Hydraulic Vibration Pile Hammer Pile Capacity And Its Frequency And Hydraulic Control System Research

Hydraulic vibratory pile hammer is a new type of environmental-friendly pile machine which depends on oil pressure to generate eccentric vibration and forces the soil to vibrate so that the soil can be liquefied to realize easy pile sinking. At present, hydraulic vibratory pile driving technique is focused on the development and testing of the pile hammer on equipment in the mechanical engineering field all over China. The mechanism of vibratory pile, especially in the analysis of vibro-driveability and the characteristics of foundation soil liquefaction has been lacking a systematic theoretical research. To solve the problem above, this paper has done the following work:(1) Based on the engineering investigation and consulting extensive literature, a analysis and summary about dynamic characteristics of soil and liquefaction mechanism has been made in the article. It is based on the theory of ultimate stress state and shearing strength of soil. According to limit equilibrium condition (Mohr-Coulomb criteria of shear strength), it derives analytical equation of vibro-driveability mechanics. In this way, it can calculate the pile-sinking resistance. What’s more, it proposed a new method to calculate the near-resonance frequency.(2) The pile-soil interaction of liquefaction problem is analyzed by finite element difference software FLAC3D. The numerical simulation model for ground soil liquefaction is established by using Mohr-Coulomb model and Finn constitutive model for static liquefaction; It analyzes the effects of different parameters on liquefaction properties and vibro-driveability.(3) Based on the previous paper on the research of the vibration frequency and eccentricity influencing liquefaction properties and vibro-driveability of vibratory pile driving, the load characteristics of the system is researched. It designs hydraulic control system of frequency and eccentric moment.Exciting force of1600kN for the nominal low-frequency vibration in the hydraulic pile hammer system, type selection calculation is discussed in the paper. And it simulates the electro-hydraulic proportional flow valve. At last, by testing research on the spot, it verifies the correctness of the new method to calculate the near-resonance frequency.This study can predict the vibro-driveability of hydraulic vibratory pile hammer and calculate the pile-sinking resistance. What’s more, according to the practical geological condition, we can select reasonable pile parameters to improve the efficiency of pile sinking. It is of great practical value and provides useful reference of the application of hydraulic vibratory pile hammer in pile foundation engineering...