Chiaro, G.Kiyota, T.Miyamoto, H.2015-10-272015-10-272015Chiaro, G., Kiyota, T., Miyamoto, H. (2015) Large deformation properties of reconstituted Christchurch sand subjected to undrained cyclic torsional simple shear loading. Rotorua, New Zealand: 2015 New Zealand Society for Earthquake Engineering Annual Conference (NZSEE), 10-12 Apr 2015. 529-536.http://hdl.handle.net/10092/11285Severe liquefaction was repeatedly observed during the 2010 - 2011 C hristchurch earthquake s , particularly affecting deposits of fine sands and silty sands of recent fluvial or estuarine origin. The effects of liquefaction included major sliding of soil tow ard water bodies ( i.e. lateral spreading ) rang ing from centimetres to several metres. In this paper, a series of undrained cyclic torsional shear tests were conducted to evaluate the liquefaction and extremely large deformation properties of Christchurch b oiled sand . In these tests, the simple shear conditions were reproduced in order to apply realistic stress conditions that soil s experience in the field during horizontal seismic shaking. Several hollow cylindrical medium dense specimens ( D r = 50%) were pr epared by pluviation method, isotropically consolidated at an effective stress of 100 kPa and then cyclically sheared under undrained conditions up to 10 0% double amplitude shear strain (γ DA ) . The cyclic strength at different levels of γ DA of 7.5%, 15%, 3 0 % and 6 0%, development of extremely large post - liquefaction deformation and shear strain locali s ation properties were assessed from the analysis of the effective stress paths and stress - strain responses . To reveal possible distinctiveness, the cyclic undra ined behaviour of CHCH boiled sand was compared with that of Toyoura sand previously examined under similar testing conditionsenConference Contributions - PublishedFields of Research::40 - Engineering::4005 - Civil engineering::400502 - Civil geotechnical engineering