Effect of soil permeability on soil–structure and structure–soil–structure interaction of low-rise structures

TY - JOUR

T1 - Effect of soil permeability on soil–structure and structure–soil–structure interaction of low-rise structures

AU - Qi, S.

AU - Knappett, J. A.

N1 - Funding Information: The authors would like to thank China Scholarship Council for its financial support of the first author during her PhD studies. The authors would also like to thank Mark Truswell, Grant Kydd, Willie Henderson and Gary Callon at the University of Dundee for their assistance in fabricating the model structures and running the centrifuge tests. Publisher Copyright: © 2021 Thomas Telford Ltd.

PY - 2022/9

Y1 - 2022/9

N2 - Earthquake-induced soil liquefaction can generate excessive damage to building structures due to significant reduction in soil effective stress. With increasing urbanisation and population growth, the performance of closely spaced buildings, such as those in towns and cities, is of greater concern where structure-soil-structure interaction (SSSI) may occur in conjunction with full or partial liquefaction. This study investigates the seismic performance of isolated and adjacent structures built on shallow foundations on soils of different permeability (i.e. with different amounts of drainage and therefore generating different amounts of excess pore water pressure) using a combination of dynamic centrifuge modelling and finite-element modelling. The results demonstrate that the reduction in free-field ground surface intensity measure (specifically, Housner intensity) due to increasing liquefaction can be correlated to an index which is the normalised integral of excess pore pressure ratio (ru) with depth. This index can express the amount of liquefaction uniquely, even when full liquefaction occurs to only partial depth, or where excess pore water pressures are increased but below the level of full liquefaction at all depths. This underlying correlation means that structural demand reduction (e.g. reduction in inter-storey drift ratio) with liquefaction (SSI effect) can be linked to either: (a) the ru-depth index; (b) the depth of the liquefaction front, which can be estimated from a liquefaction triggering analysis; or (c) the ground surface intensity amplification/attenuation in the free field from the results of one-dimensional free-field soil column analyses. Where there are adjacent structures, a strongly beneficial SSSI effect on co-seismic settlement and a detrimental effect on drift in non-liquefied soil, as observed in this and previous studies, reduced towards a null effect in both cases with increased liquefaction, with liquefaction appearing to isolate the structures from each other (at least for the configuration considered herein). This has also been linked to the amount of amplification/attenuation of surface ground motion in the free field (or amount of liquefaction) as a simple indicator of the likely importance of SSSI effects in liquefiable soil.

AB - Earthquake-induced soil liquefaction can generate excessive damage to building structures due to significant reduction in soil effective stress. With increasing urbanisation and population growth, the performance of closely spaced buildings, such as those in towns and cities, is of greater concern where structure-soil-structure interaction (SSSI) may occur in conjunction with full or partial liquefaction. This study investigates the seismic performance of isolated and adjacent structures built on shallow foundations on soils of different permeability (i.e. with different amounts of drainage and therefore generating different amounts of excess pore water pressure) using a combination of dynamic centrifuge modelling and finite-element modelling. The results demonstrate that the reduction in free-field ground surface intensity measure (specifically, Housner intensity) due to increasing liquefaction can be correlated to an index which is the normalised integral of excess pore pressure ratio (ru) with depth. This index can express the amount of liquefaction uniquely, even when full liquefaction occurs to only partial depth, or where excess pore water pressures are increased but below the level of full liquefaction at all depths. This underlying correlation means that structural demand reduction (e.g. reduction in inter-storey drift ratio) with liquefaction (SSI effect) can be linked to either: (a) the ru-depth index; (b) the depth of the liquefaction front, which can be estimated from a liquefaction triggering analysis; or (c) the ground surface intensity amplification/attenuation in the free field from the results of one-dimensional free-field soil column analyses. Where there are adjacent structures, a strongly beneficial SSSI effect on co-seismic settlement and a detrimental effect on drift in non-liquefied soil, as observed in this and previous studies, reduced towards a null effect in both cases with increased liquefaction, with liquefaction appearing to isolate the structures from each other (at least for the configuration considered herein). This has also been linked to the amount of amplification/attenuation of surface ground motion in the free field (or amount of liquefaction) as a simple indicator of the likely importance of SSSI effects in liquefiable soil.

KW - Centrifuge modelling

KW - Earthquakes

KW - Finite-element modelling

KW - Liquefaction

KW - Sands

KW - centrifuge modelling

KW - liquefaction

KW - earthquakes

KW - sands

KW - finite-element modelling

UR - https://www.scopus.com/pages/publications/85113982595

U2 - 10.1680/jgeot.20.P.109

DO - 10.1680/jgeot.20.P.109

M3 - Article

SN - 0016-8505

VL - 72

SP - 784

EP - 799

JO - Geotechnique

JF - Geotechnique

IS - 9

ER -