stratum soil, its little and mass rain fall and deep drinking water well in the plain areas of North China. The paper also puts forward the design methods about collecting pool purifying filtration system to solve the drainage problem. The first method is: collecting well + transverse drainpipes + filter pool. The second is: collecting well + transverse drainpipes + sedimentation pool with back cover + small seepage well. The third is: collecting well + transverse drainpipes + sedimentation pool without back cover+ small seepage well. When adopt the design methods, the average filling height can be reduced over 1.5 m and the drainage problem of low embankment is solved well in Heng-Da freeway project.