Static Liquefaction Tank (SLT)

General Information

Instrument:
Fluidisation and inclinable liquefaction tank

Description:
The experimental set-up consists of a liquefaction tank with dimensions of 5 m (length), 2 m (width) and 2 m (height). The side-walls are made up of strong transparent hardened glass to allow visual observation and reduce lateral friction, while the end-walls and floor are made up of steel. The tank is supported on vibration-isolating systems to avoid external vibrations affecting the (loose) soil model in the tank.

Facilities:
Water-submerged layer of fine sand will be fluidised by up-flowing water. After sedimentation of the sand a rather homogeneous very loose sand structure will be obtained. For creating a submerged slope of loose fine sand, a part of this loose sand layer will be dredged away by applying a dredging technique. The instability can be induced either by excitation at the crest of the slope using a shallow foundation or by gradual tilting of slope.

Tilting of the tank is animated in the following video created by Clemens Krapfenbauer [M.Sc. student of our research group from Swiss Federal Institute of Technology in Zurich (ETHZ)]:

Instrumentation:
The experimental set-up includes various types of sensors and actuators, which are all connected to the total data acquisition and control system. The data from all sensors can be logged at a frequency of 1 kHz upon triggering.

List of sensors in the liquefaction tank

• Pore pressure transducers at the bottom of the tank

• Pore pressure transducers at the wall of the tank

• Pore pressure transducers at the wall of the tank

• Total pressure sensors

• Differential pressure transducers between the fluidisation tubes and the base of the sand layer

• Load cells

• Inclinometer

• Encoder of the motor

• Accelerometer

• Temperature sensor

• Pore pressure transducer for the supply pipe of the fluidisation system

• Flow meter for the supply pipe of the fluidisation system

• Level detector

• Floating sensor: Pore pressure transducer, accelerometer

Location:
Laboratory of Geoscience and Engineering, Faculty of Civil Engineering and  Geosciences, Stevinweg 1, Delft (Building #23).

Key Words:
Submarine landslides, flood defence systems, flow-slides, static liquefaction, dredging, physical modelling in geotechnics.

Main Application:

• Offshore geotechnical engineering: submarine landslides and flowslides

•  Dredging in sand layers

• Dikes and embankments

• Soil structure interaction: shallow foundations

• General slope stability analysis

• Unsaturated soil mechanics

• Soil vegetation interaction

•  Dynamic effects on geotechnical structures

List of internal reports on liquefaction

• Presentation on liquefaction flow slides: Why, What, How, Frans Molenkamp, 23-11-2015. 

• Text announcement transfer lecture, Frans Molenkamp, 20-10-2015. 

• Determination of global sand density in liquefaction tank, Frans Molenkamp, Richard de Jager, 2-8-2015.

• Stationary fluidized saturated column, Frans Molenkamp, Richard de Jager, 8-8-2015.

• Overview of previous and remaining work by DEMO on instrumentation, data-acquisition and control for liquefaction tank, Frans Molenkamp, 13-7-2015.

• Instrumentation and control of experiments in liquefaction tank, Rein van den Oever, Jan Graafland, Richard de Jager and Frans Molenkamp, 24-01-2013, provisionally extended FM, 27-01-2014 & 29-06-2015.

• Superposed modes of deformation and flow in saturated heterogeneous Geomechanics. Transient hydrostatics and relative motion of pore fluid. Richard de Jager and Frans Molenkamp, 25-06-2015.

• Ordering instrumentation for triaxial equipment enabling fluidization, Frans Molenkamp, 05-04-2015.

• Characteristics of sensors and control of triaxial equipment for saturated sand samples prepared by fluidization, Richard de Jager, Frans Molenkamp, 11-3-2015.

• Preparatory study of protocol and equipment for undrained triaxial testing of saturated sand samples prepared by fluidization, Richard de Jager and Frans Molenkamp, 8-3-2015.

• Review of intergranular stress measure based on micro-macro approach, Richard de Jager and Frans Molenkamp, 20-01-2014.

• Tilting of liquefaction tank and corresponding movements of spindles and couple axis, Richard de Jager and Frans Molenkamp, 11-11-2013.

• Thermo-hydro-mechanical framework of saturated geomaterials, Frans Molenkamp and Richard de Jager, 30-08-2013.

• Transient heterogeneous hydrostatics and viscous pore fluid flow, Frans Molenkamp, Richard de Jager, 10-12-2012.

• Thermo-hydro-mechanical framework of heterogeneous unsaturated geomaterials,  Frans Molenkamp, 05-07-2012.

• Design of fluidization system for liquefaction tank, Frans Molenkamp, Richard de Jager,  v2, 02-12-2014.

• Considerations on requirements of hollow cylinder torsional shear testing of water-saturated loose fine sands for research programme on static liquefaction and subsequent flow, Richard de Jager, Frans Molenkamp, 15-03-2011.

•  Interactions between saturated soil phases involving linear momentum, Frans  Molenkamp, 31-10-2009.

•  Mohr-Coulomb model, Frans Molenkamp, 12-06-2005.

Reference:

• Tesegaye, A.B. (2009), “Evaluation of material models for modeling static liquefaction”, MSc thesis, Delft University of Technology.

• Braakenburg, L.C.H. (2011), “Modelling static liquefaction with the simplified version of MONOT”, MSc thesis, Delft University of Technology.

• Tesegaye, A.B., Molenkamp, F., Brinkgreve, R.B.J., Bonnier, P.G., De Jager, R.R., Galavi, V. (2010a), “Modelling liquefaction behaviour of sands by means of hypoplastic model”, In T. Benz & S. Nordal (Eds.), Numerical methods in Geotechnical Engineering: NUMGE 2010, pp 81-88.

• Tesegaye, A.B., Galavi, V., Brinkgreve, R.B.J., De Jager, R.R., Molenkamp, F., Bonnier, P. (2010b), “Modeling static liquefaction with multilaminate framework”, In T. Benz & S. Nordal (Eds.), Numerical methods in Geotechnical Engineering: NUMGE 2010, pp 95-100.

• de Jager, R.R., Braakenburg, L.C.H., Hicks, M.A., Molenkamp, F. (2011), “Towards modeling of static liquefaction of saturated loose sand”, In S Pietruszczak & GN Pande (Eds.), Computational Geomechanics Comgeo II, pp. 1-13.

• de Jager, R.R., Molenkamp, F. (2012), “Fluidization system for liquefaction tank”, Proceedings of Eurofuge, Delft University of Technology and deltares, doi:10.4233/uuid:47ce6506-b678-46ee be42-414cc1a00d69.

• de Jager, R.R., Mathijssen, F.A.J.M., Molenkamp, F. (2013), “Hydrostatics and relative motion of pore fluids”, Proceedings of COMGEO III, Krakow, 359-370.

• Molenkamp, F., de Jager, R.R., Mathijssen, F.A.J.M. (2014), “Stress measures affecting deformation of granular materials”, Vadose Zone Journal, Vol. 13, Nr. 5, 17 pages, doi:10.2136/vzj2013.07.0130.

• de Jager, R.R., Molenkamp, F. (2014), “Stress measures for interparticle sliding and particle rolling”, Proceedings of NUMGE, Delft, 18-20 June, pp. 61-66.