REMEDIATION WORK

Engineering, Construction and Mine Surveyors

Spatial Data Services are proud to be supporting the $100m Waka Kotahi Far North state highway resilience programme to repair the 15 significant slips along SH1 at Mangamuka Gorge .

The situation

State Highway 1 (SH 1) stands as the New Zealand road network's longest and most significant thoroughfare, spanning the length of both main islands. A robust and dependable roading network is crucial for preserving connections among whānau, friends, businesses, and communities. This significance becomes even more pronounced in the Far North region, where many residents reside in rural areas and rely on state highways for safe travel.

In August 2022, SH1 through Mangamuka Gorge Scenic Reserve faced its second closure within two years due to extensive slip damage caused by severe weather conditions.

Repair work has commenced to address the consequences of the August 2022 event, focusing on 15 significant slips. As part of the restoration efforts, our objective is to enhance the ground's stability and minimize the susceptibility to future slips by improving drainage systems within the gorge. These enhancements will equip the area to better cope with the increasing severity and frequency of weather events.

Waka Kotahi's goal is to reopen the road and restore full operational capacity by May 2024.

The Mangamuka Gorge faces a long-term resilience challenge, attributable to both the impacts of climate change, which contribute to more frequent and severe weather events nationwide, and the delicate geology of the Maungataniwha Ranges. It is essential to address these issues to ensure the sustained reliability and functionality of this critical transportation corridor.

Mangamuka Gorge - Underslip

Mangamuka Gorge - Overslip

Mangamuka Gorge Slips and Remediation Project

Collecting Satellite data to coordinate site control.

Accurate coordination by surveyors prior to construction is essential for minimizing risks, ensuring compliance, optimizing design, and facilitating a smooth construction process. Our expertise in data collection, measurement, mapping, and alignment significantly contributes to the success of the project from its earliest stages through to completion.

Safety and Innovation

Surveying a small excavation with an iPhone 14

The image to the left isn't a photo. It's actually a LiDAR scan of a small excavation.

This site was deemed unsafe for physical entry due to its depth of approximately 3 meters and the slippery edges.

Traditional surveying methods were considered unsafe and inefficient for this particular area. To address this, the available equipment, along with drone survey techniques, were utilized to survey the site.

A few Ground Control Points (GCPs) were marked at the top of the excavation and surveyed to obtain coordinates and RLs (Reduced Levels) based on the project control.

The iPhone's LiDAR capabilities were then employed to capture the site, along with the Ground Control Points (GCPs).

Upon returning to the office, a 3D transformation was performed on the LiDAR GCP positions to align them accurately with their surveyed project control positions. The calculated transformation parameters were then applied to the entire excavation LiDAR dataset; which resulted in the entire excavation LiDAR dataset being correctly coordinated.

Monitoring - temporary works

Deformation monitoring of temporary retaining structures is crucial for safety due to the following reasons:

Structural Integrity: Temporary retaining structures are typically erected to provide temporary support and stability during construction or excavation activities. Monitoring their deformation helps ensure that the structure remains intact and does not exhibit excessive movement or deformation that could compromise its stability. Early detection of deformation allows for timely corrective actions to be taken to maintain structural integrity.
Risk of Failure: Temporary retaining structures often operate in challenging and dynamic environments, such as slopes, excavations, or areas prone to ground movement. These conditions increase the risk of potential failures, including slope instability, wall collapse, or sliding. Deformation monitoring provides valuable data to assess and mitigate these risks, allowing for proactive measures to prevent catastrophic failures that could harm workers or the surrounding environment.
Worker Safety: Construction sites with temporary retaining structures are typically active areas with workers present. Monitoring deformation helps identify any signs of structural distress or movement that could pose a hazard to workers. By promptly detecting such issues, appropriate safety measures can be implemented, such as restricting access to hazardous areas, reinforcing the structure, or relocating workers to safer locations.
Adjacent Structures: Temporary retaining structures are often installed in close proximity to existing structures, such as buildings, roads, or utilities. Excessive deformation in the temporary structure could induce stress or displacement in adjacent structures, potentially leading to damage or compromising their stability. By monitoring deformation, any potential impact on neighboring structures can be assessed and appropriate measures can be taken to protect them.
Environmental Considerations: Deformation monitoring is crucial for assessing the impact of temporary retaining structures on the environment. Excessive movement or deformation can lead to soil erosion, sedimentation, or changes in groundwater flow, which may have adverse effects on ecosystems, water bodies, or natural resources. By monitoring deformation, potential environmental risks can be identified and mitigated to ensure the preservation of the surrounding environment.

Overall, deformation monitoring of temporary retaining structures is essential for ensuring the safety of workers, nearby structures, and the environment. It allows for early detection of structural issues, proactive risk mitigation, and timely interventions to maintain stability and prevent accidents or failures that could have severe consequences.

A Slip repair method

Digital Engineering

The Mangamuka Gorge slip demanded immediate repair measures prior to permanent repairs.

To facilitate the construction phase, the site surveyor must perform a Spatial Analysis, using digital engineering techniques,. Firstly existing infrastructure and works completed during the immediate repair measures must be precisely located and overlaid on accurate up to date orthophotos; created from drone surveys.

Hard copy engineering plans (schematic designs ) are then used to create 3D temporary and permanent works models. During creation of these models the digital engineer must use his/her experience to identify issues affecting that design and liaise with the site engineer. The site engineer will raise an RFI with the designer seeking clarification and/or guidance.

This digital model encompasses the existing services, emergency repair works, and new temporary and permanent design elements. Having this model and a collaborative approach allows for a thorough spatial examination of all elements and helps to prevent delays.

To ensure constructability we perform a spatial analysis utilize the physical dimensions of machinery to ensure that the equipment can access the specific work areas while maintaining safe distances from surrounding structures. Our approach involves careful consideration of clearances to ensure that the machines remain outside of any potential obstructions or obstacles.

In addition to addressing access challenges, we also specialize in designing temporary works that provide necessary support to the machinery during its operations. These temporary structures are designed to ensure stability, functionality, and safety, allowing the machinery to efficiently perform its intended tasks.

To further enhance safety and efficiency, we employ sweep path analysis techniques. This analysis enables us to assess and advise engineers regarding the movement of other vehicles and equipment in proximity to the temporary work area. By identifying potential "pinch points" or areas of potential conflict, we can ensure that the required space is wide enough to accommodate the passing vehicles and equipment, minimizing any potential risks.

Our comprehensive approach combining physical dimensions assessment, temporary works design, and sweep path analysis allows us to optimize the efficiency and safety of machinery operations within work areas. By prioritizing precision and safety, we provide valuable insights and solutions to support successful project execution.

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