Experimental Study On Horizontal Bearing Capacity Of Large Diameter Precast Hollow Square Pile Foundation

As a kind of deep foundation,pile foundation is an important part of building structure.In practical engineering,pile foundation not only bears large vertical load,but also bears large horizontal load.However,the high-voltage power transmission tower foundation needs to bear large horizontal tension and wind load in actual work,especially in winter,the horizontal load of the tower foundation is greatly increased by the snow and ice of the wire,so the transmission tower foundation has higher requirements on the horizontal bearing capacity.As a kind of transmission tower foundation,large-diameter prefabricated hollow square pile foundation is widely used in transmission tower foundation because of its advantages of simple construction,short period and reliable quality.This paper summarizes the research progress and achievements of the horizontal bearing capacity of pile foundation at home and abroad,makes a systematic theoretical analysis of the horizontal bearing capacity of single pile,introduces the calculation method of the horizontal bearing capacity of single pile and derives the calculation formula.Taking the test pile of high voltage power transmission tower foundation of a 500 kV switchyard as the research object,the horizontal static load test of large diameter prefabricated hollow square pile foundation is carried out.The ABAQUS finite element software is used to further analyze the horizontal bearing capacity of large-diameter prefabricated hollow square pile foundation,providing theoretical support for the actual project.The main conclusions are as follows:(1)The horizontal bearing characteristics of the large-diameter prefabricated hollow square pile foundation with the length of 6m pile are consistent with the horizontal bearing characteristics of the rigid short pile,and the pile body has high bending rigidity.Finally,because the horizontal displacement of the pile top exceeds the allowable value of the building,the ultimate horizontal bearing capacity of the pile is reached.(2)The large-diameter prefabricated hollow square pile foundation with a length of 6m can bear the horizontal load of 190 kN on the upper part of the transmission tower of 500 kV switchyard.The pile body has a high bearing capacity,but the horizontal displacement of the pile top is large.It is suggested to improve the horizontal bearing capacity of the large-diameter prefabricated hollow square pile foundation by compacting the soil around the pile and increasing the length of pile.(3)The theoretical calculation formula of horizontal bearing capacity of largediameter prefabricated hollow square pile foundation is obtained,which can provide theoretical reference for practical engineering.