Artificial ground freezing of a volcanic ash: laboratory tests and modelling

Small-strain deformation behaviour of a clay at frozen and unfrozen states: A comparative study

“…Artificial ground freezing technique is an effective method in securing sufficient ground stability or preventing ground water seepage during underground construction. Prediction of the ground behaviour during/after freezing is attempted by increasingly sophisticated thermo-hydro-mechanical coupled models in recent years [1]. Whilst the mechanical properties of frozen soils have been widely studied over many years [2], the laboratory testing practice is yet to meet demands of the complex coupled models.…”

“…Whilst the mechanical properties of frozen soils have been widely studied over many years [2], the laboratory testing practice is yet to meet demands of the complex coupled models. Critical Statebased constitutive models of frozen soils [1,3,4] require carefully designed laboratory tests in which the state (as defined by the stress and density) and its history are clear for their calibration and further development [5,6]. Reappraising the frozen soil behaviour in this new perspective, it is evident that more fundamental study on frozen soil stiffness is necessary.…”

Mathematical models of steady-state temperature fields produced by multi-piped freezing

“…This creates a strong, watertight frozen soil wall which serves as a temporary support structure during excavation. Due to its strong water-sealing ability and the mechanical strength of a frozen soil wall, and its superiority for safety and environmental conservation, AGF has been widely employed in many types of construction projects, including shield launching and receiving, retaining and protecting foundation pits, mine shaft sinking, tunnel boring machine (TBM) maintenance (Li et al, 2004;Itoh et al, 2005;Primentel et al, 2007;Schmall and Maishman, 2007;Viggiani and de Sanctis, 2009;Hu and Long, 2010;Russo et al, 2012;Viggiani and Casini, 2015;Casini et al, 2016), and recovery of shield tunnels (Ju et al, 1998;Wang, 2006;Xiao et al, 2006). As the properties of a frozen soil wall, such as its mechanical properties and thickness, are functions of temperature, the calculation of the temperature field is a pre-requisite for studying the temperature distribution, i.e., it is a significant part of the basis for design and construction using AGF.…”

Editorial

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The use of artificial freezing for temporary improvement of mechanical properties in granular deposits motivates the fourth paper (Casini et al, 2016). The authors present preliminary results that were obtained using a full thermo-hydro-mechanical model, calibrated against experimental data obtained in the laboratory on temperaturecontrolled tests.

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“…■ Survey of potential topics and of interlacing contributions in Environmental Geotechnics (Imre, 2016, Pellet, 2016) ■ use of numerical modelling for the interpolation of experimental results (Casini et al, 2016;Leung, 2016;de Repentigny and Courcelles, 2016) ■ applications to engineering problems (Adem and Vanapalli, 2016;Leung, 2016;de Repentigny and Courcelles, 2016;O'Kelly, 2016), leading to suggestions for field tests and monitoring (Leung, 2016;de Repentigny and Courcelles, 2016) and to recommendations for analytical developments (Adem and Vananpalli, 2016;O'Kelly, 2016).…”