Experimental study on workability and permeability of sandy soils conditioned with thickened foam

Water spewing and muck plugging often occur during earth pressure balance (EPB) shield machines tunnelling in water-rich sandy strata, even though the conventional foam has been employed to condition sandy soils. In this study, a novel thickened foaming agent suitable for EPB shield tunnelling in water-rich sandy strata is developed. In...

Unlined Length Effect on the Tunnel Face Stability and Collapse Mechanisms in c-ϕ Soils: A Numerical Study with Advanced Mesh Adaptive Strategies

This paper presents a stability study on the collapse mechanisms of a plane-strain tunnel face in c-ϕ soils using the upper bound finite element method with rigid translatory moving elements (UBFELA-RTME) and nonlinear programming technique. Practical considerations are given to the unlined length influence behind the tunnel face. An advanced...

A material point/finite volume method for coupled shallow water flows and large dynamic deformations in seabeds

A hybrid material point/finite volume method for the numerical simulation of shallow water waves caused by large dynamic deformations in the bathymetry is presented. The proposed model consists of coupling the nonlinear shallow water equations for the water flow and a dynamic elastoplastic system for the seabed deformation. As a constitutive...

Stabilised Material Point Method for Fluid-Saturated Geomaterials

Large deformations in fluid-saturated geomaterials are central to numerous geotechnical applications, such as landslides and dam failures, pile installations, and underground excavations. An in-depth understanding of the soil's hydromechanical behaviour during large-deformation processes is essential for quantitative predictions about such...

Fully implicit, stabilised MPM simulation of large-deformation problems in two-phase elastoplastic geomaterials

The Material Point Method (MPM) has been gaining increasing popularity as an appropriate approach to the solution of coupled hydro-mechanical problems involving large deformations. This study extends the implicit GIMP-patch method for coupled poroelastic problems recently proposed by Zheng et al. (2021b) to tackle large-deformation problems...

Fully implicit, stabilised, three-field material point method for dynamic coupled problems

This study presents the formulation and implementation of a fully implicit stabilised Material Point Method (MPM) for dynamic problems in two-phase porous media. In particular, the proposed method is built on a three-field formulation of the governing conservation laws, which uses solid displacement, pore pressure and fluid displacement as...

An explicit stabilised material point method for coupled hydromechanical problems in two-phase porous media

This paper presents a single-point Material Point Method (MPM) for large deformation problems in two-phase porous media such as soils. Many MPM formulations are known to produce numerical oscillations and inaccuracies in the simulated results, largely due to numerical integration and stress recovery performed at non-ideal locations, cell...

Predicting adsorption isotherms of organic micropollutants by high-silica zeolite mixtures

One framework type of high-silica zeolite only can effectively remove a limited range of organic micropollutants (OMPs) from water. In order to extend the OMP removal range, different types of high-silica zeolites need to be combined in the adsorption process. In this study, Mordernite (MOR) and ZSM-5 (MFI) high-silica zeolite powders were mixed...

Development of a Robust Coupled Material Point Method

The material point method (MPM) shows promise for the simulation of large deformations in history-dependent materials such as soils. However, in general, it suffers from oscillations and inaccuracies due to its use of numerical integration and stress recovery at non-ideal locations. The development of a hydro-mechanical model, which does not...

On stress oscillation in MPM simulations involving one or two phases

Stress oscillations in the material point method (MPM) are one of the major reasons unrealistic results are obtained. In this paper an investigation of the stress oscillations occurring when using one- and two-phase approaches is performed. Specifically, an axisymmetric benchmark and a two-dimensional plane strain problem are used to demonstrate...

Thermal Comfort Research in Naturally Ventilated High-Rise Residential Building: For one student dormitory with field study and simulation approach

Natural ventilation is a traditional but effective way in buildings to adjust the indoor environment. It has also been proved to be effective in today’s design, if applied appropriately. At the same time, there is a growing trend that higher and higher buildings are constructed in the crowded city area. Air velocity, temperature and other...

An Energy based Method to Measure the Crowd Safety

How to evaluate crowd safety in crowded areas is a tough, but important, problem. According to accident-causing theory, uncontrolled release of hazardous energy among overcrowded pedestrians is the basic cause of crowd disaster. Therefore, crowd energy is modeled in this paper, which takes both pedestrian kinetic energy, pedestrian potential...

Switch the sun on: Manual for Daylight Strategies

This "designers' manual" is made during the TIDO-course AR0533 Innovation & Sustainability. This manual directs a designer to develop his own ideas on deep building day lighting strategies. After an introduction that defines the need for daylighting, critical regional aspects are discussed, followed by solutions. The daylighting solutions are...