Geomechanics Research Group

Geomechanics covers activities related to the characterisation of granular materials, soil, clays etc and understanding, and modelling, their behaviour under a range of conditions and time scales.

Particular areas of interest are the modelling of soil-structure interactions including soil-vehicle interactions for extra-terrestrial applications and the behaviour of liquefiable soils subject to seismic and other dynamic effects.

  • Mechanics and micro-mechanics of granular materials including image analysis
  • Discrete Element Modelling (DEM) of granular materials including laboratory validation
  • Physical modelling of geotechnical problems including soil-structure interaction with particular emphasis to off-shore wind turbines
  • Soil-Vehicle interactions including extra-terrestrial applications
  • Wave propagation in, and constitutive models for, nonlinear materials
  • Pipelines and piles in seismic areas including liquefiable soils
  • Study of soil liquefaction using element tests

We can carry our Advanced Soil Testing as well as bespoke scaled model tests of geotechnical problems. Please contact us if you need any further information.

We are pleased to announce our new MSc course in Advanced Geotechnical Engineering.

Please find a list of the academic, research and support staff that make up the Ground Engineering group.

Academics

Technical staff

Mr George Nikitas

SAGE (Surrey Advanced Geotechnical Engineering) Lab is a geotechnical testing facility to carry out advanced laboratory testing of soils and scaled model tests of geotechnical problems. The following are our capabilities.  

  1. Advanced Laboratory testing of soil: We are fully capable of carrying out all types of soil testing including Triaxial testing with local strain measurements (bender element), Cyclic Triaxial, Resonant column and Dynamic Simple Shear.
  2. Scaled model tests for different geotechnical problems: Example problem studies are: behaviour of offshore wind turbines under cyclic and dynamic loading, behaviour of pipelines crossing a fault and other Dynamic Soil-Structure Interaction (DSSI) problems. We also can carry out vibration monitoring of small scale models using non-contact devices, shaking table tests for small scale models and also can develop of customized sensors (e.g. water proof MEMS accelerometers).

Click here for the SAGE Lab Leaflet

Some examples of advanced soil testing

  • Cyclic Triaxial Apparatus: We can carry out element testing of soil to understand the cyclic behaviour including liquefaction susceptibility and also multi-stage test (for example cyclic testing of soil to liquefaction and then applying monotonic loading).
  • Using the tests results we can construct bespoke p-y curves (Winkler Springs for pile-soil analysis) for any soils. Currently codes of practice provides methodology to constructy p-y curves for standard soils (such as sand, soft clay, stiff clay). We can construct continuous p-y curves for a soil from the element test data based on our published research.
  • Resonant Column Apparatus: We can carry out Shear Modulus and Damping characteristics of soils.
  • Dynamic Simple Shear Apparatus: We can carry out cyclic simple shear tests on soils applying hundreds of thousands of cycles.
  • Triaxial with Local Measurement (Bender Element): Our monotonic triaxial apparatus is also equipped with bender element equipment and we can also carry out other local measurements.

Physical modelling in geotechnical engineering

We have two calibration chambers with transparent sides for visualization purposes-

  1. Large Calibration Chamber: (2.4m × 1.4m × 2.6m) with a transparent front. This chamber has been used before to carry out shaking table tests.
  2. Small Calibration Chamber: (450mm × 200mm × 400mm) with a transparent front. This has been used before to carry out 1-g and shaking table tests

Examples of small scale testing

  • Small scale models of Offshore Wind Turbine Foundations: We carried out wind turbine model tests to understand the dynamic soil structure interactions as well as long term performance. Apart from standard measuring devices, we are able to monitor the structure frequency during shaking using non-contact device such as Laser Vibrometer. See the above photograph.
  • Some examples of pipeline testing: Models to investigate the effects of fault movements or landslides on buried pipelines: we carried out model test to study the effect of fault movement (both reverse and thrust) on pipeline behaviour.
  • Examples of Micro Mechanical Behaviour of Soil: We developed a custom made inter-particle friction apparatus. This has been used to carry out inter-partical friction test on irregular surface under different normal loads.
  • Physical model of retaining wall: We are able to carry out shearing tests on granular material confined by a moving wall.

Research Students

The high CO2 emissions associated with production of Portland cement and over-consumption of traditional stabilisers (cement and lime), requires viable, sustainable and economical alternative binder systems. Treating tropical expansive soil with metakaolin based geopolymer has not been widely investigated, and this research addresses that knowledge gap. Geopolymer is an alkali-activated binder with low calcium content. The major key influential factor for selecting metakaolin (also known as calcined kaolin) and alkali-activators (sodium silicate and sodium hydroxide) as geopolymer stabiliser, is due to local availability of kaolin, and alkali-activators can easily be sourced in the research location. In addition, it synthesis requires low: CO2 emissions; cost and energy consumption compared to traditional stabilisers.

This research is mainly focus on investigation of geotechnical properties of alkali-activated metakaolin stabilised tropical expansive black cotton soil as a subbase material. Series of laboratory test will be conducted according to British standard soil testing method and the results will be analysed with statistical analysis software (SAS) and validated using relevant literatures, and other related geotechnical software packages.

Moment resisting capacity of different offshore wind turbines under different soil/ground conditions and introduction to new type of wind turbine foundation and finding the suitability and long term effects.

My concern around energy shortage, diminution of fossil fuels, global warming and pollution has always driven me throughout my academic studies to learn more about renewable energy and what can be done now to avoid future catastrophic ramifications. However, there is now a general consensus among academics and the public about the necessity to find a solution or combined solutions to tackle these issues. I am currently carrying out research on the use of ground source heat pumps in underground tunnels (“Energy Tunnels”). In order to address some of the design challenges facing energy tunnels, my research is focused on optimising and improving energy tunnels thermal efficiencies and to also understand the thermo-mechanical effect of the cyclic heating and cooling on the tunnel.

Geothermal energy pile is a proven source of renewable energy for space heating and cooling. It harnesses the constant ground temperature for human comfort due to its thermal inertia. Geothermal energy pile is defined as a dual-purpose structural element and an innovative way of reducing the carbon footprint of any new building constructed on pile foundations. Geothermal energy piles are a direct adoption of vertical borehole closed loop ground source heat pump (GSHP) technology into pile foundations where closed heat exchanging loops are installed within the pile. Despite many studies in the past on geothermal energy pile, there are still unanswered questions regarding how to increase its thermal performance. To increase the thermal performance of geothermal energy pile, there is a need to improve its thermal energy storage capacity. In this study, different types of heat exchanger piles will be designed with the aim of investigating their thermal performance, and thermo-mechanical behaviour under heating-cooling cycles.

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Department of Civil and Environmental Engineering
University of Surrey
Guildford
Surrey
GU2 7XH