Why Are D-Walls Becoming Extremely Popular with Construction Companies in India?

Diaphragm walls for top-down construction and deep basements have now become commonplace in the industry, and among construction companies in India. But how did D-Wall construction (another name for diaphragm walls) become a popular choice with civil engineers who are now confident to build towering superstructures with basements as deep as 5 levels?

Let us begin by understanding what a diaphragm wall is, how it is different from other traditional methods of ground engineering like Piling, and what makes it a desirable choice for deep basement construction.

What is a diaphragm wall?

Reinforced concrete walls built in the ground to provide support to the structure to be built above, and act as walls for the deep basement space to be built later, are known as diaphragm walls. They act as the cut-off walls for the excavated area of the site, provide a strong foundation to the surface and enclose the structure.

Piling — The traditional method of deep foundation construction

Piling is one of the oldest methods of building foundational bases for under-construction structures to transfer and manage the structural load on a deeper level. They are long, cylindrical structures that are made of either concrete, wood or steel.

There are two types of pile foundations used in building strong bases

1. End-bearing piles, that can transmit weight load directly to the deeper, stronger soil or the rock base of the site.

2. Friction piles, which transfers the load of the building to the soil across the full height of the pile, by friction.

Piling, a traditional method, is used when the structure above has heavy, concentrated loads and the spread footing won’t be able to bear the weight. So the building structure needs to bypass this layer and transfer the weight to the stronger base at depth.

While a diaphragm wall is constructed by excavating a narrow trench with a thickness ranging between 300 mm to 1200 mm, as deep as 45 metres underneath. It actually does the exact same job, and moreover, offers to act as a retaining wall for the basement, making the foundation stronger.

Yet, what makes construction companies in India choose diaphragm walls for basements?

Lower steel consumption

The cage walls made for diaphragm wall construction require lesser steel bars compared to constructing and inserting piles into the ground below. And in scenarios of unstable soil on the site, an additional casing is required on the piles, which may add an extra cost to the materials consumed.

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