五峰山长江大桥南锚碇倾斜基岩地质条件分析  

Analysis on Geological Conditions of Inclined Bedrock of South Anchorage of the Wufengshan Yangtze River Bridge

作　　者：李守明 张鑫全 王猛 曾洪贤[1] LI Shouming;ZHANG Xinquan;WANG Meng;ZENG Hongxian(China Railway Major Bridge Reconnaissance and Design Institute Co.,Ltd.,Wuhan 430056,China)

机构地区：[1]中铁大桥勘测设计院集团有限公司,武汉430056

出　　处：《铁道勘察》2024年第1期47-53,共7页Railway Investigation and Surveying

摘　　要：五峰山长江大桥南锚碇位于五峰山山壑间,采用圆形扩大基础,外径90 m,场地内地形变化大,岩土层分布复杂,合理设置适应于地质条件的锚碇基础方案,对工程安全性、经济性意义重大。为了充分利用南锚碇场地内工程性能良好的微风化凝灰质砂岩地基,准确评价岩土体稳定性及对工程的适宜性,采用了露头调查、钻探、物探、原位测试及室内试验的综合勘察手段。基于地质成因分析及赤平投影方法,发现岩面、风化面总体产状具有一致性,倾角约18°,沿倾斜方向分布较稳定;通过进一步分析倾斜岩体及其风化面分布与锚碇基坑的相互作用关系,评价采用台阶式基础方案的可行性,并分析了其对岩石地基的利用优势,针对性提出了锚碇基坑的施工建议。经优化,考虑倾斜基岩工程地质条件的锚碇基础设计可减少约4万m3的微风化岩石开挖量,使工程兼具安全性与经济性。The South Anchorage of the Wufengshan Bridge is located between Wufengshan mountains.It adopts a circular expanded foundation with an outer diameter of 90m.The topography of the site relieves greatly,and the distribution of rock and soil layers is complex.It is of great significance for engineering safety and economy to reasonably recommend the anchorage foundation scheme suitable for geological conditions.In order to make full use of the slightly weathered tuffaceous sandstone foundation with good engineering performance in the south anchorage site,find out the distribution and properties of the rock and soil layer,provide accurate and reliable rock and soil indicators,and accurately evaluate the stability of the rock and soil mass and its suitability for the project,the comprehensive survey means of outcrop survey,drilling,geophysical prospecting,in-situ test and indoor test were adopted.Based on the geological genesis analysis and stereographic projection method,it was concluded that the overall occurrence of rock surface and weathered surface is consistent,with an inclination of about 18°,and the distribution along the inclined direction is relatively stable.By further analyzing the interaction between the inclined rock mass and its weathering surface distribution and the anchorage foundation pit,the feasibility of adopting the stepped foundation scheme was evaluated,and its advantages in the utilization of rock foundation were analyzed.The construction suggestions of the anchorage foundation pit were put forward.Practice had proved that the anchorage foundation considering the engineering geological conditions of inclined bedrock could directly reduce the excavation volume of slightly weathered rock volume of about 40000 m^(3),making the project both safe and economical.

关 键 词：高速铁路 五峰山长江大桥 工程地质 倾斜岩层 重力式锚碇 稳定性 

分 类 号：U238[交通运输工程—道路与铁道工程] U443.1[建筑科学—桥梁与隧道工程]