Driving Features of Tapered-Prismatic Piles and Their Resistance to Static Loads

The field tests of large-scale models of driven tapered prismatic and prismatic piles for driving static vertical and horizontal loads are presented. Field tests were carried out on sandy loam on piles models (M 1:3) with different lengths and cross-sections of the pyramidal segment. It has been established that the driving of tapered-prismatic piles is accompanied by both large (by 1.10-1.60 times) and lower (by 8.0-37.0%) energy consumption for their driving in comparison with conventional prismatic and pyramidal piles. It was also revealed that under the vertical pressing load, the bearing capacity of the tapered-prismatic piles is 1.09-1.48 times, and under the horizontal static load, it is 1.17-1.80 times higher than the prismatic pile. It has been established that with an increase in the length of the pyramidal part of the experimental piles, there is an increase in their bearing capacity by 1.12-1.34 times. Equations are proposed for determining the bearing capacity of tapered-prismatic piles. The research results serve as the basis for the development of recommendations for the calculation and design of tapered-prismatic piles. The revealed features of the behaviour of tapered-prismatic piles allow to reasonably assign the length and dimensions of the cross-section of their pyramidal segment.