Project Overview
Moore Construction delivered deep foundation piling works at Heaton Street, Christchurch, within a tightly constrained residential environment.
The project involved the installation of 45 bored piles, 750mm in diameter and extending to depths of approximately 25 metres, providing a high-capacity foundation system under challenging ground conditions.
Engineering Solution
A polymer-supported bored piling methodology was adopted to maintain bore stability and control groundwater conditions during deep excavation.
Polymer support fluid was used to stabilise the borehole walls and prevent collapse, allowing drilling to proceed safely through variable soils and groundwater conditions.
Construction Methodology
The piles were constructed using a fully controlled sequence incorporating casing, polymer drilling fluid, and tremie concrete placement.
- Installation of temporary starter casing to stabilise upper soils
- Continuous drilling using specialist bored piling equipment
- Maintenance of positive polymer fluid head to prevent collapse
- Real-time monitoring of depth, torque, and drilling performance
- Base cleaning and pre-pour quality inspection
Maintaining fluid pressure above groundwater level was critical to ensuring bore stability, preventing sudden inrush of water and potential failure of the excavation.
Tremie Concrete Placement
Piles were constructed using a tremie concrete system, allowing concrete to be placed from the base upward, displacing the polymer fluid and ensuring a continuous, defect-free pile.
- Concrete placed through tremie pipe to base of pile
- Minimum embedment maintained to prevent contamination
- Polymer fluid recovered and recycled during pouring
- Continuous monitoring of concrete levels during placement
This method ensures full pile integrity and avoids segregation or contamination, which is critical for deep bored piles.
Construction Delivery
Works were undertaken using Moore Construction’s in-house plant including a Geax EK110 drilling rig, crawler crane, and concrete pump systems, ensuring full control of quality and sequencing.
Reinforcement cages were installed in a single lift, ensuring structural continuity and meeting durability requirements for long-term performance.
Project Video
The video demonstrates the precision and control required to install deep bored piles within a constrained urban environment.
Site Challenges
- Deep piling in variable ground and groundwater conditions
- Restricted urban site and limited working space
- Maintaining bore stability at significant depths
- Strict quality control for deep foundation performance
Outcome
The project was successfully delivered with all piles constructed to specification, providing a high-capacity, reliable foundation system for the development.
This project highlights Moore Construction’s capability in delivering advanced deep foundation systems using controlled, engineered methodologies.