Route south of Charlestown to reopen temporarily as permanent fix delayed

Valley News Correspondent
Published: 3/25/2022 9:58:37 PM
Modified: 3/25/2022 9:57:47 PM

CHARLESTOWN — Route 12 south of Charlestown, which has been closed since last August, will reopen on a temporary basis after work on a permanent repair had to be halted earlier this month.

The project to stabilize the railroad embankment, which sits several yards east of the road, was stopped because of excessive groundwater and movement in the embankment supporting the train tracks during the soil nail wall construction. Freight and passenger trains travel the tracks daily.

Kathleen Mulcahey-Hampson, legislative liaison with the state Department of Transportation, said in an update this week that the railroad owners were “amenable” to the New Hampshire DOT’s short-term fix.

“Under the short-term plan, the current soil nail wall will be discontinued. The embankment will be stabilized,” Mulcahey-Hampson said in a letter to local officials in Charlestown, Walpole and Claremont. “The road will be built back up with fill and gravel and paved so that the two-lane section of Charlestown Rte. 12 can be re-opened.”

About 600 feet of roadway was damaged when runoff from heavy rains in late July washed away soil and silt under the road, causing it to settle several inches. Engineers determined that tearing up and rebuilding the road would jeopardize the embankment supporting nearby train tracks because the road acts as a buttress.

The road closure on the main route between Claremont and Keene begins in Charlestown just south of the Main Street business district and in South Charlestown at the intersection of routes 12 and 12A.

Mulcahey-Hampson said the section of the road that needs to be built back up for reopening is “relatively short” so the work should proceed fairly quickly, though there was no timeframe given for when that would happen.

The soil nail wall was to be constructed by installing steel bars into the embankment that would be covered with a wire mesh and shot with concrete. But with the high groundwater, movement was detected in the embankment as work progressed, and trains were forced to slow to 10 mph. The railroad rescinded its approval of the soil nail construction.

As for a permanent solution, Mulcahey-Hampson said DOT is working with the railroad’s engineers and the contractor on the best approach. Dewatering the site to resume soil-nail work could create more instability, it was determined.

“The short-term solution would be the route until the long-term solution can be designed and implemented,” Mulcahey-Hampson said. “This will likely involve full reconstruction and consideration of realignment alternatives to increase the distance between the road and the railroad.”

Patrick O’Grady can be reached at pogclmt@gmail.com.




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