While the road is back open after the sinkhole was repaired, the work to correct the problem which caused the sinkhole Father Hurley Boulevard in Germantown will continue for a few months.
The work to fill in the sinkhole and get the roadway open again was the first phase of the project. According to Bruce Johnston, Chief of the Division of Transportation Engineering for the Montgomery County Department of Transportation, the existing corrugated metal pipe which failed during the storm on July 22, and created the sinkhole has been filled with cement and abandoned. The MCDOT has created a short-term diversion pipe to convey the rainwater that used to go through the failed culvert. The short-term fix has been installed, and now sends rainwater to a nearby box culvert.
The 20-foot by 20-foot sinkhole on Father Hurley Boulevard was caused by the failure of a 38-year-old culvert pipe which had rusted out, according to County officials. The sinkhole was the result of the massive amounts of rain coupled with an aging piece of infrastructure which Montgomery County didn’t even know was there until January of this year.
Another issue which had to be dealt with was the shoring up of the gas lines which were exposed when the soil washed away. Johnston said those gas pipes have been fully backfilled and secured.
The first phase of the work took about 10 days, County officials had hoped to complete the work in three or four days, but weather hampered their efforts. “The weather was certainly an issue,” said Johnston, who will retire from MCDOT on Friday, Aug. 3, after 30 years of service to the County. “With this kind of work, you don’t want holes that you dig to fill up with water, so you have work around that. It went very well, better than I expected.”
In a few weeks, workers will begin the second phase of this project, which is to install a new culvert next to the old one. The installation process is called “boring and jacking.”
He said the ‘boring and jacking” process would involve some deep and large pits being excavated on either side of the roadway. “We’ll excavate pits alongside the road, and we will get down in that hole at the right elevation, and we will push a series of pipes through dirt, underneath the roadway to get to the other side,” said Johnston.
“Work (on phase two) should start within the next month or two,” said Johnston. “It will take several weeks, maybe or month or so to complete the new culvert. They may have to close a lane or two — one in each direction occasionally.” The boring and jacking process is an expensive operation because it allows the work do be done without closing the entire road for an extended period of time.
Photos by Germantown Pulse