University of Southampton
There is considerable uncertainty concerning the lateral stresses for which embedded retaining walls in an overconsolidated deposit must be designed, with the results of recent research providing conflicting but incomplete evidence. One reason for this is the absence of case records in which the behaviour of both the wall and the soil have been monitored continuously throughout all stages of construction and service.
This issue is currently being investigated by means of a comprehensive programme of monitoring, back analysis and interpretation of the behaviour of the retaining walls for the cut-and-cover tunnel that will take the Channel Tunnel Rail Link under Ashford in Kent (Contract 430) . A key aim of this research is to link the behaviour of the wall to the state of the surrounding ground during wall installation and construction and into the long term.
A total of 120 instruments have been installed at the instrumented section and are currently measuring total lateral earth pressures, pore water pressures, wall bending moments and temporary and permanent prop loads. The instrument readings are recorded to an on-site data logger at regular intervals. The data is currently transferred daily from site to Southampton through a GSM data link modem incorporated into the data logger.
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WJ Groundwater Limited
WJ Groundwater Limited specialises in sub-contract dewatering and groundwater remediation works in the UK and overseas. WJ has successfully carried out some of the largest and most challenging groundwater control projects in Europe. Our unrivalled in-house technical ability, experienced staff and our long track record of completed projects allow us to offer cost effective solutions to all groundwater problems encountered on site. Recent projects have included immersed tube tunnels at Medway, Kent and Cork, Eire; the Jubilee Line Extension, London including Canada Water Station and the Channel Tunnel Rail Link, London and South East England.
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MGS Geosense
GeoSense is one of Europe’s leading manufacturers and suppliers of instrumentation to the geotechnical, civil engineering, mining and environmental industries.
A division of Marton Geotechnical Services Limited, a group with an annual turnover in excess of £12 million and an extensive worldwide sales network, GeoSense specialises in the manufacture of a range of vibrating wire sensors which are used to measure strain, load, force, pressure and temperature, together with a full range of other instrumentation. Vibrating wire sensors are universally recognised for their long- term stability within the harsh environment often found in civil engineering construction sites.
Manufacturing is located on a 1 hectare site in Suffolk, England, where there are more than 3,000 square metres of manufacturing and warehousing facilities, ensuring large stocks of products are readily available for immediate delivery.
The company now has a workforce of more than 60 and an annual turnover in excess of £9.5 million.
GeoSense products are used in the following applications:
Dam instrumentation
Tunnel instrumentation
Bridge instrumentation
Deep excavation & pile testing
Diaphragm & retaining walls
Slope stability
Pile testing
GeoSense is the European and MENA (Middle East and North Africa) distributor for RST Instruments of Vancouver, Canada.
GeoSense engineers have been involved with major geotechnical and civil engineering projects throughout the world for more than 30 years.
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Lankelma
A leading specialist in static cone technology, Lankelma is able to use their extensive range of rigs to install a variety of geotechnical instruments. The push-in method of installation is suitable in a surprisingly broad assortment of ground conditions. The technique is fast and highly efficient, with a single rig often achieving penetration rates in excess of 150m per day. And as the method causes minimal disturbance to the ground, it can provide installations that are technically superior to those installed by traditional methods.
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