Four methods for dewatering excavations in constructions

March, 31 2020

There are four primary different dewatering methods; each process is better suited for various excavation dewatering tasks and projects. Below we outline 4 ways for dewatering excavations in construction to enable you to select the most practical way for dewatering at your next construction project.

1. Open sump/drain

When considering all types of dewatering methods, open sump draining is often the most cost-effective, as gravity is the main force. To complete this method drains and sump of various sizes are placed by the sides, or in the corner, of a construction foundation. Subsoil water is collected from the pit sides and carried into the sump.

2. Deep wellpoint

The deep wellpoint method for dewatering is often favored when a large quantity of water needs to be removed as, on average, deep wellpoints can drain water up to a maximum of 24m in depth. This method is executed by placing a deep well system at the center of the excavation site. After the groundwater is collected, the water at the lower end of the wells is removed from the construction site via a pump.

3. Wellpoint system

A wellpoint system is often used when an excavation site not only needs to be drained, but further groundwater must be prevented from entering the site. To do this, a wellpoint system intercepts groundwater with pipe wells, preventing its flow. A perforated pipe is placed into the excavation site with a ball valve to stop mud from entering and altering the pipe. This method, however, can only be used if the depth of the groundwater is 18m or below.

4. Chemical

The chemical method involves converting water-logged soil, which will have a damp mud-like texture, into a semisolid mass through a chemical reaction. Soda and calcium chloride silicates are added to the damp soil, making it easier to remove.

Things to consider

As the above information indicates, when deciding which method of dewatering is right for your construction project, you must consider the area of groundwater you need to remove, how deep it is and what tools/systems are available to you. It is essential to select the right dewatering method for your construction project to ensure all the water is removed efficiently and in the most cost-effective manner.


Contact G3Soilworks

G3Soilworks provides elite consultancy services and can ensure your construction site is being dewatered in the most efficient and effective way possible. Contact us today, and we will help you maximize your profitability and get the most potential out of your construction project in California. Our geological and geotechnical experience is unparalleled, and we are able to work on projects of all sizes.


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