The following publications are works either authored by our staff or, in some cases, co-authored with people from outside the company.This selection of conference papers and journal articles can be accessed by requesting individual items from our Tonkin + Taylor Ltd Library (library@tonkintaylor.co.nz) or by clicking on the button beside the item. There is no charge for this service. However, please note that our Library follows Library Association (LIANZA) guidelines (link to their guidelines here) and reserves the right not to supply any item if these conditions are not met.
Geotechnical Monitoring and Management of TBM (EPB) Tunnelling Induced Settlement: The case of Waterview Connection Project Tunnel
This paper presents measurements of tunnelling induced settlements collected during the
construction of the Waterview Connection project. The NZ Transport Agency’s Waterview Connection
project involves the construction of 5 km of motorway to complete Auckland’s Western Ring Route.
Half of this new link includes twin 14.5 m diameter mainline tunnels constructed by Earth Pressure
Balance (EPB) Tunnel Boring Machine with 16 sequentially excavated cross-passages. Over most of
the tunnelled length the excavation is through extremely weak to weak interbedded sandstones and
siltstones of the East Coast Bays Formation (ECBF) overlain by weathered ECBF and alluvium.
However, tunnelling was also undertaken through stronger, volcanoclastic sandstone, and, through
alluvial soils at low cover. In the following paper the instrumentation methodology, monitoring regime
and analysed results are presented. The attention is given mainly to the monitoring data recorded
under free field conditions during and after the construction of the mainline tunnels. Settlement
readings are back-analysed using the classical Gaussian empirical predictions, in traverse arrays, and
at particular sections in longitudinal direction, providing a detailed description of the EPB tunnelling
performance under varied geotechnical conditions. The use of TBM calibration zones in selected
green field sites and how that data helped optimize TBM performance in relation to ground effects, is
discussed. Finally the influence of different parameters, such as tunnel depth, overlying geological
layers and tunnel face pressure, to the induced settlement, estimated ground loss and the shape of
settlement trough is investigated.
Fissure grouting and rock defect characterisation for the Waterview cross passage tunnels
The NZ Transport Agency’s Waterview Connection project in Auckland, New Zealand
involved the construction of a new 5km long, three lane motorway with twin, 2.4km long, three lane
tunnels up to 35m deep beneath urban Auckland. Pre-excavation fissure grouting was undertaken to
limit the inflow of groundwater into a number of the cross passage tunnel excavations. Investigation
and characterisation of rock mass defects at each cross passage ensured that fissure grouting was
only undertaken at cross passages to be excavated through highly permeable rock. This paper
outlines the geology of the tunnel alignment, the investigations carried out to characterise the rock
mass defects and the process followed to identify ‘at risk’ cross passages to be grouted. The grout mix
design and the grouting methodology are also discussed. Results and observations from the preexcavation
fissure grouting operation are presented and conclusions drawn as to the suitability of this
technique for the local ground conditions.
Liquefaction vulnerability increase at North New Brighton due to subsidence, sea level rise and reduction in thickness of the non-liquefying layer
The Canterbury Earthquake Sequence (CES) of 2010 - 2011 caused widespread liquefaction related land damage to the city of Christchurch. This paper addresses the impact the CES had on the eastern Christchurch suburb of North New Brighton with emphasis on the ground condition at the time of the initial 4 September 2010 earthquake, as well as subsidence caused by the CES, and the future potential for increased liquefaction vulnerability due to Sea Level Rise (SLR).
Subsidence at North New Brighton accumulated throughout the CES due to a reduction in volume of the soil profile through liquefaction; and overall settlement due to regional tectonic subsidence. The total amount of subsidence caused by the CES at North New Brighton was a much as 1 m in some places and this has changed the relationship between the position of the ground surface and the top of the groundwater table. A reduction in the thickness of the non-liquefying layer has been shown to increase the vulnerability of the soil profile to liquefaction related land damage during earthquake events. As a coastal suburb, North New Brighton is vulnerable to the impact of SLR and this paper considers the response of the groundwater table to rising sea level and the influence this will have on the thickness of the non-liquefying layer and liquefaction vulnerability.
Waterview Connection Tunnels: Engineering Geology Assessment of East Coast Bays Formation from Investigation through to Construction
The NZ Transport Agency’s Waterview Connection project in Auckland, New Zealand
involved the construction of a new 5km long, three lane motorway with twin, 2.4km long, three lane
tunnels up to 35m deep beneath urban Auckland. The mainline tunnels were constructed using a 14.5m
diameter Tunnel Boring Machine (TBM). Sixteen cross-passages up to 12m in length with diameters
ranging from 6m to 8.5m were constructed using the Sequential Excavation Method (SEM) between the
two mainline tunnels. Tunnelling was undertaken in ground typical of the East Coast Bays Formation
and comprised extremely weak to weak interbedded sandstone and siltstone varying in degrees of
cementation from uncemented (grain-locked) sands to well-cemented siltstones and coarse-grained
volcaniclastic sandstones of the Parnell Grit Member. The Project was subject to detailed investigations
from concept design through to TBM and SEM tunnelling, with particular attention given to intact rock
characteristics, rock structure, groundwater and ground behaviour. The ground was mapped, RMR
recorded and the rock mass classified according to GSI during each TBM maintenance intervention and
SEM tunnelling advance. This paper summarises the results of these engineering geology assessments
and discusses the ground conditions prevalent when localised over excavation or convergence was
observed.
Transforming Victoria Street : working together to tackle utility design (1)
The Victoria Street Transformation Project has provided Wellington with a tree lined boulevard, enhancing the pedestrian experience with wider footpaths and parks. This has facilitated and encouraged development within the area as well as improved traffic and cycling flows.
The project had a short timeframe from its announcement in September 2014 to its completion by 30
June 2015. In order to achieve these optimistic timeframes, the project was delivered by the
already established and successful Memorial Park Alliance (the Alliance).
The challenge for wet services was to remove, replace and add new components to the water supply,
stormwater and wastewater networks in a busy part of Wellington where these services were critical
to the wider city network. The urban complexity meant that design and construction issues were
inevitable and could only be discovered and solved once the ground was opened up. Further
complications included the need to move services before other elements of the design were complete,
the quantity of services underground, and the need to keep Victoria Street and Vivian Street (State
Highway 1) open at all times.
The Alliance delivery model allowed for close collaboration between the design and construction
teams and the owner, Wellington City Council (WCC). This enabled swift decision making which was
essential to the successful completion of the project. This collaborative approach resulted in
innovative and time-efficient solutions, which had a significant contribution to the project being
completed on time.
Golden Cross Landslide - effects of stabilisation works 17 years later
Catchment Level Modeling of Green Roofs using InfoWorks CS (1)
Green roofs are vegetation installed on top of buildings to provide flow control by attenuation, storage and losses due to evapotranspiration. A green roof consists of several-layered materials to achieve the desired vegetative cover and drainage characteristics. An attempt has been made to use the different runoff and infiltration models available in the widely used hydraulic modeling software - InfoWorks CS to model runoff from green roofs during storm events and over a longer continuous simulation period. The most suitable model was then applied to test the benefits across 03 catchments in InfoWorks CS considering a range of percentage uptake of green roofs within the catchments. The benefits of green roofs implemented on a catchment level are assessed in terms of Combined Sewer Overflows (CSO) performances.
Seismic assessment and life extension for the Mahinerangi Dam
The Mahinerangi dam – arguably the most valuable in Trustpower’s portfolio of 47 large dams – is
over 80 years old and needs a plan of work to confirm it meets current design standards.
The dam was completed in 1931, subsequently raised in 1944-1946, and strengthened with steel tendon anchors in 1961.
A comprehensive safety review (CSR) in 2007 noted a potential deficiency in the fully grouted
anchors and a program of work commenced to re-evaluate the overall stability of the dam.
A potential failure mode assessment revealed that the dam may need upgrading to meet the criteria
for maximum design earthquake (MDE). Areas of uncertainty were identified and a significant
programme of survey, geological mapping, concrete testing and site specific seismic assessments
have been carried out to reduce risk and uncertainty in design.
The paper discusses the dam’s history, current condition, and describes the ongoing programme of
work planned to extend the life of the dam for another 80+ years.
Onehunga foreshore restoration project
Pipeline damage predictions in liquefaction zones using LSN (2)
Liquefaction is a major concern regarding earthquake damage to infrastructure. Recent earthquakes in New Zealand and resulting liquefaction caused significant damage to buried pipeline systems. Following the 4 September 2010 Mw=7.1 Darfield earthquake, five earthquakes (22 February 2011, Mw=6.2, 13 June 2011, Mw=5.3 at 1 p.m. and Mw=6.0 at 2:20 p.m. and 23 December 2011, Mw=5.8 at 1:58 p.m. and Mw=5.9 at 3:18 p.m.) and thousands of aftershocks have been recorded in the area of Christchurch, NZ. These earthquakes termed the Canterbury Earthquake Sequence (CES) are unprecedented in terms of repeated earthquake shocks with substantial levels of ground motion affecting a major city with modern infrastructure. This study focuses on the effects of 22 February 2011 Christchurch earthquake induced liquefaction on buried pipelines. Correlations were developed between pipe damage, expressed as repairs/km, and a recently developed parameter called liquefaction severity number (LSN). Cone Penetration Test (CPT) based liquefaction triggering procedures were used to calculate LSN values. Studies by Tonkin and Taylor [1,2] and van Ballegooy et al. [3, 4, 5, 6] have shown that LSN provides a good correlation with land and esidential house foundation damage observations recorded in Canterbury. According to results obtained in this study for buried pipelines, LSN has reasonably good correlation with asbestos cement (AC), cast iron (CI) and polyvinyl chloride (PVC) pipeline damage
Considering post disaster damage to residential building construction - is our modern building construction resilient?
The 2010-2011 Canterbury Earthquake Sequence (CES) brought into stark relief the disconnection between building practice and natural hazard susceptibility. Despite the knowledge that most of the residential land in eastern Canterbury was susceptible to liquefaction, and possibly prone to flooding and tsunami hazards, brittle, heavy, unreinforced slab-on-grade residential house construction has predominated, particularly over the past 20 years. It is remarkable that the very same housing construction policies and methods that aggravated damage and recovery in New Orleans following Hurricane Katrina would reappear in Christchurch little more than 5 years later. This paper examines the lessons learnt from the CES and presents a case for a consideration in how we build our homes to be affordable, resilient and more readily repairable, by better matching construction styles to the hazard.
A new approach for assessing seismic performance of structures - a geotechnical perspective
Request Document
This document "" is copyright therefore we are required to ask for your name and we will email the document to you.