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Progress

An updated programme will be available here in order to reference the duration of drilling each borehole and when work on each borehole will commence.

adobe icon Borehole Locations Map [2Mb],

adobe icon Drilling Programme [249kb],

adobe icon Weekly update no 1 [30kb],

adobe icon Weekly update no 2 [33kb],

adobe icon Weekly update no 3 [34kb],

adobe icon Weekly update no 4 [33kb],

adobe icon Weekly update no 5 [65kb],

adobe icon Weekly update no 6 [33kb]

  • Weekly update no 7 w/c 01 July 2013

Work on an additional borehole (BH19), behind the Cliff House Hotel, was carried out this week.  The decision to include an additional hole was made in order to provide redundancy within the groundwater monitoring infrastructure at this location and a further opportunity to core and sample a critically important shearing horizon (known as the "D" shear surface), which had been encountered earlier in the investigation.  This required the drilling programme to extend into the seventh week.  Minor works, such as fitting data loggers to monitor groundwater in the boreholes in the undercliff and installation of steel covers, also continued during this week.  Final demobilisation of all contractor site staff was undertaken on Wednesday 10 July.

Borehole BH19 was completed using rotary open hole drilling techniques to a final depth of 40m.  All of the major landsliding horizons were identified in this borehole and this allowed accurate positioning of two vibrating wire piezometers within the hole, one within the deepest and most significant slip surface to operate at Barton on Sea (the "D" shear surface), and an additional one at a shallower horizon (the "F" shear surface).

Borehole instability experienced during the drilling of borehole BH19 again highlighted a potential zone of increased sub surface porosity that was possibly connected with the persistent groundwater flow and active landsliding and mudflows on the undercliff here.  A standpipe piezometer was also installed within the Chama Sand Formation in this borehole to allow the completion of in situ variable head permeability tests.

Updated: 24 Apr 2015
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