Dewatering system with wellpoint filters

Experts in Wellpoint Installation

Water filtration system using wellpoint filters is the most practical and economical system for temporary lowering and control of the water table for onshore excavation of aquifers.

The principle of operation consists mainly of extracting water from underground by means of a set of filtering spikes driven into the ground at a depth greater than the excavation depth.

The Wellpoint installation must be kept in working order 24 hours a day for the duration of the intervention. Knowing the specific terrain on which the work is to be carried out is a determining factor in identifying the exact amount of material required and knowing how long the installations will take.

Pumps and Wellpoint

The pump-Wellpoint circuit must be kept under pressure. This is done by the suction pump, which has a vacuum pump capable of removing air due to leakage along the installation and air absorbed with the water during lowering of the water table.

Typical installations of Wellpoint systems

The many possible uses of Wellpoint systems can be summarised in the following three types of intervention:

- loop system,
- system in stages,
- continuous excavation.

System in the loop

The collector, in the loop system, is mounted along the perimeter of the excavation, around the intervention area. This is the most common type of collector where a continuous foundation slab is required.

The system in stages

If excavations are to be carried out where it is necessary to reduce the level of the topsoil to 5.00-5.50m, the Wellpoint system should be used in stages.

This method involves the installation of the first Wellpoint ring in the first stage, which, once started up, will carry out an initial lowering of the water table. A partial excavation will then be carried out, down to the depth determined by the water table obtained.

A second Wellpoint ring will be installed at the bottom of the partial excavation, which will further lower the water table, allowing excavation to continue to the desired depth.

Continuous excavations

Commonly used to guarantee the lowering of the water table in all those works where continuous progress is foreseen, such as, for example, the installation of new buried pipelines, the Wellpoint system will have to ensure the lowering of the water table within the area of work, guaranteeing in any case the continuity of the works when the site will necessarily have to progress and open a new excavation front.