Stone column ground improvement consist of inserting upright columns of stone into the soil to a depth of at least 4m below the ground surface. A layer of compressed gravel can then be put over the top of the columns, ready for the construction of new house foundations. The stone column method is quick to construct and can be done at any time of the year.
How are stone columns built?
Stone columns are built by qualified contractors using expert equipment. The structure uses a machine with a vibrating probe to supply stone into the ground, forming a vertical column of stone.
Some stone column rigs feed stone into the soil through the vibrating probe, exiting at the bottom, and other rigs require the stone to be fed in from the ground surface down the vertical hole in the ground. Both types use a vibrating probe that densifies the nearby soils to help feed the stone into the ground.
How do stone columns enhance the ground?
Stone columns help to reduce the extent and concerns of future liquefaction by:
- Densifying the soil using vibration and introducing stone into the soil
- Strengthening the soil creating a rigid composite soil mass
By accomplishing this, the non-liquefying soil coating is condensed and strengthened to reduce the chances of folds, slopes, and uneven ground surface subsidence from liquefaction of the core soil layers, therefore lowering damage to the house foundations.
In addition, stone columns may occasionally offer the soil with an improved drainage path to help ease water pressure that can lead to liquefaction, so the columns can lessen the effects of liquefaction when this happens.
We have an excellent range of used Stone Column Piling Rigs for sale. Stone Column piling machines to allow work to be completed efficiently and effectively.
Please contact one of our Team for further information on Soil Column Piling Rigs, Geotechnical Drilling or Mini Piling Rigs.
Vibro Stone Columns (VSCs) offer a highly economical and sustainable alternative to piling and deep foundation solutions; removing the need to by-pass problem ground by densifying and strengthening weak or poorly compacted soils in-situ. A vibrating poker known as a vibroflot is fitted to a purpose-built vibropiling rig and is used to penetrate the ground. Penetration is achieved using the vibroflot’s own mass, the pull down facility of the rig when used, and pressurised air flushes. There are two methods of Stone Column Piling, 1. Top Feed Method: Once refusal or design depth is reached the vibroflot is withdrawn and charges of graded stone. aggregate are tipped into the bore hole from the surface: this is known as the Top Feed Method. 2. Bottom Feed Method, Where a high water table or weak soils are present the collapse of the bore hole is much more likely when the vibroflot is withdrawn. In these conditions the purpose-built Bottom Feed system is used to ensure integrity of the stone column from top to bottom. The vibro rig is fitted with a hopper which feeds stone into a tremie pipe running down the length of the vibroflot.
The benefits of using a stone column piling rig are:
• Fast set up.
• No high-pressure water or air injection required.
• Can be used in collapsing soils.
• Less power required as no need to supply a high frequency vibrator.
• Fuel savings due to smaller power consumption overall.
• Only two machines needed, one to drill the other to load the stone for bottom feed stone column hopper.
• Binder can be introduced to provide rigid inclusions in the soil
• Does not create liquefaction state of soil.
• Recognised by international geotechnical engineering design companies.
• No high wear or maintenance due to high frequency vibrating parts.
• Proven technique in several different soil types.