GEOTECHNICAL ENGINEERING

Stabilisation of Weak Slopes

STABLE-EARTH^TM  is a design service developed by OGI Groundwater Specialists Ltd, to provide innovative, robust and cost effective solutions for the construction of safe, steep, earth embankments in challenging ground conditions.

We believe our design process is intrinsic to our objective of technical excellence and so provides a efficient solution to the Client. As such, we have a track record of providing high quality designs to a variety of permanent earthworks projects across the North of England and further afield.

OGI’s designs use the most appropriate drilling and pumping methods for the job, including wellpoints, borehole pumps, suction pumps, ejectors pumps or sump pumps.

Slope Stability Analysis

As part of the STABLE-EARTH^TM  design service, OGI undertakes slope stability analysis using the geotechnical finite element software tools PLAXIS 2D and 3D.

The analysis is based on the design criteria set out in Eurocode EC7.

By combining our knowledge of groundwater control with slope stability analysis, we can achieve considerable cost savings for the client by eliminating the requirement for large scale sheet piling or other retaining wall structures.

Having completed the slope stability calculations, OGI undertake internal design checks (Category 2), and issue a design certificate. We will provide all supporting documentation which includes all calculations including assumptions made, source data and parameters used in the model.

Uplift Pressure Calculations

OGI can assess uplift pressures associated with groundwater.  Uplift occurs when pore-water pressure under a structure or a low permeability confining layer becomes larger than the mean overburden pressure.

If the upward forces become higher than the downward forces the whole structure can be uplifted.  OGI can undertake calculations based on available site investigation.  For each scenario a Factor of Safety in accordance with Eurocode 7 is calculated as the relationship between the uplift forces and the resistant forces.

Settlement Calculations

OGI can undertake settlement/heave calculations for a wide variety of applications.

Settlement/heave to existing structures can occur for many reasons, however, it is often associated with changing groundwater levels.  Drainage and dewatering associated with construction activities can reduce groundwater levels. This potentially causes settlement to existing structures.

When a construction site is close to sensitive structures, such as railways or a gas pipelines,, it is prudent to assess the predicted settlements in advance.  If necessary, OGI can design mitigation measures such as recharge wells, which will maintain the groundwater level up to the predetermined minimum level to pro-actively prevent settlement from ever occurring to structures adjacent to construction dewatering activities.