Slope Stability in Swelling Soils Using Cement Grout: A Case Study

Control and stabilization of swelling soils have been a basic challenge in geotechnical engineering since 1970s till now. Major stabilization methods applied for swelling soils lead to minimum one of the disadvantages of high construction cost, laboratory-scale application, implementation only in flat areas and diseases caused by the use of chemical materials. Several instabilities and collapses have happened in side slopes excavated in swelling soils of the under construction highways of Iraq-Kurdistan. This necessitates presenting a method statement to decrease and control swelling potentials. This study aims to describe the cement grouting method applied in Salaheddin side slope which is known as one of the most critical instabilities of Erbil–Haj Omran highway where the optimal grout content was first determined in the laboratory and then it was used in the project as the consolidation grouting. Results indicated that the soil swelling decreases for > 90% by injecting 6% of cement grout. The grouting also increases the uniaxial compressive strength of the soil for more than two times.