Chesham, Buckinghamshire
April 2019
Risk Management Limited were commissioned to install 2 No. deep borehole Soakaway installations for a new care home in Chesham, Buckinghamshire.
The work involved undertaking two 15m deep cable percussion borehole in 8” diameter through the superficial beds and into the underlying Chalk strata. After a basic permeability test two 6” diameter soakaways were subsequently installed to 15m depth within each borehole.
Following installation three falling head tests within each soakaway were performed using a 2000-gallon lorry mounted bowser and hose and more than adequate soakage was observed.
Merton, Surrey
March 2019
Risk Management Limited were commissioned to undertake a Phase II, intrusive, Site Investigation at an existing Warehouse in Merton, Surrey. The investigation comprised verification of the existing slab condition and surrounding ground conditions for a small Barrier Booth building adjacent to the warehouse.
A concrete coring crew were subcontracted to core the existing warehouse slab in multiple locations with the resultant cores scheduled for Unconfined Compressive Strength testing. Drive-in-Sampler boreholes and MEXE Probe CBR tests were undertaken within the above-mentioned core holes to enable foundation design parameters.
Tonbridge, Kent
November 2018
Risk Management Limited were commissioned by WCJ Structural Engineers to undertake a ‘heave assessment’ at a property in Tonbridge, Kent.
Due to excessive cracking on the property an 8m deep borehole was undertaken close to the area of interest. A moisture content profile was undertaken and, by comparing this to assumed ‘equilibrium’ natural moisture contents, a Heave Assessment was undertaken.
Sutton, Surrey
October 2018
Risk Management Limited work regularly with many local developers who often instruct us to undertake a ‘package’ consisting of a Phase I, non-intrusive, Desk Study and Phase II, intrusive, Site Investigation with contamination assessment, gas/groundwater monitoring and an Interpretative Report.
This package was utilised at a site in Sutton, Surrey, where the intrusive investigation comprised one 7m deep borehole with in-situ SPT testing and 3 shallow drive-in-sampler boreholes. Subsequent permeability, gas/groundwater monitoring was undertaken along with two contamination tests including asbestos.
Gladstone Parade, Dollis Hill, London
September 2018
Risk Management Limited were commissioned to undertake a Phase I, non-intrusive, Desk Study and Walkover Survey together with a Phase II, intrusive, Site Investigation at a parade of shops in Dollis Hill, London. The proposed development included the demolition of existing buildings and garages and the construction of a multi-storey building with associated landscaping and parking areas.
Two 20m deep cable percussion boreholes and six shallow drive-in-sampler boreholes were undertaken across the site to aid in providing geotechnical information. In addition, soakage tests to BRE 365 were undertaken to assess the soakage properties of the underlying geological strata and gas/groundwater monitoring performed.
Laboratory testing included the normal geotechnical testing as well as Oedometer tests and Contamination and Waste Acceptance Criteria (WAC) testing.
Pear Tree Street, London
August 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.
Childrey Warren, Wantage
July 2018
Risk Management Limited were contracted to undertake an intrusive Site Investigation along the linear route for a new watermain running from Childrey Warren Water Treatment Works (WTW) to Lark Hill Reservoir for Thames Water. Thames Water are committed to ceasing water abstraction at Childrey Warren WTW and the proposal to construct a link main between Lark Hill Reservoir and Childrey Warren WTW would allow this.
A total of fifteen geotechnical Trial Pits were undertaken using a Kubota mini-excavator and eight Rotary Cored boreholes, up to 25m deep, using a tracked Commachio 250 drilling rig at locations along the proposed link main route.
Laboratory testing included, moisture contents, Atterberg Limits, CBR tests, Compaction tests, pH and Water Soluble Sulphate tests, Saturation Moisture Content, Chalk Crushing Value, Natural Moisture Content of Chalk, Unconfined Compressive Strength and Point Load Index of Chalk and Contamination testing.
Melior Place, London
June 2018
Risk Management Limited were contracted to undertake a Phase II, intrusive, Site Investigation at a warehouse unit in Southwark, London. The scope for the investigation required a deep borehole to at least 20m depth to enable foundation and pile design.
Considering the limited headroom and access difficulties Risk Management Limited utilised a low-headroom ‘cut-down’ cable percussion rig in order to achieve the required depth. The ‘cut-down’ rig is ideal in environments where depths in excess of 10m are required, or tough ground conditions require a cable percussion rig, and headroom is limited.
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