Site Investigation, Waste Classification and Consultancy

Client / Kier Major Projects Limited
Site / Kings Cross, London - Various Plots including T1 Goods Way, G1 Pavilion, R7, Midlands Goods Shed and Handyside Canopy
Value / £2.25m combined including Remediation works
Timescale / Four years

Summary

Sanctus has undertaken site investigation, consultancy and waste classification on various plots of the 67 acre Kings Cross redevelopment, central London; as part of a legacy of over 150 years of heavy industrial land use, the site as a whole, contains highly variable Made Ground with an array of underground footings and foundations. The investigation works have led to full scale remediation and enabling works packages across the development.

Site investigation has mainly been for the purpose of classifying excavated arisings with respect to waste; the investigation of groundwater for dewatering purposes during development; the investigation of Geotechnical data of existing foundations, and to identify the extent and composition of Made Ground. Contaminants encountered included heavy metals, hydrocarbons and asbestos in free fibre and fragmental form.

Investigative techniques have included;

  • Trial pitting using various types of excavator suitable for the particular investigation
  • Suction excavation using a vacuum extractor around groups of services
  • Borehole techniques using cable percussive and windowless sample rigs
  • Concrete coring and civil engineering
  • Trenching techniques using concrete cutting, and reinstatement
  • Benched and battered hand-dug trial pits down to 4m bgl
  • Investigative works undertaken under controlled conditions, using suitable PPE and RPE for asbestos hazards encountered at the site.

Works have been undertaken around existing services, over the top of live London Underground tunnels, and through former railway platforms, under controlled conditions, within structures and confined spaces, and adjacent to the Grand Union Canal.

The T1 plot involved intrusive borehole techniques to assess Geotechnical properties and ground water contamination to facilitate a new ‘Energy Centre’.

The Handyside Canopy SI involved over 125m of trial trenches cut into the canopy floor, with concurrent reinstatement to reduce downtime for retrofitting within the structure.

The Midland Goods Shed, which housed Victorian railway sidings and local marketplace was investigated under controlled conditions using task specific PPE and RPE due to the risk of asbestos in underlying fill material.

On G1 Pavilion Site, trial pits were excavated to depths of around 4.00mbgl by hand digging teams, in order to identify and record Geotechnical structures forming part of the London Underground Network below the site, to facilitate future development of the site.

Sanctus has also undertaken bulk earthworks including waste classification and disposal of contaminated materials in order to provide the client with the most economically feasible solution to surplus materials. This was due to an extensive knowledge of the materials disposal market, and the sustainable solution of re-using surplus materials as structural fill, on another development run by Sanctus approximately 15 miles away, under an EA Exemption.

The constraints on both space and time are extremely limited in the centre of London. Sanctus has worked closely with Kier Major Projects, local archaeologists and other contractors involved in the development to ensure that the investigative brief is fulfilled and that the correct information is obtained during the various phases of SI.