Experimental Study On The Mechanical Characteristic Of Group-Pile Foundation In Soft Soil Under Active Horizontal Loading

The soft soil has the characteristic of low strength and high compressibility. The mechanical characteristic of the bridge pile foundation in soft soil area is a very complex process of pile-soil interaction under horizontal load. So far, there has been less research on the model test of laterally loaded pile. Based on the research status of laterally loaded pile at home and abroad, we have solved the preparation problem of model soil and ensured test precision. The model tests of laterally loaded pile were performed to study the load transfer laws and the deformation characteristics of pile-soil interaction, and the test results were compared with the theoretical results. The main results and conclusions are presented as follows:(1)The horizontal displacement of the pile increases with increase of the horizontal load for the single pile and the pile group. Along the horizontal direction of the force, the horizontal displacement of the same row pile in pile group are same.(2)The location of the maximum bending moment in the pile below ground0.20to0.35times the length of pile, the location of the maximum soil resistance in the pile below ground0.35to0.50times the length of pile. As the pile group effect caused by the relaxation effect of soil between piles, it leads to mechanical inhomogeneity of single piles in pile group, the maximum bending moment and maximum soil resistance of the rear pile is less than the front pile in the same pile group.(3)The average horizontal bearing capacity of single piles in pile group is higher than the single pile under the same horizontal load. Along the horizontal direction of the force, the average horizontal bearing capacity increases with decreases of pile spacing. As the pile spacing increases, the average horizontal bearing capacity of single piles in pile group closer to the single pile.(4)Due to be bound by the cap, the maximum bending moment of single piles in pile group are significantly less than the single pile under the same horizontal load, and the top bending moment of single piles in pile group are higher than the single pile.(5)By measuring the foundation coefficient M, the theoretical results obtained by M-method show that they are closed with the model test results and reliable.