A large section of an even larger commercial building had suffered differential settlement of up to 156mm. Staff facilities
and amenities areas as well as offices above suffered during this settlement with cracks opening as well as floors sloping
severely. The building had been founded on compacted fill placed following open-cast coal mining.
The task comprised of two main parts
The two tasks were to be completed without delay or compromising the complex building and its occupants. All the works had to be carried out while the production and operation remain active in the building as business interruption was not an option.
JOG Computer Controlled Grouting levelling system was initially utilised to level correct the building. The fine precision and absolute control which the system provides allowed full correction without disturbance to the surrounding areas.
During the second phase, LPDG Low Pressure Deep Grout, was utilised to fill voids at depth without fracturing the cohesive soils of the compacted fill material.
Injection rods were inserted in sections at 112 locations down to 6m. Grouting took place at 1m intervals starting from the bottom up. The grout was introduced at low designed pressures allowing voids to be filled without fracturing the soils or creating uplift.
The structure was re-levelled and voids filled successfully returning the building to design levels all while the building remained in occupation.
JOG and Low Pressure Deep Grouting