CN112633554B - Slope thin-layer water flow velocity correction coefficient prediction method and device - Google Patents
Slope thin-layer water flow velocity correction coefficient prediction method and device Download PDFInfo
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Abstract
The invention provides a slope thin-layer water flow velocity correction coefficient prediction method and a device, comprising the following steps: paving a ground surface covering object at the bottom of the flushing water tank which is obliquely arranged, and simulating the natural slope covering condition; adjusting the inclination angle of the flushing water tank, and simulating the gradient of a natural slope; providing stable water flow for the flushing water tank, and adjusting the water flow parameter value to the test target flow; measuring the surface flow velocity and the water depth of the thin-layer water flow in the flushing tank, and further calculating the submergence degree of the thin-layer water flow in the flushing tank on the surface covering object, and the average flow velocity, the Reynolds number and the correction coefficient of the thin-layer water flow in the flushing tank; and respectively establishing a slope thin-layer water flow velocity correction coefficient prediction model under a non-submerged state and a submerged state according to the submergence degree. The method can effectively improve the prediction precision of the correction coefficient and the calculation precision of the average flow velocity, provide theoretical basis for developing the hydrodynamic force research of the slope thin-layer water flow, and reduce the experimental research cost.
Description
Technical Field
The invention relates to the technical field of surface hydrologic processes, in particular to a slope thin-layer water flow velocity correction coefficient prediction method and device.
Background
The water depth of the slope thin-layer water flow is generally only in the millimeter level to a few centimeters, and many flow-rate measuring instruments and devices cannot directly measure the flow rate of the thin-layer water flow due to the limitation of the water depth. In practice, therefore, the slope sheet flow rate is usually measured by a dye tracer method, and the flow rate obtained by the method is the surface flow rate of the slope sheet flow. However, the flow rate parameter used in the hydrologic model and the hydraulic calculation is the average flow rate, and in order to obtain the average flow rate of the water flow, the surface flow rate is multiplied by a flow rate correction coefficient α. Currently, there are numerous studies regarding the flow rate correction factor as a constant value, and α is generally taken to be 0.67 (laminar flow), 0.70 (transitional flow) and 0.80 (turbulent flow) according to different water flow patterns.
The natural slope is distributed with a plurality of coarse elements with different sizes, such as stones, herbs, withered objects and the like. When the slope thin-layer water flows through the coarse elements, the characteristics (such as flow velocity and water depth) of the water flow can be obviously changed along with the change of the submerging conditions of the coarse elements. Thus, the vertical flow velocity distribution of the thin layer water flow under different flooding conditions is no longer logarithmic, but exhibits an irregular distribution form, such as an S-shaped distribution. At this time, the correction coefficient α is also changed accordingly, and the value of α is no longer constant. Therefore, under the condition that the slope is covered with the rough element, the proper and accurate flow velocity correction coefficient value is determined, and the calculation accuracy of the average flow velocity is directly related.
Disclosure of Invention
The invention provides a method and a device for predicting a slope thin-layer water flow velocity correction coefficient, which are used for solving the defect that the slope thin-layer water flow velocity correction coefficient cannot be predicted under the coating condition in the prior art, realizing accurate prediction of the thin-layer water flow velocity correction coefficient under the coating condition, being simple and easy, and providing theoretical basis and technical support for slope flow velocity measurement and related hydrologic calculation in the field.
The invention provides a slope thin-layer water flow velocity correction coefficient prediction method, which comprises the following steps:
paving a ground surface coating object at the bottom of the flushing water tank, and simulating the natural slope surface coating condition;
adjusting the inclination angle of the flushing water tank to simulate the gradient of a natural slope;
providing stable water flow for the flushing water tank, and adjusting the water flow parameter value to the test target flow;
measuring the surface flow velocity and the water depth of the thin-layer water flow in the flushing water tank, and further calculating the submergence degree of the thin-layer water flow in the flushing water tank on the surface covering object, and the average flow velocity, the Reynolds number and the correction coefficient of the thin-layer water flow in the flushing water tank;
and respectively establishing slope thin-layer water flow velocity correction coefficient prediction models under a non-submerged state and a submerged state according to the submergence degree.
According to the slope thin-layer water flow velocity correction coefficient prediction method provided by the invention, the step of paving the surface coating object at the bottom of the flushing water tank and simulating the natural slope coating condition further comprises the following steps:
and paving a simulated soil layer at the bottom of the flushing water tank, and paving the surface coating object with the set size on the surface of the simulated soil layer according to the set coating proportion Cr.
According to the slope thin-layer water flow velocity correction coefficient prediction method provided by the invention, the step of providing stable water flow to the flushing water tank and adjusting the water flow parameter value to the test target flow further comprises the following steps:
the flow of water flow entering the flushing water tank is adjusted to the test target flow Q by adjusting the variable-frequency water pump and the ball valve on the connecting pipeline of the water supply water tank and the flushing water tank.
According to the slope thin-layer water flow velocity correction coefficient prediction method provided by the invention, the surface flow velocity and the water depth of the thin-layer water flow in the flushing water tank are measured, so that the submergence degree of the thin-layer water flow in the flushing water tank on the surface covered object is calculated, and the steps of the average flow velocity, the Reynolds number and the correction coefficient of the thin-layer water flow in the flushing water tank are further included:
setting a plurality of flow velocity measurement sections along the inclination direction of the flushing water tank, setting a distance between two adjacent flow velocity measurement sections at intervals, setting a plurality of flow velocity measurement points on each flow velocity measurement section, repeatedly measuring the surface flow velocity of thin-layer water flow at each flow velocity measurement point by adopting a dyeing tracing method for a plurality of times, calculating the average value of the flow velocity measurement values of each flow velocity measurement point and each flow velocity measurement section, and further obtaining the surface flow velocity V of the slope thin-layer water flow s 。
The invention provides a slope thin-layer water flow velocity correction coefficient prediction method, which further comprises the following steps:
the water depth measuring device comprises a flushing water tank, a water level probe, a plurality of water depth measuring sections, two adjacent water depth measuring sections, a plurality of water depth measuring points and a slope surface thin-layer water flow.
The invention provides a slope thin-layer water flow velocity correction coefficient prediction method, which further comprises the following steps:
through the water depth h of the thin-layer water flow and the dimension value k of the surface coating object, the inundation degree Λ of the water flow in the flushing water tank to the surface coating object is calculated and obtained,
the invention provides a slope thin-layer water flow velocity correction coefficient prediction method, which further comprises the following steps:
calculating the calculated value V of the average flow velocity of the slope thin water flow according to the flow value Q and the water depth h of the thin water flow m ，
w＝W×(1-Cr)
Wherein w is the effective water flow width; w is the width of the flushing water tank, and Cr is the coating proportion of the surface coating object.
The invention provides a slope thin-layer water flow velocity correction coefficient prediction method, which further comprises the following steps:
calculated value V based on water depth h and average flow rate of thin-layer water flow m Calculating the Reynolds number Re of the slope thin-layer water flow,
wherein v is the viscous coefficient of water, t is the temperature of water, and q is the single-width flow.
According to the slope thin-layer water flow velocity correction coefficient prediction method provided by the invention, in the step of establishing the correction coefficient prediction model according to the inundation degree, the method further comprises the following steps:
according to the measured superficial flow velocity V of the laminar water flow s And a flow velocity calculation value V m Calculating the flow velocity correction coefficient calculation value alpha of the thin-layer water flow,
a prediction model of the correction coefficient is established,
α＝a×logRe+b×logΛ-c×logS+dΛ＜1
α＝a×logRe-b×logΛ-c×logS+dΛ≥1
wherein a, b, c, d is a regression prediction model coefficient, and S is the inclination angle of the flushing tank.
The invention also provides a slope thin-layer water flow velocity correction coefficient prediction device, which comprises a water supply tank, a steady flow water tank and a flushing water tank, wherein the water supply tank is connected with the steady flow water tank through a conveying pipeline, and a variable-frequency water pump, an electromagnetic flowmeter and a ball valve are sequentially arranged on the conveying pipeline along the flow direction of water flow;
the flow stabilizing water tank is internally provided with a baffle plate with holes, the flow stabilizing water tank is divided into a first flow stabilizing area and a second flow stabilizing area by the baffle plate with holes, the conveying pipeline is connected with the first flow stabilizing area, and the second flow stabilizing area is communicated with the first end of the flushing water tank;
the washing water tank is arranged on the support frame, the second end of the washing water tank is hinged with the support frame, the support frame is provided with a hydraulic cylinder, and the output end of the hydraulic cylinder is hinged with the bottom side of the first end of the washing water tank.
According to the slope thin-layer water flow velocity correction coefficient prediction method and device, natural slope coverage condition setting, slope setting, flow setting, surface flow velocity, water depth and inundation degree measurement are simulated in the flushing water tank, an average flow velocity value, a Reynolds number and a correction coefficient are obtained through calculation, and further correction coefficient prediction models under non-inundation and inundation conditions are respectively built; the experimental research cost is reduced, and the method is suitable for field slope hydrologic research work and has very wide universality.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a slope thin-layer water flow velocity correction coefficient prediction device;
FIG. 2 is a schematic plan view of a slope surface coating slope surface setting in the slope surface thin-layer water flow velocity correction coefficient prediction device provided by the invention;
FIG. 3 is a linear plot of predicted values versus measured values of correction factors for thin layer water flow rates simulating gravel coverage down-hill surfaces.
Reference numerals:
100. a water supply tank; 200. a delivery line; 210. variable-frequency water pump; 220. an electromagnetic flowmeter; 230. a ball valve; 300. steady flow water tank; 310. a baffle plate with holes; 400. flushing the water tank; 410. a support frame; 420. a hydraulic cylinder; 430. measuring the section of the water depth; 440. a water level probe; 450. and (5) covering the ground surface.
Detailed Description
Embodiments of the present invention are described in further detail below with reference to the accompanying drawings and examples. The following examples are illustrative of the invention but are not intended to limit the scope of the invention.
In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In describing embodiments of the present invention, it should be noted that, unless explicitly stated and limited otherwise, the terms "coupled," "coupled," and "connected" should be construed broadly, and may be either a fixed connection, a removable connection, or an integral connection, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in embodiments of the present invention will be understood in detail by those of ordinary skill in the art.
In embodiments of the invention, unless expressly specified and limited otherwise, a first feature "up" or "down" on a second feature may be that the first and second features are in direct contact, or that the first and second features are in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the embodiments of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
The following describes a slope thin-layer water flow velocity correction coefficient prediction method with reference to fig. 1 and 2, which comprises the following steps:
paving a ground cover 450 at the bottom of the flushing water tank 400 to simulate the natural slope cover condition;
adjusting the inclination angle of the flushing water tank 400 to simulate the gradient of a natural slope;
providing a steady water flow to the flushing tank 400 and adjusting a water flow parameter value to a test target flow;
measuring the surface flow rate and the water depth of the thin-layer water flow in the flushing water tank 400, and further calculating the submergence degree of the thin-layer water flow in the flushing water tank 400 on the surface covering object 450, and the average flow rate, the Reynolds number and the correction coefficient of the thin-layer water flow in the flushing water tank 400;
and respectively establishing slope thin-layer water flow velocity correction coefficient prediction models under a non-submerged state and a submerged state according to the submergence degree.
According to the method for predicting the slope thin-layer water flow velocity correction coefficient provided by the invention, in the step of paving the surface coating 450 at the bottom of the flushing tank 400 and simulating the natural slope coating condition, the method further comprises the following steps:
a simulated soil layer is laid at the bottom of the flushing tank 400, and the ground surface coating 450 of a predetermined size is laid on the surface of the simulated soil layer in a predetermined coating ratio Cr.
According to the method for predicting the slope thin-layer water flow velocity correction coefficient provided by the invention, the step of providing stable water flow to the flushing water tank 400 and adjusting the water flow parameter value to the test target flow further comprises the following steps:
the flow rate of the water flow entering the flushing tank 400 is adjusted to the test target flow rate Q by adjusting the variable frequency water pump 210 and the ball valve 230 on the connection line of the water supply tank 100 and the flushing tank 400.
According to the method for predicting the slope thin-layer water flow velocity correction coefficient provided by the invention, the steps of measuring the surface flow velocity and the water depth of the thin-layer water flow in the flushing water tank 400, further calculating the submergence degree of the thin-layer water flow in the flushing water tank 400 to the surface coating object 450, and the average flow velocity, the Reynolds number and the correction coefficient of the thin-layer water flow in the flushing water tank 400 further comprise:
a plurality of flow velocity measurement sections are arranged along the inclination direction of the flushing water tank 400, the interval is set between two adjacent flow velocity measurement sections, each flow velocity measurement section is provided with a plurality of flow velocity measurement points, the surface flow velocity of thin-layer water flow is repeatedly measured for a plurality of times by adopting a dyeing tracing method at each flow velocity measurement point, the average value of the flow velocity measurement values of each flow velocity measurement point and each flow velocity measurement section is calculated, and then the surface flow velocity V of the slope thin-layer water flow is obtained s 。
The invention provides a slope thin-layer water flow velocity correction coefficient prediction method, which further comprises the following steps:
a plurality of water depth measuring sections 430 are arranged along the inclination direction of the flushing water tank 400, the distance between two adjacent water depth measuring sections 430 is set at intervals, a plurality of water depth measuring points are arranged on each water depth measuring section 430, the water depth of thin-layer water flow is repeatedly measured for many times at each water depth measuring point by adopting a water level probe 440, the average value of water depth measuring values of each water depth measuring point and each water depth measuring section 430 is calculated, and then the water depth h of the slope thin-layer water flow is obtained.
The invention provides a slope thin-layer water flow velocity correction coefficient prediction method, which further comprises the following steps:
the inundation degree Λ of the water flow in the flushing water tank 400 to the surface covering object 450 is calculated and obtained through the depth h of the water flow and the size value k of the surface covering object 450,
the invention provides a slope thin-layer water flow velocity correction coefficient prediction method, which further comprises the following steps:
calculating the calculated value V of the average flow velocity of the slope thin water flow according to the flow value Q and the water depth h of the thin water flow m ，
w＝W×(1-Cr)
Wherein w is the effective water flow width; w is the width of the flushing tank 400, and Cr is the coating ratio of the surface coating 450.
The invention provides a slope thin-layer water flow velocity correction coefficient prediction method, which further comprises the following steps:
calculated value V based on water depth h and average flow rate of thin-layer water flow m Calculating the Reynolds number Re of the slope thin-layer water flow,
wherein v is the viscous coefficient of water, t is the temperature of water, and q is the single-width flow.
According to the slope thin-layer water flow velocity correction coefficient prediction method provided by the invention, in the step of establishing the correction coefficient prediction model according to the inundation degree, the method further comprises the following steps:
according to the measured superficial flow velocity V of the laminar water flow s And a flow velocity calculation value V m Calculating a water flow velocity correction coefficient calculation value alpha,
a prediction model of the correction coefficient is established,
α＝a×logRe+b×logΛ-c×logS+dΛ＜1
α＝a×logRe-b×logΛ-c×logS+dΛ≥1
wherein a, b, c, d is a regression prediction model coefficient, and S is the inclination angle of the flushing tank.
The invention provides a slope thin-layer water flow velocity correction coefficient prediction method, which comprises the following specific steps:
step 1, setting a thin layer simulating a slope
Firstly, filling test soil in layers at the bottom of a flushing water tank 400, or sticking screened soil and sand particles at the bottom of the flushing water tank 400, or sticking coarse sand paper at the bottom of the flushing water tank 400 to finish the simulation of a soil layer;
then, the surface coating 450 with a certain size, such as stones, dead objects and the like, is distributed on the surface of the soil layer according to a certain coating proportion Cr and a certain arrangement mode, so as to simulate the coating, and the simulation of the natural slope coating condition is completed.
Step 2, setting the gradient
The inclination angle of the flushing tank 400 is adjusted to simulate the slope of a natural slope.
Step 3, setting the flow rate of water flow
And opening the variable-frequency water pump 210 on the connecting pipeline of the water supply tank 100 and the flushing water tank 400, adjusting the opening of the ball valve 230, setting the flow parameter of the electromagnetic flowmeter 220 to the test target flow Q, and finishing the test flow setting after the water flow is stable.
Step 4, measuring the flow velocity of the water flow
Setting a plurality of flow velocity measurement sections along the inclination direction of the flushing water tank 400, setting a distance between two adjacent flow velocity measurement sections at intervals, setting a plurality of flow velocity measurement points on each flow velocity measurement section, repeatedly measuring the surface flow velocity of thin-layer water flow at each flow velocity measurement point by adopting a dyeing tracing method for a plurality of times, calculating the average value of the flow velocity measurement values of each flow velocity measurement point and each flow velocity measurement section, and finally calculating the average value of the flow velocity measurement values of the slope thin-layer water flow under the test working condition, namely the surface flow velocity V of the slope thin-layer water flow s 。
Step 5, measuring the water depth of the thin-layer water flow
A plurality of water depth measuring sections 430 are arranged along the inclination direction of the flushing water tank 400, the distance between two adjacent water depth measuring sections 430 is set at intervals, a plurality of water depth measuring points are arranged on each water depth measuring section 430, the water depth of thin-layer water flow is repeatedly measured for many times at each water depth measuring point by adopting a water level probe 440, the average value of water depth measured values of each water depth measuring point and each water depth measuring section 430 is calculated, and finally the average water depth h of slope thin-layer water flow under the test working condition is calculated.
Step 6, calculating the flooding degree
The inundation degree Λ of the water flow in the flushing water tank 400 to the surface covering object 450 is calculated and obtained through the depth h of the water flow and the size value k of the surface covering object 450,
if Λ < 1, the surface covering 450 is in an unsubmerged state; if Λ is greater than or equal to 1, the surface covering 450 is submerged.
Step 7, obtaining the calculated value of the average flow velocity
Calculating the calculated value V of the average flow velocity of the slope thin water flow according to the flow value Q and the water depth h of the thin water flow m ，
w＝W×(1-Cr)
Wherein w is the effective water flow width; w is the width of the flushing tank 400, and Cr is the coating ratio of the surface coating 450.
Step 8, calculating Reynolds number
Calculated value V based on water depth h and average flow rate of thin-layer water flow m Calculating the Reynolds number Re of the slope thin-layer water flow,
wherein v is the viscous coefficient of water, t is the temperature of water, and q is the single-width flow.
Step 9, calculating correction coefficients
According to the measured flow velocity V of the water flow s And a flow velocity calculation value V m Calculating the flow velocity correction coefficient calculation value alpha of the thin-layer water flow,
step 10, establishing a correction coefficient prediction model
And (3) adjusting the submerging degree, changing the target flow, gradient and coverage proportion, and setting a plurality of groups of working conditions. Repeating the steps 1-9 to obtain flow velocity correction coefficient calculated values under all working conditions, and establishing a correction coefficient database under all working conditions.
And establishing a correction coefficient prediction model according to a stepwise linear regression method by using the correction coefficient database. Because the inundation and the correction coefficient are in a non-monotonic relationship, the correction coefficient prediction model is a piecewise function. And respectively establishing a correction coefficient prediction model under a non-submerged state and a correction coefficient prediction model under the submerged state by taking the submerged degree as a division basis. The independent variables of the correction coefficient prediction model comprise the Reynolds number, the inundation degree and the gradient.
α＝a×logRe+b×logΛ-c×logS+dΛ＜1
α＝a×logRe-b×logΛ-c×logS+dΛ≥1
Wherein a, b, c, d is a regression prediction model coefficient, and S is the inclination angle of the flushing tank.
Examples
In the present embodiment, the flushing tank 400 has a length of 6m, a width of 0.5m, and a gradient adjustment range of 0 to 15 degrees; simulating gravel by using a plastic hemisphere, wherein the diameter of the gravel is 2cm, and the measured value k=1cm, wherein the gravel is arranged in a plum blossom shape, the coverage degree of the gravel is respectively 10%, 20% and 30%, and 5 gradients are respectively 2 °,4 °, 6 °,8 ° and 10 °; 9 flows were set at 5.63 liters/min, 8.44 liters/min, 11.26 liters/min, 22.52 liters/min, 45.03 liters/min, 70.36 liters/min, 84.43 liters/min, 100.00 liters/min, and 122.00 liters/min, respectively; in total, 135 sets of experiments were performed in this example.
Sandpaper cloth (sand grain size of 0.25 mm) was stuck to the bottom of the flushing tank 400 to simulate a rough soil layer. Plastic hemispheres with the diameter of 2cm are distributed on the surface of a soil layer in a quincuncial arrangement mode, and the coverage Cr of gravels is respectively set to be 10, 20 and 30 percent;
the gradient of the flushing water tank 400 is adjusted to 2 degrees, 4 degrees, 6 degrees, 8 degrees and 10 degrees by utilizing the hydraulic cylinder 420;
turning on the variable frequency water pump 210 and the ball valve 230, setting and adjusting the flow rate of the electromagnetic flowmeter 220 to the test target flow rate Q, which are set to 5.63 liters/minute, 8.44 liters/minute, 11.26 liters/minute, 22.52 liters/minute, 45.03 liters/minute, 70.36 liters/minute, 84.43 liters/minute, 100.00 liters/minute, and 122.00 liters/minute, respectively;
setting 5 flow velocity measurement sections from the upper part to the lower part of the slope along the water flow direction, wherein the distance between the two flow velocity measurement sections is 1m, setting 4 measurement points on each flow velocity measurement section, measuring the flow velocity 5 times at each measurement point by using a dyeing tracing method, thus obtaining 100 flow velocity measurement values in each test working condition, calculating the average value of the 100 flow velocity measurement values, and obtaining the surface flow velocity of the slope thin-layer water flow under the test working condition;
5 water depth measurement sections 430 (1.70 m,2.70m,3.70m,4.70m and 5.70 m) are arranged in the water flow direction from the upper part of the slope to the lower part of the slope, 4 measurement points are arranged on each water depth measurement section 430, the water depth is measured 3 times at each measurement point by using a water level probe 440, 60 water depth measurement values are obtained under each test working condition, the average value of the 60 water depths is calculated, and the average water depth of the slope thin-layer water flow under the test working condition is obtained;
the degree of flooding Λ is calculated,
calculation value V for calculating average flow velocity of water flow m ，
w＝W×(1-Cr)
The reynolds number is calculated and the number,
the correction coefficient is calculated and the correction coefficient is calculated,
a prediction model of the correction coefficient is established,
α＝0.235log Re+0.219logΛ-0.107Λ＜1；
α＝0.311log Re-0.646logΛ-0.216logS-0.302Λ≥1。
as shown in fig. 3, the calculated correction coefficient value obtained by the test is summarized with the predicted correction coefficient value obtained by the prediction model, so that the calculated correction coefficient value is better matched with the predicted correction coefficient value, which indicates that the method for predicting the slope thin-layer water flow velocity correction coefficient provided by the invention has higher prediction precision and can accurately predict the slope thin-layer water flow velocity correction coefficient under the coating condition.
As shown in fig. 1 and 2, the present invention further provides a slope thin-layer water flow velocity correction coefficient prediction apparatus, which comprises a water supply tank 100, a steady flow water tank 300 and a flushing water tank 400, wherein the water supply tank 100 is connected with the steady flow water tank 300 through a conveying pipeline 200, and a variable frequency water pump 210, an electromagnetic flowmeter 220 and a ball valve 230 are sequentially arranged on the conveying pipeline 200 along the flow direction of water flow;
a baffle 310 with holes is arranged in the steady flow water tank 300, the baffle 310 with holes divides the steady flow water tank 300 into a first steady flow area and a second steady flow area, the conveying pipeline 200 is connected with the first steady flow area, and the second steady flow area is communicated with the first end of the flushing water tank 400;
the flushing water tank 400 is arranged on a supporting frame 410, a second end of the flushing water tank 400 is hinged with the supporting frame 410, the supporting frame 410 is provided with a hydraulic cylinder 420, and an output end of the hydraulic cylinder 420 is hinged with the bottom side of the first end of the flushing water tank 400. It will be appreciated that the water supply tank 100 is used to provide a stable water source, and the bottom side thereof is provided with a water outlet and is connected to the delivery line 200, and the variable frequency water pump 210, the electromagnetic flowmeter 220 and the ball valve 230 are used to ensure a constant flow rate in the test.
Wherein, the steady flow water tank 300 is internally provided with a baffle 310 with holes vertically, the steady flow water tank 300 is divided into a first steady flow area and a second steady flow area, the conveying pipeline 200 is connected with the lower part of the first steady flow area of the steady flow water tank 300, flows into the second steady flow area through the baffle 310 with holes, flows into the flushing water tank 400 after overflowing, and the steady flow water tank 300 can reduce the turbulence of water flow to the greatest extent for forming uniform laminar water flow.
The flushing water tank 400 is formed by enclosing a toughened glass bottom surface and a toughened glass side wall, a rubber pad is arranged at the bottom side of the flushing water tank 400, a support frame 410 is provided with a hydraulic cylinder 420, the output end of the hydraulic cylinder 420 is hinged with the first end of the flushing water tank 400, and the second end of the flushing water tank 400 is hinged with the support frame 410 and is used for simulating a slope in a natural state and can simulate bare land, stone slope, grassland, withered object coverage and the like. The water source enters the stable water supply tank 100, and the water source provided by the water supply tank 100 flows out after flowing through the variable frequency water pump 210, the electromagnetic flowmeter 220 and the ball valve 230, flows out after flowing into the stable water supply tank 300, flows into the flushing water tank 400, and flows out after flowing through the simulated natural slope.
According to the slope thin-layer water flow velocity correction coefficient prediction method and device, natural slope coverage condition setting, slope setting, flow setting, surface flow velocity, water depth and inundation degree measurement are simulated in the flushing water tank, an average flow velocity value, a Reynolds number and a correction coefficient are obtained through calculation, and further correction coefficient prediction models under non-inundation and inundation conditions are respectively built; the experimental research cost is reduced, and the method is suitable for field slope hydrologic research work and has very wide universality.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
The above embodiments are only for illustrating the present invention, and are not limiting of the present invention. While the invention has been described in detail with reference to the embodiments, those skilled in the art will appreciate that various combinations, modifications, or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and it is intended to be covered by the scope of the claims of the present invention.
Claims (9)
1. A slope thin-layer water flow velocity correction coefficient prediction method is characterized by comprising the following steps:
paving a ground surface coating object at the bottom of the flushing water tank, and simulating the natural slope surface coating condition;
adjusting the inclination angle of the flushing water tank to simulate the gradient of a natural slope;
providing stable water flow for the flushing water tank, and adjusting the water flow parameter value to the test target flow;
measuring the surface flow velocity and the water depth of the thin-layer water flow in the flushing water tank, and further calculating the submergence degree of the thin-layer water flow in the flushing water tank on the surface covering object, and the average flow velocity, the Reynolds number and the correction coefficient of the thin-layer water flow in the flushing water tank;
respectively establishing slope thin-layer water flow velocity correction coefficient prediction models under a non-submerged state and a submerged state according to the submerged degree;
the step of establishing the slope thin-layer water flow velocity correction coefficient prediction model under the non-submerged state and the submerged state according to the submerged degree respectively further comprises the following steps:
according to the measured superficial flow velocity V of the laminar water flow s And a flow velocity calculation value V m Calculating a water flow velocity correction coefficient calculation value alpha,
a prediction model of the correction coefficient is established,
α＝a×logRe+b×logΛ-c×logS+dΛ＜1
α＝a×logRe-b×logΛ-c×logS+dΛ≥1
wherein a, b, c, d is a regression prediction model coefficient, and S is the inclination angle of the flushing tank.
2. The method for predicting slope sheet water flow rate correction factor as set forth in claim 1, wherein said step of laying a surface coating on the bottom of the flushing tank to simulate natural slope coating conditions further comprises:
and paving a simulated soil layer at the bottom of the flushing water tank, and paving the surface coating object with the set size on the surface of the simulated soil layer according to the set coating proportion Cr.
3. The method for predicting a slope sheet water flow rate correction factor as set forth in claim 1, wherein said step of providing a steady water flow to said flush tank and adjusting a water flow parameter value to a test target flow further comprises:
the flow of water flow entering the flushing water tank is adjusted to the test target flow Q by adjusting the variable-frequency water pump and the ball valve on the connecting pipeline of the water supply water tank and the flushing water tank.
4. The method according to claim 1, wherein the step of measuring the surface flow rate and the water depth of the thin-layer water flow in the flushing tank to calculate the submergence of the thin-layer water flow in the flushing tank to the surface coating object, and the average flow rate, the reynolds number and the correction coefficient of the thin-layer water flow in the flushing tank further comprises:
setting multiple flow velocity measurement sections along the inclination direction of the flushing water tank, setting a distance between two adjacent flow velocity measurement sections at intervals, setting multiple flow velocity measurement points on each flow velocity measurement section, repeatedly measuring the surface flow velocity of thin-layer water flow at each flow velocity measurement point by adopting a dyeing tracing method for multiple times, calculating the average value of flow velocity measurement values of each flow velocity measurement point and each flow velocity measurement section,thereby obtaining the surface flow velocity V of the slope thin-layer water flow s 。
5. The slope sheet water flow rate correction factor prediction method of claim 4, further comprising:
the water depth measuring device comprises a flushing water tank, a water level probe, a plurality of water depth measuring sections, two adjacent water depth measuring sections, a plurality of water depth measuring points and a slope surface thin-layer water flow.
6. The slope sheet water flow rate correction factor prediction method of claim 5, further comprising:
through the water depth h of the thin-layer water flow and the dimension value k of the surface coating object, the inundation degree Λ of the water flow in the flushing water tank to the surface coating object is calculated and obtained,
7. the slope sheet water flow rate correction factor prediction method of claim 4, further comprising:
calculating the calculated value V of the average flow velocity of the slope thin water flow according to the flow value Q and the water depth h of the thin water flow m ，
w＝W×(1-Cr)
Wherein w is the effective water flow width; w is the width of the flushing water tank, and Cr is the coating proportion of the surface coating object.
8. The slope sheet water flow rate correction factor prediction method of claim 7, further comprising:
calculated value V based on water depth h and average flow rate of thin-layer water flow m Calculating the Reynolds number Re of the slope thin-layer water flow,
wherein v is the viscous coefficient of water, t is the temperature of water, and q is the single-width flow.
9. A slope thin-layer water flow velocity correction coefficient prediction device for implementing the slope thin-layer water flow velocity correction coefficient prediction method according to any one of claims 1 to 8, characterized by comprising a water supply tank, a steady flow water tank and a flushing water tank, wherein the water supply tank is connected with the steady flow water tank through a conveying pipeline, and a variable frequency water pump, an electromagnetic flowmeter and a ball valve are sequentially arranged on the conveying pipeline along the flow direction of water flow;
the flow stabilizing water tank is internally provided with a baffle plate with holes, the flow stabilizing water tank is divided into a first flow stabilizing area and a second flow stabilizing area by the baffle plate with holes, the conveying pipeline is connected with the first flow stabilizing area, and the second flow stabilizing area is communicated with the first end of the flushing water tank;
the washing water tank is arranged on the support frame, the second end of the washing water tank is hinged with the support frame, the support frame is provided with a hydraulic cylinder, and the output end of the hydraulic cylinder is hinged with the bottom side of the first end of the washing water tank.
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