| In deep foundation pit engineering,pile-anchor support is the most common form.Pile-anchor support utilizes the joint action of piles and prestressed anchor rods to provide support for the foundation pit.Large-scale excavation of deep foundation pits will cause ground uplift in the foundation pit and ground settlement outside the pit.However,in actual construction,it can be found that the pile-anchor supporting structure will cause upward displacement of the supporting pile when excavating a large area of the foundation pit,which will cause differential settlement with the ground outside the foundation pit.Based on the reconstruction project of Kangjiagou public transit electrical protection base,this article uses the theoretical deep foundation pit software to theoretically analyze and analyze the supporting structure of each section of the foundation pit.Stress and strain and ground settlement,at the same time,the Midas GTS NX software is used to perform numerical simulation calculations on the pileanchor supporting foundation pit project,and the calculated ground settlement and displacement of the supporting pile are compared and analyzed with on-site monitoring data.The parameters such as pile diameter,pile length,and pile spacing are used to study the deformation characteristics of pile-anchor supporting foundation pit engineering.The specific research contents are as follows: 1)For each section of foundation pit support,the software is used to calculate the deep foundation pit software,and the displacement,bending moment,shear force and ground settlement of each support pile are obtained;2)Midas GTS NX The software performs numerical simulation calculations on the foundation pit engineering,and obtains the displacement and deformation of the foundation pit supporting structure system and the settlement and horizontal displacement of the foundation pit ground;Verify the reliability of the numerical model;4)Change the parameters of the supporting piles and explore the law of the deformation of the supporting piles on the ground deformation of the foundation pit project.Taking the verified numerical model as the basic model,by changing the three parameters of the pile diameter,pile length and pile spacing of the supporting piles,the influence rules of the three and the deformation of the foundation pit engineering are explored.Through the above research contents and methods,the conclusions are as follows: 1)The maximum value of ground settlement occurs at a certain distance behind the pile,and the influence range of the ground settlement is about double the diameter of the pile;2)The sections supporting the foundation pit In the middle section,the ground settlement and the horizontal displacement of the soil are relatively large,and local ground uplift and stress concentration will occur at the negative corner of the foundation pit;3)increase the pile diameter and pile length and reduce the pile within a certain range The spacing is beneficial to control the ground deformation of the foundation pit project,but when the pile length increases to a certain length,the influence on the control of the foundation pit deformation is small;when the pile spacing increases to a certain size,the foundation pit deformation will increase significantly,and the foundation pit To destruction.Through the above analysis and research,the deformation law of pile-anchor supporting foundation pit engineering is obtained,which can provide reference and reference for similar pile-anchor supporting foundation pit engineering in the future;4)The numerical simulation results of MIDAS GTS NX software show that when the pile length is increased and the pile spacing is reduced,the overall anti uplift ability of the supporting pile is enhanced,and the vertical displacement of the pile top is reduced;when the pile diameter is increased,the vertical displacement of the pile top is increased.Therefore,in the actual engineering construction,in order to control the vertical displacement value of the pile top,we can increase the pile length and reduce the pile spacing. |
