BertB.
Active member
In years past I've worked in sewer and water operations some of our excavations reached over 10 metres deep installing large diameter storm and sanitary sewers for new housing and industrial developments and expanding trunk lines that fed in to sewage treatment plants. But with most of those jobs those excavations were 'vee'd out with nearly 45 degree slopes and sometimes more if the soil wasn't as stable as the engineers would like. But I also worked on some jobs in built up area's where the crew I was working with was replacing water mains or even doing new service hook ups but anytime we worked on jobs like that it was with some sort of shoring. When I worked on the water line renewal crews we were usually anywhere from 8 feet to around 12 feet deep and the trench was seldom more than 3 or 4 feet deep unless we had a coring machine pit where the old pipe was pushed out and new pipe pushed in, thus minimizing how much excavation had to be done. But often the shoring was simple to place consisting of plywood sheets with a 2"x6" nailed across the center and a gas actuated strut would spread across and be pinned in while the pipe was replaced. If the trench had to stay open for a few days whalers were put in which were long 4"x6" timbers placed lengthwise helping brace those boards.
Then there have been jobs like this one a couple years ago where the company I was working for was attempting to install a sanitary sewer line in unfamiliar ground condtions that consisted of cobble like gravel sitting on a hard layer of heavy clay with a lot of ground water, they had been warned about the ground water and there had been room on the tender to hire out a dewatering company to set up sand points but they thumbed their nose at it just to bid low as possible and get the job as they were pretty much desperate for work.
Then there have been jobs like this one a couple years ago where the company I was working for was attempting to install a sanitary sewer line in unfamiliar ground condtions that consisted of cobble like gravel sitting on a hard layer of heavy clay with a lot of ground water, they had been warned about the ground water and there had been room on the tender to hire out a dewatering company to set up sand points but they thumbed their nose at it just to bid low as possible and get the job as they were pretty much desperate for work.
