17th - 18th September 2025
Other Stream Schedule
Registration and Welcome Coffee (Foyer)
Kick off No-Dig Down Under 2025 with a warm welcome! Join us for registration and a coffee to start your day right, connect with fellow attendees, and get ready for a full day.
Opening Address (Auditorium)
A welcome from ASTT Secretary Trevor Gosatti.
Trenchless Technologies for a Resilient Future: Decarbonising, Digitising, and Deploying Smarter Infrastructure (Auditorium)
As urbanisation accelerates and climate resilience becomes imperative, trenchless technologies are emerging as essential tools for modernising underground infrastructure. This talk explores a transformative approach to utility design and deployment, centered on a “Triple Mandate” to decarbonise, digitise, and deploy smarter systems. Through case studies and global best practices, we examine how digital twins, AI-driven simulations, and next-generation construction methods can dramatically reduce emissions—up to 90%—while enhancing operational efficiency, safety, and adaptability. We also spotlight the role of trenchless innovation in enabling underground electrification, supporting smart cities, and mitigating disruptions from extreme weather events and cyber threats. With policy support, workforce development, and continued R&D, trenchless technologies are poised to redefine how cities build resilient, future-ready infrastructure.
Local Authority Panel Session (Auditorium)
This panel brings together leaders from local water authorities to discuss current challenges, emerging opportunities, and the strategies shaping the future of water utilities.
How to use an incident to future proof ageing assets
As our urban environments expand, underground utilities need to accommodate the increased use and effects of severe weather events. In recent years, Auckland has been impacted by severe rain events, successive flooding, and a cyclone in 2023. The Orakei Main Sewer was constructed at the beginning of the 20th century and has a non-circular-shaped tunnel that consists of an unreinforced concrete invert and brick lining at the crown. In September 2023, part of the sewer collapsed, creating a large sinkhole at the surface and causing uncontrolled discharges of untreated sewage into the Waitematā Harbour. Preceding the incident, the amount of rain in the first nine months was 50% more than the average for an entire year. This paper discusses the climate change effects on ageing assets, lessons learnt from this incident, and how other similar assets could be maintained and their design life expanded. We will also revisit how the sewer tunnel has been constructed, what we can learn from the failure mechanisms and what options are out there to rehabilitate them before it is too late.
Optimisation of Temporary Works in Tunnelling - Key Lessons Learned over the past 15 years in New Zealand
Temporary works play a critical role in the success of tunnelling projects and can often be the deciding factor for contractors in winning or losing contracts. However, their importance is frequently underestimated by clients during project commissioning. This paper presents the author’s experience in the design of temporary works across a range of tunnelling projects in New Zealand over the past 15 years. It highlights how advances in the understanding of soil-structure interaction—particularly as it relates to temporary works—have led to significant design optimisations, driven by the integration of site observations from completed projects. Key considerations for Clients and Contractors will be discussed, including the establishment of realistic baseline conditions, the structuring of project consent requirements, the benefits of including provisional sum items for critical temporary works in tender documentation and how the integration of temporary and permanent works can result in substantial overall reduction in carbon. The paper also offers insights for Designers, emphasizing the importance of accounting for transient groundwater conditions, stress rotation and soil arching effects in shaft designs, and the influence of tensile strength and suction forces in various geological formations. Finally, it explores the application of the recently published Temporary Works Procedural Controls and their relevance to tunnelling projects.
Advancing Exit-Side HDD Operations: Improving Safety and Precision through Mechanised Torque Management
Historically, horizontal directional drilling (HDD) exit-side operations have relied on manual laborers using chain or "tong" wrenches to torque and un-torque joint connections as hole openers (reamers) and drill string components are added or removed from the tail string. This traditional approach often results in over- or under-torqued connections, operational inefficiencies, and elevated safety risks due to worker proximity to rotating joints and heavy equipment. Advancements in mechanized exit-side technology, led by innovations such as the TONGHAND® exit-side wrench, now enable these operations to be performed with precision by a single operator from within the safety of an excavator cab. This shift removes workers from danger zones, ensures connections are torqued to exact specifications at the joint itself, and significantly enhances exit-side efficiency. Over the past decade, numerous contractors across North America and other international regions have successfully deployed mechanized exit-side solutions, achieving measurable improvements in jobsite safety, productivity, and tooling longevity. This paper introduces the Australasian trenchless market to this evolved exit-side methodology. It presents case studies, field performance data, and practical deployment insights gathered from leading HDD contractors. By showcasing real-world outcomes and best practices, the paper aims to illustrate the value of mechanization in enhancing safety, precision, and project economics for trenchless pipeline construction across Australia, New Zealand, and the wider region.
Avoca Lagoon Water Trunk Main
• Enhancing water supply infrastructure. • $3.9M contract posed by deteriorating DN450 CICL assets. • Existing trunk main, on lagoon bed, increasingly difficult to access. • Early engagement required before construction with key users. • Installation of DN560 PE main strategically positioned 29m into rock bed beneath lagoon. • Pathway essential for navigating sand/sediment, enabling effective management of drill fluid and spoil through dedicated mud return lines. • DN560 PN20 poly pipe (12m welded lengths) pushed through a 400m under bore, secured to casing. How does it contribute to better outcomes for the trenchless industry? • Innovation integration of advanced technology and strategic planning. • Installation of mains relied on state-of-the-art compact HDD rigs. • Cutting-edge equipment essential for navigating complex landscapes. • Compact drill rig required precision and creativity (drill mast operated just clear of fences), highlighting logistical intricacies. • Ingenuity by constructing 100m temporary recycled material road to safeguarding against flooding. • Facilitate installation the pipe string, creatively utilised oval to maintain usability, protect infrastructure, manage poly welding and HDD string-out process. • Harmonious blends of advanced technology, environmental awareness, community consideration, and new standard for innovative trenchless methods. What did you find out? • Value of community consultation. • Community interest to protect lagoon, Bell Frogs, and lagoon water quality. • Two additional water outages were required to complete final works. • Engagement: 111 businesses/residents, 900 letterbox drops, 130 door knocks, 6 site visits. Why are your finding important to the trenchless industry? • Enhancing resilience and sustainability, uninterrupted water supply, ecosystem stability, mitigated Lagoon damage, preserved biodiversity. • Integrating technologies, environmentally conscious construction methods, compact HDD rigs, sustainable materials. Do your findings bring value to the broader community, and if so, how? • Security of water services, improving recreational areas. • New infrastructure long-term savings, minimising repairs, support development.
Beneath the Yarra - Duplicating the Hobsons Bay Main Sewer
The construction and commissioning of Melbourne Water’s Hobsons Bay Main Sewer Duplication Project was completed in October 2024. The new 670-metre siphon sewer, constructed underneath the Yarra River between Westgate Park, Port Melbourne and Scienceworks in Spotswood, now transfers 30% of Melbourne’s waste water to the Western Treatment Plant in Werribee. The duplication of the sewer main has enabled service delivery partners John Holland to commence the trenchless rehabilition of the existing 605m sewer to cater for Melbourne’s future growth and demand. This presentation will address the significant differing ground conditions at the launch and retrieval sites and along the tunnel alignment including the river crossing, that required a risk-based approach to design and construction of the new sewer tunnels and shafts. With review of the geology at the tunneling sites, we will discuss the ground improvement works required for shaft excavations and a new mined tunnel between the new and existing sewers. We will also explore the technical scope of works; tunneling and pipe-jack operation at depths of up to 27 metres under the water table, constructing shafts over critical live sewers and completing live connections into the sewer network.
Welcome Coffee and Networking (Foyer)
Start Day Two off on the right foot by connect with peers, catching up on yesterday’s highlights, and fuelling up for another day.
Latest International Trenchless Trends Panel Session
Discover what’s shaping the future of trenchless technology by joining industry experts as they discuss the latest international trends, innovative techniques, and emerging solutions that are transforming the way we plan and deliver underground projects.
Estimation and Reliability of Jacking Force Models based on Geological Conditions
This paper presents a critical review of various Jacking Force (JF) models and their reliability in predicting thrust requirements for pipe-jacking projects across different geological conditions. Despite advancements in trenchless technology, the design of jacking forces continues to rely heavily on outdated models and assumptions, often resulting in overdesign, increased equipment costs, and unnecessary use of high-strength pipes. This study aims to improve design accuracy by evaluating the suitability of commonly used international JF models through a comparative literature review with a focus on their application in clay, sand, and rock formations. The analysis revealed that for clay soils, JF Model 1 provided the most reliable and consistent results. In sandy conditions, JF Model 2 was found to be more accurate, while JF Model 3 was best suited for rock environments. These findings are essential for designers and contractors in the trenchless industry, offering a clearer framework for selecting appropriate jacking force models based on ground conditions, rather than relying on broad statistical estimates or conservative assumptions. By aligning JF model selection with geological context, practitioners can prevent overestimating jacking forces, leading to more efficient designs, reduced equipment requirements, and cost savings across the project lifespan. Beyond technical contributions, this research promotes a deeper understanding of pipe-jacking mechanisms within the industry, encouraging the adoption of evidence-based practices. Ultimately, this contributes to more sustainable and cost-effective trenchless projects, benefiting both the engineering community and broader society through improved infrastructure delivery.
SmartCover Helps Water Utilities Optimise Sewer-Collection Systems
This paper explores the integration of real-time, satellite connected remote monitoring technology in sewer collection systems to address growing challenges such as capacity constraints, inflow and infiltration (I&I), hydrogen sulfide (H₂S) corrosion, fats, oils, and grease (FOG) blockages, and climate-induced storm impacts. With aging infrastructure and increasing environmental regulations, water utilities are turning to smart sewer technology to proactively manage risks and improve operational efficiency. Smart Cover case studies include real-world deployments of the ultrasonic monitors mounted under maintenance hole covers, transmitting continuous data on flow levels and gas concentrations to a secure online dashboard and mobile app. These systems deliver real-time alerts, integrate with SCADA (Supervisory Control and Data Acquisition), and support CMOM (Capacity, Management, Operations, and Maintenance) programs by identifying emerging issues—such as overflows, backups, and over-cleaning—before they escalate. Findings show that users of this technology gain 24/7 visibility of site conditions, enabling earlier, targeted interventions that reduce maintenance costs and prevent environmental incidents. Monthly Smart Insights reports summarise system performance, identify high-risk areas, and track progress against previous periods, providing actionable insights for both immediate operations and long-term planning. For the trenchless industry, this technology enhances asset longevity by reducing the frequency of emergency excavations, informing trenchless rehabilitation prioritisation, and improving data-driven decision-making. It shifts the approach from reactive to proactive, supporting sustainable management of underground infrastructure. The broader community benefits from fewer sewer overflows, lower greenhouse gas emissions, reduced disruption from emergency repairs, and improved regulatory compliance—delivering both environmental protection and operational resilience.
Value of a PDB versus a traditional DBB style delivery model for rehabilitation civil projects
In the civil construction industry, the choice between a Progressive Design-Build (PDB) contract and a Traditional Design-Bid-Build (DBB) contract can significantly impact project outcomes. This paper will explore two sewer rehabilitation project case studies in the Pacific Northwest for King County: a traditional DBB style contract (Interbay Conveyance Rehabilitation and Odour Control project - comprising a twin DN1200 forcemain via CIPP and a DN2400 gravity sewer via geopolymer for a collective length of approximately 1.5km) and a PDB style contract (Eastside Interceptor Section 8 rehabilitation project – comprising a DN2400/DN2300 gravity sewer tunnel via sliplining for a length of approximately 1.7km). The paper will share various perspectives drawing on Client, Contractor and Consultant experience and learnings. A PDB contract integrates design and construction, fostering collaboration among the owner, designer, and contractor from the start. This allows for real-time adjustments, cost estimations, and value engineering, enhancing efficiency and reducing risks. Early contractor involvement ensures constructability reviews and feasibility assessments, leading to innovative solutions and optimised designs. This collaborative environment often results in faster project delivery as design and construction activities can overlap. Conversely, a DBB contract follows a linear process where design is completed before construction begins, potentially leading to discrepancies and longer timelines. While DBB contracts offer clear responsibility delineation and competitive bidding, they can result in unforeseen challenges and cost overruns due to the lack of contractor input during design. PDB contracts are ideal for complex projects requiring adaptive solutions, while DBB contracts suit well-defined, less complex projects. The choice depends on project specifics, including complexity, timeline, and risk tolerance.
How additional geophysical methods have advanced in a stronger geotechnical baseline report to significantly increase ground condition certainty while working in Melbourne’s Dandenong Ranges
At Yarra Valley Water (YVW), the Community Sewerage Program (CSP) provides properties in Melbourne with new access to sewerage infrastructure. These areas are existing (brownfield) neighbourhoods, and several challenges are present being the last essential service to be delivered. Melbourne's Dandenong Ranges specifically presents challenges which are characterised by steep undulating terrains. The use of trenchless technology proves highly effective, although contractors often encounter highly variable and unpredictable ground conditions. While trenchless technology allows YVW to deliver these projects successfully, there is a high level of risk. To navigate this risk, CSP have previously developed an approach of providing contractors with a Geotechnical Baseline Report (GBR). The benefits have previously been showcased to the industry at No Dig Down Under 2023 titled "How geotechnical baseline reports and geophysical methods resulted in greater ground condition certainty while working in Melbourne’s Dandenong Ranges." This submission now advances on the previous methodology and adopts additional geophysical techniques to strengthen the GBR, and ultimately further reduce ground condition uncertainty. Results indicate that with the combination of Ground Penetrating Radar (GPR) and Electrical Resistivity Imaging (ERI) studies, along with traditional bore sampling, classified heat maps can accurately represent expected ground conditions, thereby reducing uncertainty and risks for the Project. CSP’s Delivery Panel contractor, Melbourne Pipelines, have started works utilising this new GBR and have been recording encountered conditions to verify that the approach greatly reduces ground uncertainty. The GBR now provides the contractor with the ability to mitigate risks due to unforeseen ground conditions.
Precision and Safety in Microtunnelling: Automating Control Measurements
This paper examines the challenges of automating control measurements in microtunnelling and presents an innovative approach to improving the performance of gyro-based navigation systems in small-diameter and restricted-access pipeline applications. As cities grow and urban density increases, project owners and contractors seek solutions to navigate around assets and obstacles rather than relying on shorter, straight alignments. Our trenchless industry must meet the demand for longer and curved drives through advances that contribute to better outcomes for all stakeholders. Precise alignment control remains a challenge, particularly in projects where manual calibration of gyro navigation systems is difficult or not feasible due to access restrictions. Traditional calibration requires a pause in production so a Surveyor may perform manual measurements with a Total Station. This process is time-consuming, physically demanding, and requires clear access throughout the tunnel. Where personnel access within the tunnel is not possible, alternative solutions are required to ensure navigation accuracy without compromising efficiency. An automated control measurement system has been developed that establishes a geometric link between fixed reference points in the launch shaft and the tunnelling machine. A key innovation is the integration of compact, high-precision camera-based sensors that replace conventional Total Stations and glass prisms. These sensors track LED light points, enabling continuous position determination and calibration with minimal disruption to operations. This paper is important to our trenchless industry by supporting key metrics in challenging tunnelling environments, particularly for pipe diameters below 1200 mm: enhance performance, reduce time and costs, and improve personnel safety. Practical case studies illustrate how this system enables improved tunnel alignment planning, supports greater project efficiency, and contributes to the advancement of digital navigation solutions in microtunnelling. By meeting the demand for long-distance and curved drives we collectively bring value to the broader community by minimising launch sites for tunnelling machines, fewer manholes and reduced personnel entry, while maintaining overall production.
Behaviour of internal replacement pipe systems under vehicular traffic loads
A presentation from Shanika Kiriella from the University of Southern Queensland about how internal replacement pipe systems perform under real-world traffic conditions.