Analysis of stress distribution characteristics of transmission tower pile foundation considering soil properties in high latitude and extremely cold regions

• Published in: Structural Engineering and Industrial Architecture pp. 395 - 404
• Main Authors: Jiang, Guangwei, Zhang, Yu, Duan, Yana, Wang, Panpan, Fan, Xiaoqi, Sun, Yang, Zhang, Wei, Zheng, Kai
• Format: Book Chapter
• Language: English
• Published: CRC Press 2024
• Edition: 1
• ISBN: 9781032546162; 1032546166; 9781032546131; 1032546131
• DOI: 10.1201/9781003425793-50

With the rapid development of the economy in our country, the demand for electric energy is gradually increasing, and new transmission lines are being erected. Foundation engineering is one of the projects with a large investment proportion in transmission line engineering, accounting for 15%-30% of the total investment proportion. Its cost is largely affected by soil properties on the stress distribution law of the foundation. Engineering survey report based on a line project, considering the changing effect of elastic modulus E of soil with different depths for the foundation on stress distribution, the influence of soil and pile foundation interface first hypothesis smooth top load all passed to the foundation soil, and the second hypothesis of the circular foundation is under vertical uniformly distributed load curve of stress cone downward diffusion. Then, the Boussinesq solution is used to calculate the additional stress values at each point of the load center line of the soil at the bottom of the pile foundation under the circular vertical uniform distribution load (E 1 < E 2 , E 1 = E 2 , E 1 > E 2 ) under three conditions (i.e. E 1 < E 2 , E 1 = E 2 , E 1 > E 2 ), and the foundation stress values are obtained by superimposing with the dead weight stress. Finally, three-dimensional finite difference software FLAC3D is used to simulate the z direction vertical stress and x and y direction horizontal stress of subsoil at the bottom of the transmission tower pile foundation. According to the above research, the change of E 1 and E 2 will lead to a large change in the distribution of ground stress, and the ground stress in the case of E 1 < E 2 is significantly higher than that in the other two cases. It is concluded that the factors affecting the foundation stress will change with the increase of depth, both dead weight stress and additional stress will become the key factors to determine the foundation stress within a certain range. Through research of this paper, it provides a theoretical basis for the design and construction of the transmission tower pile foundation of line A, and at the same time, it will reduce the investment of the foundation engineering to a certain extent to ensure the maximization of enterprise benefits. Engineering survey report based on a line project, considering the changing effect of elastic modulus E of soil with different depths for the foundation on stress distribution, the influence of soil and pile foundation interface first hypothesis smooth top load all passed to the foundation soil, and the second hypothesis of the circular foundation is under vertical uniformly distributed load curve of stress cone downward diffusion. Many domestic and foreign scholars have conducted a large number of experiments and research on the law of foundation stress transfer under vertical concentrated loads, and they all agree that the foundation stress under vertical concentrated loads spreads downward in a curve cone. The main factor controlling foundation stress in the upper soil is the change of additional stress, while the main factor controlling foundation stress in the lower soil is the change law of dead stress to additional stress and then to dead stress with the increase of depth.