2 modern techniques fail to check erosion on Solan NH

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Twin technologies

Rock-bolting is a long anchor bolt technique used to stabilise excavations. It transfers load from unstable outer surface to the confined and much stronger interior of the rock mass

Shotcrete is the process of placing concrete to achieve high strength and low permeability

Ambika Sharma

Tribune News Service

Solan, November 19

The failure of engineering technologies shotcrete and rock-bolting in containing large-scale erosion along excavated hilly slopes at vulnerable spots on the Parwanoo-Solan national highway, where four-laning is underway, has raised a question mark over the implementation of these modern techniques.

After failing to contain erosion at two key points, the twin techniques, used abroad on erosion-prone highways, were again put to use at Rabon Chowk in Solan where a high-tension tower lied precariously perched atop the hill.

Nearby residents, however, seemed wary whether rock-bolting and shotcrete would work when these had “failed miserably” near a petrol pump in Dharampur and besides a school in Jabli.

In Dharampur, the twin technologies couldn’t check erosion even for a few months. Six houses along the hill were rendered unsafe and had to be demolished. The same technique was used to repair the damaged retaining wall of Government Senior Secondary School, Jabli, but not much success could be achieved. The school too had to be vacated.

Kiran, a commuter, said, “The four-laning company should instead construct high retaining walls so that the tower doesn’t collapse amid heavy rains. The district administration must intervene to ensure the work is effective.”

Susheel Ahuja, a senior official at GR Infraprojects Limited, the company executing the project, said technical experts were already handling the work at Rabon Chowk to ensure a stable structure was put in place.

Solan Deputy Commissioner KC Chaman said the work was being monitored minutely and an expert would be roped in to examine the site to gauge the stability of the work. “The company has assured us it will build a strong structure, which can withstand adverse conditions,” he said.