Modifying the Strength of Soft Soils via Heating and Cement Grouting Method

Abstract

Soft clayey soils present geotechnical engineering challenges with significant stability and settlement. Various methods are employed to enhance the geotechnical properties of these soils. Heating and grouting are the methods used to improve such soil. A new heating and cement grouting system using gas as a source of heating through boreholes and Portland cement for grouting was designed and manufactured to enhance the soft soil. Different parameters were investigated, including the shear strength and the angle of internal friction, as well as the water/cement ratio, W/C (0.5, 0.75, 1, 1.25, 1.5, and 1.75), and the period of curing (3, 14, and 28 days). The results showed the shear strength and angle of internal friction increased from 14 to 300 kPa and 0 to 50 degrees, respectively. If only the heating system is running, the strength and behavior of the soil will improve via heated and cement grouting with a water/cement ratio. If the w/c ratio increases from 0 to 1.25, the ultimate bearing capacity ratio (qu treated/qu untreated) increases from 6.5 to 14.3 at 15% settlement. However, when the water/cement ratio increases from 1.25 to 1.75, the ultimate bearing capacity ratio (qu treated/qu untreated) decreases from 14.3 to 11.4. The ultimate bearing capacity ratio improves with increasing curative time. It climbs from 14.3 to 19.6 during 3 to 28 days for cement grouting models, while the ultimate bearing capacity ratio grows from 6.5 to 7 during 3 to 28 days for heating process models only, at 15% settlement.

Keywords

• soft soil
• bearing capacity ratio
• grouting, heating
• portland cement
• curing period