The effects of the method of installation of sand drains on the in situ characteristics of the subsoil being treated are critically important in evaluating the design assumptions and cost of construction in establishing the feasibility of employing sand drain stabilization for any given project. The factors entering into the design of sand drain installations for use in embankment foundation stabilization are being reviewed, and the concept of grid efficiency as a basis for comparing the performance of drains installed by various methods is being developed. This concept is employed to explain the greater effectiveness of drains installed by the newly developed flight auger method as compared to results obtained with drains installed by the mandrel method. Depending on factors controlling the construction, such as right-of-way limitations, availability of materials, etc, the use of sand drain stabilization may effect substantial savings over alternative procedures in the construction of highways over compressible soils.
Abstract