Experimental Research On Erosion Mechanism And Restoration Of Tombolo In Bijia-mount Island

It develops a tombolo connecting the island with the mainland on the northside of Jinzhou Bijia-mount island. It is one of few tombolos that retained the original eco-geomorphological features completed in the world, it has an unparalleled position in similar landscapes in the world, it has been chose to or reached the level of the World Heritage. However, with the construction of coastal engineering near the sea areas in recent years, Marine dynamic field in Bijia-mout waters has changed fundamentally. Tombolo has been eroded by waves from east, four tidal ditches have been appeared, it changed the morphology of tombolo seriously and reduced its charm enormously.Firstly, this paper introduces the background and significance of research about Bijia-mount tombolo, as well as the recent development and progress in the research about tombolo by the domestic and foreign scholars including theory analysis, physical model experiment. It summarizes the rule of formation about tombolo. On account of the erosion status for Bijia-mount tombolo, it is caused by the change of marine dynamic conditions that sustain the balance of tombolo, so this paper mainly studied the cause of erosion for tombolo from the point view of the hydrodynamic.Therefore, on the basis of summing up the results of previous research on Bijia-mount tombolo, this paper made a comprehensive analysis on the formation of Bijia-mout tombolo, it made a overview of situation about Bijia-mout waters and describtion about the erosion and deposition environment and hydrodynamic characteristics in detail, it compared the morphological evolution of tombolo before and after the the construction of Jinzhou Port as well as the change of wave and tide in Bijia-mout waters, it made a analysis on the erosion mechanism of tombolo, and verified the results of theoretical analysis by integral physical model test and cross-sectional physical model test.Under the condition of not be able to restore the balance of hydrodynamic, the fundamental measures that repair the form of tombolo and keep it stable is to reduce hydrodynamic conditions on the east for the erosion. We used submerged breakwater as measures for repairing tombolo, and proposed two layout programs about submerged breakwater, we verified the effectiveness of the measures for repair by physical model test.