The studies of pile-anchor supporting structure of deep foundation pits have aroused the attention of scholars

and the interaction between supporting structure and soil still needs to be further researched. We established the static equilibrium equation considering the combined action of soil resistance after the pile and anchor tensile. The pile anchor deformation compatibility condition is modified and compared with the other three algorithms of deformation compatibility condition. The results show that the improved method can reflect the actual situation of the pile anchor supporting structure deformation. The designed pulling force of anchor is larger than other methods of designed pulling force of anchor. To overcome the ignored obliquity of the anchor

the anchors' elongation is increased and the stress states are not considered. FLAC3D is used to simulate the pile body’s internal force. The calculated internal force of pile body by the modified method is consistent

indicating the advantage of the proposed method.