Force Calculation of Mechanical Model of Pile-anchored Support Structure Based on Elastic Foundation Beam Method

Abstract

With the widespread use of deep foundation pit engineering in engineering construction, the force calculation problem about deep foundation pit support engineering has become a common problem in today’s engineering construction process. In this paper, based on the elastic foundation beam method, a simplified mechanical model of pile-anchored structure is proposed, and a systematic and practical calculation method is proposed for the force and deformation calculation of deep foundation pit support structure. The method simplifies the support structure as a vertically placed elastic foundation beam, the support, anchor and geotechnical body are replaced by a spring system, the spring stiffness of geotechnical soil can be calculated by the deformation modulus of geotechnical soil, and a systematic calculation method is proposed for the dynamic characteristics of the construction and structure of the foundation pit project; Based on the monitoring data of a deep foundation pit project, the calculation method of the simplified mechanical model proposed in this paper is verified, and the theoretical calculation value is compared with the field monitoring results; Single factor analysis is carried out on the detailed parameters of pile-anchor supporting structure to study the influence of cable prestress, cable dip Angle, pile diameter, pile length and other related parameters on the deformation and stress characteristics of supporting structure. Then the orthogonal combination of all factors is carried out to propose the optimization design. The results show that the maximum settlement deformation of the calculated value is 23.437 mm, and the maximum settlement deformation of the monitored value is 26.517 mm, and the difference between them is small. The maximum bending moment is 1210 kN⋅m after 150 kN and 250 kN horizontal prestressing is added to the second- and third-layer anchors respectively. After optimization, the maximum bending moment of pile row is 336.87 kN⋅m, and the maximum horizontal displacement of pile body is 16.505 mm, which is reduced by 11.97% compared with the original design.