Importance of Diaphragm Walls in Metros – A Case Study

India’s first metro rail started back in 1984 in Kolkata (then Calcutta), West Bengal . Ever since, India has seen a rapid expansion of metro rail in various cities, with Delhi leading, and other cities catching up like Ahmedabad, Bengaluru, Gurugram, Kanpur, Kochi, Lucknow, Mumbai and now even Agra.

India being a country with densely populated cities, building metro railway lines and stations is nothing short of a challenge. Heritage Infraspace Pvt Limited has assisted and provided metro diaphragm wall construction services to many metro contractors in India. Here, we break down the importance of diaphragm walls in the construction of metro railways, as an interesting case study.

Types of stations built by metro contractors in India

There are majorly two types of metro stations: elevated and underground stations.

An elevated metro railway station or elevated train station is a railway platform alongside the tracks above street level on a viaduct or other elevated structure, usually constructed from steel, cast iron, concrete, or bricks by metro contractors in India.

An underground metro railway station is where the platform is built multiple levels beneath the ground as deep basements. The metro rail tracks run parallel to these stations, with a bustling city above it.

Elevated railways are normally found in urban areas where there would otherwise be multiple level crossings. Usually, the tracks of elevated railways that run on steel viaducts can be seen from street level.

Underground metro stations are generally proposed in older, dense parts of the cities where roads are narrow and sharp turns do not allow elevated rail alignment without major demolitions.

Importance of diaphragm walls for underground metro stations

Diaphragm walls are sturdy underground structures that can act as a permanent structural wall. Diaphragm walls can be installed to deeper depths, which helps in building multi-basement stations.

Compared to construction of a station on an elevated metro corridor, underground metro diaphragm wall construction services require less temporary propping. The top-down construction method can be applied in building an underground metro railway station.

The diaphragm wall is a rigid structure, hence the ground movement induced by basement excavation for underground metro is lesser compared to usage of flexible retaining walls. Diaphragm walls act as a strong guide wall for the launching shaft for metro stations.

Challenges faced by HIPL Ground Team

A major challenge HIPL faces as a commercial construction company in India working on various underground metro projects is accurately/precisely identifying the quality of the soil. With urbanisation, soil quality cannot be determined with a single inspection, and as the excavation takes place, the teams come across various forms of soil, which affects the metro diaphragm wall construction to a great extent.

The other challenges are as below:

Metro construction area sees a lot of activity and hence securing an entire stretch for the excavation work and diverting the traffic is a challenge.

Transportation of various construction materials, utilities, machinery, etc. is a big challenge, as urban areas have constant and heavy flow of vehicular and foot traffic in congested spaces.

Continue reading

Odhav Pump House: Structural concrete diaphragm wall construction for water tank

Heritage Infraspace Private Limited (HIPL) works with various national and local government bodies and construction companies in building crucial water supply infrastructure in Gujarat and all over the country. In 2018, HIPL got the opportunity to work on the structural concrete diaphragm wall construction for the Odhav Pump House.

Here’s a look into the challenges faced by HIPL, solutions provided by the Heritage Infraspace diaphragm wall team and the crucial observations made during the project.

The client : Ankita Constructions and Ahmedabad Municipal Corporation

Ankita Constructions is an Ahmedabad-based construction company specializing in waste water and sewerage treatment plants for residential and commercial properties.

Amdavad (Ahmedabad) Municipal Corporation is the local government body that is responsible for the infrastructure and administration of the city of Ahmedabad.

Ankita Construction joined hands with Heritage Infraspace Private Limited for this particular project since they have the experience of working on many water treatment, storage and supply plants, while HIPL is the pioneer in structural concrete diaphragm wall construction.

The Odhav Pump House in Ahmedabad can collect, store and treat storm water underground and supply it to the adjoining areas of the city.

Projects awarded to HIPL for the Odhav Pump House

The project of building a storm water pump house in Odhav, east Ahmedabad was awarded to Ankita Constructions by the Amdavad Municipal Corporation

The project given to HIPL was of concrete diaphragm wall construction for the underground water storage tank.

Since HIPL has the experience and expertise of working on ground engineering for underground construction projects, we were brought into work on the initial stages of building the water pump.

What makes this project very unique, is the fact that no anchors were used during the diaphragm wall construction, which showcases HIPL’s engineering expertise in water tight projects like these.

Continue reading

Everything You Need To Know About Building Concrete Diaphragm Walls

Right from metro rail construction to new age super structures like towering residential and commercial complexes, building of concrete diaphragm wall has become a common practice and projects are now seeking only the best diaphragm wall company, like HIPL, to be building these D-Walls. But, what exactly is a diaphragm wall, and how does it help building structures? Here’s everything you need to know.

What is a concrete diaphragm wall?

Diaphragm walls or slurry walls are generally reinforced concrete walls, constructed in the ground using an under-slurry technique developed in Europe. This technique involves excavating a narrow trench that is kept full of an engineered fluid of slurry. This way, walls with thickness ranging between 300 mm to 1200 mm can be formed as deep as 45 metres underneath. Inclined rock or soil anchors are used for this purpose. Diaphragm walls are commonly used while constructing structures with deep basements in congested areas, as they can be installed in close proximity to the existing structures.

Previous history of diaphragm wall being used in construction in India

The earliest recorded use of diaphragm wall technology is said to be during the excavations for the construction of Milan Metro in Italy back in the 1950s. In India, this technique can be traced back to the construction of metro rail stations and tunnels, Kolkata Metro being the first ones.

This is a civil engineering technique of construction, pioneered by Heritage Infraspace in deep basement diaphragm walls in India.

Now, in metro construction, D-walls ranging between 800 to 1200 mm are built. But while constructing deep basements for residential and commercial complexes, there are varying sizes used, they are as follows:

• For a single basement construction, we build 300 mm diaphragm walls
• For a double basement construction, we build a minimum 400 mm diaphragm wall
• For a 3-basement construction, we build a minimum 500 mm diaphragm wall
• And for a construction of 4-basement or more, we build diaphragm walls starting at 600 mms.

But here’s a crucial point to remember, all the above depends majorly on the soil strata. For a D-wall to do its job perfectly, the soil must not be loose. D-wall construction makes it cost effective compared to the other older, traditional methods like Piling. The major challenge with Piling, apart from being costly and time consuming, is that it doesn’t maintain the verticality.

Continue reading

How We Became the Leaders in Diaphragm Wall Construction in India

Building strong foundations for a glorious future

Heritage Infraspace Pvt Ltd (HIPL) is an Ahmedabad-based award-winning, ISO 9001: 2015 accredited construction company in India with over a decade’s experience in diaphragm wall construction. We are pioneers of ground engineering solutions for commercial and residential construction projects In India, such as diaphragm wall in basement construction, as well as, deep foundation projects. HIPL also provides critical geotechnical solutions for leading metro construction companies in India, dam projects and subway systems.

HIPL was founded in March 2011, by Gagan Goswami, a civil engineer with a rich and extensive experience of over 16 years, working across construction projects in India and the Middle East, for companies such as ITD Cementation Ltd and Reliance Industries. He decided to start his own engineering construction company in India, without any financial backing, built entirely from the ground up.

What motivated Gagan to start HIPL was his observation that open excavation projects were replete with accidents, causing financial loss, but more importantly a loss of precious human life. Through his research and experience abroad he realised that both the quality of work and safety of workers was taken a lot more seriously abroad. So he decided to introduce some of this innovation in underground construction to India. Introducing diaphragm wall construction, a European method of constructing a slurry wall, while building basements for commercial and residential projects. Apart from safety, this also improved the timeline of constructing major projects. As the company grew, HIPL added other services such as piling, anchoring, waterproofing, RMC and more.

In all this, engineering excellence and continuous innovation remain the core values of the company. HIPL operates across 11 Indian states and more than 25 cities. We have completed over 300 projects, built 42 kilometres of diaphragm walls, and installed over 50,000 anchors, with a devoted team of over 450 of our Heritage family members.

Meet Gagan Goswami, our founder

Mr. Gagan Goswami comes from a family of teachers in the small village of Gandhisagar in Madhya Pradesh’s Mandsaur region. He began his career as a training engineer, working on numerous projects around India. For four years, he worked as an independent consultant on building projects in Oman, Muscat, and Dubai, gaining international experience.

Upon his return to India, he formed HIPL with just 8 team members, and pioneered the use of diaphragm walls for deep basement construction as an important element of underground construction. Under his leadership, HIPL’s focus on worker’s safety, as well as, the use of new technology and machinery in all our projects has made us the leaders in this segment, which we have helped establish in India.

Continue reading