Pear Tree Street, London

POSTED ON: 15/08/2018

Risk Management Limited were commissioned to undertake a Phase I, non-intrusive, Desk Study and Walkover Survey and Phase II, intrusive, Site Investigation at an existing National Grid Car Park. The Phase I, non-intrusive, Desk Study found that the site lay within the boundary of the ‘Chartered Gas Works’ in 1877, by the end of the nineteenth Century the majority of the Gas Works had been removed.

A four to five storey office/residential building was proposed at the site. Due to the past usage of the site as a Gas Works the site was designated a ‘Red Site’ in accordance with the ‘Specification for Ground Investigation’ publications by the Site Investigation Steering Group of the ICE. 

A total of three deep cable percussion boreholes and six shallow drive-in-sampler boreholes were undertaken across the site to provide suitable information to allow for foundation design. Subsequent gas/groundwater monitoring was undertaken on six occasions along with organics measured using a MiniRae Lite PID. 

Laboratory testing included the normal geotechnical testing as well as Coal Tar, SVOC and TOC analysis and groundwater contamination testing owing to the past usage. 

Following on from the Phase I and II work noted above a Phase III Remediation Method Statement and Phase IV Verification Report were undertaken.