RU2171333C1 - Method for erecting temporary ice bridge - Google Patents

Abstract

FIELD: ice technology. SUBSTANCE: method used for erection of temporary ice bridges mainly in reservoirs with under-ice flow involves mounting damping devices in the form of plates under ice; they are attached to ice by means of bars. Novelty is that damping devices used for the purpose are made in the form of plates provided with anchors on rigid supports; mentioned plates are installed in shallow underwater flow reservoirs for turning through certain angle to velocity vector of under-ice flow due to impact of ice covering vibrations. EFFECT: improved bearing capacity of ice covering on shallow sections of reservoir in freight haulage. 2 dwg

Description

 The invention relates to the field of ice engineering and can be used to create ice crossings mainly in water bodies with ice flow.

 The prior art is known from a method of creating an ice crossing, which consists in installing dampers under the ice made in the form of horizontal plates attached to the ice using vertical rods and immersed to a depth at which there are no wave vibrations caused by the movement of goods on the ice cover (1. B .M. Kozin, Method for creating an ice crossing. RF patent N 2137877 from 09.20.99).

 The disadvantage of this method is the impossibility of using it to increase the bearing capacity of the ice cover in shallow areas of the reservoir, when wave vibrations of water propagate throughout the depth of the reservoir (see 2. Sretensky LN Theory of wave motion of a liquid. OMTI, 1936).

 The task of the invention is to reduce the amplitude of the bending-gravitational waves (IGW), excited in the ice sheet from the movement of goods on it.

 The technical result achieved by solving the problem is to increase the bearing capacity of the ice cover when moving goods on it in shallow areas of the reservoir.

 The essential features characterizing the invention.

 Restrictive: an ice crossing is created by installing dampers under the ice made in the form of horizontal plates attached to the ice using vertical rods and immersed to a depth at which there are no wave vibrations in the water caused by the movement of goods on the ice cover.

 Distinctive: an ice crossing is created on bodies of water with ice flow, while dampers, due to wave vibrations of the ice sheet, are able to rotate at an angle to the ice velocity vector.

 It is known (3. Ya. I. Voytkunsky et al. Hydromechanics. L .: Shipbuilding. - 1982. - 455 p.) That a plate located at an angle α to the incident flow, in accordance with the theory of N.E. Zhukovsky, acts lifting force, the direction of which is determined by the sign of the angle α. Using this law, it is possible to reduce the amplitude of IGWs excited by the movement of goods along the ice cover if the horizontal plates attached to the ice using vertical rods are rotated in a certain way with respect to the ice velocity vector.

 The method is as follows.

 In the ice cover in a shallow area with ice flow along the intended axis of the ice crossing, perpendicular to the speed of the current, slots are made through which plates with rods and anchors fixed on them are lowered onto the hard supports. The total length of the rods and supports should not be less than the depth of the reservoir. The plates are connected to the rods and supports using cylindrical hinges, the axis of rotation of which is oriented perpendicular to the ice velocity vector. To compensate for the hydraulic moment arising during the rotation of the plates, the points of attachment of the hinges of the rods are placed in line with the centers of the hydrodynamic pressure of the plates (see [3]), and to obtain the desired direction of lift, counteracting the vertical movements (vibrations) of the ice sheet, the anchors are attached to the plates along the edge on which the ice flow flows. The ratio of the rod and support lengths should be such that, in the absence of ice vibrations and when anchors are installed on the bottom of the reservoir, the plates occupy a horizontal position, i.e. so that α = 0. After complete freezing of the water entering the slots and reliable freezing of the rods in the ice cover as a result, the ice ferry is ready for operation. Indeed, if the top of the IHV passes over the plate installation site, the rods will begin to move upward, which will cause the plate to rotate through angle α and the appearance of the corresponding lifting force directed in the opposite direction, i.e. way down. As the IHV passes over the sole plate, the bar starts to lower and the plate rotates through an angle -α. The direction of the lifting force will also change its sign, i.e., it will be directed upwards. Thus, such plate rotations due to ice vibrations in the presence of an under-ice flow will decrease the IGW amplitude, i.e. level of bending stresses, which will increase the bearing capacity of the ice cover.

вдоль намеченной оси переправы 2 выполняют прорези 3, через которые опускают пластины 4 с закрепленными на них штангами 5 и якорями 6 на жестких опорах 7. Суммарная длина штанг 5 и опор 7 L должна быть не меньше глубины водоема Н. Пластины 4 соединяют со штангами 5 опорами 7 и якорями 6 при помощи цилиндрических шарниров 8, оси вращения которых ориентируют перпендикулярно вектору скорости подледного течения

. Для компенсации гидродинамического момента Мг.д. места крепления шарниров штанг 8' располагают на одной линии 9 с центром гидродинамических давлений 10 пластин 4, т.е. шарниры 8' располагают на линии действия подъемной силы R, возникающей на пластине 4 при ее повороте на угол α. Якоря 6 крепят к пластинам по кромке 11, на которую набегает поток подледного течения со скоростью

. Соотношение длин штанг 5 и опор 7 должно быть таким, чтобы при отсутствии колебаний льда 1 и при установке якорей 6 на дно водоема 12 пластины 4 заняли горизонтальное положение, т.е. чтобы α=0. После полного замерзания воды 13, поступившей в прорези 3 и вмораживания штанг 5 в ледяной покров 1 ледяная переправа готова к эксплуатации. Действительно, если над пластиной 4 будет проходить вершина ИГВ 14, то штанги 5 начнут перемещаться вверх, что вызовет поворот пластины 4 на угол α и появление подъемной силы R, направленной вниз. При прохождении над пластиной подошвы ИГВ (на чертеже не показано) сила R, будет направлена вверх. Таким образом повороты пластины от колебаний льда будут уменьшать амплитуду ИГВ, что увеличит несущую способность ледяного покрова.The invention is illustrated in the drawing (Fig. 1 and 2) which shows a diagram of its implementation, In the ice sheet 1 with ice current

along the intended axis of the crossing 2, slots 3 are made through which the plates 4 are lowered with the rods 5 fixed on them and the anchors 6 on the rigid supports 7. The total length of the rods 5 and the supports 7 L must be not less than the depth of the reservoir N. The plates 4 are connected to the rods 5 supports 7 and anchors 6 with the help of cylindrical hinges 8, the axis of rotation of which is oriented perpendicular to the ice velocity vector

. To compensate for the hydrodynamic moment Mg.d. the mounting points of the hinges of the rods 8 'are located on the same line 9 with the center of the hydrodynamic pressures 10 of the plates 4, i.e. the hinges 8 'are located on the line of action of the lifting force R arising on the plate 4 when it is rotated through an angle α. Anchors 6 are attached to the plates along the edge 11, on which the flow of ice flows at a speed

. The ratio of the lengths of the rods 5 and supports 7 should be such that, in the absence of ice oscillations 1 and when the anchors 6 are installed on the bottom of the reservoir 12, the plates 4 occupy a horizontal position, i.e. so that α = 0. After complete freezing of the water 13 entering the slot 3 and freezing the rods 5 into the ice cover 1, the ice ferry is ready for operation. Indeed, if the top of the IVG 14 passes over the plate 4, then the rods 5 will begin to move upward, which will cause the plate 4 to rotate through an angle α and the appearance of a lifting force R directed downward. When passing over the plate of the sole of the IHV (not shown in the drawing), the force R will be directed upward. Thus, plate rotation due to ice vibrations will decrease the IGW amplitude, which will increase the bearing capacity of the ice sheet.

Claims (1)

 The method of creating an ice crossing, consisting in the installation of dampers under the ice made in the form of plates attached to the ice using rods, characterized in that the dampers are used in the form of plates having anchors on the hard supports of the plates, which are mounted on shallow reservoirs with underwater flow with the possibility of rotation at an angle to the ice velocity vector under the action of ice cover vibrations.

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