Underground construction is the largest application for shotcrete and this trend is projected to continue in the next five years owing to increase in infrastructure development, rapid advancements in technology and raw materials, and the growing need for transportation and underground excavations. In fact, shotcreting equipment is expected to grow at a CAGR of 8 per cent. VG Sakthikumar, Managing Director, Schwing Stetter Sales and Services, Convenor for Membership Committee, ICEMA, and Chairman, Mechanisation Committee, Builders Association of India, shares more on the demand for tunnelling equipment...
What opportunities do you see for your shotcreting equipment?
India has ongoing metro-rail construction in many towns, such as Delhi, Pune, Nagpur, Bengaluru, Mumbai, Chennai, etc. This sector is driving the Schwing shotcreting pump business of models like TSR 30.14, TSM 30.10, TSM 20.8 and BPN 300 RE. Also, Schwing shotcrete machinery is in use during the construction of hydroelectric power projects and irrigation projects, which create more opportunities for tunnel construction. Shotcreting also finds application in the storage of gas and hazardous materials.
Which metro projects will present opportunities, and for what kind of shotcreting machines?
Most metro projects have opportunities for shotcrete and shotcreting machines. But the volume of shotcrete and type of machine will be decided based on the methodology of execution. For instance, in Kolkata, for underwater tunnelling, the contractor Afcons has used a TBM (tunnel boring machine) for the main tunnel and there was no scope for shotcreting as per the design of construction of the support structure. But for the two tunnels in between, there are some cross passages, which form connectors, where they have used shotcrete machinery.
What scope does India present for underwater tunnelling?
Work on India's first undersea tunnel has begun in Mumbai. The legwork for this tunnel, part of the Prime Minister's ambitious Mumbai-Ahmedabad bullet train corridor, has taken off in the city. The train, which will cover a distance of 508 km between Mumbai and Ahmedabad, has a 21-km underground corridor from BKC to Kalyan Shilphata. Of this, 7 km is under Thane Creek, with 1.8 km of it to be built under the seabed and the remaining under the mangroves marshland on either side of the creek.
Does the use of shotcrete machinery change based on the soil? What are the features of shotcreting equipment that suit different metro projects?
The use of a shotcrete machine does not directly depend on soil.
But the support structure is designed depending on soil geology conditions and this design defines the requirement and type of shotcrete. Shotcreting machines are chosen mainly on two criteria: Type of shotcrete required and diameter of the tunnel. Currently, the market demands shotcreting machines that are compact and self-propelled and have a chassis with four-wheel drive and steering, crab steering facility, low turning radius, concrete pump with agitator, radio remote and automated functions, reach and manoeuvrability of spraying boom, PLC-controlled dosing system with display dual operations, inbuilt compressor, inbuilt water cleaning system and DGMS certification.
Chennai Metro Rail will soon carry out soil tests for a tunnel to connect the satellite terminal of Chennai airport. What shotcreting machines are likely to be preferred for this 1.5-km tunnel?
The length of the tunnel is not the major criteria to decide on shotcrete machinery. We need to know other parameters, such as tunnelling methodology, type of support, type of shotcrete to be used and the diameter of the tunnel. We already have TSR 30.14 and TSM 30.10 in action with Chennai Metro Rail.