Six ½ years after the earthquakes there are still a few demolitions taking place. This one is a block of council owned flats. Whether the whole complex is being demolished or not I don't know., but here the centre block of three is being demolished. The green grass is what was sections and houses demolished in 2012-2015 as it is too close to t...
Today was the first time I have been to the earthquake memorial since it was completed and opened on 22nd February 2017, six years after the devastating quake that killed the 185 that are named on this wall. I knew two of the people on the list.
Only two of 20 houses left in the Rawhiti Earthquake Village. This from the sign on perimeter fence: "Since 2011, Rawhiti Domain has been used to provide temporary accommodation for those affected by the Canterbury earthquakes. Over 200 households have used the 20 houses while their own homes have been repaired or rebuilt. The demand for acco...
73 months after the earthquake that damaged it, the jetty at South New Brighton Domain is still not repaired. Seven years ago it was straight and level. Dull, flat and orrible (horrible) light meant this image was destined to become monochrome!
The Canterbury Earthquake Sequence (CES) of 2010-2011 caused widespread liquefaction in many parts of Christchurch. Observations from the CES highlight some sites were liquefaction was predicted by the simplified method but did not manifest. There are a number of reasons why the simplified method may over-predict liquefaction, one of these is the dynamic interaction between soil layers within a stratified deposit. Soil layer interaction occurs through two key mechanisms; modification of the ground motion due to seismic waves passing through deep liquefied layers, and the effect of pore water seepage from an area of high excess pore water pressure to the surrounding soil. In this way, soil layer interaction can significantly alter the liquefaction behaviour and surface manifestation of soils subject to seismic loading. This research aimed to develop an understanding of how soil layer interaction, in particular ground motion modification, affects the development of excess pore water pressures and liquefaction manifestation in a soil deposit subject to seismic loading. A 1-D soil column time history Effective Stress Analysis (ESA) was conducted to give an in depth assessment of the development of pore pressures in a number of soil deposits. For this analysis, ground motions, soil profiles and model parameters were required for the ESA. Deconvolution of ground motions recorded at the surface during the CES was used to develop some acceleration time histories to input at the base of the soil-column model. An analysis of 55 sites around Christchurch, where detailed site investigations have been carried out, was then conducted to identify some simplified soil profiles and soil characteristics. From this analysis, four soil profiles representative of different levels of liquefaction manifestation were developed. These were; two thick uniform and vertically continuous sandy deposits that were representative of sites were liquefaction manifested in both the Mw 7.1 September 2010 and the Mw 6.3 February 2011 earthquakes, and two vertically discontinuous profiles with interlayered liquefiable and non-liquefiable layers representative of sites that did not manifest liquefaction in either the September 2010 or the February 2011 events. Model parameters were then developed for these four representative soil profiles through calibration of the constitutive model in element test simulations. Simulations were run for each of the four profiles subject to three levels of loading intensity. The results were analysed for the effect of soil layer interaction. These were then compared to a simplified triggering analysis for the same four profiles to determine where the simplified method was accurate in predicting soil liquefaction (for the continuous sandy deposits) and were it was less accurate (the vertically discontinuous deposits where soil layer interaction was a factor).