Soleares Avenue, Christchurch

120m long, 8m high failed rock cutting after the Sept 2011 earthquake. Rock Control was engaged by the delivery team to install 275no double corrosion protected RB32 ground anchors. Anchors were pre grouted off site to BS EN 1537 standards. 120mm diameter holes to a depth of 7m were drilled in a 2m x 2m grid pattern. 90% proof testing was successfully conducted along with 6 sacrificial verification anchors. The face is protected from further spalling with 850m² of Geobrugg Tecco-Mesh. The 5no 600mm diameter rock socket piles were also installed by Rock Control.

Roberts Point Bridge, Franz Joseph

This project required the construction of a 120m swing bridge at Roberts Point on the remote west coast - all plant and materials were flown in by helicopter. 4no rock anchors were drilled at each end of the bridge 6m into competent rock through varying overburden using a lightweight mast and frame with hydraulic powerpack. Anchors are RB32 bar with double corrosion protection. 4no cables were installed to support a 300mm timber deck. All construction work was carried out using rope access techniques.

Galilee Lane, Christchurch

Remedial work to a 13 metre high failed crib wall. Rock Control installed 55no Dywidag and 105no RB25 anchors through extremely challenging non-engineered fill using a fully cased system. All anchors required an isolated free length, double corrosion protection and 90% proof testing to BS EN 1537. Temporary works to provide a working platform for the upper anchors and protection of the excavation face was also provided. The wall was finished with the application of a mesh reinforced, 200mm thick shotcrete facing with a dry stipple finish and etched lines to match surrounding precast elements.  

Rossmore Terrace, Christchurch

This project required a staged, hit-and-miss construction sequence to avoid destabilising the bank behind – the project was carried out during the winter months. The wall was removed in five metre sections and soil anchors were installed followed by placement of drainage and mesh reinforcing and shotcrete application. This full sequence was carried out each day to avoid leaving sections of the bank exposed overnight. Soil anchors were installed in a 150mm hole through varying strata that required the use of both DTH and drag bits to complete. Anchors were RB32 with double corrosion protection and 10% proof testing. The 24m³ outer wall was poured in situ against the shotcrete wall using a proprietary formwork system. The affected by pavement and footpath was reinstated upon completion of construction.

Clifton Terrace, Christchurch

Rock Control was engaged to carry out all physical works on this SCIRT project. Significant earthworks were required to provide an access track for drilling adjacent to a narrow section of live carriageway. Rock Control fabricated and installed over 150no soil nails between 6 and 9m length. A high level of quality assurance was carried out to stringent British Standards including installation and testing of 3no sacrificial anchors, full grout sampling sand testing and 90% anchor accetance testing. Rock Control also supplied and installed weepholes and drainage before installing a mesh-reinforced, 250mm thick shotcrete facing to complete the retaining structure.

Dyers Pass, Christchurch

This project required the innovation of new methods to allow drilling of anchors through an existing gabion basket wall. This was achieved by installing a permanent casing through the basket and drilling with a mechanically expanding drill bit on our 4m TEI excavator attachment mast. All drilling was undertaken from above the wall in a narrow dead lane on Dyers Pass. A scaffold platform was erected along the length of the job to allow face access for rod changes and installation of a heavy steel whaler. A total of 120no, 10.5m length anchors were installed with double corrosion protection and testing to BS EN 1537 including 100% proof testing. 

Te  Rongo Road, Whangarei

Acting as head contractor, Rock Control carried out this project during the winter months in Northland in 2015. Works were undertaken to repair a slumped section of the road. Earthworks to remove 330m³ of clay were carried out on a steep bank above a stream to provide a benched face for the construction of a 4.5m high gabion basket retaining wall. 18no rock bolts were installed through stiff clay and embedded 3m into Greywacke rock to tie back the gabion basket wall. A lane closure was in place for the duration of works, this was controlled using temporary traffic signals. Rope access and fall arrest systems were used to mitigate the risk of falls while placing fill and attaching end hardware. All project plans, reports and as-built drawings were submitted on time and to the satisfaction of the client.

Glenstrae Road, Christchurch

The Glenstrae Road earthquake remedial work was completed as part of the SCIRT/delivery team model with Rock Control and our civil construction partner, CMS, undertaking all physical works on the project. A range of construction elements were installed on the steep rock wall to prevent further rockfall and allow reopening of the footpath. 60no rock bolts were installed using rope access systems on the face below, a further 25no anchors were installed using our SM-5 crawler to provide the foundation for a CIP retaining wall. The curved wall was cast using a large prefabricated plywood form, with finished shotcrete terminations and a steel handrail in line with SD621. 

Whaka Terrace, Christchurch

This SCIRT project was undertaken by McConnell Dowell with Rock Control and our civil construction partner, CMS, carrying out all physical works. A 4m high gabion basket wall was installed with a stepped foundation pad and tie-back soil nails. Rock Control also provided a preliminary temporary works design for a shotcrete wall to protect the cut face using the permanent anchor system. The design was accepted and developed for use on the project, resulting in significant savings in both time and cost. You can read more about this in our 'Shotcrete in Christchurch' article under downloads. CMS installed a fully formed foundation pad, several CIP cantilever walls and a fabricated steel handrail with mesh infill to match the existing. Minor reinstatement was also undertaken to repair the road surface and install a new footpath. 

Makakaho Road, Taranaki

This head contract project was carried out by Rock Control to stabilise and reduce erosion on the abutments of a small bridge. 25no ground anchors were installed through soil and into competent rock, a mesh reinforced shotcrete wall was sprayed on one side and concrete foundation beams were installed on both abutments. All face access was carried out by rope access. Rock Control won the project based on our strong environmental record and were able to gain resource consent to carry out the urgent project during winter by installing robust controls including cut-off drains and a submerged silt fence system to isolate part of the stream during drilling and excavation works.