| With the expansion of the application of pile foundation and the increase of superstructure system weight,the way to improve the bearing capacity of pile foundation has become a problem which requires more considerations for the researchers in the field of foundation engineering.The rectangular pile has a larger specific surface area than the circular pile,so it can bear larger load through the pile friction resistance.Gravel soil is a kind of soil with complex material composition and different fabric characteristics.Even the engineering geological characteristics of gravel soil in different sites in the same area are different.In engineering practice,the research on lateral bearing characteristics of rectangular piles in gravel soil site is rare.In view of this,this paper carried out the field test of laterally loaded rectangular pile in gravel soil,studied the lateral bearing characteristics of rectangular pile in gravel soil,and carried out theoretical calculation based on the "m" method.Finite element solid model is established by using the finite element software and numerical simulation results of lateral bearing characteristics of rectangular pile in gravel soil are obtained.The results obtained by the above methods are compared and analyzed.The main research contents and achievements include:(1)Lateral bearing tests of rectangular piles were carried out in gravel soil foundation before and after grouting,and the load-displacement curves,load-displacement gradient curves,pile displacement and bending moment of rectangular piles were obtained under various loads.The tset results show that for a rectangular pile with a specific section size,the lateral displacement of the rectangular pile with lateral load perpendicular to the short side is smaller than that of the rectangular pile with lateral load perpendicular to the long side.For the same rectangular pile,the pile displacement after grouting under the same grade of load is smaller than that before grouting,and the bending moment of pile under the same grade of load after grouting is lower than that before grouting.(2)Based on the in-situ plate loading test data,the "m" value of the rectangular pile in the gravel soil of the site was estimated,and the rectangular pile before grouting was calculated by the "m" method based on the estimated value.According to the field lateral load test data,the "m" value in post-grouting state was back-calculated.The results show that post-grouting can significantly improve the "m" value.(3)Compared with the laterally loaded rectangular pile in the field,the finite element solid model is established by using the finite element software,and the numerical simulation before and after grouting is carried out for the laterally loaded rectangular pile.The lateral bearing characteristics of rectangular piles before and after grouting are analyzed by the output of pile displacement,pile bending moment and pile side soil resistance through post-processing module.The field test,"m" method theoretical calculation and numerical simulation are compared and analyzed.By comparison,it is found that the "m" method can better reflect the pile displacement along the depth under large load grade,but it will also overestimate the pile bending moment and pile side soil resistance. |
