Slip Repairs and Stabilisation
Ground Structures has extensive knowledge and experience in a broad range of slip repairs and stabilisation solutions including clifftop stabilisation, environmental and geosynthetic solutions, erosion control (including reno mattress) and provides a complete service from piling, retaining walls and foundations, to drilled horizontal drains and dewatering of slopes.
We offer cost effective, single source ground retention solutions for the remediation and prevention of residential, land or coastal slips, including all site works and the capability to work in difficult access areas, in a range of geotechnical environments and challenging site conditions. We can respond quickly in the event that slip repairs require immediate attention.
Coastal clifftops can be unstable for several reasons – marine erosion at the foot of the cliff, or erosion of the slope due to geo-technical instability. There are a number of solutions to arrest and remediate movement and secure land, including palisade pile walls, anchoring, mesh and coir mat, and geosynthetic solutions.
Environmental and Geosynthetic Solutions
Synthetic products used to provide stability to the terrain where high levels of durability are required. Geosynthetic solutions are applied to a range of civil and geotechnical applications to arrest and remediate movement, and are generally polymeric products which fall into a range of categories including geotextiles, geogrids, geonets, geomembranes, geosynthetic clay liners, geofoam, geocells and geocomposites.
Geotextiles, a generally more common application, are sheets of flexible, permeable, knitted or stitch bonded fibres or yarns which are either woven or non-woven, creating the appearance of fabric. Geogrids consist of apertures which allow direct contact between soil particles on either side of the sheet. Geocells are three dimensional interconnected cells which are filled with soil and occasionally concrete.
Palisade Timber or Concrete Piles
Palisade timber or concrete piles are used in the construction of highly effective permanent piling solutions. Typically for heavy duty applications supporting substantial loads, palisade walls are also known as inground or barrier pile walls. They are often constructed with a concrete capping beam and are an effective measure to preserve or remediate cliff erosion and arrest the effects of ground subsidence. It is not uncommon for piles of this nature to be completely buried.
Soldier piles, or barrier pile walls utilise either encased timber or reinforced concrete piles, are closely spaced and penetrate into more competent subsoils, thereby retaining the more unstable upper layers. Often a capping beam is used to link the piles.
Tiebacks and Anchoring to Piles and Retaining Walls
A tieback is a horizontal wire or rod, used to reinforce retaining walls for stability. With one end of the tieback secured to the wall, the other end is anchored to a stable structure, such as a concrete deadman pile which has been installed into the ground or anchored into earth with sufficient resistance. This application reduces the loading on the main structure by transferring the load to the deadman pile which can be located on more competent ground, thereby resisting forces that would otherwise cause the wall to lean. Deadman piles are retrofitted to both existing walls, and used in new wall construction to transfer loads back to more competent ground away from the main structure. This can be an economical solution, rather than completely replacing an existing structure.
Some tiebacks are referred to as ground anchors where the anchor is drilled and grouted into the ground to provide resistance.
Drilled Horizontal Drains
High levels of groundwater can affect the stability of hillsides and slopes. Horizontal drains can help reduce groundwater levels and potential soil pressure, and are a useful solution for long term stabilisation of a slope. Horizontal drainage is installed by drilling horizontally and installing slotted drain pipes to drain the water from the slope into a central collection point.