The Instability Analysis and Processing Scheme of ChangXin Viaduct Abutment

In order to solve the abutment instability problem of the ChangXin Viaduct in JiLin to YanJi highway, we had the detailed geology survey and exploration of the abutment and its back roadbed, and had also the test of soil bulk density and the shear strength, and the deformation monitoring. The results show that the groundwater runoff and seepage functions for the abutment and its back roadbed are both strong because they are in the slope which in the junction of large diameter group sandstone and mudstone. Because of the two months consecutive rain function, the group stratum became soft in water, and added the combined function of the abutment and its back filled soil, so caused this group stratum sliding under the abutment and its back subgrade, and led to the abutment instability. To prevent the continuing landslide development, and maintain the landslide stability and the security of the bridges and roadbed, according to the causes above, we took the following treatment measures: Dismantling the finished 0th abutment and 1st pier, increasing two holes bridges, so making the abutment away from the landslide area, and at the same time transforming the extending foundation form to pile foundation, so they can reduce the damage function to the original slope body; Appropriately cutting earthwork and lessening weight of the landslide, using antiskid pile supporting baffle in the landslide body, and adopting blind ditch and cutting, drainage ditch to process drainage treatment, all of these ensure the stability of landslide and no adverse effects on bridge foundation.