Investigation of the vibration impact method of pile deepening

Abstract

Piles for the construction of foundations have been used since ancient times. The piles were first used in soil compaction in order to significantly increase the load-bearing capacity of the foundation bases, and then as supporting elements that can transfer the load from the foundation plate to the soil. The piles were originally made of timber and hammered. The pile heads were cut below the water level, thus protecting them from contact with air. At present, more than 100 types of piles are used in the foundation, which are classified by the three most important features: this is a feature of the transfer of load to the soil (piles, hanging, sealing, friction); - by the method of deepening or embedding piles in the soil (previously produced and deepened in finished form; made in the design position; combined); - by material: wooden, concrete, reinforced concrete, combined.
The most widespread piles - pillars and hanging piles - are the most widespread. Piles are used to transfer soil loads mainly to the lower end on low-compressed soils (rocky, sandy, hard clays). Hanging piles transfer the load to any soil at the lower end, as well as due to the friction forces on the side surface.
With each passing year, the use of vibration impact equipment, the so-called vibrating hammer, is increasingly beginning. This technique is successfully used in the construction of reliable foundations for various structures. The implementation of the above requires a thorough study and study of the process of vibration shock piles. and creating the most productive ways to accomplish it.
One of the promising areas is the introduction of pile foundations in the construction of buildings with dense construction in cities and towns.
It should also be noted that the construction of pile foundations makes it possible to implement complex mechanization and automation of technological processes, which significantly increases the productivity of work.
Vibrating piles is one of the most productive ways to build a solid foundation for a variety of structures. The vibration shock absorption, which is widely implemented in construction, is a percussion technology for deepening piles. The method of vibration-shocking deepening of piles is that the vibration significantly reduces the forces of emerging friction and the adhesion force between the pile and the soil, and as a result, the resistance to the deepening of the pile is significantly reduced.
The vibration impact of the piles was considered by us in the interaction of mechanical and electromagnetic processes and the result was a mathematical model of dynamic processes in the operation of the hammer, which included nonlinear differential equations of motion of the mass of the vibrating hammer and a linear differential equation of electromagnetic phenomena in the drive motor. Implemented the created mathematical model, we built graphs that characterize the process.
The vibration impact of the piles was considered by us in the interaction of mechanical and electromagnetic processes and the result was a mathematical model of dynamic processes in the operation of the hammer, which included nonlinear differential equations of motion of the mass of the vibrating hammer and a linear differential equation of electromagnetic phenomena in the drive motor. Implemented the created mathematical model, we built graphs that characterize the process.
Analyzing the information obtained, it can be emphasized that the vibration-shock method of pile-driving has received little attention and broad information is practically absent.
Therefore, it is important to create productive samples of vibratory hammers, methods of their calculations and to conduct scientific studies of the dynamics of the working processes of these machines, which is what this master's work is aimed at.
In this work, we theoretically investigated, using a mathematical application MathCAD, the dynamics of a hammer and obtained the results that can be used in the design and determination of the dynamic loads of such vibration impact machines.
When calculating the hammers for static and fatigue strength, the oscillatory processes of structures and their dynamic loads are not taken into account at this time. However, their load-bearing capacity can be significantly increased if their amplitude-frequency characteristics are taken into account in their design calculations. The lack of a refined methodology for calculating modern vibrating machines, including vibratory hammers, for the effective immersion of various piles complicates their design and operation.
The purpose of the article is to elucidate the results of mathematical modeling of oscillatory processes in deepening piles with a hammer and to determine the dynamic loads on its elements.
In the work, the dynamics of the mechanism of vibrating hammer drive was theoretically investigated, using mathematical software environment MathCAD, and results were obtained that can be used in the design, calculation and determination of dynamic loads of such vibrating machines.