关键词: 定性分析, 极限平衡法, 主塔, 锚杆

Abstract: The slope stability of riverbanks at the propose Lixianjiang River Crossing Bridge was a concern. The global stability of the entire riverbanks was first evaluated using the engineering geology method. The stabilities of both the entire and local slopes (main tower upper and lower slopes) of both side of the riverbanks were evaluated and analyzed under both initial conditions and constructed conditions. The following conclusions can be obtained: 1) Based on the qualitative evaluation of the site conditions, it is concluded that the global stability of the Dalicheng riverbanks could be warranted and the local collapses and instabilities could be occurred. 2) under the natural conditions, the global stability of both riverbanks was satisfactory and the shallow slides that could not meet the engineering requirements and need to be improved. 3) under the constructed conditions the upper slope at the main tower had surficial stability concern and the lower slope was stable globally and locally. 4) for the excavated slope after changing the topography, it was suggested that the riverbank slope could be stabilized using ground anchors with 3 m (vertically)×3 m (horizontally) pattern with the anchor length of 30 m and no less than 15 rows. It is important the ground anchor grouted length should be imbedded into the strong weathered bedrock with no less than 10 meters deep. Based on the above evaluations, it is also concluded that the selection of the bridge site was appropriate and the minor stability concerns could be mitigated throughout the engineering stabilization methods.

Key words: qualitative analysis, limit equilibrium method, main tower, ground anchors