The major task during the month’s two work parties was building the two 40 metre long sections of bank in the subsidence areas located at roughly mid-point in Phase 2. The work involved shifting large quantities of stone which, in turn, required the cooperation of the weather. The first event had unseasonable dry and mild weather apparently caused by the Jet Stream. By the time of the second work party the Jet Stream must have gone somewhere else because we got a dose of Shropshire wind and rain for our troubles.
Construction of the banks consumed about 500 tonnes of stone each work party. This is delivered by tipper lorry to the Crickheath compound. The immediate problem is fitting it all into the limited space available whilst simultaneously being able to move plant around. The material is then moved by dumper to the banks and consolidated using an excavator mounted compactor. The first work party saw the offside bank finished and covered with (as yet unfilled) IBC water tanks – all 68 of them. This makes an impressive sight with a towering stone bank topped off with a two metre bank of IBCs. Attention then switched to the towpath side which is, including the overfill (an extra amount of fill to compensate for likely settlement), the largest structure on the site. Good progress on this during the second weekend rather disappointingly came to an end when the compactor broke down. Additionally the main haul road was surfaced with reclaimed brick waste.
The society has installed a system of monitoring subsidence as part of the construction of the two new banks. These consist of a concrete pad located on the original ground beneath the banks, and a vertical tube located above the pad. The level at the bottom of the tube is measured each work party using the laser level, and the amount of settlement calculated from this. The settlement has already started. The midpoint of the new offside bank has already gone down 75mm in four weeks. It has some way to go however since the predicted settlement at that point is nearly half a metre!
The weather during the first weekend was ideal for the annual vegetation bash – cutting back the new growth on the various hedges surrounding the site – and burning this and the vast accumulation of other assorted brash at Crickheath. The main ‘other jobs’ during the second weekend was setting out all of the Phase 2 channel, and the first excursion by surveyors into Crickheath South.