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New School, Grimsby

09 154 Electromagnetic Survey Data Showing Historical Features

New School, Grimsby

Proposed School Building (Edward Heneage Primary School), Grimsby

Date – May 2010

Client – Northeast Lincolnshire Council

Value – c.25k

Arc Environmental carried out a Phase 1: DTS across an area of land which was to be developed for the construction of a 2-story school building with areas of soft landscaping and which was to be utilised by Edward Heneage Primary School.

The findings of the DTS identified that the site was once the location of a historical clay pit, reservoir, potential settling lagoons etc. which was present below 75% of the proposed school building.

Prior to the completion of Phase 2: GIR it was deemed beneficial to complete an appropriate geophysical survey to map the extents of the clay pits and other below ground features which would then help us target any subsequent intrusive works, as well as to aid in subsequent foundation design (i.e. pile design).

To complete the required fieldworks a combined survey using techniques including Electromagnetic Survey (EM) and Ground Penetrating Radar (GPR) were completed across the development area with the results shown on representative cross sections.

An EM survey provides rapid coverage of a site; and by measuring relative changes in ground conductivities across the area should be able to locate the extents of the features recorded on site. Along with the GPR survey, the interface between made ground and the underlying natural deposits up to depth of 15 metres depth can be identified.

The historical maps within the DTS were then superimposed on to the geophysical results with these plans then utilised to design the subsequent Phase 2 intrusive works to target anomalies and areas of interest leading to a comprehensive investigation completed on time and within budget for the client.

09 154 Electromagnetic Survey Data Showing Historical Features

09 154 Gpr Radargram Cross Sections

09 154 Interpretation Of Geophysical Data Showing Revised Proposed Development Layout And Exploratory Hole Positions

09 154 Magnetic Gradient Data Showing Historical Features

09 154 Site Cross Sections A1