复杂地质因素下神农溪大桥岸坡稳定性研究-《高速铁路技术》

文章信息/Info

Title:: Research on the Stability of Shennongxi Bridge Bank Slope under Complex Geological Environment

Author(s):: HE Ping; XU Sheng; DU Yuben; China Railway Eryuan Engineering Group Co., Ltd., Chengdu 610031, China

Keywords:: Zhengzhou-Wanzhou high speed railway|Shennongxi|karst|stability of bank slope

摘要:: 郑万高速铁路神农溪大桥桥基岸坡工况复杂，受到频繁低震、库水位反复涨落、滑坡浪涌及岩溶的综合影响。文章在宏观地质概念的指导下，采用野外调查、钻探、理论计算及数值模拟方法，综合各因素的影响，分析桥基岸坡的长期稳定性，评估桥基位置的合理性。研究表明：（1）线路规避了右侧大型溶槽及左侧既有高速公路的影响，为最优方案；（2）万州端基底灰岩中有多层溶洞，建议深埋至溶穴很少的泥灰岩层中；（3）由于地震、库水位涨落过程中的水岩作用及动水压力，万州岸主墩基础底部岩体的塑性区与岸坡边坡点的塑性区逐渐靠近。为避免两个塑性区贯通，引发岸坡整体失稳，建议采取一定的工程措施。

Abstract:: Shennongxi Bridge of Zhengzhou-Wanzhou high speed railway is comprehensively effected by frequent low earthquake, repeated fluctuation of reservoir water level, landslide surge and karst. Based on the macroscopic geological concept and the influencing factors, the long-term stability of bank slope is analyzed and the rationality of the bridge foundation position is evaluated by using field investigation, drilling, theoretical calculation and numerical simulation. The results show that the railway line is optimal scheme because it avoids the large tank on the right side and impact of the existing highway on the left side. There are many layers of karst caves in the basement limestone,it is suggested that the length of the pile be burieded into marl layer. The plastic zone of rock mass at the bottom of main pier foundation of Wanzhou bank is close to the plastic zone of slope point gradually because of the water-rock action and hydrodynamic pressure in the process of earthquake, reservoir water level fluctuation, In order to avoid the connection of two plastic zones and the overall instability of bank slope, some engineering measures are suggested.