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Images, UC QuakeStudies

Damage to River Road in Richmond. The road is badly cracked and buckled, and is partly blocked off with road cones and warning tape. In the background is a truck carrying more road cones and signs. The photographer comments, "Major slumps and cracks along River Rd. Near 381 River Rd, looking towards the Banks Ave - Dallington Terrace corner".

Images, UC QuakeStudies

A pile of liquefaction silt on Medway Street is cordoned off with road cones. The photographer comments, "Piles of sand and subsiding roads at the intersection of Medway St with Woodchester Ave and Flesher Ave, 10 days after the February quake".

Images, UC QuakeStudies

A car drives across the damaged Dallington bridge. The bridge has visibly moved relative to the road, leaving a large gap, which road cones have been placed in. The photographer comments, "Service pipes snapped as the land sank but the bridge remained".

Images, UC QuakeStudies

Damage to Medway Street in Richmond. The road surface is cracked and buckled, and covered in liquefaction silt. A temporary road sign restricting speed to 30 is visible, with road cones behind. The photographer comments, "Medway St, Woodchester Ave on right just beyond the 30 sign".

Images, UC QuakeStudies

A car drives across the damaged Dallington bridge. The bridge has visibly moved relative to the road, leaving a large gap, which road cones have been placed in. The photographer comments, "Service pipes snapped as the land sank but the bridge remained".

Images, UC QuakeStudies

A fence, road cones and a no entry sign block off part of the road at the intersection of North Parade and Banks Avenue in Richmond. A spray-painted sign on the fence reads "No thru traffic. Residents only." The photographer comments, "The entry to Banks Avenue from North Parade".

Images, UC QuakeStudies

Damage to Medway Street in Richmond. The road surface is cracked and buckled, and covered in liquefaction silt. A temporary road sign restricting speed to 30 is visible, with road cones behind. The photographer comments, "Medway St, between Woodchester Ave and River Rd. Woodchester Ave on right just beyond the 30 sign".

Images, UC QuakeStudies

A power pole on the corner of Medway Street and Woodchester Avenue is on a lean, standing in a puddle of water and liquefaction silt. In the foreground road cones surround a pile of silt. The photographer comments, "Intersection of Medway St with Woodchester Ave and Flesher Ave, 10 days after the February quake".

Images, UC QuakeStudies

Damage to River Road in Richmond. The road is badly cracked and has slumped towards the river. Road cones and warning tape block off the road to vehicles. The photographer comments, "The end of River Rd, at the corner of Banks Ave-McBratneys Rd-Dallington Tce. Morons in 4WDs kept wanting to drive through here".

Images, eqnz.chch.2010

The earthquake re-pair work has started on the Knox Church on Bealey Avenue, August 14, 2013 Christchurch New Zealand. While building after building is torn down in Christchurch, plans are in place to ensure as much of a 131-year-old church is retained as possible. Knox Church on Bealey Avenue suffered major damage in the February 22 earthquak...

Images, UC QuakeStudies

Damage to River Road in Richmond. The road surface is badly cracked and slumped, and liquefaction silt covers part of the road. Two people in gumboots walk towards a barrier erected across the road using road cones and warning tape, and in the background the badly twisted Medway Street bridge can be seen. The photographer comments, "Longitudinal cracks indicate lateral movement as the land sagged towards the river. Near 373 River Rd, looking south-east towards Medway St. The Medway St bridge is visible in the background".

Images, UC QuakeStudies

Damage to River Road in Richmond. The road is badly cracked and slumped, and is closed off with a row of road cones tied with warning tape. The word "closed" has been spray painted on the road surface. The photographer comments, "These photos show our old house in River Rd and recovery work around Richmond and St Albans. River Rd was again subject to severe lateral spreading. The river is still grey with silt, the road is ripped and sunken, and power poles lean at random angles. The red car belonged to a postie, who had to come back with a tow truck to extricate the car from the hole that had opened underneath it. Looking along River Road to the north-east. Taken outside 79 Medway St".

Research papers, University of Canterbury Library

Well-validated liquefaction constitutive models are increasingly important as non-linear time history analyses become relatively more common in industry for key projects. Previous validation efforts of PM4Sand, a plasticity model specifically for liquefaction, have generally focused on centrifuge tests; however, pore pressure transducers installed at several free-field sites during the Canterbury Earthquake Sequence (CES) in Christchurch, New Zealand provide a relatively unique dataset to validate against. This study presents effective stress site response analyses performed in the finite difference software FLAC to examine the capability of PM4Sand to capture the generation of excess pore pressures during earthquakes. The characterization of the subsurface is primarily based on extensive cone penetration tests (CPT) carried out in Christchurch. Correlations based on penetration resistances are used to estimate soil parameters, such as relative density and shear wave velocity, which affect liquefaction behaviour. The resulting free-field FLAC model is used to estimate time histories of excess pore pressure, which are compared with records during several earthquakes in the CES to assess the suitability of PM4Sand.

Research papers, University of Canterbury Library

Semi-empirical models based on in-situ geotechnical tests have become the standard of practice for predicting soil liquefaction. Since the inception of the “simplified” cyclic-stress model in 1971, variants based on various in-situ tests have been developed, including the Cone Penetration Test (CPT). More recently, prediction models based soley on remotely-sensed data were developed. Similar to systems that provide automated content on earthquake impacts, these “geospatial” models aim to predict liquefaction for rapid response and loss estimation using readily-available data. This data includes (i) common ground-motion intensity measures (e.g., PGA), which can either be provided in near-real-time following an earthquake, or predicted for a future event; and (ii) geospatial parameters derived from digital elevation models, which are used to infer characteristics of the subsurface relevent to liquefaction. However, the predictive capabilities of geospatial and geotechnical models have not been directly compared, which could elucidate techniques for improving the geospatial models, and which would provide a baseline for measuring improvements. Accordingly, this study assesses the realtive efficacy of liquefaction models based on geospatial vs. CPT data using 9,908 case-studies from the 2010-2016 Canterbury earthquakes. While the top-performing models are CPT-based, the geospatial models perform relatively well given their simplicity and low cost. Although further research is needed (e.g., to improve upon the performance of current models), the findings of this study suggest that geospatial models have the potential to provide valuable first-order predictions of liquefaction occurence and consequence. Towards this end, performance assessments of geospatial vs. geotechnical models are ongoing for more than 20 additional global earthquakes.