The Shield Machine Hydraulic Long Pipeline Vibration Modal Analysis And Experimental Research

The characteristics of the hydraulic piping system in Tunnel Boring Machine (TBM) are large slenderness ratio, high fluid pressure and low flow velocity. Due to fluid structure interaction, the vibration of pipe was increased, and control signal was lagged feedback. Meanwhile, the effects of FSI were intensified by the valve closure, the changes of loads and even the impurities interfused in the oil. These also result in severe vibration of pipelines, and even there might be extreme conditions such as pipe's cracking. Combined with characteristics of hydraulic piping system of shield machine, studies of several following aspects were done in this article:1. The hydraulic experimental platform was set by referencing the long hydraulic piping system in TBM. In structure design, the devices of two hydro cylinders in opposite vertex with a large thrust load were imitated to the characteristics of a large thrust load in the TBM piping system. In testing system, a multi-stream combination test devices were developed for vibration effect of TBM piping system, to ensure test scientifically and reliably.2. The axial and lateral vibration differential equation considering fluid-structure interaction for hydraulic long pipeline of shield machine was derived and summed, and the overall transfer matrix considering fluid-structure interaction of hydraulic long pipeline was deduced in detail; for a typical long straight hydraulic pipeline(length 8000mm, length to diameter ratio greater than 900),the numerical analysis of its modal parameters considering fluid-structure interaction was done; compared with modal parameters got from the test, the validity and limitation of the method used for the modal calculation of the actual hydraulic long pipeline were analyzed.3. The modal pilot study of hydraulic long pipeline was carried out. The first 14 frequencies and mode shapes of the long straight pipeline (length 8000mm) been filled with the stationary oil, under the three spans (single span, double-cross and four-cross), were measured and analyzed; The test and analysis for the vibrating mode of hydraulic long pipeline under many actual working conditions were done; From two aspects of the optimization parameters and optimization motivators, the damping measures of hydraulic long pipeline were proposed.