巴东长江大桥地质环境与岩土工程问题研究

STUDY ON GEOENVIRONMENT AND GEOTECHNICAL PROBLEMS OF BADONG YANGTZE BRIDGE

巴东长江大桥是连接 2 0 9国道的特大型公路大桥 ,地处长江三峡地质条件最复杂的地区 ,桥位区滑坡崩塌较发育 .为确保大桥安全稳定并为设计提供科学依据 ,采用结构面网络模拟技术进行了岩体结构模拟 ,应用弹塑性有限元法及块体极限平衡法 ,对桥位存在的桥台斜坡和桥墩基础地基稳定性等岩土工程问题进行了系统的分析论述 .同时 ,对断裂破碎岩体及风化岩体、滑坡对大桥的影响进行了分析 .在此基础上提出了桥墩基础形式、桩基深度、持力层及承载力和桥台斜坡治理的建议 .

The Badong Yangtze Bridge is a large-sized road bridge across the Yangtze River, linking the No. 209 national highway. It lies in middle part of the Three Gorges where geotechnical condition is the most complex. In the bridge area, the landform is cliffy; the valley incised sharply; and the geostructure is complicated with the rock mass heavily cracked. While landslides and debris-flows are particularly common. By rock structure simulation, the rock discontinuity net and the RQD distributing figure were obtained. Moreover, the slope and groundsill stability about the bridge were analyzed systemically by the elastic-plastic finite element method and plot utmost balance way. At the same time, the influences of the aired and the fractured rockmass on the bridge were discussed. Based on the above, proposals have been made about the pier foundation style, the picket ground's depth and carrying strength. At last, more suggestions for the slope remedy have been put forward.