Modelling the collapse of metastable loess soils

Miller, H, 2002. Modelling the collapse of metastable loess soils. PhD, Nottingham Trent University.

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Abstract

Loess is a geologically young deposit, found all over the world. Large volume reductions can occur in the deposit due to loading and/or wetting. The collapse of a soil due to wetting is often referred to as hydrocollapse. Hydrocollapse of loess soil is a significant hazard for the built environment. This thesis discusses some of the modelling techniques that can be used for collapsible loess soils.

Estimation of the likely magnitude of hydrocollapse can be made by conducting a series of one-dimensional oedometer tests on specimens of the soil. The percentage hydrocollapse calculated in these tests can be used to compare loess samples from different regions. The amount of hydrocollapse observed will depend on the factors such as the density of the deposit and the amount of pore water present in the soil. The influence of each of these properties on the magnitude of hydrocollapse is difficult to determine from natural samples because the properties will be different from one region to another.

An artificial material has been developed to model the behaviour of collapsible loess soils. The properties of the artificial material can be varied and so the relative roles of the constituents can be determined. Another advantage of the artificial material is that it can be formed in the testing rig and therefore is not subjected to any sampling effects before testing. The artificial material has been tested in the oedometer and triaxial equipment. The behaviour of the artificial soil compared well with natural loess soil from the UK. The artificial material also shows similar strength and stiffness to the natural loess soil.

The artificial material was used in a small-scale test of a strip footing. Rising ground water was simulated in the test and the settlement of the footing was monitored. The strip footing test was modelled using finite element techniques and compared with the laboratory results. A simple but effective method of estimating collapse below a strip footing on a collapsible loess soil was determined.

Item Type:	Thesis
Creators:	Miller, H.
Date:	2002
ISBN:	9781369314687
Identifiers:	Number Type PQ10183202 Other
Divisions:	Schools > School of Architecture, Design and the Built Environment
Record created by:	Linda Sullivan
Date Added:	21 Sep 2020 15:06
Last Modified:	28 Jul 2023 14:07
URI:	https://irep.ntu.ac.uk/id/eprint/40854

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