Study on bearing behavior of a single pile under combined vertical and lateral loads in sand

The vertical bearing behavior of a single pile is influenced by change of the friction resistance of soils around the pile, which is caused by the lateral deformation of the pile. Around the pile, the lateral resistance of soils can be affected by vertical load, and meanwhile with the change of flexural deformation, additional moment will be aroused and the horizontal bearing behavior of the single pile is influenced. The bearing behavior of the single pile under the combined vertical and lateral loads in sandy soils is studied through indoor model tests. The results show that the horizontal bearing capacity of the single pile increases with the increase of the pre-applied vertical load in sandy soils, which is contrary to the horizontal displacement. The lateral friction resistance in the upper part of the pile decreases with the increase of the horizontal load, while the resistance at the pile end increases actually, and as a whole, the vertical bearing capacity of the single pile decreases in sandy soils with the increase of the pre-applied horizontal load. The depth of the maximum moment caused by the horizontal load is about 5 to 7 times the diameter of the pile, and the influence depth of bending moment along the pile and lateral friction resistance caused by the lateral load is about 10 times the diameter of the pile below the surface of sandy soils. Based on the relevant current research results and theoretical analyses, the interaction mechanism of the components of combined vertical and lateral loads of the single pile in sandy soils is analyzed, and the rationality of the test results is verified.