Geotechnical Investigations and Sheet Pile Wall Design for Slipway, Jetty, and Access Stairs – Mona Vale, NSW

20 June 2025

LOCAL: NORTHERN BEACHES – MONA VALE NSW 2105

DATE: NOV 2024 TO JUN 2025

A construction site with a house in the background.
A building is being built next to a body of water.

Project Title

Geotechnical Investigations and Sheet Pile Wall Design for Slipway, Jetty, and Access Stairs – Mona Vale, NSW



Project Description:

This project involved detailed geotechnical investigations and the design input for a sheet piling wall system associated with the construction of a slipway, jetty, and access stairs in Mona Vale, New South Wales. The site is located in a coastal and marine-influenced environment, requiring careful consideration of groundwater conditions, tidal impacts, and soil erosion risks.


The geotechnical scope included borehole drilling, in-situ testing, groundwater monitoring, and laboratory analysis to characterise subsurface conditions, assess soil strength parameters, and inform the structural design of the proposed waterfront infrastructure. Special attention was given to the variability of marine and estuarine sediments, as well as the stability of the shoreline.


Based on the geotechnical data, recommendations were provided for the installation of a steel sheet pile wall system to support excavation and prevent soil displacement during construction. The wall design was developed to resist lateral earth pressures, accommodate tidal fluctuations, and provide long-term durability in a saline environment.


Scope of Services Included:

  • Geotechnical site investigation (boreholes, soil sampling, groundwater observation)
  • Soil profiling and assessment of coastal/marine geotechnical conditions
  • Engineering recommendations for sheet pile wall design and installation
  • Assessment of slope stability and foundation conditions for the slipway, jetty, and stairs
  • Advice on construction methodology and temporary works requirements
  • Compliance with Australian Standards and local council regulations


This project highlights Soilsrock Engineering’s expertise in delivering geotechnical solutions for challenging coastal and marine environments, supporting the successful design and construction of public infrastructure in sensitive shoreline settings.

A large hole in the ground with a fence around it.

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