High mobility (cement slurry) grouting, also know as cement grouting or rock grouting, is normally done in fissured rock to reduce the flow of water along the joints and discontinuities in the rock. Occasionally, cement grouts are injected into the void space within coarse granular soils (see permeation grouting).

Cement grouting illustration

Common uses

Create barriers to groundwater flow
Underpin foundations
Provide excavation support
Stabilize and strengthen granular soils

Process

High mobility grouting, fills pores in granular soil or voids in rock/soil, with flowable particulate grouts. The grout particle size and void size must be matched properly to allow the cement grout to permeate. Depending on the conditions, Portland cement or microfine cement grout is injected under pressure at strategic locations through single port or multiple port pipes. The grouted mass has an increased strength, stiffness, and reduced permeability. 

Cement grouting can offer an economic advantage for underpinning applications over alternative approaches such as removal and replacement or piling, and can be performed where access is difficult and space is limited. Since the effectiveness of cement grouting is independent of structural connections, this technique is readily adaptable to existing foundations and can typically be accomplished without disrupting normal facility operations.

Advantages

Can be effective in reducing ground water flows
Reduce pumping costs during basement excavation
Reduced lowering of groundwater levels outside an excavation
Can reduce rock deformation

Quality assurance

Keller has developed proprietary equipment and software (iGroutTM) to allow real-time monitoring of all parameters during the cement grouting process. The operator can adjust the parameters (such as mix type, flow rate, pressure, and volume limits) based on the real-time acquisition of drilling and grouting data, while simultaneously monitoring for any movements or deflections of the ground or nearby structures. Data collected during drilling and grouting is recorded on a server that produces grouting reports, as well as CAD drawings depicting a visual representation of the completed work. Use of this advanced monitoring and control system increases accuracy, efficiency, and quality control of cement grouting.