真空圧密ドレーン工法研究会 Company Profile

Consolidation drainage method using capped drains

The Vacuum Consolidation Drain Method Research Association conducts research and dissemination activities on the consolidation drainage method called "Vacuum Consolidation Drain Method," which uses capped drains. The vacuum consolidation method (atmospheric pressure loading method) was devised in Sweden in the 1940s and was introduced to our country in the early 1960s. This method utilizes vacuum pressure to discharge pore water contained in soft ground, aiming to achieve consolidation settlement and increased strength of the ground. In conventional vacuum consolidation methods, sealing sheets are used to maintain airtightness. In this method, capped drains with pre-installed drainage hoses are vertically driven to a depth of about 1 meter (in cohesive soil layers) to ensure airtightness through negative pressure sealing effects. Therefore, since the sealing effect can be achieved in one step of vertical drain installation, this leads to labor-saving in construction, cost reduction, and shortened construction periods.