Horrocks Highway Corridor Upgrade


South Australian Government, Department of Infrastructure and Transport

Project Overview

$55 million dollar project to upgrade 245 kilometres of highway

The Horrocks Highway Corridor Upgrade forms part of the South Australian Rural Roads (SARR) Package, which is focussed on upgrading the 245 kilometres length of highway between Wilmington and Gawler, to improve safety, connectivity and freight efficiency, whilst importantly creating jobs.
Works include shoulder sealing, pavement rehabilitation, new overtaking lanes and overtaking lane extensions, bridge upgrades, safety barrier, Audio Tactile Line Marking (ATLM) and improvements to the Gladstone rail corridor and level crossing.

This $55 million dollar project is jointly funded (80:20) funded by the Australian and South Australian governments.

ENGEO were engaged to understand the ground conditions and assess the condition of existing road cutting to inform design of new batters to widen the road, in a section near Yacka, in South Australia’s Mid- North region.

Engeo's Role

For this project ENGEO undertook geotechnical investigation of ground conditions, slope stability assessment, and analysis in order to provide geotechnical recommendation of an angle for new soil batters, as well as rock slope stabilisation.


The main challenge was limited space to widen the road on one side, which limits options for changing the existing slope geometry.

Our solution

The solution ENGEO recommended was having appropriate batter angle for soil slopes, as well as active slope stabilization options for a rock slope.


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