基于卡丘金法和两段法对金沙江上游某拟建大桥塌岸预测分析

Prediction and Analysis of Bank Collapse of a Proposed Bridge in Upper Reaches of Jinsha River Based on Kachujin Method and Two-Section Method

位于川滇交界的某跨金沙江大桥,在下游电站蓄水运营后,桥台岸坡将经历持久的库岸再造过程,该地表为第四系堆积物,易发生变形和塌岸,影响岸坡稳定,威胁桥梁安全.通过现场地质调查结果,结合现场地质钻探所揭示的地层特点,运用“卡丘金法”和“两段法”分别对塌岸宽度进行预测,因研究区河床高程低于水库运行低水位和死水位,地质条件有自身的特殊性,原有模型与实际条件不完全吻合,故预测时对建模方式和参数选取都进行了适当修正,本研究为此类岸坡的塌岸影响区域的界定和桥台防护措施的选择提供了重要依据.

The abutment slope of a bridge across Jinsha River at the junction of Sichuan and Yunnan will undergo a long-term reconstruction of a reservoir bank after the downstream power station has been put into operation.The surface quaternary deposits are prone to deformation and bank collapse,which affects the stability of bank slope and threatens the safety of the bridge.Based on the field geological survey results and combined with the stratum characteristics revealed by geological drilling,this paper uses“Kachujin method”and“two section method”to predict the width of bank collapse.Considering the river bed elevation is lower than the low water level and dead water level when the reservoir is in operation,and that the geological conditions also have their own particularity,the original model is not completely consistent with the actual conditions,so the modeling method and parameter selection are properly modified in the prediction,which provides an important basis for the determination of the area affected by bank collapse and the selection of abutment protection measures.