In recent years, heavy rains have frequently occurred in Japan, and a large amount of soil, rocks, and trees that were dislodged by landslides have flowed into rivers, causing damage to bridges. When a bridge is blocked by driftwood and boulders, the river water overflows onto and around the bridge abutment and the back face banking of the abutment is eroded, rendering the bridge impassable. We propose cement soil stabilization as a countermeasure to the erosion for the back of abutments. In this study, channel experiments on a 1:15 scale into the effect of cement soil stabilization were carried out. It was observed that erosion started from the downstream corner of the abutment when the overflow water returned to the river at the downstream point. In addition, when the back face banking of the abutment was strengthened with the minimum additional amount of concrete (set as 50 kg/m3) and cured for approximately two days, erosion was inhibited in both the reinforced back face banking and the unimproved levee.