Engineering behaviour of thanet sand
Author(s)
Ventouras, Konstantinos
Type
Thesis
Abstract
Thanet sand is a soil stratum that lies deep enough within the central London area not to have been the topic of extensive research to date, as most foundation works, foundation designs and tunnels have mainly been focused on the London Clay stratum. Recently, as buildings and construction works in general tend to get bigger and heavier and as tunnelling techniques are constantly being improved, Thanet sand has attracted increasingly larger scientific interest. The research programme primarily consisted of an extensive series of triaxial tests. Most of the intact samples available were rotary cored and the rest were extracted using block sampling. Intact samples were compared with reconstituted sample formed in the lab in an attempt to locate and quantify the effect of structure within Thanet sand. Additionally, by cutting samples in different directions from the extracted block, the effects of anisotropy within the soil were also examined. To run these tests, three different triaxial cells were used out of which one was modified with pressure multipliers. This, along with some previously conducted experiments, allowed the full stress range to be covered from a starting effective pressure of 125kPa till 20MPa. It had previously been suggested by others that Thanet sand could be divided into two sub-strata based on its particle size distribution curves as well as based on findings from in-situ testing and large scale on-site pile tests. The work in this Thesis has established that two parallel CSLs, one per sub-stratum can be found which has a significant influence on its behaviour in laboratory tests and in-situ. Thanet sand was shown to be a cross-anisotropic material with a distinct effect of structure, even though the soil is neither cemented nor does it have a locked fabric.
Version
Open Access
Date Awarded
2005
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Coop, Matthew R.
Publisher Department
Department of Civil and Environmental Engineering
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)