The soil-atmosphere interface: an important boundary condition or an unnecessary complicating factor?

Soil-atmosphere interaction occurs frequently in most geotechnical situations. By including it in analyses, a high computational load can occur, and analyses are made more complex. This paper explores the key processes and demonstrates the impact and advantages of quantifying soil-atmosphere interactions. Possibilities of utilising the soil...

Clay micromechanics: experimental challenges and perspectives

The importance of physico-chemical processes at the particle scale for the engineering scale behaviour of fine-grained geomaterials is undisputed. Yet, despite great advances in the discipline, experimental evidence that fully resolves the clay micromechanics i.e. linking the evolving microstructure and interparticle actions under loading, is...

Mechanisms causing injectivity decline and enhancement in geothermal projects

In geothermal projects, reinjection of produced water has been widely applied for disposing wastewater, supplying heat exchange media and maintaining reservoir pressure. Accordingly, it is a key process for environmental and well performance assessment, which partly controls the success of projects. However, the injectivity, a measure of how...

Heterogeneous Swelling of an Isotropically Compacted Bentonite-Based Material: Experimental Observations and Modelling

This paper presents a comprehensive investigation of the swelling behaviour of a compacted bentonite–sand mixture subjected to hydration under constant volume conditions. Contrary to previous studies, the tested sample was isotropically compacted before being hydrated under constant volume conditions until full saturation was reached. The...

Effects of Carbonate Distribution Inhomogeneity on the Improvement Level of Bio-cemented Sands: A DEM Study

Microbially induced carbonate precipitation (MICP) involves bacteria to drive calcite precipitation and naturally cement soils, thereby improving soils performance. Experimental studies have shown that bio-cemented specimen can suffer from severe spatial inhomogeneity of the calcite content, leading to large uncertainty in treatment...

Mechanisms governing carbon and nitrogen pathways during enhanced waste degradation in landfill simulator reactors

Nitrogen undergoes multiple biogeochemical transformations during waste degradation, which depend on speciation, prevailing geochemical boundary conditions, and waste surface properties. This study developed a waste biodegradation model with high flexibility in accommodating reaction pathways to assess different process dynamics. The model was...

Modelling gas fracturing in saturated clay samples using triple-node zero-thickness interface elements

Geological Disposal Facilities (GDF) for radioactive waste will generally rely on clay-rich materials as a host geological formation and/or engineered barrier. Gas will be produced within the GDF, which can build up significant gas pressure and will activate the migration of gas through the clay materials via different transport mechanisms....

Effects of carbonate distribution pattern on the mechanical behaviour of bio-cemented sands: A DEM study

Microbially induced carbonate precipitation is a promising ground improvement technique which can enhance the mechanical properties of soils through the precipitation of calcium carbonate. Experimental evidences indicate that the precipitated carbonate can display different distribution patterns. Crystals can develop at grain–grain contacts ...

An experimental and numerical study of bentonite swelling under constant-volume conditions

Experimental characterisation of self-healing in reconstituted Boom Clay

Numerical modelling of discrete gas flow pathways in water saturated clay

Numerical Study of Fluid Loss into a Thief Zone overlying a Geothermal Reservoir

and boundary connected with aquifer respectively, are discussed. On the basis of these two boundary conditions, several factors that influence the fluid loss process are studied. For the thief zone with no-flow boundary, our key conclusions illustrate that once the pressure front reaches an opening in the sealing, fluid loss occurs. However,...

Drilling report: Delftse Hout multipurpose research borehole - DAPGEO-02

The multi-purpose research borehole at the Delftse Hout is the third of four seismic monitoring locations of the seismic monitoring network for the geothermal research project on the TU Delft campus (Geothermal Delft GTD, also known as DAPwell, https://geothermiedelft.nl/). For the geothermal research project, two deep wells (“a doublet”...

Numerical simulation of a water infiltration test on a proposed backfill material in nuclear waste repositories

A water infiltration test was numerically simulated using the finite element method. The modified Barcelona Basic Model and the double-structure water retention model was used for the numerical analysis. A methodology is presented for parameter identification and calibration purpose. The experimental results highlighted the porosity...

Coupled hydro-mechanical analysis of expansive soils: Parametric identification and calibration

A methodology for identifying and calibrating the material parameters for a coupled hydro-mechanical problem is presented in this paper. For validation purpose, a laboratory-based water infiltration test was numerically simulated using finite element method (FEM). The test was conducted using a self-designed column-type experimental device,...

A fully coupled hydro-mechanical framework for expansive clays