Correction Factor on Dynamic Force in a Marsh Funnel Test for Tunneling

This paper presents an improvement on a previous model for predicting the Marsh funnel (MF) test that is used in slurry shield tunneling for evaluating the rheological properties of bentonite slurries. The improvement focuses on the prediction of the dynamic part for fluids with small MF times. The velocity profile of the Herschel-Bulkley...

Geogrid-anchored sheet pile walls: a small-scale experimental and numerical study

The use of geogrids to anchor Sheet Pile Walls (SPW) is relatively new. A series of small-scale tests was performed to investigate the behaviour of geogrid-Anchored SPWs subjected to strip footing surcharge loading. Particle Image Velocimetry (PIV) techniques were used to measure soil displacement and analyse the global failure mechanism and...

Analytical solutions for excess pore water pressures generated by TBM tunnelling in a semi-confined aquifer

Tunnel-boring machine (TBM) tunnelling through an aquifer will generate excess pore water pressures in the soil around the tunnel face. Accurately predicting the magnitude of the excess pore water pressures is significant because it directly determines the effective face support pressure. In this study, an analytical solution for transient...

The influence of apparatus stiffness on the results of cyclic direct simple shear tests on dense sand

A series of undrained cyclic direct simple shear (CDSS) tests on dense Toyoura sand has been performed with the aim to investigate the influence of the stiffness of the DSS device on test results. To this end, springs were installed to reduce deliberately the stiffness of the apparatus. It is shown that the cyclic resistance of the sand...

Validation of analytical models for the design of basal reinforced piled embankments

Van Eekelen et al., 2012a, Van Eekelen et al., 2012b and Van Eekelen et al., 2013) have introduced an analytical model for the design of the geosynthetic reinforcement (GR) in a piled embankment. This paper further validates this model with measurements from seven full-scale tests and four series of scaled model experiments. Most of these...

An analytical model for arching in piled embankments

Most analytical models for the design of piled embankments or load transfer platforms with geosynthetic reinforcement (GR) include two calculation steps. Step 1 calculates the arching behaviour in the fill and step 2 the load-deflection behaviour of the GR. A calculation method for step 2 based on the results of model tests has been published by...

Source brightness and useful beam current of carbon nanotubes and other very small emitters

The potential application of carbon nanotubes as electron sources in electron microscopes is analyzed. The resolution and probe current that can be obtained from a carbon nanotube emitter in a low-voltage scanning electron microscope are calculated and compared to the state of the art using Schottky electron sources. Many analytical equations...