Study On Horizontal Bearing Capacity Of Helical Pile In Clay Soil Under Serviceability Limit State Condition

From a construction perspective,the main advantages of helical piles include fast installation,low noise,and superior bearing performance.Therefore,it is a basic type with great promotion prospects for offshore wind turbines in deep water.As the foundation of the offshore wind turbine,the helical pile needs to resist the wind,wave,current,and other loads acting on the wind turbine,and the horizontal bearing capacity of the helical pile is the key to its engineering application and design.For the aforementioned reasons,a study on the behavior of a laterally loaded model of the rigid and rigid-flexible helical pile in soft clay under the serviceability limit state is performed,through numerical simulation.The bearing capacity,failure mechanism,and deformation mode of the helical pile are analyzed,and the following key issues have been addressed in this study:(1)Through the numerical simulation of a laterally loaded model of the rigid helical pile,the normalized load-displacement curves at the mud surface with different shaft diameters,helical plate diameters,and helical plate burial depths are obtained,and the results show that the shaft diameter,helical plate diameter,and helical plate burial depth all affect the horizontal bearing capacity of the rigid helical pile.The larger the shaft diameter,the larger the horizontal bearing capacity of the rigid helical pile,the shaft diameter and the horizontal bearing capacity of a helical pile are approximately linear relationship,the horizontal bearing capacity of a helical pile with a shaft diameter of 3 m is 79% higher than that of a shaft diameter of 1.5 m;the horizontal bearing capacity of a rigid helical pile increases linearly with the increase of the helical plate diameter,the horizontal bearing capacity of a helical pile with a helical plate diameter of 5 times the shaft diameter is 75%higher than that with a helical plate diameter of 2 times the shaft diameter;the horizontal bearing capacity of a rigid helical pile increases at first and then decreases with the depth of a helical plate,and there is a non-linear relationship between the helical plate depth and the horizontal bearing capacity of the helical pile.(2)The effects of shaft diameter,helical plate diameter,and helical plate burial depth on the horizontal bearing capacity of the rigid-flexible helical pile are analyzed by numerical simulation.The larger the shaft diameter,the greater the horizontal bearing capacity of a rigid-flexible helical pile,the horizontal bearing capacity of a helical pile with a shaft diameter of 0.95 m is 435% larger than that of a shaft diameter of 0.65 m;the larger the helical plate diameter,the greater the horizontal bearing capacity of a rigid-flexible helical pile,the horizontal bearing capacity of a helical pile with a helical plate diameter of 5 times the shaft diameter is 33% higher than that with a helical plate diameter of 2 times the shaft diameter;the shaft diameter and helical plate diameter are approximately linear with the horizontal bearing capacity of a rigid-flexible helical pile,the relationship between the depth of a helical plate and the horizontal bearing capacity of a rigid-flexible helical pile is nonlinear,with the increase of the depth of a helical plate,the horizontal bearing capacity of the helical pile first remains approximately the same,and then decreases with the increase of the depth of a helical plate.(3)Based on the effects of shaft diameter,helical plate diameter,and helical plate embedment depth on the horizontal bearing capacity of rigid and rigid-flexible helical piles,a calculation method for predicting the horizontal bearing capacity of the rigid and rigidflexible helical piles is proposed.(4)The method of calculating the horizontal bearing capacity of rigid and rigid-flexible helical piles is proposed in this paper can predict more accurately the horizontal bearing capacity of helical piles in soft clay under the serviceability limit state.