考虑桩-土界面力学特性的桩体内力变形规律研究

摘要

Using the deep foundation pit project of Bagou station of Beijing metro line 10 as an example, and con-sidering the mechanical properties of the pile-soil interface, a three-dimensional finite difference model was built, and the internal force and deformation of the retaining piles were analyzed, as compared with the monitored data. Furthermore, the effects on the internal force and deformation of the retaining piles caused by the soil frictional an-gle and the friction coefficients of normal and tangential coupling springs of the pile-soil contact interface are dis-cussed. It is concluded that the bending moments and horizontal displacements of the retaining piles decrease with the increase of the soil frictional angle, and the influence degree diminishes gradually;both the maximum bending moment and horizontal displacement increase at first and then remain invariant with the increase of the friction coef-ficient of the normal coupling spring, while the friction coefficient of the tangential coupling spring has little effect on them. This conclusion provides a reference for the design and calculations of retaining structures with similar deep foundation pit projects.%文章以北京地铁10号线巴沟车站深基坑工程为依托,建立考虑桩-土接触界面力学特性的数值计算模型,分析桩体受力变形规律,并与实测数据进行对比,进而分析土体内摩擦角、界面法向耦合弹簧摩擦系数、界面切向耦合弹簧摩擦系数3个因素对桩体内力及变形的影响.研究结果表明:随着土的内摩擦角的增大,桩的弯矩减小,桩的水平位移减小,且影响程度逐渐减弱;随着法向耦合弹簧摩擦系数的增大,桩的最大弯矩和最大水平位移均先增大,后保持不变;切向耦合弹簧摩擦系数对桩的弯矩和水平位移的影响不大.研究结果对深基坑支护结构的设计计算具有重要的指导意义.