RU2765260C1 - Method for laboratory studies of river flows in the civil works area - Google Patents

Abstract

FIELD: river flow test simulation.

SUBSTANCE: invention relates to the field of hydraulic testing and concerns laboratory studies of river flows. The method consists in conducting research using a laboratory model of a water flow made in the form of an open water channel, a regulated water supply device, a water level control device, a catchment tank and measuring and computing equipment, and includes the creation of a water channel on the simulated site with a model of a building structure placed on it of a given hydrological regime identical to the regime of a river flow at the studied site, subsequent measurements of the kinematic characteristics of the flow in the area of the placement of the laboratory model of the building structure and the submission of the measured results in digital form to a computing device. At the same time, the bottom of the water channel in the simulated area along its entire width and height of at least 20 cm is evenly filled with calibrated sand with a particle diameter in the range of 0.1-0.4 mm, a water flow with a given hydrological regime is passed for 1.5-2 hours, then the water from the water channel is drained by gravity, after which the parameters of the formed sandy relief are measured with a measurement step of at least 20 mm in the transverse and longitudinal directions, according to the measured data of the water flow velocities and the size of the depressions and protrusions of the relief in the area of the placement of the model of the building structure, a three-dimensional picture of the similarity of the relief in the area of the planned location of the building structure is built using a computing device.

EFFECT: possibility of laboratory studies of the influence of river flows on the bottom relief in the civil works area at various parameters of flows encircling the objects.

1 cl, 2 dwg

Description

The invention relates to the field of hydraulic testing and relates to laboratory modeling of river flows in the area of building structures.

Laboratory methods of research and hydraulic modeling have long been widely used in hydrotechnical practice in the design, construction and operation of building structures (see, for example, “Device for testing a model of a marine engineering structure” according to RF patent No. 2308397, IPC B63B 9/02, publ. October 20, 2007; "Experimental basin for testing models of offshore engineering structures" according to the patent of the Russian Federation No. 2308397, IPC B63B 9/02, published on July 23, 1996). These analogs are intended for hydromechanical testing of ship models and marine engineering structures in still water.

The disadvantage of the methods is the lack of means to simulate the movement of water flows, as a result of which they cannot be used for laboratory hydraulic studies of river flows.

A known method of modeling water flow around a towed body, described in US Pat. RF No. 2013285, IPC B63B 9/02, publ. 04/17/1991. According to the method, a water flow is created in a laboratory hydrotray, which, flowing around the towed body model, forms a low-pressure field recorded on a battery pressure gauge. At the same time, readings of strain gauge sensors are taken, which allow, taking into account the initial readings, to determine the load on the model of the towed body. As a result, the forces of attraction of the towed body and its sections are determined separately to the bottom of the reservoir, for which the model results are recalculated for full-scale ones.

The disadvantage of this method is the lack of means to study the parameters of the water flow in the event of obstacles in its path in the form of building structures.

Among the known solutions, the closest analogue (prototype) of the claimed invention in terms of technical essence and purpose is a method for laboratory studies of river flows in the area of building structures, described in US Pat. RF No. 2737238, IPC G01M 10/00, B63B 9/02, publ. 11/26/2020. Prototype method is based on research of river flow dynamics in a laboratory installation containing an open hydroflume, a controlled water supply device, a water level control device, a catchment reservoir and measuring and computing equipment. With the help of devices for regulating the supply and level of water, a given hydrological regime was established, which was identical to the regime of the studied river flow in the area under consideration. Further, the measuring equipment devices measured the kinematic characteristics of the flow, which were digitally fed to the computing device.

The disadvantage of this method is the lack of opportunities to study in the laboratory the influence of the existing river flow on the bottom topography in the area of the proposed construction of hydraulic structures.

The claimed invention allows solving the problem of laboratory studies of the influence of river flows on the bottom topography in the area where building structures are located at various parameters of flows flowing around objects.

To solve the problem, the following set of essential features is used: in the method of laboratory research of river flows in the area of building structures, (based as well as the prototype on conducting research on a laboratory model of a water flow, made in the form of an open hydroflume, a device for adjustable water supply, a level control device of water, a catchment reservoir and measuring and computing equipment, and including the creation of a hydro-flume on the simulated site with a model of a building structure of a given hydrological regime placed on it, identical to the regime of the river flow in the study area, subsequent measurements of the kinematic characteristics of the flow in the area where the laboratory model of the building structure is located and the supply measured results in digital form on a computing device), in contrast to the prototype, the bottom of the hydro tray in the simulated area over its entire width and a height of at least 20 cm is evenly filled with a caliber bathed sand with a particle diameter in the range of 0.1÷0.4 mm, a water flow is passed with a given hydrological regime for 1.5-2 hours, then the water is drained from the hydro tray by gravity, after which the parameters of the resulting sandy relief are measured with a step measurements of at least 20 mm in the transverse and longitudinal directions, according to the measured data of water flow velocities and the dimensions of the recesses and protrusions of the relief in the area of the building structure model, using a computing device, a three-dimensional relief similarity picture is built in the area of the planned placement of the building structure.

The essence of the proposed method is as follows.

и составило с запасом 1,5-2 часа. Для сохранения сформировавшегося во время водотока рельефа дна на моделируемом участке, слив воды из гидролотка производился самотеком, что заняло ≈ 12 часов. Измеренные данные (кинематические характеристики потока и параметры рельефа) позволили построить трехмерную картину рельефа деформированного участка дна для последующего составления прогноза о возможных образованиях намывов и размывов русла реки вблизи строящегося объекта и принятию мер по устранению или уменьшению этого явления. Установка позволяет проводить исследования по выбору оптимальной формы строительного объекта и расположению по отношению к нему дополнительных конструкций, повышающих обтекаемость сооружения и препятствующих изменению кинематики речного потока в районе расположения объектов и, соответственно, изменению рельефа дна русла реки. As mentioned above, studies of the influence of river flows on the nature and size of erosion and alluvium of the riverbed in the area of construction facilities were carried out on the basis of a laboratory installation, one of the main advantages of which is to ensure the geometric similarity of the model and the real object under study. The laboratory model of the river bottom was reproduced taking into account the granulometric composition of the soil in the natural environment, the coefficient of sediment mobility distortion and the size of sand fractions when recalculating the results of the modeling of bottom deformations and sediment flow to natural conditions. Based on the experience of studying the picture of real erosion (when recalculated to the model, the maximum depth is ≈ 10 cm), the height of the filled soil (sand) in the hydro flume was chosen to be ≈ 20 cm. In the process of conducting experiments on the speed and depth of a real river flow, the required flow rate and water level in the flume and a steady-state equilibrium regime has been reached, in which the shape and size of the erosion in the vicinity of the building structure would remain practically constant. The estimated time to reach such a regime was determined by the formula

and amounted to a margin of 1.5-2 hours. To preserve the bottom topography formed during the flow in the simulated area, water was drained from the hydroflume by gravity, which took ≈ 12 hours. The measured data (kinematic characteristics of the flow and relief parameters) made it possible to build a three-dimensional picture of the relief of the deformed section of the bottom for the subsequent forecasting of possible formations of alluvium and erosion of the riverbed near the facility under construction and taking measures to eliminate or reduce this phenomenon. The installation allows carrying out research on the choice of the optimal shape of the construction object and the location of additional structures in relation to it, which increase the streamlining of the structure and prevent changes in the kinematics of the river flow in the area of the objects location and, accordingly, changes in the relief of the river bed.

Comparison of the proposed invention and the prototype showed that the task - the possibility of conducting laboratory studies of the influence of river flows on the bottom topography in the area of building structures with different parameters of flows flowing around the object - is solved as a result of a new set of features, which proves the compliance of the proposed invention with the criterion of patentability "novelty" .

In turn, the conducted information search in the field of hydraulic testing did not reveal solutions containing individual distinctive features of the claimed invention, which allows us to conclude that the method meets the criterion of "inventive step".

The essence of the proposed technical solution is illustrated by drawings, where:

in fig. 1 shows a schematic representation of a laboratory setup on which the proposed method was implemented;

in fig. 2 - photographic image of the bottom topography in the area where the building structure model is located.

The proposed method was implemented on a laboratory installation (figure 1), mounted on the basis of the flume of the Department of hydraulic structures, structures and hydraulics FSBEI HE "State University of the Sea and River Fleet named after Admiral S.O. Makarov" with the length of the channel part - 40.0 m; width - 2.0 m; wall height - 0.8 m; possible water flow - up to 100 l / s. The installation is an open hydrotray 1, the bottom section of which (6 m) is evenly filled with calibrated sand 2. In the middle part of the site along the longitudinal axis of the hydrotray 1, there is a model of a building structure 3, made on a scale of 1:50 to the actual dimensions of the structure. The installation also includes: a device for controlled water supply to the hydro tray, consisting of a pressure tank with a triangular weir 4, a water level control device installed at the end of the hydro tray 1, made, for example, in the form of a flat shield, with adjustable height, a catchment tank and measuring and computing equipment . The composition of the measuring equipment, in addition to instruments that measure the kinematic characteristics of the flow (devices for measuring the slopes of the water surface; directions, trajectories and velocities of surface currents; current velocities at various points of the cross section of the flow, distributed along the width and depth of the flow; directions and trajectories of the bottom current velocities in various near-bottom points of the cross-section of the flow, see RF Pat. Spitz scale 5 is mounted on a metal frame mounted on the walls of the hydro tray 1 with the possibility of moving the latter in the longitudinal direction of the tray, while the spitz scale 5 itself is configured to move along the frame.

In the process of research, the hydraulic characteristics of the water flow and the parameters of deformations of the river bottom in the area of the channel supports of the projected bridge crossing in the city of Blagoveshchensk were experimentally determined with various options for its design and location of the ice-cutting device supports in the alignment. To carry out hydraulic studies on a laboratory installation, at a scale of 1:50, a 250 m long estuarine section of the Zeya River (500 cm in scale on the model) was reproduced, a model of channel supports (a box with dimensions of 392 × 252 mm) with a longitudinal axis located on the central longitudinal the axis of the tray and the front (pressure) face, located at a distance of 225 cm from the beginning of the area under study. The distance was chosen from the condition of establishing a uniform flow structure and the distribution of velocities along the width of the channel on the approach to the support model. When modeling the bottom of the studied section of the river, quartz sand with a particle diameter of at least 0.1 mm and not more than 0.4 mm was used, based on the condition of sufficient mobility and the mechanism of movement of bottom sediments in a laboratory installation.

The necessary water flow was set, controlled by a triangular weir, which determines the given hydrological regime, identical to the regime of the Zeya River in the study area. After setting the mode, the hydraulic characteristics of the flow around the model were measured (slopes of the water surface; directions, trajectories and velocities of surface currents; current velocities at various points of the flow cross section, distributed along the width and depth of the flow; directions and trajectories of near-bottom current velocities at various near-bottom points flow cross section). After 1.5 - 2 hours, the water supply to the tray stopped. From the tray, the water drained by gravity, exposing the bottom in the vicinity of the model with the formed structure of erosion (figure 2). After draining the water, using a Spitzenscale 5 in the transverse and longitudinal directions, the sizes and localization of erosion and alluvium at the bottom of the stream were determined with a measurement step of at least 20 mm. Based on the measurement data of the bottom surface marks, a three-dimensional relief similarity picture was built in the area of the planned location of the building structure, which makes it possible to evaluate the relief formed as a result of the flow around the structures placed in the channel for subsequent analysis of the results.

The invention was created by specialists of the Department of Hydraulic Structures, Structures and Hydraulics of the Federal State Budgetary Educational Institution of Higher Education “State University of the Sea and River Fleet named after Admiral S.O. Makarov" in the course of research work. The laboratory installation was mounted on the basis of the flume of the Hydrotechnical Laboratory of the University. Comparison of full-scale and model studies of the river flow dynamics showed the correspondence of the absolute values of the natural and model flow parameters and confirmed the adequacy and performance of the model.

The foregoing allows us to conclude that the claimed utility model meets the criterion of "industrial applicability".

Claims (1)

A method for laboratory studies of river flows in the area of building structures, based on conducting studies on a laboratory model of a water flow, made in the form of an open hydro-flume, a controlled water supply device, a water level control device, a catchment reservoir and measuring and computing equipment, and including the creation on a simulated section of the hydroflume with a model of a building structure of a given hydrological regime located on it, identical to the regime of the river flow in the study area, subsequent measurements of the kinematic characteristics of the water flow in the area where the laboratory model of the building structure is located and the submission of the measured results in digital form to a computing device, characterized in that the bottom the hydrotray on the simulated area over its entire width and height of at least 20 cm is evenly filled with calibrated sand with a particle diameter in the range of 0.1-0.4 mm, a water flow is passed with a given hydrologist in the static mode for 1.5-2 hours, then the water from the hydro tray is drained by gravity, after which the parameters of the resulting sandy relief are measured with a measurement step of at least 20 mm in the transverse and longitudinal directions, according to the measured data of the water flow rates and the dimensions of the recesses and ledges of the relief in the area where the building structure model is located, a three-dimensional relief similarity picture is built using a computing device in the area where the building structure is planned to be placed.

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