Cement grouting, also known as slurry grouting or high mobility grouting, is a grouting technique that fills pores in granular soil or voids in rock or soil, with flowable particulate grouts. Depending on the application, Portland cement or microfine cement grout is injected under pressure at strategic locations either through single port or multiple port pipes. The grout particle size and soil/rock void size must be properly matched to permit the cement grout to enter the pores or voids. The grouted mass has an increased strength and stiffness, and reduced permeability. The technique has been used to reduce water flow through rock formations beneath dams and to cement granular soils to underpin foundations or provide excavation support.