Post on 30-Jun-2015
Use of plastic sheets for slope protection in a shallow excavation
E A R T H W O R K S U P P O R T S
TIMBER PLANKING
TIMBER SOLDIERS
E A R T H W O R K S U P P O R T S
STEEL SOLDIER PILES
TIMBER PLANKING
E A R T H W O R K S U P P O R T S
Excavation supports using soldier beam and lagging.
Two examples of soldier beams and lagging method used for retaining walls
Two examples of soldier beams and lagging method used for retaining walls
Examples of soldier beams and lagging method used for retaining walls
E A R T H W O R K S U P P O R T S
STEEL SHEET PILES
E A R T H W O R K S U P P O R T S
STEEL SHEET PILES
Bracing for shallow trenches (a) intermittent sheeting and bracing
Bracing for shallow trenches. (b) continuous sheeting and bracing,
Bracing for shallow trenches. (c) trench shielding
A typical trench box
Soil Nailing Examples
Soil Nailing Examples
Soil Nailing Examples
Schematic diagram of narrow excavation bracing
Internal struts
Support for Rakers
Raker bracing for wide excavations
Excavationsub-grade
Ground surface
Grout or transfer materials
Stressing unit
Sheeting
Tendon
10-200
Bond freezone
Assumed surface of sliding wedge
Tieback installed at 10 to 20° down from horizontal
Tied-back concrete wall constructed underground for excavation support
Tieback being installed
Tieback Examples
Ground freezing is a technique that has been used extensively for groundwater control and excavation support in the underground construction industry for over 100 years.
The process involves the circulation of a refrigerated coolant through a series of subsurface pipes to convert soil water to ice, creating a strong watertight material.
The material is so strong, in fact, that it is routinely used as the only method of groundwater control and soil support for the construction of shafts hundreds of feet into water-bearing soils.
Most ground freezing systems are quite similar in principal.
The single most important co mponent of a ground freezing system is the subsurface refrigeration system, consisting of a series of refrigeration pipes installed with various drilling techniques.
Depending upon the application, the coolant can be brought to temperatures well below -150 degrees celcius
Ground freezing can be achieved by using either a large portable
refrigeration plant or liquid nitrogen.
After the initial freezing has been completed and the frozen barrier is in
place, the required refrigeration capacity is significantly reduced to
maintain the frozen barrier.