Dynamic Behavior Of Cable-guided Hoisting System For Vertical Shaft Construction

As an essential part of the transportation system for sinking a vertical shaft, the hoisting system for shaft construction is a kind of hoisting system guided by cables, and its hoisting height varies with the construction of the vertical shaft. The lower ends of the guiding cables are fixed to the suspension platform while their upper ends are connected to the winches that can provide preloads for the guiding cables. The bucket, known as the hoisting conveyance of the system in this thesis, is used to transport gangue, water, workers and sinking devices. On the one hand, due to the inertia, flexibility and small bending stiffness of the guiding cable, the hoisting bucket is subjected to the lateral vibration under the external excitation during the hoisting process. On the other hand, the preload of the guiding cable plays an important role in affecting the lateral vibration of the bucket. However, the preload per 100 m gradually decreases with the increase of the depth and up to the smallest at the bottom of the shaft, which is the most dangerous period for the hoisting bucket. At the present, China will excavate the shafts that exceed 1600 m, which sets higher requests for the dynamical carrying capacity, efficiency and the reliability of the cable-guided hoisting system. However, the mass of the existing platform cannot satisfy the preload demand of 1t/100 m, thus, the research on the dynamic characteristics of the cable-guided hoisting system, which aims at proposing an approach of predicting the lateral vibration of the bucket and revealing the relationship between the preload and the lateral vibration, has an essential significance for enhancing the safety and efficiency of the shaft construction.In this thesis, the theoretical modeling, numerical calculation, Adams simulation and experiment are combined to investigate the dynamic behavior of the cable-guided hoisting system. The main research work and new ideds are summarized as follows:Firstly, the equivalent mass and stiffness of the guiding cable is obtained, and the lateral vibration model is established using the assumed mode method. In order to analyze each order modal and discuss the energy characters and stability, the natural frequencies are calculated though solving the boundary transcendental function and the vibration model is developed based on the normal modes. An Adams simulation model is presented to validate of the numerical solution, where a high-efficiency driving strategy is proposed. The numerical results show that the first order frequency of the guiding cable will firstly decrease, and then increases, which agrees with its lateral time-varying stiffness. The stability analysis indicates the hoisting system is stable and unstable during downward and upward movement, respectively.Secondly, the lateral coupled vibration model of the bucket and the platform is established and used to analyze the effect of the constraint conditions of the platform on the lateral vibration. Then, the lateral-torsional vibration model of the bucket with tension difference between two guiding cables is derived from Lagrange equations of the first kind. From the frequency analysis, it is can be seen that the frequency from the second order of the guiding cable increases with the growing length of the hoisting cable. The effects of various parameters on the lateral and torsional vibrations are analyzed and numerical results reveal that the appropriate tension difference between the two guiding cables could decrease the maximum lateral displacement of the bucket. The actual situation of the Cixi No.1 shaft is adopted as an example, where the lateral vibration of the bucket is reduced by the reasonable tension difference, thus, the optimal tensin could be determined by the presented model.Subsequently, in order to master the longitudinal-lateral-torsional vibration of the cage with the eccentric load in the temporary reequipping system, the continuously distributed model was established and applied to two cases. The time-variant and time-invariant three-node elements are combined to establish the finite element model, in which the number of the element keeps constant. One changeling problem is addressed that in the mode summation method the deformation of the guiding cable is not clear with less modes, while the solution will diverge with more modes because the trial functions at the top and bottom of the cage are approximately equal.Finally, the experimental setup of the cable-guided hoisting system is designed and established, where the lateral acceleration and the pitch angle of the hoisting conveyance is obtained by wireless measurement to verify the theoretical models. Further, the field experiments are conducted in Cixi and Tangkou shafts, where the lateral vibration of the bucket is measured by the high-precision laser displacement sensors. In addition, the wireless transmission of data and images is explored and applied to monitor the dynamic behavior of the bucket.