悬索桥地下连续墙—锚碇复合基础协同承载特征分析

Numerical Simulation of the Bearing Mechanism of Underground Diaphragm Wall-Anchor Combined Foundation

传统的重力式锚碇设计方法不考虑围护结构对基础承载力的贡献,随着施工技术与质量的进步,发挥地连墙围护结构承载力贡献的新型复合基础成为新的研究方向。以虎门二桥工程锚碇基础为背景采用有限元软件模拟了锚碇基础的建造过程,分析了缆力施加前后地下连续墙-锚碇的受力与位移变化,验证了地下连续墙-锚碇复合基础协同承载假定。研究表明:地下连续墙的抗剪强度、地下连续墙与周围土体的摩阻力对锚碇基础水平向抗滑移承载力均有贡献;采用地下连续墙作为基坑围护结构的大跨悬索桥锚碇基坑设计可考虑地下连续墙-锚碇基础的协同承载特性。

The traditional designing method which takes anchor foundation as a rigid-body without considering the contribution of underground diaphragm wall is too conservative. As construction technology and quality advance, the combined foundation which takes account of the contribution of underground diaphragm wall is becoming a new research direction. This paper studies the bearing mechanism of diaphragm wall-anchor combined foundation with the numerical code. The simplified construction process of anchor is simulated. The conditions of anchor before and after the application of designed cable force are investigated. The results show that not only the friction force between anchor and soil can provide bearing capacity but also the friction force between underground diaphragm wall and soil. In addition, the shear strength of underground diaphragm wall is also contributed to bearing capacity in some degree. The anchor foundation of long-span suspension bridge could be taken as underground diaphragm wall-anchor combined foundation in design.