支护结构作用的箱基沉降计算新方法

A new method for settlement computation of box foundation with supporting structure

现行规范在计算箱基沉降时,没有考虑支护结构的作用,使得理论计算与实际沉降之间存在误差。通过物理模拟、理论分析和数值模拟,研究箱基与支护结构结合、分离下,不同墙体材料、不同墙体厚度、不同插入深度比等工况下侧摩阻力对箱型基础沉降的影响,试验结果显示,摩擦力在箱基沉降中的作用很明显,它与墙体与土体之间的摩擦系数、墙体与土体的接触面积密切相关。在此,提出了一种计算箱基沉降的新方法,该法将箱基沉降分为3部分:箱型基础底上段回弹再压缩变形带来的地基变形、箱型基础底上段压缩变形、箱型基础的下段土体变形。以青岛中银大厦为实例,应用FLAC3D对基础沉降进行了数值分析。数值分析中按文中方法以及按前人方法的计算结果与实测数据进行了对比,结果表明文中的方法具有更好的可行性,对修订规范具有借鉴意义。

The current criterion doesn＇t consider the effect of supporting structure in computing the box foundation settlement, which makes the error between academic settlement and practical settlement. In order to exploring the settlement mechanism of box foundation, a series of tests were accomplished. The influence of profile friction on box-foundation settlement is studied under the condition of the different wall materials, wall thicknesses and inserting depth ratios. The test results show that the friction force is very important to the settlement of the box foundation, and the force is correlated with the friction factor, the interface between the wall and the soil. And the FLAC^3D numerical code is adopted to simulate the box foundation settlement under these conditions. Based on the results of the physical model test and numerical simulation, a new box foundation settlement calculation method considering the influence of profile friction is put forward. The results indicate that the method is more feasible and can be used for reference to revise codes.