Research Of The Features Of Dredging Grab's Excavation Action And The Flat-excavation Strategy

As transport ships become larger it requires the construction of deeper water port and to dredge the waterway, this makes the large or medium-sized dredger to become more and more popular. The grab dredger is a member of the dredger, as it can excavates larger depth, more flexibility, small contradiction with navigation, and many other advantages, so it has a more broad prospects in the field of dredging. The purpose of the paper is to research the excavating characteristics of dredging grab and flat-dredging strategy. Integrated use of the research method like theory analysis, simulation analysis and test. Firstly, research on the excavating characteristics of dredging grab in theoretical, Secondly, to research the practical ability of grab to realize flat-dredging and flat-dredging strategy, and get the excavating features of the example grab by simulation, Finally, research the example grab features when excavating on the flat surface and slope, and test the digging force. All works have got a series of achievements, mainly includes as the followings:(1)To analyze the key structure's parameters and kinematic relations of the grab, and get the kinematics equation and the kinematics expression of the bottom edge. And get the calculation process of the excavating condition and performance characterization parameters. To simulate the grab's excavating state by use MATLAB software, in the research, made the distance of the upper block and the lower block movement at the same time in the proportion to total travel position or the digging depth as the control condition. Have completed the simulation the process when the grab is excavating in different working conditions with the ordinary way, and obtained the operation conditions to get the optimal excavating performance and the rules of the curve change with and excavating conditions.(2)Combined the existing mechanics theory of the dredging grab and the related theory in soil mechanics, is to get the calculation formulas of the resistances when the dredging grab working, and simulation analysis of the eight resistances changing rules in the excavating process when excavating in flat or ordinary ways.(3)Realization of the theory that through the upper block's reverse compensation to dig, realize flat to realize flat-dredging, and have explored the reasonable mode of operation through the simulation method, and phased when the ratio of upper and lower block movement at the same time is equal, what the excavating curve changing rules with excavating depth, meanwhile, when the upper and lower block movement at the same time is not equal, to excavate a same depth, what about the characteristics of the curves and the excavating performance parameters in each working condition, also, have researched the flat-dredging strategy when excavating at the surface of the object was plane or slope, and illustrated the application of flat-dredging strategy method by 0.2m3 grab.(4) Through the test of grab excavating on plane, got the characteristics of the upper and lower block's movement relations and the curve. Studied the grab's characteristics of the curves when excavating on slope. And through the test have measured the force of the grab key positions when excavating on plane. The test results and the simulation results are obtained. At last, Confirmed the feasibility of flat-dredging strategy by the test which used the 0.2m3 grab and 16m3 dredging grab.