Herman Peiffer - Profile on Academia.edu (original) (raw)

Papers by Herman Peiffer

The variation of pore gas pressure caused by rainfall infiltration is an important factor that le... more The variation of pore gas pressure caused by rainfall infiltration is an important factor that leads to slope failures. The purpose of this study is to propose a new slope stability analysis method that considers pore gas pressure and examines the effect of airflow on slope stability by using a numerical method. A water-air two-phase flow analysis was conducted to investigate the distribution of pore air pressure, pore water pressure as well as water saturation triggered by rainfall infiltration. Then the variation of the load resulting from pore gas pressure was incorporated into the slope stability analysis method on the basis of the unsaturated soil shear strength theory and the residual thrust method to simulate the influence of airflow on the Tanjiahe landslide in China. In order to study the infiltration behavior with respect to initial saturation, water and gas flow analyses were performed considering various initial statuses of saturation under similar settings. Results show...

Theoretical and Experimental Investigations into Screws for Extruding Polypropylene

International Polymer Processing, May 1, 1994

Abstract In the processing of polypropylene via a melt, the extruder exerts an important influenc... more Abstract In the processing of polypropylene via a melt, the extruder exerts an important influence on product quality. Trials were carried out on production extruders with the aim of improving melt quality. As an aid to evaluating the screws, a computer model was developed which could simulate extruders. This model is described in the first part of this paper. In the second part, the computer model is tested using experimental data taken from a range of different extruders. The comparisons illustrate the excellent correlation and hence validity of the model. On the basis of these results, recommendations are given for the optimization of single-screw extruders.

Influence of pile installation on the stress state in the soil

Influence of screw pile installation on the stress state in the soil

Design of Axially Loaded Piles European Practice, 2020

This paper describes the development of an instrumented dilatometer which is identical in dimensi... more This paper describes the development of an instrumented dilatometer which is identical in dimensions and thus soil disturbance during penetration to the standard dilatometer introduced by Prof. Marchetti in 1980, except for the use of a rigid piston with a larger displacement up to 2.35 mm and instrumentation allowing measurements of full pressure-displacement curve and porewater pressure at the piston center. The fabrication of this instrumented dilatometer was assisted by a novel metal 3D printing technique, which may provide further insight in improving other geotechnical testing apparatus. The new instrumented dilatometer was tested at a site of silty sand in Belgium, along with a DMT and a CPT located 1 m apart. Results show that the instrumented DMT can provide an opportunity to improve the estimation of lift-off pressure , which is crucial to the DMT interpretation, ba sed on the judgement of the full expansion curve. RÉSUMÉ : Cet article décrit le développement d'un dila...

De DMT-proef: state of the art-analyse uitgebreid tot de beoordeling van de wijzigingen van de spanningen in de grond ten gevolge van de installatie van schroefpalen

De bepaling van de schuifweerstandskarakteristieken op basis van een gecombineerd DMT/CPT onderzoek

Concept en ontwerp van betonvloeren

Flow through unsaturated clay barriers

Considerations on the effects of installation on the displacement auger pile capacity

In Belgium the Boom Clay is a well known overconsolidated clay formation. This Tertiary clay, wit... more In Belgium the Boom Clay is a well known overconsolidated clay formation. This Tertiary clay, with the same geological origin as the London Clay, is used for the fabrication of bricks, roofing tiles. In the article is described how the DMT can be used to evaluate the stability of slopes, to determine the risk of instability and how the cause of the failure directly could be related to the results of the DMT-measurement. The results of the tests before the period of instability, during the period of instability and after stabilization are discussed. The KD-value is a representative value to judge the risk of instability.

Bearing capacity of auger piles

Recente (r)evoluties in het in-situ grondonderzoek

Geotechnische aspecten bij de uitvoering van rioleringswerken

Inverse determination of soil characteristics with a bench-scale centrifuge

We utilize a bench-scale centrifuge to speed up the process of porous media in ltration. This all... more We utilize a bench-scale centrifuge to speed up the process of porous media in ltration. This allows to obtain measurements in a fraction of the time needed by standard in ltration methods, especially for clayey soils. By measuring only transient data like water level in an inflow or outflow chamber, gravitational center of the sample, or the rotational momentum of the sample, it is possible to determine the soil characteristics. This is done by solving the inverse problem based on the mathematical model for saturated and unsaturated water infi ltration in soil. The model for the unsaturated flow is based on Richards' equation and the Van Genuchten-Mualem formula. We present the experimental set-up, accuracy of the measurements, and the numerical solution method. For saturated flow we compare with standard tests and the classical formula for hydraulic conductivity in a centrifuge from two discrete measurements.

Developments in determination of geotechnical parameters

Atlas screw piles and tube screw piles in stiff tertiary clays : assessment of pile performance and pile capacity on basis of instrumented loading tests