Nexus Toowoomba Second Range Crossing (TSRC) - Drilling Embankment 24

GeoDrill Australia was selected as the primary drilling contractor and has been engaged on the project since 2015, operating up to three rigs simultaneously. During this time GeoDrill Australia successfully completed in excess of 500 boreholes.

The overall earthworks volume for the TSRC Project is in excess of 10 million m³, which involved the excavation of 42 cuts and the construction of 40 earthwork embankments. The largest of these embankments, Embankment 24, is almost 80m in height and located near the top of the Toowoomba Range at Ballard. During construction of the TSRC, Embankment 24 experienced a complex deep-seated movement due to the re-activation of an ancient shear plane.

Works progress prior to June 2017 movement Challenge Ground monitoring systems were installed along the length of the TSRC which consisted of geotechnical instrumentation, such as inclinometers,

In June 2017, ground monitoring systems identified movement at Embankment 24. GeoDrill Australia undertook a highly detailed drilling geotechnical investigation, utilizing three rigs (GDR06 Comacchio GE05, GDR02 Hydrapower and GDR03 Hydrapower Scout). The program consisted of over 50 boreholes, up to 85m in depth in a localised area. Geotechnical and Geological experts on large scale ground movements were engaged from Australia, New Zealand and the United States to help the project team thoroughly understand the extent and mechanism of the issue.

‍