This paper expounds the applicability and merits and demerits of the treatment of the collapsible loess foundation of the transformer station with the cushion method,and introduces the matters needing attention in the construction of the cushion method.

Owing to spot limited, cushion method of densely covered ash soil pile makes up for the shortage of plane treating scope of sheet soil cushion.

Based on soil test and the portable dynamic penetration test on high fluvial terrace of Lanzhou,it is found that the cushion is an available treatment to improve subgrade bearing capacity and to decrease collapsibility and permeability in small-sized engineering projects.

It discusses the importance of foundation processing in collapsible loess area,illustrates the usual foundation processing method in Shanxi such as cushion,dynamic compaction,hole extrusion method etc.

The common method for treating collapsible loess foundation is soil- bedding method, but because the site is limited in actual construction and the plane treatment scope can t satisfy the requirements of the norms, the lime- soil pile is used as a subsidiary one to cover the shortage of the soil- bedding method.

Connecting with the practices of treatments of the soft roadbed, this paper introduces several common treatment methods of soft roadbed, including soil replacement cushion method, tamping method, vibroflotation method and high-pressure rotary method.

In addition the construction technology of reinforced sand cushion method is introduced as well as the application effect of this method in soft soil foundation treatment of road.

Engineering application of replacement cushion method;