Research On Application Of Vertical Anchor Rope+Prestressed Support Pile In A Deep Foundation Pit

In order to study the application of vertical anchor cable + prestressed supporting pile in a deep foundation pit,this paper studies it by using the software of the straightening software plus numerical calculation,comparing the calculation characteristics and calculation results of the two calculation methods,and then According to the actual situation,a better calculation method is selected.Finally,the application of the vertical anchor cable +prestressed support pile in deep foundation pit is expanded and analyzed,so as to achieve the vertical anchor cable + prestressed support pile in deep foundation.Purpose of applied research in pits.Research indicates:(1)The calculation results of surface settlement by numerical software are between the calculation results of the software parabola method and the triangle method,and are close to the triangle method.When using lizheng software for foundation pit support calculation,it is necessary to judge the change trend of surface subsidence according to the parabolic method of lizheng software.However,in order to ensure the accuracy of the calculation,it is necessary to deal with the settlement value accordingly to avoid the calculation being conservative.(2)Based on the comparison between the numerical calculation results and the calculation results of the rationality calculation,the input parameters of the rationality calculation are suggested,and the prestress size is recommended to be increased to 1.5 times the design prestress;the diameter of the supporting pile is recommended to be reduced to the design support.The diameter of the pile is 0.85 times;the distance between the design position of the prestressed anchor cable and the edge of the supporting pile is doubled.(3)The maximum displacements of the support piles with prestressed anchor cables for the deep section pit GA support piles are 7.64 mm and 9.57 mm,respectively.The difference between the two is 20.17%;no prestressed anchor is added.The maximum displacement values of the cable supporting piles for numerical simulation and straightening calculations were 9.53 mm and 11.94 mm,respectively,and the calculated results differed by 20.18%.(4)During the increase of the prestress of the anchor cable from 100 kN to 300 kN,the increase in the vertical prestress’ s ability to restrain the horizontal displacement of the foundation pit,the ground settlement of the foundation pit,and the deformation of the supporting piles increased by 32.61%,30.93%,and 27.58%,respectively.;Shear force value of supporting pile decreased by 33.01%,and bending moment value decreased by 37.19%.During the increase of the supporting pile diameter from 1.0m to 2.6m,compared with the supporting pile diameter of 2.6m,the horizontal displacement of the foundation pit,the ground settlement,the maximum shear force value,the maximum bending moment valueand the deformation of the supporting pile were respectively Increases were 42.74%,12.66%,39.86%,34.07% and 20.02%.During the increase of the distance from the vertical anchor cable to the outer wall of the supporting pile from 150 mm to 870 mm,the horizontal displacement of the foundation pit,the ground settlement,the maximum shear force value,the maximum bending moment value,and the deformation of the supporting pile increased by 49.89%,24.62%,and 31.53,respectively.%,29.87%,and 18.72%.(5)After calculation,it can be known that the optimal prestress of each anchor cable in this project is 100 kN,the optimal pile diameter of the supporting pile is 1.8m,and the optimal distance between the vertical anchor cable and the outer wall of the supporting pile is 455 mm.