Socket piles
Foundations provide support for structures, transferring their load to layers of soil or rock that have sufficient bearing capacity and suitable settlement characteristics.
Very broadly, foundations can be categorised as shallow foundations or deep foundations. Shallow foundations are typically used where the loads imposed by a structure are low relative to the bearing capacity of the surface soils. Deep foundations are necessary where the bearing capacity of the surface soils is insufficient to support loads imposed and so they are transferred to deeper layers with higher bearing capacity.
Pile foundations are a type of deep foundation. They are formed by long, slender, columnar elements, typically made from steel or reinforced concrete, or sometimes timber. A foundation is described as 'piled' when its depth is more than three times its breadth.
Pile foundations are principally used to transfer loads from superstructures, through weak, compressible strata or water onto stronger, more compact, less compressible and stiffer soil or rock at depth. They are typically used for large structures, and in situations where soil is not suitable to prevent excessive settlement.
The term ‘socket piles’ (or rock sockets), refers to a technique that is used to embed a pile into solid rock. This can be necessary to utilise the full structural capacity of the piles for both compressive and tensile forces. It is a technique that is typically used for offshore applications, such as drilling into a rocky seabed, where the depth is shallow or there is sloping solid rock.
The technique involves drilling into the rock layer to create a socket which is slightly larger than the pile. This creates a void around the outer edge of the pile which is filled with grout, usually Portland cement or an ultra-high strength grout depending on the structural requirements. This 'socket' in the rock provides the pile with stability by providing to resistance against lateral loads and uplift forces.
The safe load-carrying capacity of the socket piles will depend on a number of factors in relation to the behaviour of the rock mass:
- The properties of the rock.
- The presence of fractures in the rock.
- The size and spacing of any fractures.
- The degree of weathering of fractures.
- The presence of any soil within fractures.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Download your free guide.
Four new types of prior approval for solar developments
Online Planning Portal application types from 5 September.
Election fails to spark construction industry revival
Contract awards and planning; post election.
Making diversity and inclusion easy for SMEs
The CIOB tool for companies with limited resources.
Sustainable Futures: Redefining Retrofit for Net Zero Living
BSRIA Briefing 2024, initial speakers announced.
Looking back at the UK's first Passivhaus leisure centre
Reflections on St Sidwell’s Point with CIAT.
A-Level results and electrical apprenticeships
Electrical Skills Index highlights areas with skills shortages.
One of the world's more unusual drive-throughs.
A quick introduction.
Hadrian's Wall Path and the national trails
The trails are heritage assets in their own right.
Articles on timely advice and hydraulic lime.
Building Designers Association of Australia
CIAT and BDAA sign Memorandum of Understanding.
Built Environment Inclusive partners issue statement committed to inclusion.
Building regulation requirements can have unintended consequences.
CIOB announces 2024/25 vice president
Sustainability champion Professor Saul Humphrey.
Accelerating towards a net-zero built environment.