Rockbolting Profiles

Soil Nail Stabilisation – Putty Road, Howes Valley.
Rock Face Stabilisation – Mt Keira, Wollongong.
Stabilisation of Excavated Construction Site.

Rockbolting Profile 1:

Project:

Soil Nail Stabilisation – Putty Road, Howes Valley.

Client:

Roads and Traffic Authority.

Duration:

1 week.

Description:
Specialist Site Services were engaged by the Roads and Traffic Authority to drill and place 50 soil nails on the Putty Road within the Yengo National Park. The galvanised soil nails were 3 metres in length and consisted of plastic corrugated sheath for added corrosion protection. The lane closure and traffic control was carried out by the RTA. The drill area was around a road culvert that appeared to be failing internally creating a wash-out area on the road embankment. The area had been temporarily stabilised with cement bags years before, but this was also failing. SSS suggested the entire area be sprayed with Steel Fibre Reinforced Steel (SFRS) immediately prior to any drilling commenced.

The drilling was difficult due to the fragile nature of the rock causing most holes to immediately collapse when retracting the drill steels. The mesh installed was galvanised F81 before 200mm of 40mpa shotcrete. All drilling, grouting, meshing and shotcreting was carried out from a boomlift. The work also included a shotcrete spillway to be constructed and included a concrete energy dissipater. All works were completed within time and to the total satisfaction of the client.

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Rockbolting Profile 2:

Project:

Rock Face Stabilisation – Mt Keira, Wollongong.

Client:

Wollongong City Council.

Duration:

5 Weeks.

Description:
Specialist Site Services were awarded the tender for the stabilisation of rock face areas over hanging the scenic road on Mt Keira. A 5km section of road was closed daily to traffic from 7am to 5pm, Monday to Friday. The stabilisation work undertaken included devegetation, rock removal and scaling, grooming of batters, rockbolting, shotcreting and drainage. All vegetation was chipped and sent to the council depot for use within the shire. All excavated materials (scaling/grooming) approximately 300m³ were used in conjunction with the National Parks and Wildlife on their walking trails and to block unauthorised access trails.

The majority of scaling was carried out using a longreach excavator, 30 tonne excavator/hammer and manually from Elevated Work Platforms. Blasting mates were used on the roadway to minimise damage from scaled rock. Specialist Site Services drilled and placed over 60 rock bolts ranging from 3 metres to 6 metres at heights of 30 metres above the roadway. There was over 1000m² of coloured shotcrete sprayed. All health, safety and environmental issues were managed by Specialist Site Services to the total satisfaction of the client.

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Rockbolting Profile 3:

Project:

Stabilisation of Excavated Construction Site.

Client:

Danny Smith Professional Building.

Duration:

5 weeks.

Description:
Specialist Site Services were engaged by a local builder to stabilise a benched excavation overlooking Scenic Drive, Merewether. The geotechnical engineer specified over 100 x 3 metre thread bar rockbolts. All bolts were stressed to 20t prior to fixing a double layer of F82 mesh. All drilling was carried out from a boomlift with rotary percussive rock drills and airlegs.

Due to the position of the development, drilling was restricted to the hours between 7.30am and 3.00pm. All shotcrete was sprayed from the basket of a boomlift with the bottom lift (ground floor) requiring a wood float finish. The 2 levels above required a gun finish only. Due to the design of the development, mine subsidence requirements called for a number of vertical footings up to 4 metres high. These were all sprayed in by starting from the ground. All shotcrete sprayed was 32mpa. The project is still a work in progress with all work to the clients satisfaction.

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