Study On The Methods Of Acquiring Design Parameters In The Actions Between Sea Ice And Coastal Structures

The design of coastal structures in the Bohai Sea area of our country should take into account the impact of sea ice disaster.So it is important to study on the method of acquiring design parameters in the actions between sea ice and coastal Structures.When the action of ice on structures,ice is crushed or not crushed in two cases.When the ice is not crushed,the ice force on structures depends on the kinetic energy.When the ice is crushed,it depends on the failure mode of ice.The kinetic energy of ice depends on the mass and speed of floating ice.The mass of the floating ice is related to the area and thickness of the ice,the speed of floating ice is related to the wind,tide,and flow at that time.The failure of ice depends on the ice thickness and strength,and the strength of the floating ice is related to its temperature and movement speed.The coastal structures of the Bohai Sea are mostly vertical columns or walls,inclined cylinders and slopes.The uniaxial compressive strength of ice is the key mechanical property of the sea ice force on the vertical structure.The flexural strength and elastic modulus are the key mechanical properties of the sea ice force on the slope structure.Most of the flowing ice which can act the structure are near the structures,under the combined action of wind,current and tide,the floating ice will surge up the structures and generating force.But the floating ice far away from the structures have little effect on the structures.So the first thing to determine is the characteristic parameters of ice near structures,and the ice area,concentration and speed are the most important factor.Secondly,according to the action form of ice in the front of the structure,to determine whether the mechanical parameters of ice are needed.Finally,in the form of a structure,the ice force on structure is calculated or simulated.In this paper,we study the methods of the three core elements of ice engineering,including the scale parameters of the ice,mechanical parameters of the ice and the ice force on structures.For Bohai coastal ice,study on the methods of obtaining ice floe area and density with remote sensing image analysis,study on method of obtaining the flexural strength and elastic modulus by situ cantilever beam test,determination of total ice force by physical model test.Firstly,based on the remote sensing images of sea ice nearby port and other coastal structures in the Bohai Sea area.Acquiring remote sensing image of high resolution from HJ-1A/B/C satellite,Application of image processing technology,Analysis of 15 points in Liaodong Bay,6 points in Bohai Bay and 5 points in Laizhou Bay.Respectively to establish the relationship between concentration and floe area with water temperature.Obtaining the maximum concentration of Liaodong Bay,Bohai Bay and Laizhou Bay were 98%,78%,and 92% respectively.The maximum equal floe areas are 0.41km2,0.38km2,0.30km2.Secondly,the relationship between the flexural strength,elastic modulus of the ice sheet and the equivalent ice temperature is obtained by the method of situ cantilever beam.At last,the most common seen wide body vertical structure is chosen as the research object,and applying physical model test,getting the ice force when the ice kinetic energy exceeds the maximum energy of ice failure.The experimental results show that the ice force and the reduction coefficient of the model ice decreases with the increase of the width under the design compression strength of 60 kPa and the crushing failure condition.The failure modes of ice in front of the different width structures and the ice force in different failure modes are discussed.Analysis of the existence of the piled ice in the case of ice damage and the ice force.This study did not solve the practical engineering problems.However,the research methods of sea ice force to structures are systematically expounded.It has a positive guiding significance to the construction of Bohai sea area.