What we do atIndependent Ground Improvement
Independent Ground Improvement Company Limited (IGI Ltd) is the up and coming force in the Ground Improvement sector of ground engineering, becoming renouned for providing innovative and technically advanced solutions to problems in a cost effective way. We pride ourselves on the fact that if a job does not require treatment we will let you know.
We are a small company, which prides itself on providing solutions with a personal touch, keeping a close working relationship with the clients, main contractors and the structural/consulting engineers. This has been shown by the high level of repeat business that the comopany affords.
We are solely based within the United Kingdom, with our offices within Risley Warrington, but able to service any enquiry or work within the Unioted Kingdom. Our engineers have a wealth of Experience, as do our site operatives can therefore can advise on all aspects of ground improvement design to site based operations.
The use of vibro displacement (stone columns) relies heavily upon the soil properties of the material to be improved.
The soil must be appraised in terms of:
- Type (cohesive/granular/intermediate)
- Soil Description (Clay/Sand/Gravel/Peat/Fill)
- Strength/density (ability to provide lateral stability for the stone column)
- Swell/Heave potential
- Water Content/Standing Water Level.
- Granular Soils Treatment - vibration increases the density by reduction of the void ratio of the granular soils. The vibrations act to overcome the frictional contacts (effective stress) between the soil particles, and forms a state of greater relative density
- Cohesive Soils Treatment - reduces pore water pressure therefore increasing effective stress (strength). The cohesive soils also confine the stone column and this passive resistance allows the dense granular column to reinforce the soil.
This is carried out by the following proceedures:
- Vibro Rig displaces the soil by vibrating a mandrel into the ground to the required depth or refusal, whichever is achieved first.
- The mandrel is withdrawn and the subsequent void filled with a clean stone. The stone is generally a 40mm - 75mm clean quarried material, however other sources of materials can be used (crushed concrete, screened railway ballast).
- The mandrel is then re-introduced to the in-filled void and taken down to close to the base of the previously formed void, displacing the stone laterally into the surrounding soil. The process is repeated with subsequent filling and compaction of the stone to form a vertical stone column, with close interlocking into the surrounding soils.
- This method provides the ground with the ability of increased load bearing characteristics.
- 1.Mandrel penetrates weak soils under down force from the leader mounted mandrel and the vertical vibration
to form a hole to design depth or refusal
- 2.The mandrel is withdrawn and a charge of stone is placed in the hole
- 3.The mandrel is reintroduced into the hole, and the stone is compacted and displaced, and tightly interlocked with the surrounding ground
- 4. By adding successive charges and noting softer bands the column is built up and pushed out into the poorer soils