Ganga Sridhar’s everyday palaver is now punctuated with civil engineering terms. “I have become half a civil engineer,” she discloses, surveying the scene outside her apartment on Raja Street in Mandaveli. A panoply of grouting machinery greets the eye. When neighbours at Raja Street (as also those on Velayutham Raja Street) meet, they cannot shoot the breeze with banal words anymore. Weather talk is officially out the window. In these times, engaging in that kind of talk would even be construed as a sign of insensitivity.
As an integral element of tunnelling work, CMRL carries out interventions to strengthen and repair structures impacted by it. A scene from Raja Street in Mandaveli on May 17, 2024. | Photo Credit: PRINCE FREDERICK
At Santhosh Kumar’s house in Raja Street, Mandaveli, metal props have been placed inside the house to support it. As the borewell has been rendered unusable, a new one has been sunk inside the house. These exercises had to be carried out as part of CMRL tunneliing work in the neighbourhood. The image was taken on May 17, 2024. | Photo Credit: PRINCE FREDERICK
Instead, if one spoke about settlement markers and tilt markers, the nitty-gritty of grouting and about structures propped up vertically, they would be in line with reality. The changed dynamics of quotidian conversations has to do with Chennai Metro Rail Limited’s tunnelling work under Raja Street.
Ganga notes that the first familiar stranger one sees now while stepping out of one’s house is invariably a personnel engaged in Metro Rail work — CMRL or L&T personnel. CMRL engineers are on residents’ phonebook. Ganga observes that they are a constant presence, a presence that offers much-needed reassurance.
Tunnelling work under Raja Street has left Metro Rail work team busy over it, setting things in order, and as Ganga puts it, proactively. Ganga walks this reporter through the visible signs of intervention, first at her apartment Dwaraka Apartments and then through the street.
She points at settlement markers sitting lower down the pillars and tilt makers higher up. They are part of instrumentation technology that assesses how much a structure has settled or tilted — in this case, due to tunnelling work. Based on the white lines outside the road, she describes the position of the tunnel boring machine under the road right outside her apartment.
Ganga notes the maximum settlement at her apartment is 25mm. The intake nozzle for grout on the flooring of the stilt parking is meant to strengthen the structure and address the settlement. A bundle of metal props lie nearby. As one walks through the street, props are in place, vertically supporting the buildings before and during the tunnelling work. Ganga notes that the level of settlement varies from building to building, and one structure on the street has registered settlement between 30 mm and 40 mm. And of course, there are minor cracks in structures that would be addressed by CMRL at the fag end of the work in the neighbourhood.
Ganga Sridhar, a resident of Raja Street in Mandaveli, pointing to a tilt marker placed on a pillar in the stilt parking of her apartment. Metal props to shore up buildings are found in the backdrop. As an integral element of tunneling work, CMRL is carrying out interventions to strengthen and repair structures impacted by it. The image was taken on May 17, 2024.
Pausing from her report of the effects of Metro Rail work on Raja Street, Ganga (who is a committee member of Mandaveli Raja Street Residents Welfare Association) places things in perspective. Ignorance fuels fear, and the cure for it knowledge. “Knowing what the CMRL team is doing has been able to quell my fear. They are going about it with great efficiency. They are proactive, and that is what matters,” Ganga explains. “Let us face it. One has to live with this. Metro Rail work has to be carried out. But knowing that the engineering team knows what to expect and how to address it is reassuring.”
Ganga notes that residents of one apartment Copper Chimney had an unsettling experience, when foam was oozing out of an EB vent. This happened a few weeks ago. SR Ramasubramanian, a resident of Viswams (an old apartment next door) points out how residents of his apartment are battling a greater problem. Sewage was flowing into the borewell. CMRL plugged the supply, and is providing water by tankers to this day, says Ramasubramanian.
Ganga remarks that grouting is a wonder remedy, but is not without its “side effects”. As it strengthen structures under the earth, it enters and plugs vents, and sometimes in that process, interferes with the functions of underground utility lines.
A sewage pipeline having been plugged, in one apartment, sewage is being directed through a hose into the main line.
There are the rare, curious cases of borewells being shifted indoors. In his house, Santhosh Kumar (who is secretary of Mandaveli Raja Street Residents Welfare Association), the borewell had to be shifted to a storeroom (related to his distribution work) inside his house, as there was no space outside for sinking a new borewell. Besides, props are the new “guests” in his house. “My one-and-a-half-year-old child bumps into these props,” says Santhosh.
Ganga remarks that when Metro Rail work moves further up, this feature could be a leitmotif. “According to our knowledge, on Narayana Lane, Salai Street, Robertson Lane and Gurukkal Street, CMRL has sought permission from Greater Chennai Corporation to sink borewells on the roads as most houses do not have enough space to shift the borewell to a new location within. These residents’ concern is this: in the future who will be responsible for any problem relating to the borewells on the road. Problems could crop up on account of road-relaying work, or any utility line being installed on the road.”
Back at Raja Street, what one now sees are the effects of downline work. When upline work, which Ganga says is expected in July, would rumble under the earth, these residents would get to refresh their newly-acquired lingo.
‘An open communication line’
Says a CMRL higher official: “In Mandaveli, regular meetings with residents were conducted as per their request. There were minor structure settlement issues in Mandeveli due to geological conditions. Residents had once attended a meeting with CMRL officials at Nandanam. They need reassurance and we so stay in touch with them.”
