Engineering Properties of CIPS Cemented Calcareous Sand

An innovative new technology, known as the Calcite Insitu Precipitation System (CIPS), has been developed for improving insitu the geotechnical properties of porous sediments and rocks. CIPS is based on the crystallisation of calcite within the pore fluid and on the surfaces of constituent sand/silt grains so that the grains become strongly cemented but pores essentially remain open. This calcite cement crystallises from a proprietary solution which is permeated into the material. Because it is a non-particulate, low viscosity and water-based solution, multiple permeations are possible. Mechanical strength is significantly increased with each injection but porosity is reduced only slightly. Improvements in the mechanical properties of calcareous sands treated with CIPS have been demonstrated by a variety of laboratory tests including unconfined compressive strength (UCS), direct shear and triaxial tests. Results show that CIPS cemented calcareous sands have similar stress-strain relationships to those of natural calcarenites of similar strengths.