Bentonite mechanical behaviour

Abstract Coupled THM simulation of the FEBEX, which is the full-scale in-situ Engineered Barrier System Experiment performed in Grimsel Test Site in Switzerland, is one Task in the international cooperation project DECOVALEX III. In the Task, the simulation of the thermal, hydraulic and mechanical behaviour in the buffer during heating phase is required, e.g. the evolutions and the distributions of stress, relative humidity and temperature at the specified points in bentonite buffer material. 

A buffer of compacted bentonite is planned to be used to prevent the movement of groundwater and the consequential escape of material from a geological repository for spent nuclear fuel. Fluid flow, phase changes, mechanical behaviour of the buffer, rock, and the waste canisters, and the heat produced by the waste constitute a coupled thermohydromechanical system. The aim of the study is to derive a general thermodynamically consistent THM model for an arbitrary mixture. The general theory is applied to the thermohydraulic modelling of a mixture of compacted bentonite, liquid water, vapour, and air. 

TEMPERATURE INFLUENCE ON THE MECHANICAL BEHAVIOUR OF A COMPACTED BENTONITE... 

Different experimental techniques and equipments to study the influence of the temperature on the mechanical behaviour of the FEBEX bentonite under saturated and partially saturated states have been presented. 

In tests with suction reduction, the structure changes due to hydration are more relevant in the subsequent mechanical behaviour of the bentonite than the effects of temperature. 

Villar, M.V. Lloret, A. 2002. Temperature influence on the hydro-mechanical behaviour of a compacted bentonite. Proc. Int. Meeting Clays in Natural and Engineered Barriers for Radioactive Waste Confinement. ANDRA, Reims. 

FABRIC CHANGES OF A PELLET-BASED BENTONITE BUFFER MATERIAL AND THEIR EFFECTS ON MECHANICAL BEHAVIOUR... 

PART B THERMO-HYDRO-MECHANICAL ANALYSIS OF THE BENTONITE BEHAVIOUR. 

UPC, 2000, Task definition DECOVALEX III, Task 1 Modelling of FEBEX in-situ test. Part B Thermo-hydro-mechanical analysis of the bentonite behaviour. Polytechnical University of Catalonia, Barcelona, Spain. 

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