Experimental Study On Characteristics Of Rock-Type Landslide Surge And Impact For Navigable Conditions Of The River—Channel Type Reservoir In Mountainous Area

In recent years, with the growing construction of water conservancy project for mountain river reservoir, a large number of potential、hidden and once occurred slopes, especially the existing rock landslides, which all have been affected by long-term high-water and the operation schedule of reservoir, are all likely to be induced by the influence of long-term high-water and the operation schedule of reservoir, which will finally results in the slump and surge of slopes with a larger volume and energy. With the continuous spread of the swell, ports、ships、channel buildings and affiliated facilities in reservoir area will be severely destroyed by the enormous energy of surge and run-up. In practical engineering, our understanding and research of the characteristics and harm of landslide surge for mountain river reservoir is not through and complete. Consequently, studying the influence of surge characteristics of rock landslide for mountain river reservoir on channels has important practical significance. On the basis of site investigation and analysis of landslide data, the means of physical model tests and theoretical analysis are adopted to study the surge characteristics of rock landslide、analyze the spreading and run-up of rock landslide surge、study the mooring and impact force of ships and mooring system interaction under the action of landslide surge, and the main research results achieved are as follows:(1) On the basis of investigation and data analysis along coastal segments among landslides occurred in the Three Gorges Reservoir, the characteristics of landslides having occurred are briefly summarized and furthermore analysis、 induction and conclusion are made from the aspects of material composition and geological structure of landslide. Finally landslides occurred in the Three Gorges Reservoir are classified from different levels.(2) Taking the landslides occurred in the Three Gorges Reservoir as objects of study and from the perspective of the overall energy, the simulation technology of laboratory for landslide surge is optimized separately and test research on physical model which takes the landslides occurred in the Three Gorges Reservoir as objects of study is determined.(3) The characteristics of initial and on-way surge of rock landslide is obtained by model test and data calculation and analysis of rock landslide surge. The primary and secondary relationships of influence factors are obtained by mathematically inducting and analyzing influence factors of surge. By the method of mathematical regression, the empirical formula of the first wave height of rock landslide is established.(4)According to the arrangement of measuring points of wave height for surge test and through the analysis of experimental data, the propagating regulation of surge in curved river channel is obtained. Four attenuation regions of surge in curved river channel are induced by analyzing the contour map of wave height of all the measured data. In addition, on the basis of factor analysis and regression analysis, the empirical formula of wave height attenuation of surge in different regions is given.(5)The main characteristics and influence of various factors of reservoir banks run-up under the effect of landslide surge is analyzed and the empirical formula of the maximum run-up under the effect of surge is given.(6) By testing model test and calculation and analysis of data for the mooring and impact force of ships under the effect of surge, the change regulation of the mooring and impact force of ships under the effect of surge is obtained, the rated peak value of the mooring and impact force of ships in the same wharf is given and the influence degree of landslide surge on wharfs and ships is determined. Meanwhile, the corresponding countermeasures are put forward.(7)The empirical formula of the effective impact energy for mooring ships is revised on the basis of factor analysis and regression analysis, the result of which shows that this formula has a high accuracy and it can be used in engineering.(8) By testing model test and calculation and analysis of data for mooring ship system under the effect of surge, the change regulation of anchor chains tension for mooring ships under the effect of surge is obtained, the rated peak value of mooring ships in different regions under the effect of surge is given and the influence degree of landslide surge on mooring ships is determined.