Abstract: The stiffness coefficient of anchor is composite stiffness obtained by considering the deformation of free section, anchorage section and relative displacement of anchor to soil. In the derivation of the existing formulas for calculating the stiffness coefficient of anchor, only the deformation of free section and the anchorage section were considered, while the deformation of soil was not taken into account. The relationship between the actual displacement of anchor head and the internal force can not be truly reflected. Based on the coordinated deformation of anchor and soil, the formulas for calculating the stiffness coefficient of anchor rod considering the deformation of free section, anchorage section and soil were derived by using Mindlin solution, and the calculated codes was compiled with the software of MATLAB. Finally, combined with an engineering example, Plaxis2D was used to simulate the stiffness coefficients of anchor. The stiffness coefficients of anchor were solved by displacement and internal force. Compared with the calculation method and the standard method in this paper. The results show that the calculation method in this paper is more consistent with the simulation results.

Key words: excavation, anchor, stiffness coefficient, displacement