Research on Uplift Bearing Performance of Assembled Steel Pipe Pile used in Transmission Lines in Mountainous Terrain

Kun Zhou,Qi Zhang,Linhua Chen,Xiangyu Gu,H Li,L Wang,I Corbi,O Corbi,M Ashraf,P Yang

doi:10.1051/matecconf/201927503008

Abstract

Assembled steel pipe pile, which is a novel pile foundation, is developed in the paper. The ultimate uplift bearing capacity of the pile is proposed, and simulation by Plaxis3D and the corresponding experiment are performed to verify the theory. In the simulation, ultimate uplift bearing capacity of the assembled steel pipe pile and ultimate lateral frictional resistance of the interface of pile-soil increases with the increasing of the strength and stiffness of the interface of pile-soil, and with the increasing of length-diameter ratio, ultimate uplift bearing capacity of the assembled steel pipe pile increases while the ultimate lateral frictional resistance decreases gradually. The ultimate lateral friction is influenced by both of the strength of the soil around the pile and the interface of pile-soil, and the ultimate uplift bearing capacity obtained by simulation and theoretical calculation are close. Long-gauge FBG sensors are used in the experiment for measuring the longitudinal strain of the pile, and the error of ultimate uplift bearing capacity between the results of experiment and theory is less than 10%.

Highlights

With the development of the social economy, the construction of electrical engineering is becoming increasingly important
The steel pipe pile is convenient to construction in the spot, the diameter and length of the pile is usually large which leads that the transportation of it is inconvenient in mountainous terrain
Combined with the advantages of the steel pipe pile, a novel foundation form of transmission line is proposed as assembled steel pipe pile foundation

Summary

1.Introduction

With the development of the social economy, the construction of electrical engineering is becoming increasingly important. Where U is the pile girth, qsik and αi are the interface ultimate friction and the corresponding correction coefficient about the ith layer of the soil respectively, li is the thickness of ith layer of the soil, Gp is the weight of assembled steel pipe pile and the inner soil, ξ is the empirical coefficient, which is 0.8 for the permanent anchor and 1 for the temporary one, ur is the girth of the anchor, hr is the length of the embedded section of the anchor, and f is the characteristic value of bonding strength between mortar and rock, which can be set according to the GB. Plaxis3D is used for simulating the assembled steel pipe pile in this paper as shown, and the influences about different grouting conditions on the ultimate bearing capacity of the pile is researched. The soil with the depth ranges from 0 to 3m is hard plastic clay and the soil with the depth exceeds 3m is decomposed rock

Constitutive relation and hypothesis

Analysis of the characteristic about uplift bearing capacity

Parametric analysis

Ultimate uplift bearing capacity of the simulated pile

Findings

Conclusion