Device and method for measuring initial water level of confined water

Abstract

The invention belongs to the field of confined aquifer exploration in water-power engineering, and particularly relates to a device and method for measuring the initial water level of confined water. A series of measuring balls with the same size and different masses are sequentially put into vertical direct water flow formed by a flow stabilizing guide pipe from light to heavy, and the suspension state of the measuring balls is observed; and the initial water level (water head elevation) of the confined water can be reversely deduced by using the mass and suspension height of the measuring ball. The device is light, durable, low in manufacturing cost, free of a matched power supply and suitable for severe environments, high-pressure and high-speed water flow or sand-containing water flow can be easily coped with through a heavy measuring ball, and the precise pressure sensor is prevented from being damaged by flushing. The method is simple in measurement step and short in time, and can reduce the measurement error to the greatest extent. Compared with traditional manual observation of the height of the spraying water level, observation of the position of the measuring ball through the scheme is more visual and accurate.

Description

Technical Field

[0001] The present invention belongs to the field of surveying confined aquifers in hydropower projects, and more particularly relates to a device for measuring the initial water level of confined water and a method for measuring the initial water level of confined water. Background Art

[0002] In engineering geology, the "first sighting level" refers to the groundwater level observed when drilling first reveals the impermeable roof of a confined aquifer. Engineers use the height of the first sighting level to determine the hydraulic head of the confined water.

[0003] Among numerous hydrogeological parameters, the initial and stable water levels of confined water provide crucial insights for engineers in assessing the recharge capacity of aquifers. This information is used to constrain the structures of key hydropower project structures, such as dam anti-seepage curtains and foundation pit anchoring structures designed to resist buoyancy and pullout. While the stable water level is readily available and can be obtained through long-term monitoring, the initial water level is characterized by immediacy and transient stability, making it difficult to accurately and promptly measure. Traditional hydrogeological surveys typically rely on pressure sensors and manual visual monitoring to determine the initial water level. As precision electronic instruments, pressure sensors are fragile in complex and volatile field environments, are costly to maintain, and are susceptible to damage and failure under the impact of transient high-pressure water flow, particularly when the confined water contains high sediment content. Because the initial water level of confined water fluctuates rapidly during the initial outburst, manual readings can result in significant errors and low reliability. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a device for measuring the initial water level of pressurized water, which is not easily damaged during implementation and has the advantages of good reliability and relatively accurate measurement results.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: a device for measuring the initial water level of pressurized water, comprising a conduit base, a flow-stabilizing conduit and a measuring ball, the conduit base having a drilled positioning connection structure, the axis of the flow-stabilizing conduit being arranged vertically, the lower end of the flow-stabilizing conduit being sealed and fixedly connected to the conduit base, and the flow-stabilizing conduit and the conduit base as a whole having a cylindrical through hole coaxial with the flow-stabilizing conduit, a plurality of measuring balls being provided, all of which have the same outer diameter and can be placed in the cylindrical through hole with a clearance fit, the density of the measuring ball calculated based on its external volume being less than the density of water, and the masses of the plurality of measuring balls being arranged in an increasing trend; the side wall of the flow-stabilizing conduit having a transparent observation window for observing the axial position of the measuring ball in the cylindrical through hole.

[0006] A preferred solution is that the flow stabilizing duct is composed of a plurality of flow stabilizing duct unit elements that are coaxially fixedly connected, and a closed connection structure is formed between the side walls of two adjacent flow stabilizing duct unit elements.

[0007] The preferred solution is that the side walls of two adjacent flow stabilizing duct units are connected through an annular slot and a connecting ring. The annular slot and the connecting ring are arranged in a ring around the axis of the flow stabilizing duct. The annular slot is provided at the butt joint end face of one of the flow stabilizing duct units, and the connecting ring is provided at the butt joint end face of the other flow stabilizing duct unit. A sealing ring is provided between the butt joint end faces of the two adjacent flow stabilizing duct units.

[0008] A preferred solution is that one of the flow stabilizing conduit units is integrated with the conduit base.

[0009] A preferred solution is that the drilling positioning connection structure includes a positioning cannula, which is located at the lower end surface of the catheter base and is an integral structure with the catheter base. The positioning cannula and the flow stabilizing catheter are coaxially arranged and have the same inner diameter.

[0010] The preferred solution is that the inner diameter of the flow stabilizing tube is 15 cm, the number of measuring balls is 10, the outer diameter of the measuring balls is 12 cm, and the masses of the measuring balls are 5 g, 10 g, 20 g, 40 g, 60 g, 100 g, 120 g, 140 g, 160 g and 200 g respectively.

[0011] The preferred solution is that the measuring balls are all made of nylon; and the flow stabilizing conduit is entirely made of transparent material.

[0012] A preferred solution is that the transparent observation window is provided with a length scale arranged vertically.

[0013] A preferred solution is that the present invention further comprises a storage box, wherein storage positioning cavities adapted to the catheter base, the flow stabilizing catheter and the measuring ball are respectively provided in the storage box.

[0014] Based on the device for measuring the initial water level of confined water described above, the present invention also provides a method for measuring the initial water level of confined water, comprising the following steps: Step 1: Drill vertically. When the impermeable roof of the confined aquifer is first exposed during the drilling process and water gushing occurs, install a flow stabilization conduit at the outer end of the borehole through the conduit base. The flow stabilization conduit is coaxial with the borehole and has the same inner diameter as the borehole. Record the vertical distance H between the upper end surface of the confined aquifer and the ground surface. Step 2: Drop measuring balls of calibrated mass into the steady flow conduit one by one from the upper port of the steady flow conduit, and observe the state of the measuring balls; the order of dropping the measuring balls is from small to large in terms of their mass; If the measuring ball flies away from the steady flow conduit, the next measuring ball with a larger mass is thrown into the steady flow conduit; If the measuring ball is in a stable state of suspension in the steady flow conduit, then the mass m corresponding to the measuring ball is recorded. i and suspension height h iAfter that, take out the measuring ball; then put the next measuring ball with larger mass into the steady flow conduit; where i is the number of the measuring ball, h i Refers to the vertical distance between the bottom of the measuring ball and the ground surface; If the measuring ball gradually sinks in the steady flow conduit, stop inserting the measuring ball; Step 3: Calculate the initial water level H of the confined water according to the following formula i , , Where A refers to the radial cross-sectional area of ​​the inner cavity of the steady flow conduit, and ρ refers to the groundwater density corresponding to the confined aquifer; Step 4: The initial water level H of the confined water calculated in step 3 is i Take the average value as the final calculation result.

[0015] The principle by which the measuring ball in the present invention can be in a suspended and stable state in the flow-stabilizing conduit is as follows: when high-speed water flows vertically upward, the lightweight ball can be suspended at the top of the water column by utilizing the Bernoulli effect and fluid dynamic balance, thereby maintaining dynamic balance without sinking or flying away. This type of suspended ball design is often used as a landscape in hotels or scenic spots, but has not been used to measure the initial water level of pressurized water.

[0016] The specific design principle and derivation process of the calculation formula involved in the above step 3 of the present invention are as follows: , The present invention utilizes the core equation of fluid mechanics, the Bernoulli equation, which describes the relationship of mechanical energy conservation in the steady-state flow process of an ideal fluid. The complete form of the steady-state flow equation along the same streamline is: Where W is a constant, P is the static pressure at a point in the fluid, is the fluid dynamic pressure, is the gravitational potential energy, v is the velocity of the fluid at that point, ρ is the fluid density, g is the acceleration due to gravity, and h is the height of the point.

[0017] When the measuring ball is positioned below a vertical, stable flow, the fluid below it flows at a higher velocity and lower pressure, while the fluid above it flows at a slower velocity and higher pressure. This pressure differential, combined with the ball's own weight and the upward momentum of the water flow, creates a vertical mechanical equilibrium. The lateral pressure exerted by the suspended ball also operates according to the Bernoulli principle. When the ball deviates from the central axis of the vertical flow, the deviated flow channel narrows, causing the velocity to change, creating a lateral pressure differential that forces the ball to re-center and maintain dynamic equilibrium.

[0018] The mass of the measuring ball directly determines whether it can maintain balance on the water flow. When the measuring ball is too light, it will be accelerated and pushed up until it breaks away from the water flow. When the measuring ball is too heavy, it will gradually sink.

[0019] The following is the calculation process of the total mechanical energy head of the confined aquifer when the measuring ball with mass m is suspended at a height of h (the vertical distance between the bottom of the measuring ball and the ground surface): For the gravity of the measuring ball and the impact force of the water flow, the pressure difference between the upper and lower fluids is very small and can be ignored. Then the mechanical balance of the measuring ball in the vertical direction is: , From the above formula, we can get the following formula (1): , Wherein A is the area of ​​the radial cross-section of the inner cavity of the steady flow conduit described above, v is the flow velocity of the fluid at that point (i.e., the flow velocity of the pressurized water in the steady flow conduit in the present invention), ρ is the fluid density (i.e., the density of the pressurized water in the present invention), and g is the acceleration due to gravity.

[0020] Measure the total mechanical energy W of the water surface below the ball 总 The calculation formula is the gravity head plus the velocity head, as shown in the following formula (2): , Where H is the vertical distance between the upper end surface of the confined aquifer and the ground surface mentioned above.

[0021] Substituting formula (1) into formula (2), we can get: , The total mechanical energy head height H0 (initial water level) of the pressurized water can be calculated according to the following formula (3): , When the weight of the measuring ball is neither too light nor too heavy, it can form a suspended dynamic equilibrium above the flow stabilization tube. According to formula (3), the suspension height h is inversely proportional to the mass m of the measuring ball.

[0022] The beneficial effects of the present invention are as follows: the present invention utilizes a series of measuring balls of the same size but different masses, which are sequentially dropped from light to heavy into the vertical direct water flow formed by the flow-stabilizing conduit, and the suspension state of the measuring balls is observed. When a certain measuring ball reaches a basically stable suspension state, the mass and suspension height of the measuring ball can be used to infer the initial water level (head elevation) of the pressurized water. The present invention is lightweight and durable, inexpensive, does not require a supporting power supply, and is adaptable to harsh environments. Heavier measuring balls can easily cope with high-pressure, high-speed water flows or sand-laden water flows, thus preventing the precise pressure sensor from being damaged. The measurement steps of the present invention are simple and time-saving, and can minimize measurement errors. Compared with the traditional manual observation of the height of the spray water level, the use of the solution of the present invention to observe the position of the measuring ball is more intuitive and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0024] Figure 1 It is a schematic diagram of the overall structure when the present invention is implemented; Figure 2 yes Figure 1 A local enlarged view of point A; Figure 3 yes Figure 1 The schematic diagram of the exploded structure of the area at location A shown (i.e., a schematic diagram of the state of two adjacent flow stabilizing duct units before connection); Figure 4 yes Figure 1 BB cross-sectional view; Figure 5 It is a schematic diagram of the overall structure when the present invention is not in use.

[0025] The components in the figure are marked as follows: conduit base 1, flow stabilizing conduit 2, annular slot 21, connecting ring 22, length scale 23, measuring ball 3, storage box 4, and pressurized aquifer. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0027] See also Figures 1 to 4The present invention discloses a device for measuring the initial water level of pressurized water, comprising a conduit base 1, a flow-stabilizing conduit 2 and a measuring ball 3. The conduit base 1 has a drilling positioning connection structure, the axis of the flow-stabilizing conduit 2 is arranged vertically, the lower end of the flow-stabilizing conduit 2 is sealed and fixedly connected to the conduit base 1, and the flow-stabilizing conduit 2 and the conduit base 1 as a whole have a cylindrical through hole coaxial with the flow-stabilizing conduit 2 (the flow-stabilizing conduit 2 and the conduit base 1 are usually an integrated structure, that is, the part where the conduit base 1 is located also has a through hole consistent with the inner diameter of the flow-stabilizing conduit 2, so as to ensure that the measuring ball 3 is in a suspended state. The diameter of the water column in the square is consistent), a plurality of measuring balls 3 are provided, all of which have the same outer diameter and can be placed in the cylindrical through hole with a clearance fit. The density of the measuring balls 3 calculated based on their external volume is less than the density of water (that is, it is equivalent to the measuring balls 3 being able to float on the water surface under a static pressure water environment), and the masses of the plurality of measuring balls 3 are arranged in an increasing trend; the side wall of the flow stabilizing conduit 2 has a transparent observation window for observing the axial position of the measuring balls 3 in the cylindrical through hole (that is, for observing whether the measuring balls 3 are in a suspended and stable state, and for simultaneously detecting the height of the measuring balls 3).

[0028] All measuring balls 3 have the same outer diameter but different masses. This can be achieved by changing the material of the measuring balls 3 or the volume of the cavity inside the measuring balls 3, or by changing both the material of the measuring balls 3 and the volume of the cavity inside. In a preferred embodiment of the present invention, the measuring balls 3 are made of the same material, and this is achieved by designing the volume of the cavity inside the measuring balls 3 to be different. In order to make the structure simple, practical, and easy to process and manufacture, the material of the measuring balls 3 in the present invention is all nylon; the flow stabilizing conduit 2 is made of a transparent material as a whole. The flow stabilizing conduit 2 and the conduit base 1 are usually an integrated structure, and correspondingly, the conduit base 1 is also made of a transparent material as a whole. The main function of the flow stabilization conduit 2 is to convert the instantaneous turbulent groundwater into a steady flow. The overall axial length of the flow stabilization conduit 2 can be reasonably determined based on the estimated pressure head of the pressurized water. In the preferred embodiment of the present invention, the overall axial length of the flow stabilization conduit 2 is 225 cm.

[0029] For ease of portability and storage, the flow-stabilizing conduit 2 typically adopts a segmented design. Specifically, the flow-stabilizing conduit 2 is composed of multiple coaxially fixedly connected flow-stabilizing conduit units, with a closed connection structure formed between the side walls of adjacent flow-stabilizing conduit units. In a preferred embodiment of the present invention, the flow-stabilizing conduit 2 is composed of three coaxially fixedly connected flow-stabilizing conduit units, each of which has an axial length of 75 cm.

[0030] It can be understood that the specific connection structure involved in the closed connection of the side walls of two adjacent flow-stabilizing duct units can be implemented using the common knowledge of those skilled in the art; for example, two adjacent flow-stabilizing duct units can be connected and fixed using a fixing ring in combination with a bolt connection assembly, and a sealing ring can be provided at the joint to ensure the sealing effect; in addition, a step-shaped positioning screw hole can be coaxially designed at the butt joint end face of one of the flow-stabilizing duct units, and an external thread structure can be coaxially designed at the butt joint end face of the other flow-stabilizing duct unit, and the two can be directly connected and fixed through the threaded connection structure, and accordingly, a sealing ring is also provided at the joint to ensure the sealing effect. To facilitate processing, manufacturing, and assembly, the preferred assembly scheme adopted by the flow-stabilizing conduit 2 of the present invention is as follows: the side walls of two adjacent flow-stabilizing conduit units are connected by an annular slot 21 and a connecting ring 22. The annular slot 21 and the connecting ring 22 are arranged in an annular pattern around the axis of the flow-stabilizing conduit 2. The annular slot 21 is provided at the butt joint end face of one of the flow-stabilizing conduit units, and the connecting ring 22 is provided at the butt joint end face of the other flow-stabilizing conduit unit. A sealing ring is provided between the butt joint end faces of the two adjacent flow-stabilizing conduit units. As previously mentioned, the flow-stabilizing conduit 2 and the conduit base 1 are generally integral structures. Correspondingly, one of the flow-stabilizing conduit units is integrally arranged with the conduit base 1.

[0031] The main function of the drilling positioning connection structure of the catheter base 1 is to install the flow-stabilizing catheter 2 through the catheter base 1 at the outer port of the borehole, and ensure that the flow-stabilizing catheter 2 is coaxially arranged with the borehole and has the same inner diameter (that is, the inner diameter of the flow-stabilizing catheter 2 is pre-matched and designed according to the size of the borehole). In order to make the structure simple, reliable, and easy to implement, the preferred drilling positioning connection structure includes a positioning insert, which is located at the lower end surface of the catheter base 1 and is an integral structure with the catheter base 1. The positioning insert and the flow-stabilizing catheter 2 are coaxially connected and have the same inner diameter. The positioning insert is used to be inserted below the ground surface, and the borehole, positioning insert, catheter base 1, and flow-stabilizing catheter 2 form a vertical flow channel for pressurized water with a consistent inner diameter. On the one hand, the positioning insert can effectively prevent groundwater from seeping from the area between the catheter base 1 and the ground surface, thereby improving measurement accuracy. On the other hand, it can also play a role in limiting and fixing the catheter base 1 and is easy to install. In other alternative embodiments, fixed connection holes may be provided on the disc portion of the conduit base 1. Multiple fixed connection holes are provided, spaced apart around the circumference of the flow-stabilizing conduit 2. The axes of the fixed connection holes are vertically arranged, and anchor rods are inserted through the fixed connection holes and into the ground to secure the conduit base 1. To enhance the airtightness between the conduit base 1 and the ground, a sealing gasket may be provided on the lower surface of the conduit base 1.

[0032] Parameters such as the inner diameter of the flow-stabilizing conduit 2, the number of measuring balls 3, the outer diameter of the measuring balls 3, and the mass of the measuring balls 3 can be reasonably designed according to actual conditions. To facilitate measurement and calculation, in a preferred embodiment of the present invention, the inner diameter of the flow-stabilizing conduit 2 is 15 cm, the number of measuring balls 3 is 10, the outer diameter of the measuring balls 3 is 12 cm, and the masses of the measuring balls 3 are 5 g, 10 g, 20 g, 40 g, 60 g, 100 g, 120 g, 140 g, 160 g, and 200 g, respectively.

[0033] It is understood that the outer diameter of the flow-stabilizing conduit 2 and the external specifications of the conduit base 1 do not directly affect the measurement results of the initial water level of the pressurized water. As long as the overall structural strength is ensured and the flow-stabilizing conduit 2 can be properly installed through the conduit base 1 at the outer port of the drilled hole, the flow-stabilizing conduit 2 is sufficient. In a preferred embodiment of the present invention, the outer diameter of the flow-stabilizing conduit 2 is 17 cm, and the main body of the conduit base 1 is disc-shaped with an outer diameter of 55 cm.

[0034] To facilitate direct determination of the suspended height of the measuring sphere 3, a preferred solution is to provide the transparent observation window with a vertical length scale 23. This vertical length scale 23 can be used to measure height parameters. Typically, the lower surface of the circular disc portion of the catheter base 1 corresponds to the ground surface. Accordingly, the zero mark of the length scale 23 starts at the lower surface of the circular disc portion of the catheter base 1.

[0035] See Figure 5 The present invention generally includes a storage box 4, which is provided with storage and positioning cavities corresponding to the catheter base 1, the flow-stabilizing catheter 2, and the measuring ball 3. When the device is not in use, the catheter base 1, the flow-stabilizing catheter 2, and the measuring ball 3 can be placed in the storage box 4 for storage and portability.

[0036] Based on the device for measuring the initial water level of confined water described above, the present invention also provides a method for measuring the initial water level of confined water, comprising the following steps: Step 1: Drill vertically. When the impermeable roof of the confined aquifer 5 is first exposed during the drilling process and water gushing occurs, a flow stabilizing conduit 2 is installed at the outer end of the borehole through the conduit base 1. The flow stabilizing conduit 2 is coaxially arranged with the borehole and has the same inner diameter as the borehole. The vertical distance H between the upper end surface of the confined aquifer 5 and the ground surface is recorded. This drilling process is a conventional technique. A drilling rig is used to drill a hole at a predetermined location, penetrate the impermeable roof of the confined aquifer 5, and discover groundwater. The vertical distance H between the upper end surface of the confined aquifer 5 and the ground surface can be directly obtained by the drilling depth of the drilling rig. Step 2: Drop measuring balls 3 of calibrated mass into the steady flow conduit 2 one by one from the upper port of the steady flow conduit 2, and observe the state of the measuring balls 3; the order of dropping the measuring balls 3 is from small to large in terms of their mass; If the measuring ball 3 flies away from the flow stabilizing conduit 2, the next measuring ball 3 with a larger mass is thrown into the flow stabilizing conduit 2; If the measuring ball 3 is in a stable suspended state in the steady flow conduit 2, then the mass m corresponding to the measuring ball 3 is recorded. i and suspension height h i After that, take out the measuring ball 3; then put the next measuring ball 3 with a larger mass into the steady flow conduit 2; where i is the number of the measuring ball 3, h i Refers to the vertical distance between the bottom of the measuring ball 3 and the ground surface; i can usually be a positive integer. For example, the corresponding masses of the measuring ball 3 are m1, m2, and m3, and the corresponding suspension heights are h1, h2, and h3. If the measuring ball 3 gradually sinks in the steady flow conduit 2, the insertion of the measuring ball 3 is stopped, which means that step 2 is ended and all data collection work is completed. Step 3: Calculate the initial water level H of the confined water according to the following formula i , , Where A refers to the area of ​​the radial cross section of the inner cavity of the steady flow conduit 2, and ρ refers to the groundwater density corresponding to the confined aquifer 5. It can be understood that the parameters A and ρ are both known values, and ρ can usually be taken according to the conventional density of clean water. If the sediment content is large, its actual density can also be obtained by sampling and calculated according to its actual density. The parameter H is obtained in step 1, and the parameter m i and h i Then we get from step 2; Step 4: The initial water level H of the confined water calculated in step 3 is i Take the average value as the final calculation result, that is, get the final measurement result (Average value of initial water level of pressurized water).

[0037] It should be noted that, since the initial water level of the confined water is immediate and instantaneous, the water level will gradually change over time and reach a stable water level within 24 to 48 hours. Therefore, after the drilling rig discovers the confined aquifer 5, it is necessary to quickly measure it within a short period of time, otherwise the error will be proportional to the increase in measurement time. If it is necessary to continue to monitor the changes in the head of the confined water over a period of time, the above steps 2 to 4 can be repeated at regular intervals to calculate the average value of the initial water level of the confined water. Of course, in some alternative embodiments, a specific measuring ball that can form a suspended state can also be used to continuously observe the change of its suspension height in the flow-stabilizing conduit 2, and multiple calculations can be performed using the formula (3) mentioned above to obtain the change curve of the initial water level H0 of the pressurized water.

[0038] If the measurement accuracy needs to be further improved, a preliminary experiment can be carried out indoors to determine the correction coefficient of the water head height before the device is officially used for field measurement to reduce the error.

[0039] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0040] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for measuring the initial water level of pressurized water, characterized in that: The invention comprises a catheter base (1), a steady flow catheter (2) and a measuring ball (3), wherein the catheter base (1) has a drilling positioning connection structure, the axis of the steady flow catheter (2) is arranged vertically, the lower end of the steady flow catheter (2) is sealed and fixedly connected to the catheter base (1), and the steady flow catheter (2) and the catheter base (1) as a whole have a cylindrical through hole coaxial with the steady flow catheter (2), a plurality of measuring balls (3) are provided, all of the measuring balls (3) have the same outer diameter and can be placed in the cylindrical through hole with clearance fit, the density of the measuring balls (3) calculated based on their external volumes is less than the density of water, and the masses of the plurality of measuring balls (3) are arranged in an increasing trend; the side wall of the steady flow catheter (2) has a transparent observation window for observing the axial position of the measuring balls (3) in the cylindrical through hole.

2. The device for measuring the initial water level of pressurized water according to claim 1, characterized in that: The flow stabilizing conduit (2) is composed of a plurality of flow stabilizing conduit unit components that are coaxially fixedly connected, and a closed connection structure is formed between the side walls of two adjacent flow stabilizing conduit unit components.

3. The device for measuring the initial water level of pressurized water according to claim 2, characterized in that: The side walls of two adjacent flow stabilizing duct units are connected by means of an annular slot (21) and a connecting ring (22). The annular slot (21) and the connecting ring (22) are arranged in an annular shape around the axis of the flow stabilizing duct (2). The annular slot (21) is provided at the butt joint end face of one of the flow stabilizing duct units, and the connecting ring (22) is provided at the butt joint end face of the other flow stabilizing duct unit. A sealing ring is provided between the butt joint end faces of the two adjacent flow stabilizing duct units.

4. The device for measuring the initial water level of pressurized water according to claim 2, characterized in that: One of the flow stabilizing conduit units is arranged in an integrated structure with the conduit base (1).

5. The device for measuring the initial water level of pressurized water according to claim 1, characterized in that: The drilling positioning connection structure comprises a positioning cannula, which is located on the lower end surface of the catheter base (1) and is an integral structure with the catheter base (1). The positioning cannula and the flow stabilizing catheter (2) are coaxially connected and have the same inner diameter.

6. The device for measuring the initial water level of pressurized water according to claim 1, characterized in that: The inner diameter of the flow stabilizing conduit (2) is 15 cm, the number of the measuring balls (3) is 10, the outer diameter of the measuring balls (3) is 12 cm, and the masses of the measuring balls (3) are 5 g, 10 g, 20 g, 40 g, 60 g, 100 g, 120 g, 140 g, 160 g and 200 g respectively.

7. The device for measuring the initial water level of pressurized water according to claim 1, characterized in that: The material of the measuring ball (3) is nylon; the flow stabilizing conduit (2) is made of transparent material as a whole.

8. The device for measuring the initial water level of pressurized water according to claim 1, characterized in that: The transparent observation window is provided with a length scale (23) arranged vertically.

9. The device for measuring the initial water level of pressurized water according to any one of claims 1 to 8, characterized in that: It also includes a storage box (4), in which storage positioning cavities adapted to the catheter base (1), the flow-stabilizing catheter (2), and the measuring ball (3) are respectively provided.

10. A method for measuring the initial water level of confined water, characterized in that: The device for measuring the initial water level of pressurized water according to any one of claims 1 to 9 is used, and comprises the following steps: Step 1: Drilling is performed vertically. When the water-blocking roof of the confined aquifer (5) is first exposed during the drilling process and water gushing occurs, a flow-stabilizing conduit (2) is installed at the outer end of the borehole through a conduit base (1). The flow-stabilizing conduit (2) is coaxially arranged with the borehole and has the same inner diameter as the borehole. The vertical distance H between the upper end surface of the confined aquifer (5) and the ground surface is recorded. Step 2: Dropping measuring balls (3) of calibrated mass into the steady flow conduit (2) one by one from the upper port of the steady flow conduit (2), and observing the state of the measuring balls (3); the order of dropping the measuring balls (3) is from small to large according to their mass; If the measuring ball (3) flies away from the steady flow conduit (2), the next measuring ball (3) with a larger mass is thrown into the steady flow conduit (2); If the measuring ball (3) is in a suspended stable state in the steady flow conduit (2), then the mass m corresponding to the measuring ball (3) is recorded. i and suspension height h i After that, take out the measuring ball (3); then put the next measuring ball (3) with a larger mass into the steady flow conduit (2); where i is the number of the measuring ball (3), h i It refers to the vertical distance between the bottom of the measuring ball (3) and the ground surface; If the measuring ball (3) gradually sinks in the steady flow conduit (2), the insertion of the measuring ball (3) is stopped; Step 3: Calculate the initial water level H of the confined water according to the following formula i , ， Wherein A refers to the area of ​​the radial cross section of the inner cavity of the steady flow conduit (2), and ρ refers to the groundwater density corresponding to the confined aquifer (5); Step 4: The initial water level H of the confined water calculated in step 3 is i Take the average value as the final calculation result.

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