Dynamic Testing Application of Foundation Treated by Preloading in the Water Transport Engineering

After the foundation is treated by vacuum stacking pre-pressure, the bearing characteristics, dynamic parameters and characteristics of the foundation are abnormal, which has a great impact on the design of dynamic foundation. Combined with the actual water transport engineering project on the vacuum stack pre-pressure treatment of the rotary jet grouting pile composite foundation and bored pile foundation, dynamic tests were conducted to obtain the stiffness parameters of compression, shear and torsion, the first vibration mode of vertical and horizontal steering, the damping ratio of torsional steering and the total vibration mass of the foundation and pile. Based on the measured data, the vibration conversion coefficients related to the static stress on the bottom surface of rotary jet grouting pile composite foundation and bored pile foundation were calculated, and the foundation compression, shear, torsional stiffness, torsional steering damping ratio and the improvement coefficient of the first vibration mode of vertical and horizontal return steering of the foundation were also calculated. The test and calculation results of various actual parameters show that when the foundation dynamic parameters actually obtained on the site of two different types of foundations are used for the vibration and vibration isolation design of power machine foundation, parameters should be converted into the foundation dynamic parameters adopted in the design according to the actual service conditions of power machine foundation, so as to avoid deviation to the foundation design.