The invention discloses a method for preventing and controlling the
landslide risk of a side slope at a mountain road tunnel portal. The method comprises the steps of 1, extending an open
cut tunnel out of a
landslide risk area of the slide slope, and injecting double-liquid
slurry to the bottom of a foundation of the open
cut tunnel for reinforcing; 2, adding a foam
cushion layer with the thickness
ranging from 10cm to 20cm to the outer side of the open
cut tunnel, wherein the foam
cushion layer is used for buffering
impact of backfilled earth and rocks against the open cut tunnel; 3, synchronously backfilling earth and rocks at the two sides of the open cut tunnel till the height of the backfilled earth and rocks at the top of the tunnel is greater than one time the
diameter of the tunnel and a lower cut of a sliding face, subjected to
landslide, of the side slope is covered; and 4, if other sliding faces exist above the slide face mentioned in step 3, excavating away par of sliding blocks and filling the sliding blocks to the two sides of the open cut tunnel symmetrically and the top of the tunnel, and covering lower cuts of other sliding faces 1m above in height. The method targets at the landslide risk of the side slope of the tunnel portal; the combined mode that the foundation is reinforced, the open cut tunnel is extended, the earth and rocks are synchronously backfilled and part of the sliding blocks are excavated away for filling is adopted; the landslide risk of the side slope is controlled; and the method has the beneficial effects of being low in cost, little in occupied land, high in construction safety and the like.