G and P GEOTECHNICS SDN BHD Secant Pile Walls Specification 20 July 2011. SPW14 The Contractor shall be responsible for the programme and sequence of construction which is dependent on the rate of gain of strength of primary piles and which affects the time within which secondary piles can be formed.
The use of both cased bored pile and CFA pile methodologies can be used to construct secant pile walls. The secant pile wall method provides a cost effective solution for the construction of deep excavations to form basements, cut and cover tunnels, tanks, etc. in urban environments.
aSSumed conStructIon Sequence The likely construction sequence would be as follows: Secant piling to perimeter and internal piles to columns Construction of capping beam to secant piles Excavate within secant piles to a depth of approximately one metre Install temporary props below ground slab level to provide
Piles are typically installed at 4 to 8 feet centers and extend at least 8 to 10 feet below final excavation grade to provide passive toe resistance. As site excavation proceeds in lifts, typically 5 feet in depth, lagging comprised of either wood or shotcrete is placed between the piles.
Piling - Contiguous, Interlocking and Secant. A sequence of secondary piles are constructed followed by a sequence of primary piles constructed to the full design depth, cutting into the secondary piles and reinforced in the usual manner. This form of construction ensures that water entry into the subsequent excavation is greatly reduced.
of the excavation is 32 ft below grade and the excavation retained permanently by concrete secant pile walls. The circular wall is constructed of 3 ft nominal diameter concrete piles overlapping adjacent piles by 6 in; the wall penetrates 60 ft below grade.
Secant piled walls are embedded retaining wall structures mainly utilised to allow deep excavation in water charged ground conditions. The walls are constructed by installing piles in a predetermined sequence.
Secant piles are drilled shafts constructed in such a way that the shafts overlap each other to form a continuous wall. The construction sequence involves drilling every other shaft primary shafts and then returning after the concrete has partially set to drill and pour the overlapping shafts between the primary shafts secondary shafts .
Secant or tangent piles are columns constructed adjacent tangent or overlapping secant to form structural or cutoff walls. From soil mixing to drilled shafts, Hayward Baker ds on its complete suite of techniques to optimize the design and construction of these walls.
Construction of secant pile wall is normally required when the building project is to be erected on soft ground or sandy soil. The purpose of this is to ensure that the strata behind the wall would remain undisturbed during construction and to ensure safety from the risk due to high lateral pressure.
The main advantages of Secant Pile Walls are: Increased construction alignment flexibility. Increased wall stiffness compared to sheet piles. Can be installed in difficult ground cobbles/boulders . Less noisy construction.
Secant Pile Construction. Secant pile walls are formed by constructing a series of overlapping primary and secondary concrete-filled drill holes. The primary piles are constructed first, followed by secondary piles, which are cut into the previously placed primary pile concrete.
A general summary of our findings, conclusions, and recommendations with regard to the geotechnical engineering aspects of the Project are provided below: Subsurface conditions generally consist of fat clay and lean clay soils. A secant pile wall may be used as an earth retention system for the exploratory pit.
Technical Details. Sequenced construction of the elements helps ensure a tight seal for water cut off. The design can incorporate steel bar or beams for reinforcement. Anchors provide additional lateral support, if needed. Secant or tangent pile walls can be constructed in a wide variety of soil conditions, including through cobbles and boulders.
Secant piling is an ideal solution to create a retaining wall which inhibits the passage of water and is particularly effective where groundwater control is complicated by stratified ground.
ADSC-IAFD Secant and Tangent Pile Wall Construction Specifications Page 2 of 20. construction of the secant/tangent pile, including the placement of the reinforcing steel and the concrete. Natural mineral or polymer drilling fluid may or may not be used in conjunction with this method.
The wall consists of discrete piles typically installed at centres 150mm greater than their diameter, leaving gaps where soil is exposed during excavation. Application. Basement construction, road/ rail cuttings, underpasseses, cut-and-cover tunnels and portals, cofferdams, underground tanks , slope stabilisation.
The secant pile wall was designed to extend a minimum of 10 feet into the silty glacial till stratum to serve as a permanent groundwater cutoff for the underground garage. Our specialty drill method described further below , combined with in-house engineering
Pile wall construction is a method of realizing a retaining structure by making a row of tangent or secant piles. A secant pile wall is formed by constructing intersecting concrete piles so-called primary and secondary piles - so as to create a continuous wall.
Optimizing construction sequences for secant pile walls Abstract: Secant pile walls are crucial in the construction of fossil-fuel power plants for water exclusion purposes. The construction time is the most critical factor that influences the entire construction project.
Secant Piles Construction. Structural foundation element consisting of overlapping piles forming a continuous wall. Reinforced concrete rebar cages or soldier piles . Depth depends upon final design and soil and equipment characteristics. Piles diameters usually based on metric tooling size.
SECANT PILE WALL DESIGN - SECANT PILES FOR DEEP EXCAVATIONS. Primary piles are installed first with secondary piles constructed in between primary piles once the latter gain sufficient strength. Pile overlap is typically in the order of 3 inches 8 cm . In a tangent pile wall, there is no pile overlap as the piles are constructed flush to each other. The main advantages of secant or tangent pile walls are:
Optimizing construction sequences for secant pile walls . However, building secant pile walls in this sequence generally requires the primary bored piles to be excessively cured and hardened. The construction of secondary bored piles in this manner thus results in construction difficulties, wasted construction time, and poor construction quality.
Both secant and tangent pile walls are drilled to design depth and concreted in a primary/secondary sequence. Where walls are installed for structural support, the design can incorporate reinforcement for additional wall stiffness. For tangent pile walls, every pile is reinforced.