Shieldhall Strategic Tunnel, Jura Street
Scottish Water propose to build a 3.1mile long waste water tunnel in the South of Glasgow. The sewer will run between Queens Park and Craigton Industrial Estate via Pollok Park and Bellahouston Park. The £100m tunnel will improve water quality in the River Clyde and its tributaries, enable the Greater Glasgow area to grow and develop, alleviate sewer flooding issues at key locations in the area served by Shieldhall Water Treatment works (WwTW) and deal with the effects of increased rainfall and climate change.
The Shieldhall Strategic Tunnel route is partly located within rock containing coal seams and ironstone seams. Some of these have been worked, and consequently prior to the construction of the tunnel there is a requirement for the consolidation of the abandoned mine workings that will be encountered along the route and specifically at Jura Street, Bellahouston Park, Queens Park and Titwood Road.
Soil Engineering were appointed by the Costain Vinci JV to carry out remediation works to stabilise the abandoned mine workings at these four distinct locations.
Soil Engineering Solution
A phased approach was applied to the remediation works with four distinct work packages proposed. Soil Engineering completed the first phase of works at the Jura Street TBM Launch Chamber site, the scope of works comprised:
- Bulk Infill Grouting: Bulk in fill grouting of Lower Garscadden Blackband Ironstone and Garibaldi Clayband Ironstone seams via 712holes, totaling 12,046 linear meters using 1,027 tonnes of grout.
- Foundation Grouting:
- Drilling: 64no holes, 1070 linear meters of drilling to form holes for ascending stage pressure grouting in the rock, using 9365ltrs of grout comprising of Spinor 20 microfine cement, Groutaid, Rheobuild and Berkbent 163.
- Permeability Testing: 1 no pump test and 6 no in hole variable head permeability tests.
Soil Engineering Value
SEGL commenced site works forming 13No. probe holes drilled to 30m depth using Jean Lutz Drilling Parameter Recording Equipment. The equipment collected data relating to torque, thrust, flush pressure and penetration rate. To pinpoint the exact depths of voids and broken ground DPR Void Search Mode was employed and collected data at an accuracy of 10mm.
REAL TIME DATA ACQUISITION: Bachy Soletanche’s SPICE System was used to control the pumps and pressures during delivery of the grout and accurately monitored and measured the amounts of grout delivered at the site.
Upon completion of the drilling and grouting phase of works SEGL installed 42 No. pressure relief wells and 2 No. piezometer wells as part of the enabling phase of works.