CGL(Card Geotechnics Ltd) services

Due to high land values and limited development space in London, basement extensions are becoming common.  It is increasingly recognised that these may have an impact on local flooding, groundwater flow, and ground movements, potentially generating long term stability issues for neighbouring properties.  In April 2011, the London Borough of Camden adopted CPG4, as official planning guidance, for their use in the consideration of planning applications involving basements in the Borough The document presents a structured, formalised approach to identifying the potential risks, both from and to the development, in a five stage Basement Impact Assessment (BIA) process from original screening by the applicant through to review and  decision making by the Council.

The key to successful implementation of engineering designs is good site management. The complex nature of geotechnical and geoenvironmental designs and the frequent requirement for third party certification requires skilled engineers to support client teams during construction. CGL employs dedicated engineers who understand construction and the importance of timely integration of ground-related solutions into development and building projects. CGL’s activities during the construction process may be broadly divided into two main elements: firstly,monitoring and supervision of remediation measures on contaminated sites, and secondly,inspection of earthworks and building formations.

Designing of earthworks for schemes of various sizes under a variety of ground conditions, and in ensuring that these are implemented under proper construction control, is another of CGL’s capabilities. Our senior staff have substantial experience in the design of major highway and rail schemes, some of which have necessitated detailed engineering analysis to overcome difficult ground conditions and ensure long term stability and serviceability.  Our capabilities include assessment of sources to identify material suitability, the effective re-use of materials, and minimisation of the cost of imported fill. Our approach uses the principle of ‘relationship testing’ where complex engineering parameters can be correlated to routine on-site test procedures; a simplified but robust approach to compliance testing resulting in confidence in the construction and savings in earthworks programmes.

For any prospective site development, identification of contamination always poses the question as to what is the risk and how much will it cost to rectify such an issue.  On sites such as these CGL is able to provide robust qualitative and quantitative assessments and pragmatic solutions based on many years of experience and contributions to national published guidance.

CGL is a geotechnical and geoenvironmental consultancy, working at the forefront of the construction industry, offering advice on ground-related liabilities associated with sites throughout the UK.  For those wishing to buy or sell property, or simply assess the risks associated with ownership and stewardship of land, we are able to provide a range of site appraisals, including environmental audits and site assessments.

Under current planning guidance in compliance with EU Directive 97/11/EC, Environmental Assessments (EIA) are required for major development schemes (Schedule 1) or other schemes deemed likely to pose a risk to the environment (Schedule 2). CGL has provided specialist support on a number of EIA’s for major and high risk development schemes, in particular providing information on ground conditions and contamination issues and the associated impacts.  For instance, CGL was involved with the redevelopment of Minoco Wharf, the major residential development West of Waterlooville, the commercial development for a retail superstore in Bromley and numerous Thames-side developments such as Battersea Reach.
 

The final element of a successful development scheme on contaminated land sites is the formal confirmation that the remediation measures have been implemented and that the risks have been removed or reduced to an acceptable level.  Independent verification by a third party is normally essential to this process.

The number of closed landfill sites across the UK are continuing to rise, representing a significant financial burden to the previous operator or site owner.  At CGL, we continue to support a number of clients facing these ground-related issues on aspects ranging from routine monitoring, HSE, ATEX and DSEAR assessments, and computer modelling of gas generation rates through to long term leachate concentrations and biodegradation timescales.