| With the continuous advancement of urbanization,urban construction is in full swing,urban land is becoming more and more tense,the distance between buildings is getting smaller and smaller,and the excavation of foundation pit is affected by adjacent buildings.In this context,the supporting structure of foundation pit is The design must not only ensure the safety of the foundation pit,but also avoid harm to adjacent buildings.Pile-anchor support has been widely used in building foundation pit engineering due to its good support effect,small footprint,and large working surface.,especially the pile-anchor support structure adjacent to the pile foundation of the building,the interaction mechanism between it and the pile foundation of the building is not clear,so it is necessary to conduct in-depth research.In this paper,relying on the foundation pit of a building in Changsha,with the help of Midas/GTS numerical simulation analysis software,a three-dimensional numerical model is established to calculate and analyze the foundation pit,and the calculation results are compared with the field monitoring data.reliability.And on the basis of the actual engineering model,the influence of the depth of the building pile foundation,the distance between the pile foundation and the edge of the foundation pit,and the load of the building pile foundation on the pile-anchor support structure is further studied.The main research contents and conclusions are as follows.(1)Based on the mechanical properties of the adjacent building piles as end-bearing piles,a three-dimensional numerical calculation model is established according to the actual engineering conditions,and the reliability of the calculation model is verified by comparing the calculation results with the measured results.(2)On the basis of the actual engineering model,the internal force and deformation of the pile-anchor support structure were obtained by changing the embedded depth of the building pile foundation,the distance between the pile foundation and the edge of the foundation pit,and the load of the building pile foundation.It can provide reference for the design of the foundation pit supporting structure adjacent to the pile foundation of the building.(3)The horizontal displacement of the pile body and the bending moment of the pile body of the supporting pile increase with the increase of the load of the building pile foundation,and decrease with the increase of the buried depth of the building pile foundation and the distance from the pit edge.The maximum horizontal displacement of the pile body occurs at 1/3 of the depth of the foundation pit above the excavation surface of the foundation pit.When the depth of the pile foundation is less than the excavation depth of the foundation pit,the displacement of the supporting pile will increase significantly;the bending moment of the pile body will increase significantly.There is a sudden change near the excavation surface,and the maximum positive bending moment and the maximum negative bending moment are relatively close;the depth of the pile foundation of the building has a great influence on the distribution of the bending moment of the pile body.The difference between positive and negative bending moments will continue to increase.(4)The surface settlement around the foundation pit increases with the increase of the pile foundation load of the building,and decreases with the increase of the depth of the building pile foundation into the soil.When the distance between the pile foundation and the edge of the foundation pit exceeds the length of the anchor,the settlement will decrease.Rapid growth occurs and peaks. |
