Sand Drain System
Sand columns are constructed by filling the sand into the cavity for soft soils. Two types of sand draines are installed: displacement system and replacement system. A closed mandrel is driven into the design depth and the construction is completed by filling the sand into the cavity through the mandrel for the displacement system. After drilling by auger or with water jet in accordance with the diameter of the project, the construction is completed by pouring the sand into the cavity for the replacement system. The sand drain system uses to reinforce good to poor soils, including soft to stiff clay and silt, loose to dense sand, organic silt and peat. Sand drains are used to reinforce and stiffen compressible foundation soils and increase the time-rate of settlement in order to control post-construction settlement magnitudes.
Sand columns can be used instead of prefabricated drains. Sentez Insaat engineers work with you and your specific soil conditions and loads to engineer a project-specific practical solution to improve your ground.
The Construction Process
Sand drain system is an efficient and cost effective solution for increasing the time-rate of consolidation of the settlement sensitive structures.
1. A specially designed, mandrel and tamper foot is driven into the ground using a strong static force augmented by dynamic vertical impact energy. Depths normally range from about 3m to 18m, depending on design requirements. A sacrificial plate or internal compaction mechanism prevents soil from entering the tamper foot and mandrel during driving. The process eliminates spoils and displaces soils laterally, densifying and reinforcing soils.
2. After driving to design depth, the hollow mandrel serves as a conduit for sand placement. Placed inside, the sand flows to the bottom of the mandrel. The tamper foot and mandrel are then raised and the uniform column is constructed by continuing of this process to the ground surface. This results in excellent coupling with surrounding soils and reliable settlement control depending on design requirements.
The sand drains are constructed between 25cm and 50cm diameter to meet project requirements.
Rapid installation process means shorter construction schedules.
Projects are engineered by Sentez Insaat Engineers.