The Thames Gateway Bridge - Helping to Link East London

Friday 30 April 2010

The Thames Gateway Bridge - Helping to Link East London.

Challenge
Soil Mechanics was appointed by Transport for London (TfL) to obtain information on the soil, rock and ground water conditions from three different locations. The investigation met a wide variety of drilling and testing techniques, logistical challenges, land access organisation and logging requirements for the proposed location of the Thames Gateway Bridge, including a former gas works on remediated ground and the urban built up Royal Arsenal Woolwich conservation area. The sites were diverse in nature with geology consisting of gravel deposits, white chalk, alluvial clay, peat and Thanet sand as well as some contaminated fill in made ground. The project included:

• Site 1 Over water river bed drilling to obtain geotechnical information for the alignment of a proposed north/south road bridge.
• Site 2 An investigation of the existing Pier foundation piles to obtain geotechnical and environmental data for the proposed Eastern Gateway road link to the proposed Thames Gateway Bridge.
• Site 3 Investigating strata for the proposed position of a radar tower on made ground.

Solution

The site operation at location 1 was carried out from a self propelled, stable (four legged) jack-up platform which stopped the borehole drilling being affected by tidal changes thus optimising drilling accuracy.

At locations 2 and 3 the project comprised of several techniques to cater for the varied conditions and hazards. Cable percussion boreholes with rotary cored follow on to 35.0m depth and Static Cone Penetration Tests (CPT) approximately 10.0m deep, using Piezo-cone and down hole seismic geophysical logging to identify the length of an existing pier foundation pile was undertaken. Groundwater and ground-born gas level monitoring and sampling was also carried out together with down hole standard penetration (SPT) in situ testing. Hand excavated inspection pits were used to check utility services. Testing of the geotechnical and chemical properties of the soil, rock and water samples recovered was subsequently carried out at Soil Mechanics' UKAS and CLEA accredited laboratories.
 

Results
Through this work, Soil Mechanics has demonstrated its ability to manage and deliver the data and services from a multi-disciplined team to support the geotechnical and geoenvironmental decisions of Transport for London's (TfL) early strategic planning, design and costing stages of the proposed Thames Gateway Bridge, the first new crossing of the Thames for 60 years.

Project Date: February 2007

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