## 6 Conclusions  
Through the field measurement and numerical simulation of a deep foundation pit with pile-anchor supporting structure in red sandstone stratum, the horizontal displacement, axial force and ground settlement during construction were explored, and the spatial effect induced by the excavation was evaluated. The following conclusions were drawn from the above results and discussion:  
1. The field monitoring results show that the spatial effects of pile top horizontal displacement, the horizontal displacement at various depths, anchor cable axial force and surface settlement are obvious. The deformation decreases gradually from the middle part to the pit angle. It is suggested to make full use of the spatial effect of the pit corner in the design, to reduce the support grade appropriately at the pit corner of the foundation pit;
2. With the excavation of the foundation pit, the form of pile deformation curve changes from cantilever type to belly drum type. The maximum horizontal displacement occurs between 6.0 and 8.0 m from the top of the crown beam, which is about 1/3 of the pile length;
3. The axial force of the anchor cable is distributed in a parabola along with the depth of the foundation pit. The axial force of the anchor cable of layer 3, layer 4 and layer 5 is generally greater than that of layer 1, layer 2 and layer 6, and the maximum axial force appears at the anchor cable of layer 4. It is recommended to appropriately increase the distance between the bottom layer anchor cable and the upper layer anchor cable;
4. The width of ground settlement occurring in the same monitoring section is twice the length of deformation occurring in the pile, while the maximum ground settlement is half the maximum deformation of the pile, showing an obvious deformation coordination relationship;
5. When the stratum condition is poor, the spatial effect of foundation pit deformation is more obvious. With the increase of soil elastic modulus and cohesion, the horizontal displacement of pile, axial force of anchor cable, and surface settlement gradually decrease, and the influence of elastic modulus is more significant. It is suggested that the elastic modulus and cohesion should be increased to 1.5-2.0 times the initial value during grouting reinforcement;
6. With the increase of the pile diameter or the decrease of the pile spacing, the horizontal displacement of the pile, the axial force of the anchor cable and the surface settlement gradually decrease, while the influence of changing the pile spacing on the spatial effect is limited; The pile diameter of 0.8-1.2 m and the pile spacing of 1.4-2.0 m are more suitable in practical engineering;With the decrease of the prestress or the increase of the tilt angle, the horizontal displacement, the axial force and the surface settlement gradually increase. The value of the axial force is suggested to be set in the range of 100-150 kN and the tilt angle ranges from \(10^{\circ}\) to \(20^{\circ}\) in the design. The conclusions drawn from the study of deformation control technology for the deep foundation excavation of large rail transit stations in red sandstone strata have certain engineering application value for similar projects. However, there are still some problems to be further studied: the influence of the temporal effect on deep foundation excavation deformation needs to be investigated further, and the effect of temporary loads surrounding the foundation pit may influence its deformation, which is not considered in the modeling in this research. Conceptualization, W.L. ; data curation, T.L. ; methodology, W.L and T.L. ; investigation, W.L. and J.W. ; software, J.W. and T.L. ; formal analysis: W.L. and T.L. ; visualization, J.W. ; writing and editing, W.L. and T.L. All authors have read and agreed to the published version of the manuscript.