A water-sand pressure integrated monitoring device

Abstract

The present invention discloses an integrated water-sediment pressure monitoring device, including: a box frame, a plurality of sand holes are opened at the upper end of the box frame; a magnetic grating earth pressure gauge, a pair of magnetic grating earth pressure gauges are fixedly mounted at the bottom and right side of the box frame respectively; a magnetic grating osmometer, a magnetic grating osmometer is fixedly mounted at the rear end inside the box frame; a four-channel sealed junction box, a four-channel sealed junction box is fixedly mounted at the rear end inside the box frame. The integrated water-sediment pressure monitoring device is reasonably arranged at a certain elevation interval on the upstream dam surface, and the total water-sediment pressure distribution, water pressure distribution, and reservoir water temperature distribution in the horizontal and vertical directions at different elevations can be directly obtained. Through further theoretical calculation and analysis, the parameters such as silt pressure, silt elevation, silt bulk density, silt lateral pressure coefficient, muddy water bulk density, and incoming water sediment content can be obtained, providing data support for the safety status analysis of the dam.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy and hydropower engineering monitoring, and in particular to a water-sediment pressure integrated monitoring device. Background Art

[0002] The water pressure and silt pressure acting on the upstream dam surface are loads that must be considered in the design and calculation analysis of arch dams, gravity dams, earth-rock dams and other dam types. The upstream reservoir water temperature is an important boundary condition for calculating the dam temperature load. Therefore, accurately determining the distribution pattern and size of the upstream surface water pressure, silt pressure and reservoir water temperature is crucial to analyzing and understanding the dam properties.

[0003] For upstream water pressure load, the water density is usually 1000kg / m 3 , applied to the upstream dam surface in a triangular distribution, which is applicable to rivers with low sediment content, but for rivers with high sediment content, the reservoir water is mixed with a large amount of sediment after the reservoir is filled with water, and the turbid water density is greater than the clean water density. There is no effective monitoring method for the size of the turbid water density and the distribution of the turbid water pressure, and it is impossible to accurately determine it. We can only take the maximum value considering the unfavorable situation. For the silt pressure, it is generally calculated according to the formula in the "Load Design Code for Hydraulic Structures". The calculation requires parameters such as the thickness of silt deposition, the porosity of silt, the floating density and dry density of silt, and the internal friction angle of silt. Among them, the thickness of silt deposition can be obtained through physical model tests, mathematical model calculations and monitoring, but there are some assumptions and the accuracy is low. Parameters such as the porosity, density and internal friction angle of silt are generally determined by referring to the measured data of similar projects or through experiments, which is still far from the actual situation.

[0004] In summary, the magnitude and distribution of muddy water pressure and silt pressure on the upstream side of the dam cannot be accurately determined through experiments and mathematical model calculations. At the same time, there is a lack of effective monitoring methods, making it difficult to provide data support for the safety status analysis of the dam.

[0005] Therefore, technical personnel in this field are committed to developing an integrated water and sediment pressure monitoring device, which can monitor in real time the total water and sediment pressure in front of the dam, water pressure, and the distribution pattern of reservoir water temperature along the water depth, and can analyze and obtain parameters such as silt pressure, silt elevation, silt bulk density, silt lateral pressure coefficient, turbid water bulk density, and incoming water sediment content in front of the dam, so as to solve the shortcomings of the above-mentioned prior art. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide an integrated water-sediment pressure monitoring device to solve the problem that the size and distribution of muddy water pressure and silt pressure on the upstream side of the dam cannot be accurately determined through experiments and mathematical model calculations, and there is a lack of effective monitoring means, making it difficult to provide data support for the safety status analysis of the dam.

[0007] A water-sand pressure integrated monitoring device, comprising:

[0008] A box frame, wherein a plurality of sand holes are formed on the upper end of the box frame;

[0009] A magnetic grating earth pressure gauge, wherein the magnetic grating earth pressure gauge has a pair and the magnetic grating earth pressure gauges are respectively fixedly mounted at the bottom and the right side of the box frame;

[0010] A magnetic grating osmometer, wherein the magnetic grating osmometer is fixedly mounted at the rear end of the box frame;

[0011] A four-channel sealed junction box is fixedly installed at the rear end of the box frame, the four-channel sealed junction box is located on the left side of the magnetic grating osmometer, three wire inlets are arranged on the right side of the four-channel sealed junction box, and a wire outlet is arranged on the left side of the four-channel sealed junction box. The cable ends of the magnetic grating soil pressure gauge and the magnetic grating osmometer enter the four-channel sealed junction box through the wire inlet and a cable is led out from the wire outlet to connect to the data acquisition equipment.

[0012] Furthermore, the box frame is composed of a back plate, a right side plate, a top plate and a bottom plate, the sand hole is opened on the top plate, the right side plate is fixed to the right end of the back plate, the top plate is fixed to the upper ends of the back plate and the right side plate, the bottom plate is fixed to the lower ends of the back plate and the right side plate, the back plate is provided with a mounting hole, expansion bolts are installed inside the mounting hole, and the box frame is fixed to the dam surface by the expansion bolts passing through the mounting hole.

[0013] Furthermore, bolt holes are opened on the back plate, right side plate and bottom plate, the magnetic grating piezometer and the four-channel sealed junction box are connected to the back plate by bolts, the magnetic grating soil pressure gauge on the right side is connected to the right side plate by bolts, and the magnetic grating soil pressure gauge at the bottom is connected to the bottom plate by bolts.

[0014] Furthermore, the magnetic grating soil pressure gauge includes a shell body, a bottom cover, an upper bracket, a lower bracket, a magnetic grating and a detection circuit board. A pressure plate is integrally connected to the middle of the upper end of the shell body. The bottom cover is connected to the shell body by bolts. The upper bracket is fixed to the center of the lower side of the pressure plate, the lower bracket is fixed to the center of the upper side of the bottom cover, the upper bracket is located on one side of the lower bracket, the magnetic grating is fixedly installed on the inner surface of the upper bracket, the detection circuit board is fixedly installed on the inner surface of the lower bracket, the detection circuit board is opposite to the magnetic grating, and a magnetic head close to the magnetic grating is embedded on the detection circuit board.

[0015] Furthermore, a thermometer is fixedly mounted on the outer surface of the lower bracket.

[0016] Furthermore, the magnetic grid piezometer is wrapped with geotextile.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The integrated water-sediment pressure monitoring device is reasonably arranged at a certain elevation interval on the upstream dam surface, which can directly obtain the total water-sediment pressure distribution, water pressure distribution, and reservoir water temperature distribution in the horizontal and vertical directions at different elevations. Through further theoretical calculation and analysis, the silt pressure, silt elevation, silt bulk density, silt side pressure coefficient, muddy water bulk density, incoming water sediment content and other parameters in front of the dam can be obtained, providing data support for the safety status analysis of the dam;

[0019] 2. Multiple monitoring instruments are integrated into a box frame to form an independent monitoring unit, which is convenient for on-site installation. The open steel box frame can protect the safety of the instruments in the box during the construction and operation periods, and does not affect the entry of water and silt and the transmission of their pressure, thus ensuring the normal performance of the monitoring functions of each instrument;

[0020] 3. The monitoring instruments use magnetic grating earth pressure gauges and magnetic grating osmometers, which have the characteristics of large measurement range and high measurement accuracy, and can meet the needs of monitoring water pressure and silt pressure at different water depths in front of the dam;

[0021] 4. The three-in-one-out four-channel sealed junction box design improves the waterproof reliability of the wiring. The three monitoring instruments share one cable to connect to the data acquisition equipment, reducing the number of lead-out cables and facilitating on-site laying and protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an overall schematic diagram of the present invention;

[0023] Figure 2 It is a schematic front view of the whole of the present invention;

[0024] Figure 3 It is a schematic diagram of the overall left view of the present invention;

[0025] Figure 4 It is a schematic diagram of the structure of the magnetic grating type earth pressure gauge of the present invention;

[0026] Figure 5 It is a schematic diagram of the vertical total water-sand pressure distribution of the present invention;

[0027] Figure 6 It is a schematic diagram of vertical pressure distribution in the sand of the present invention.

[0028] In the figure: 1-box frame, 11-back plate, 12-right side plate, 13-top plate, 14-bottom plate, 15-sand hole, 2-magnetic grid earth pressure gauge, 21-pressure plate, 22-bottom cover, 23-upper bracket, 24-lower bracket, 25-magnetic grid, 26-detection circuit board, 27-thermometer, 28-housing body, 3-magnetic grid osmometer, 4-four-channel sealed junction box, 41-inlet, 42-outlet, 5-expansion bolt. DETAILED DESCRIPTION

[0029] See also Figure 1-Figure 4 , a water-sand pressure integrated monitoring device, comprising:

[0030] The box frame 1 is an open steel frame, which is composed of a back plate 11, a right side plate 12, a top plate 13 and a bottom plate 14. The right side plate 12 is fixed to the right end of the back plate 11, the top plate 13 is fixed to the upper ends of the back plate 11 and the right side plate 12, and the bottom plate 14 is fixed to the lower ends of the back plate 11 and the right side plate 12. The back plate 11, the right side plate 12, the top plate 13 and the bottom plate 14 are connected as a whole by welding or bolts. A large number of sand holes 15 are opened on the top plate 13, and the opening rate is more than 50%. The back plate 11 and the bottom plate 14. Bolt holes or screw holes for installing monitoring equipment are reserved on the right side plate 12. The back plate 11 is provided with mounting holes, and expansion bolts 5 are installed inside the mounting holes. The box frame 1 is fixed to the dam surface by the expansion bolts 5 passing through the mounting holes. In this way, multiple monitoring instruments are integrated in one box frame 1 to form an independent monitoring unit, which is convenient for on-site installation. The open steel box frame 1 can protect the safety of the instruments in the box during the construction period and the operation period, and does not affect the entry of water and silt and the transmission of their pressure, thereby ensuring the normal performance of the monitoring functions of each instrument;

[0031] A magnetic grating soil pressure gauge 2, which has a pair of magnetic grating soil pressure gauges 2, is respectively fixedly mounted on the bottom and right side of the box frame 1. The magnetic grating soil pressure gauge 2 on the right side is connected to the right side plate 12 by bolts, and is used to measure the horizontal total water and sand pressure. The magnetic grating soil pressure gauge 2 at the bottom is connected to the bottom plate 14 by bolts, and is used to measure the vertical total water and sand pressure. The magnetic grating soil pressure gauge 2 includes a shell body 28, a bottom cover 22, an upper bracket 23, a lower bracket 24, a magnetic grating 25 and a detection circuit board 26. The middle of the upper end of the shell body 28 is integrally connected with a pressure plate 21. The bottom cover 22 is connected to the shell body 28 by bolts. The upper bracket 23 is fixed to the center of the lower side of the pressure plate 21, and the lower bracket 24 is fixed to the center of the upper side of the bottom cover 22. The upper bracket 23 is located on one side of the lower bracket 24, and the magnetic grating 25 is fixedly mounted on the inner surface of the upper bracket 23. The detection circuit board 26 is fixedly mounted on the inner surface of the lower bracket 24. The detection circuit board 26 is directly opposite to the magnetic grid 25. The detection circuit board 26 is inlaid with a magnetic head close to the magnetic grid 25. The shell body 28 and the bottom cover 22 of the magnetic grid type earth pressure gauge 2 are made of stainless steel. Two rubber sealing rings are arranged between the shell body 28 and the bottom cover 22 to form a sealed cavity inside the equipment. The pressure plate 21 is a thin-walled structure, and the remaining parts of the shell body 28 and the bottom cover 22 are thick-walled structures, and their rigidity is much greater than that of the pressure plate 21. The pressure plate 21 will deform when under pressure, driving the upper bracket 23 to move. In this way, the vertical relative deformation value of the center of the pressure plate 21 under the action of external pressure is measured through the vertical relative displacement of the magnetic grid 25 and the magnetic head. In addition, there is a wire outlet hole on the side of the magnetic grid type earth pressure gauge 2. The special cable passes through the wire outlet hole and the wire outlet terminal to lead out of the shell. Two rubber sealing rings are arranged at the wire outlet terminal to respectively close the water seepage channel between the wire outlet terminal and the outer wall of the cable and between the wire outlet terminal and the wire outlet hole wall to ensure that there is no water leakage at the wire outlet.

[0032] A magnetic grating osmometer 3, which is fixedly mounted on the back plate 11 of the box frame 1 and is used to measure water pressure. The magnetic grating osmometer 3 is wrapped with geotextile. The integrated water-sand pressure monitoring device uses a magnetic grating earth pressure gauge 2 and a magnetic grating osmometer 3, which has the characteristics of large measuring range and high measuring accuracy, and can meet the monitoring needs of water pressure and silt pressure with great differences at different water depths in front of the dam;

[0033] A four-channel sealed junction box 4 is fixedly mounted on the back plate 11 of the box frame 1, and is located on the left side of the magnetic grating osmometer 3. The magnetic grating osmometer 3 and the four-channel sealed junction box 4 are connected to the back plate 11 by bolts. Three wire inlets 41 are arranged on the right side of the four-channel sealed junction box 4, and a wire outlet 42 is arranged on the left side of the four-channel sealed junction box 4. The cable ends of the magnetic grating soil pressure gauge 2 and the magnetic grating osmometer 3 enter the interior of the four-channel sealed junction box 4 through the wire inlet 41 and a cable is led out from the wire outlet 42 to be connected to a data acquisition device, thereby improving the waterproof reliability of the wiring. Three monitoring instruments share a common cable to be led out to the data acquisition device, thereby reducing the number of lead-out cables, and facilitating on-site laying and protection.

[0034] See also Figure 4 A thermometer 27 is fixedly installed on the outer surface of the lower bracket 24 of the magnetic grating earth pressure gauge 2. The temperature of the reservoir water can be measured simultaneously by the thermometer 27 arranged in the magnetic grating earth pressure gauge 2, and then transmitted to the data acquisition equipment.

[0035] In summary, by reasonably arranging the integrated water-sediment pressure monitoring device at a certain elevation interval on the upstream dam surface, the total water-sediment pressure distribution, water pressure distribution, and reservoir water temperature distribution in the horizontal and vertical directions at different elevations can be directly obtained. Through further theoretical calculation and analysis, the silt pressure, silt elevation, and silt bulk density in front of the dam can be obtained. 、 Parameters such as silt side pressure coefficient, muddy water density, and incoming water sediment content.

[0036] The specific calculation and analysis steps are as follows:

[0037] Step 1: The magnetic grid earth pressure gauge 2 arranged on the bottom plate 14 of each integrated monitoring device can measure the total vertical water and sediment pressure in front of the dam at the elevation. s zn , taking the measurement results of the magnetic grid earth pressure gauge 2 of the integrated monitoring device and linearly interpolating, the vertical total compressive stress distribution of water and sand in front of the dam can be obtained, as shown in Figure 5 As shown;

[0038] Vertical total water-sand pressure s zn The theoretical calculation formula is:

[0039] (1)

[0040] In the formula, k v is the velocity influencing factor, which is usually 1.0-1.2 except for the orifice area where the velocity in front of the dam is relatively low;

[0041] His the water level in front of the dam;

[0042] H n is the elevation of integrated monitoring device No. n;

[0043] H s is the silt elevation;

[0044] h a is the height difference between the top of the silt and the reservoir water level;

[0045] c an is the bulk density of muddy water above the elevation of the nth integrated monitoring device;

[0046] c a It is the total bulk density of muddy water above the top elevation of the silt;

[0047] c sat is the saturated bulk density of silt;

[0048] Step 2: The magnetic grid piezometer 3 of each integrated monitoring device can measure the water pressure in front of the dam at the elevation. s wn ;

[0049] Water pressure s wn The theoretical calculation formula is:

[0050] (2)

[0051] In the formula, c w is the bulk density of water;

[0052] Step 3: Calculate the vertical silt pressure in front of the dam s sn ;

[0053] s sn= s zn- s wn (3)

[0054] The measured values ​​of the magnetic grating earth pressure gauge 2 and the magnetic grating osmometer 3 of the integrated monitoring device are calculated and linearly interpolated to obtain the vertical silt pressure distribution in front of the dam, as shown in Figure 6 As shown;

[0055] Vertical silt pressure s sn The theoretical calculation formula is:

[0056] (4)

[0057] In the formula, c s ՛ is the buoyant density of the silt;

[0058] Step 4: Based on the total vertical water and sediment pressure in front of the dam s zn and silt pressure s sn The distribution map has an obvious turning point at the silt elevation, and the silt elevation is obtained. H s ; Then, through equations (1), (2), and (4), the density of muddy water at different elevations in front of the dam can be obtained: c an , saturated density of silt c sat and other parameters; further calculate the muddy water sediment content at each elevation in front of the dam S n ;

[0059] Muddy water sand content S n The calculation formula is:

[0060] (5)

[0061] (6)

[0062] In the formula, r s is the density of sand in a completely dense state;

[0063] r w is the water density;

[0064] Based on silt elevation H s The monitoring values ​​of the integrated monitoring device deployed above are calculated and linearly interpolated using equations (5) and (6) to obtain the distribution of muddy water sand content at different elevations in front of the dam;

[0065] Step 5: The magnetic grid earth pressure gauge 2 arranged on the right side plate 12 of each integrated monitoring device can measure the total horizontal water and sediment pressure in front of the dam at the elevation. , combined with the water pressure measurement, the horizontal silt pressure can be calculated ;

[0066] (7)

[0067] Taking the monitoring values ​​of the magnetic grating earth pressure gauge 2 and the magnetic grating osmometer 3 of the integrated monitoring device, the horizontal silt pressure distribution in front of the dam can be obtained by calculating and linearly interpolating using formula (7);

[0068] Horizontal silt pressure The theoretical calculation formula is:

[0069] (8)

[0070] (9)

[0071] In the formula, k an is the silt side pressure coefficient;

[0072] k bn is the lateral pressure coefficient of suspended sand;

[0073] f sn is the internal friction angle of silt;

[0074] Whether muddy water containing suspended sand also has equal pressure in all directions at the same depth as clean water has not yet been determined. Here, we consider it as anisotropic and introduce the suspended sand side pressure coefficient by referring to the calculation method of silt side pressure k bn The concept is used to express the ratio of the horizontal pressure to the vertical pressure of suspended sand in muddy water.

[0075] Step 6: Based on the layout of the integrated monitoring device at different elevations, the distribution pattern of the water temperature in front of the dam along the depth direction can be obtained through the thermometer 27 implanted in the magnetic grating earth pressure gauge 2.

Claims

1. A water-sand pressure integrated monitoring device, characterized in that: include: A box frame (1), wherein a plurality of sand-passing holes (15) are formed at the upper end of the box frame (1), the box frame (1) is composed of a back plate (11), a right side plate (12), a top plate (13) and a bottom plate (14), the sand-passing holes (15) are formed on the top plate (13), the right side plate (12) is fixed to the right end of the back plate (11), the top plate (13) is fixed to the upper ends of the back plate (11) and the right side plate (12), the bottom plate (14) is fixed to the lower ends of the back plate (11) and the right side plate (12), the back plate (11) is provided with a mounting hole, an expansion bolt (5) is installed inside the mounting hole, and the box frame (1) is fixed to the dam surface by the expansion bolt (5) passing through the mounting hole; A magnetic grating soil pressure gauge (2), wherein the magnetic grating soil pressure gauge (2) has a pair, and the magnetic grating soil pressure gauge (2) is fixedly mounted at the bottom and right side of the box frame (1), respectively. The magnetic grating soil pressure gauge (2) comprises a shell body (28), a bottom cover (22), an upper bracket (23), a lower bracket (24), a magnetic grating (25) and a detection circuit board (26). A pressure bearing plate (21) is integrally connected to the middle of the upper end of the shell body (28), and the bottom cover (22) is connected to the shell body (28) by bolts. The upper bracket (23) is fixed at the center of the lower side of the pressure plate (21), the lower bracket (24) is fixed at the center of the upper side of the bottom cover (22), the upper bracket (23) is located on one side of the lower bracket (24), the magnetic grid (25) is fixedly mounted on the inner surface of the upper bracket (23), the detection circuit board (26) is fixedly mounted on the inner surface of the lower bracket (24), the detection circuit board (26) is directly opposite to the magnetic grid (25), and a magnetic head close to the magnetic grid (25) is embedded on the detection circuit board (26); A magnetic grating osmometer (3), wherein the magnetic grating osmometer (3) is fixedly mounted at the rear end of the interior of the box frame (1); A four-channel sealed junction box (4), the four-channel sealed junction box (4) is fixedly mounted at the rear end of the box frame (1), the four-channel sealed junction box (4) is located on the left side of the magnetic grating osmometer (3), three wire inlets (41) are provided on the right side of the four-channel sealed junction box (4), and a wire outlet (42) is provided on the left side of the four-channel sealed junction box (4), the cable ends of the magnetic grating earth pressure gauge (2) and the magnetic grating osmometer (3) enter the four-channel sealed junction box (4) through the wire inlets (41) and a cable is led out from the wire outlet (42) to be connected to a data acquisition device.

2. The integrated water-sand pressure monitoring device according to claim 1, characterized in that: Bolt holes are formed on the back plate (11), the right side plate (12) and the bottom plate (14); the magnetic grating piezometer (3) and the four-channel sealed junction box (4) are connected to the back plate (11) via bolts; the magnetic grating soil pressure gauge (2) on the right side is connected to the right side plate (12) via bolts; and the magnetic grating soil pressure gauge (2) at the bottom is connected to the bottom plate (14) via bolts.

3. The integrated water-sand pressure monitoring device according to claim 1, characterized in that: A thermometer (27) is fixedly mounted on the outer surface of the lower bracket (24).

4. The integrated water-sand pressure monitoring device according to claim 1, characterized in that: The magnetic grid piezometer (3) is wrapped with a geotextile.

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