Water drainage test device and method for self-flowing drill hole of bed rock confined aquifer

Abstract

The invention discloses a drainage test device and method for a self-flowing drill hole of a bed rock confined aquifer, the drainage test device comprises a rock core pipe and a drill rod which are arranged in the drill hole, the drill hole exposes the confined aquifer, the upper end of the rock core pipe is flush with the top of the confined aquifer, and the lower end of the rock core pipe is adjacent to the drill hole in the section of the confined aquifer; the lower end of the drill rod is connected with the upper end of the rock core pipe, a water stop plug is arranged at the lower end of the drill rod, the upper end of the drill rod is connected with the lower end of the water conveying pipe, the water conveying pipe is sequentially provided with a branch pipe, a pressure gauge and a flow control valve from bottom to top, a switch valve is arranged on the branch pipe, and the upper end of the water conveying pipe is matched with the metering device; according to the scheme, the problem that water of a confined aquifer flows to a weathering zone of a relative water-resisting layer through a gap between the rock core pipe and the hole wall to cause leakage and pressure loss is effectively avoided; meanwhile, the drainage test device solves the problem that the height of a traditional additionally-installed drill rod is limited and cannot meet the maximum drop range of the pressure-bearing water level; the measurement is convenient, and the solved permeability coefficient is accurate and reliable.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogeological tests, and in particular to a water discharge test device and method for a self-flowing borehole in a bedrock pressure aquifer. Background Art

[0002] In geotechnical engineering surveys, water supply hydrogeological surveys, and mining area hydrogeological surveys, it is necessary to conduct hydrogeological tests on artesian wells in bedrock pressure aquifers to obtain parameters such as permeability coefficient (K). There are two commonly used methods in the field:

[0003] 1. Pumping test: This test requires selecting the model of deep well submersible pump according to the amount of water flowing out of the borehole and the test head, and then expanding the hole according to the diameter of the water pump. At the same time, it is necessary to prepare materials and equipment such as steel ropes, water pipes, cables, and generators. This pumping test takes a long time, requires many types of materials and equipment, and is expensive.

[0004] 2. Water release test: ① Use a core tube or drill pipe to raise the orifice pipe, and there must be no water leakage outside the closed pipe. Then measure the water level inside the drill pipe or core tube. The higher the water level is, the higher the water pipe will be connected until the water level is stable or the site conditions cannot be raised any higher. ② After the water level rises and stabilizes, use the distance of the water level above the ground to remove the water level pipe in three sections. From top to bottom, the length of the removed pipe is used as the values ​​of the three drop strokes S1, S2, and S3 in the pumping test, and then measure the corresponding gravity water flow Q1, Q2, and Q3 of each section. When measuring water volume and water level, observe and record according to the pumping test observation specification requirements. When the stabilization time of the flow observation reaches the specification requirements, it is equivalent to completing a complete borehole pumping test. This is the so-called water release test, and the test data of a borehole can be obtained. This test does not require deep well submersible pumps, steel ropes, water pipes, cables, generators and other materials and equipment, saving time and material and equipment costs. However, the test did not fully consider the problem of water pressure loss in the upper relative aquifer weathering zone due to leakage. At the same time, if a pressurized water column of more than 100 meters appears in the borehole, the height of the drill rod cannot meet the technical requirements of the water level drop. Both of these disadvantages reduce the effectiveness of the test.

[0005] The above two tests generally use water meters to measure water flow, but the rock chips in the bedrock drilling water will affect the water meter reading; when the hole is just drilled, the rock chips and other solid impurity particles contained in the water are easy to block the water filter and the water inlet hole of the impeller box. At the same time, the organic and inorganic substances contained in the water, such as iron salts and calcifications, are also easy to form scale on the water filter and the impeller box, thereby affecting the water meter measurement; especially when there are bubbles in the water, the bubbles enter the water meter with the water flow and pass through the water meter in the form of air impurities, which may hinder the rotation of the pointer and the digital roller, causing the water meter to have a negative error, that is, the water meter runs slowly, resulting in inaccurate measurement accuracy. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the present invention provides a water release test device and method for a self-flowing borehole in a bedrock confined aquifer, which solves the problem that the existing test device is difficult to meet the pressure water level drop range and has poor measurement accuracy.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is:

[0008] In a first aspect, a water discharge test device for a self-flowing borehole in a bedrock confined aquifer is provided, which includes a core tube and a drill rod placed in a borehole, the borehole exposes the confined aquifer, the upper end of the core tube is flush with the top of the confined aquifer, the lower end of the core tube is adjacent to the borehole located in this section of the confined aquifer, the lower end of the drill rod is connected to the upper end of the core tube, and a water stop plug is provided at the lower end of the drill rod, the upper end of the drill rod is connected to the lower end of a water pipe, the water pipe is provided with a branch pipe, a pressure gauge and a flow control valve in sequence from bottom to top, a switch valve is provided on the branch pipe, and the upper end of the water pipe cooperates with a metering device.

[0009] Furthermore, the water stop plug includes an inflatable sleeve sleeved on the lower end of the drill rod, the inflatable sleeve is connected to an external air supply device through an air pipe, and the inner and outer side walls of the inflatable sleeve in the inflated state are respectively tightly attached to the outer side wall of the drill rod and the inner side wall of the drill hole.

[0010] Furthermore, the metering device is a triangular weir metering device, the upper end of the water supply pipe is connected to the triangular weir metering device through a horizontal pipe and a hose in sequence, and the triangular weir metering device and the flow control valve are both electrically connected to the controller.

[0011] In a second aspect, a test method for a water discharge test device for a self-flowing borehole in a bedrock confined aquifer is provided, which comprises the following steps:

[0012] S1: After drilling the hole to expose the bedrock confined aquifer, the drill is started and a water discharge test device is installed in the borehole and at the port position;

[0013] S2: Observe the total static water level: Close the flow control valve and the switch valve, and observe the pressure value of the pressure gauge until the pressure value stabilizes within the preset time period, and the stabilized pressure value P 总 The converted pressure-converted dynamic water level is the total static water level;

[0014] S3: Perform several water discharge drop tests using the water discharge test device. In each water discharge drop test, observe the changing relationship between the water discharge flow rate and the pressure gauge reading, and the changing relationship between the pressure gauge reading and the measurement time when the water discharge flow rate is fixed;

[0015] S4: Based on the changing relationship of the observation records, calculate the permeability coefficient of the confined aquifer.

[0016] Furthermore, the boreholes in step S1 include complete holes and incomplete holes, the depth of the complete holes is greater than the depth of the bottom of the confined aquifer, and the depth of the incomplete holes is greater than the depth of the top of the confined aquifer and less than the depth of the bottom of the confined aquifer.

[0017] Further, step S3 specifically includes: presetting the number of tests N, after the first water level drop s1, and successively performing water discharge drop tests, wherein the specific operation of the nth water discharge drop test (n∈1, 2...N) is: lowering the water level Converted to pressure drop P n , open the flow control valve to release water, monitor the water release flow Q through the triangular weir metering device, and adjust the water release flow Q through the flow control valve. After each adjustment, the water release flow Q remains stable for a certain period of time until the pressure gauge reading drops steadily to P 总 -P n When the flow control valve is closed, the pressure gauge should be restored to P 总 During the water discharge process, observe the changing relationship between the water discharge flow rate Q and the pressure gauge reading, as well as the changing relationship between the pressure gauge reading and the measurement time t when the water discharge flow rate Q is fixed.

[0018] Furthermore, step S4 specifically includes:

[0019] S41: converting the relationship between the discharge flow rate Q and the pressure gauge reading into the relationship between the discharge flow rate Q and the drop depth s of the pressure-converted dynamic water level, and compiling a Qs relationship curve; converting the relationship between the pressure gauge reading and the measurement time t when the discharge flow rate Q is fixed into the relationship between the drop depth s of the pressure-converted dynamic water level and lg(t), and compiling a s and lg(t) relationship curve;

[0020] S42: When the relationship curve of Qs is a straight line or close to a straight line, the confined aquifer is a steady flow; otherwise, the confined aquifer is an unsteady flow;

[0021] S43: Construct permeability coefficient calculation formulas corresponding to steady flow and unsteady flow respectively, and calculate the permeability coefficient of the confined aquifer.

[0022] Furthermore, when the relationship curve of Qs approaches a straight line change, an approximate straight line of the relationship curve of Qs is obtained by interpolation.

[0023] Furthermore, the calculation formula for the permeability coefficient of the confined aquifer when it is a steady flow includes:

[0024] When the drilled hole is a complete hole, the permeability coefficient K is:

[0025]

[0026] When the drilled hole is an incomplete hole, the permeability coefficient K is:

[0027]

[0028] Among them, Q is the discharge flow rate, s is the drop in dynamic water level converted from pressure, M is the thickness of the confined water aquifer, L is the length of the confined water aquifer; r is the radius of the discharge hole; and R is the impact radius.

[0029] Furthermore, the calculation formula for the permeability coefficient of the confined aquifer when it is an unsteady flow includes:

[0030] When the drilled hole is a complete hole, the permeability coefficient K is:

[0031]

[0032] Where W(u) is the well function; S is the water release coefficient of the confined water aquifer; u is the water supply degree of the aquifer;

[0033] When u﹤0.01, the permeability coefficient K is:

[0034]

[0035] Among them, S1 and S2 are the ordinate values ​​of two points on the relationship curve between s and lg(t) that are close to the straight line segment, and t1 and t2 are the abscissa values ​​corresponding to S1 and S2 in the relationship curve between s and lg(t).

[0036] The beneficial effects of the present invention are:

[0037] 1. The water discharge test device of this scheme uses a core tube matched with the inner wall of the borehole as the water diversion pipe of the pressurized aquifer, and uses the water-stop plug on the drill pipe to seal the gap between the core tube and the inner wall of the borehole, effectively avoiding the problem of water in the pressurized aquifer flowing through the gap between the core tube and the hole wall to the weathered zone of the relative impermeable layer and leaking and losing pressure; at the same time, the water discharge test device of this scheme solves the problem that the height of the traditional drill pipe is limited and cannot meet the maximum drop of the pressurized water level; the triangular weir metering equipment can accurately measure the water discharge flow rate, avoiding the influence of rock debris and impurities in the gushing water on the water discharge flow rate measurement.

[0038] 2. The water discharge test method of this scheme reduces the influence of accidental factors of the confined aquifer on the test by conducting several water discharge drop tests, and the water level drop depth of each water discharge drop test decreases arithmetic progression in the same proportion, thereby gradually improving the accuracy of the test data, so as to accurately obtain the relationship curve between the water discharge flow rate and the drop depth of the pressure-converted dynamic water level, and the relationship curve between the drop depth of the pressure-converted dynamic water level and the measurement time lg(t), so as to distinguish whether the confined aquifer belongs to a stable flow or an unstable flow, and respectively construct the permeability coefficient calculation formulas corresponding to the stable flow and the unstable flow, so as to obtain the permeability coefficient of the confined aquifer, and make the obtained permeability coefficient accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the structure of the water release test device for the gravity borehole in the bedrock confined aquifer.

[0040] Among them, 1. borehole, 2. core tube, 3. drill rod, 4. water pipe, 5. branch pipe, 6. pressure gauge, 7. flow control valve, 8. switch valve, 9. inflation sleeve, 10. air pipe, 11. air supply equipment, 12. triangular weir metering equipment, 13. horizontal pipe, 14. hose, 15. air pressure gauge. DETAILED DESCRIPTION

[0041] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0042] like Figure 1 As shown, the water discharge test device of the bedrock confined aquifer gravity borehole 1 of the present scheme comprises a core tube 2 and a drill rod 3 placed in the borehole 1, the borehole 1 exposes the confined aquifer, the upper end of the core tube 2 is level with the top of the confined aquifer, the lower end of the core tube 2 is adjacent to the borehole 1 located in this section of the confined aquifer, the lower end of the drill rod 3 is connected to the upper end of the core tube 2, and the lower end of the drill rod 3 is provided with a water stop plug, the upper end of the drill rod 3 is connected to the lower end of the water pipe 4, the water pipe 4 is provided with a branch pipe 5, a pressure gauge 6 and a flow control valve 7 from bottom to top, the branch pipe 5 is provided with a switch valve 8, and the upper end of the water pipe 4 cooperates with the metering device.

[0043] As an optional embodiment, the water-stop plug includes an inflatable sleeve 9 sleeved on the lower end of the drill rod 3, the inflatable sleeve 9 is connected to an external air supply device 11 through an air pipe 10, a pressure gauge 15 is provided on the air pipe 10, and the inner and outer walls of the inflatable sleeve 9 inflated to a preset pressure state are respectively tightly attached to the outer wall of the drill rod 3 and the inner wall of the borehole 1; the metering device is a triangular weir metering device 12, the upper end of the water supply pipe 4 is connected to the triangular weir metering device 12 through a horizontal pipe 13 and a hose 14 in turn, and the triangular weir metering device 12 and the flow control valve 7 are both electrically connected to the controller.

[0044] The water discharge test device of the present scheme uses the core tube 2 matched with the inner wall of the borehole 1 as the water diversion pipe of the pressurized aquifer, and uses the water-stop plug on the drill pipe 3 to stop the gap between the core tube 2 and the inner wall of the borehole 1, effectively avoiding the problem of water from the pressurized aquifer flowing through the gap to the weathered zone of the relative impermeable layer and leaking and losing pressure; at the same time, the water discharge test device of the present scheme can make the height of the drill pipe 3 not need to meet the pressure drop of the pressurized water level; the triangular weir metering equipment 12 can accurately measure the water discharge flow rate, avoiding the influence of rock debris and impurities in the gushing water on the water discharge flow rate.

[0045] In a second aspect, a test method for a water discharge test device for a bedrock confined aquifer self-flowing borehole 1 is provided, which comprises the following steps:

[0046] S1: After the borehole 1 exposes the bedrock confined aquifer, the drilling is started, and a water discharge test device is installed in the borehole 1 and at the port position; wherein the borehole 1 includes a complete hole and an incomplete hole, the depth of the complete hole is greater than the depth of the bottom of the confined aquifer, and the depth of the incomplete hole is greater than the depth of the top of the confined aquifer and less than the depth of the bottom of the confined aquifer;

[0047] S2: Observe the total static water level: Close the flow control valve 7 and the switch valve 8, and observe the pressure value of the pressure gauge 6 until the pressure value tends to be stable within the preset time period, and the stable pressure value P 总 The converted pressure-converted dynamic water level is the total static water level; specifically, the pressure value of the pressure gauge 6 is measured once every hour. If the three measured numbers are the same or the pressure-converted dynamic water level within 4 hours differs by no more than 2 cm, it can be considered that the pressure value / pressure-converted dynamic water level is stable.

[0048] S3: Perform several water discharge test using the water discharge test device. In each water discharge test, observe the relationship between the water discharge flow rate and the reading of the pressure gauge 6 and the relationship between the reading of the pressure gauge 6 and the measurement time when the water discharge flow rate is fixed; specifically, include:

[0049] After the preset number of tests N and the first water level drop s1, the water release test is carried out successively. The specific operation of the nth water release test (n∈1, 2...N) is: lower the water level Converted to pressure drop P n , open the flow control valve 7 to release water, monitor the water release flow Q through the triangular weir metering device 12, and adjust the water release flow Q through the flow control valve 7, and the water release flow Q after each adjustment remains stable for a certain period of time until the pressure gauge 6 reading drops steadily to P 总 -P n When the flow control valve 7 is closed, the pressure value of the pressure gauge 6 is restored to P 总; During the water discharge process, observe the changing relationship between the water discharge flow rate Q and the reading of the pressure gauge 6, and the changing relationship between the reading of the pressure gauge 6 and the measurement time t when the water discharge flow rate Q is fixed;

[0050] When step S3 is implemented, this scheme generally conducts three water release and fall tests. For areas with low precision requirements, a second water release and fall test can also be conducted when the following three conditions are met: (1) aquifers with small water volume (Q < 0.1 L / s·m); (2) aquifers with low precision requirements or low research value; (3) areas where certain hydrogeological data have been mastered, when general exploration holes or auxiliary exploration holes are deployed for pumping water;

[0051] S4: Calculate the permeability coefficient of the confined aquifer based on the change relationship of the observation record; specifically including:

[0052] S41: converting the relationship between the discharge flow rate Q and the reading of the pressure gauge 6 into the relationship between the discharge flow rate Q and the drop depth s of the pressure-converted dynamic water level, and compiling a Qs relationship curve; converting the relationship between the reading of the pressure gauge 6 and the measurement time t when the discharge flow rate Q is fixed into the relationship between the drop depth s of the pressure-converted dynamic water level and lg(t), and compiling a s and lg(t) relationship curve;

[0053] S42: When the relationship curve of Qs is a straight line or close to a straight line, the confined aquifer is a steady flow; otherwise, the confined aquifer is an unsteady flow;

[0054] S43: Construct permeability coefficient calculation formulas corresponding to steady flow and unsteady flow respectively, and calculate the permeability coefficient of the confined aquifer.

[0055] In this scheme, when the relationship curve of Qs approaches a straight line change, an approximate straight line of the relationship curve of Qs can be obtained by interpolation.

[0056] The calculation formula of the permeability coefficient when the confined aquifer in this scheme is a steady flow includes:

[0057] When the borehole 1 is a complete hole, the permeability coefficient K is:

[0058]

[0059] When the borehole 1 is an incomplete hole, the permeability coefficient K is:

[0060]

[0061] Among them, Q is the discharge flow rate, s is the drop in dynamic water level converted from pressure, M is the thickness of the confined water aquifer, L is the length of the confined water aquifer; r is the radius of the discharge hole; and R is the impact radius.

[0062] Furthermore, the calculation formula for the permeability coefficient of the confined aquifer when it is an unsteady flow includes:

[0063] When the borehole 1 is a complete hole, the permeability coefficient K is:

[0064]

[0065] Where W(u) is the well function; S is the water release coefficient of the confined water aquifer; u is the water supply degree of the aquifer;

[0066] When u﹤0.01, the permeability coefficient K is:

[0067]

[0068] Among them, S1 and S2 are the ordinate values ​​of two points on the relationship curve between s and lg(t) that are close to the straight line segment, and t1 and t2 are the abscissa values ​​corresponding to S1 and S2 in the relationship curve between s and lg(t).

[0069] In particular, this scheme should be tested in the dry season as much as possible. If the test is carried out in the rainy season, the stability duration should be appropriately extended because the groundwater level is in a continuous rising stage. In karst areas, ground collapse and cave communication often occur during the test, generating new sources of replenishment. If the amount of water inflow varies during the water release process, the water release time should also be appropriately extended. For the water release fall test of non-steady flow, the relationship curve of the pressure conversion dynamic water level drop s and lg (t) should be determined. If there is an inflection point in the relationship curve, the water release duration can be extended to the horizontal line segment after the inflection point. During the test, the pressure value of the pressure gauge 6 should be 1, 2, and 3 after the start of the test. , 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100, 120 minutes after each observation, and then every 30 minutes; for the steady flow discharge test, when the discharge flow Q is stable, the fluctuation value of the pressure-converted dynamic water level drop cannot exceed 1% of the pressure-converted dynamic water level drop. When the pressure-converted dynamic water level drop is less than 10 meters, the converted water level fluctuation value should not exceed 3-5 cm; during the test, it is advisable to measure once at 5, 10, 15, 20, 25, 30 minutes after the start of the discharge, and then every 30 minutes or 60 minutes. The water temperature and air temperature observation time should be measured synchronously every 2 to 4 hours.

[0070] In summary, the water discharge test method of this scheme reduces the influence of accidental factors of the confined aquifer on the test by conducting several water discharge drop tests, and the water level drop depth of each water discharge drop test decreases arithmetic progression in the same proportion, and gradually improves the accuracy of the test data, so as to accurately obtain the relationship curve between the water discharge flow rate and the drop depth of the pressure-converted dynamic water level and the relationship curve between the drop depth of the pressure-converted dynamic water level and the measurement time lg(t), so as to distinguish whether the confined aquifer belongs to a stable flow or a non-stable flow, and respectively construct the permeability coefficient calculation formulas corresponding to the stable flow and the non-stable flow, so as to obtain the permeability coefficient of the confined aquifer, and make the obtained permeability coefficient accurate and reliable.

Claims

1. A water discharge test device for a self-flowing borehole in a bedrock confined aquifer, characterized in that: It includes a core tube and a drill rod placed in a borehole, the borehole exposes a confined aquifer, the upper end of the core tube is flush with the top of the confined aquifer, the lower end of the core tube is adjacent to the borehole located in this section of the confined aquifer, the lower end of the drill rod is connected to the upper end of the core tube, and a water stop plug is provided at the lower end of the drill rod, the upper end of the drill rod is connected to the lower end of a water pipe, the water pipe is provided with a branch pipe, a pressure gauge and a flow control valve in sequence from bottom to top, the branch pipe is provided with a switch valve, and the upper end of the water pipe cooperates with a metering device.

2. The water discharge test device for the self-flowing borehole in the bedrock confined aquifer according to claim 1 is characterized in that: The water stop plug includes an inflatable sleeve sleeved on the lower end of the drill rod, the inflatable sleeve is connected to an external air supply device through an air pipe, and the inner and outer side walls of the inflatable sleeve in the inflated state are respectively in close contact with the outer side wall of the drill rod and the inner side wall of the drill hole.

3. The water discharge test device for a self-flowing borehole in a bedrock aquifer according to claim 1, characterized in that: The metering device is a triangular weir metering device, the upper end of the water pipe is connected to the triangular weir metering device through a horizontal pipe and a hose in sequence, and the triangular weir metering device and the flow control valve are both electrically connected to the controller.

4. A test method using the water discharge test device for a bedrock confined aquifer using a gravity borehole as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: S1: After drilling the hole to expose the bedrock confined aquifer, the drill is started and a water discharge test device is installed in the borehole and at the port position; S2: Observe the total static water level: Close the flow control valve and the switch valve, and observe the pressure value of the pressure gauge until the pressure value stabilizes within the preset time period, and the stabilized pressure value P 总 The converted pressure-converted dynamic water level is the total static water level; S3: Perform several water discharge drop tests using the water discharge test device. In each water discharge drop test, observe the changing relationship between the water discharge flow rate and the pressure gauge reading, and the changing relationship between the pressure gauge reading and the measurement time when the water discharge flow rate is fixed; S4: Based on the changing relationship of the observation records, calculate the permeability coefficient of the confined aquifer.

5. The test method for the water discharge test device of the bedrock confined aquifer gravity borehole according to claim 4 is characterized in that: The boreholes in step S1 include complete holes and incomplete holes, wherein the depth of the complete holes is greater than the depth of the bottom of the confined aquifer, and the depth of the incomplete holes is greater than the depth of the top of the confined aquifer and less than the depth of the bottom of the confined aquifer.

6. The test method of the water discharge test device for the self-flowing borehole in the bedrock confined aquifer according to claim 4, characterized in that: Step S3 specifically includes: presetting the number of tests N, after the first water level drop s1, and then successively performing water discharge and fall tests, wherein the specific operation of the nth water discharge and fall test (n∈1, 2...N) is: lowering the water level Converted to pressure drop P n , open the flow control valve to release water, monitor the water release flow Q through the triangular weir metering device, and adjust the water release flow Q through the flow control valve. After each adjustment, the water release flow Q remains stable for a certain period of time until the pressure gauge reading drops steadily to P 总 -P n When the flow control valve is closed, the pressure gauge should be restored to P 总 During the water discharge process, observe the changing relationship between the water discharge flow rate Q and the pressure gauge reading, as well as the changing relationship between the pressure gauge reading and the measurement time t when the water discharge flow rate Q is fixed.

7. The test method of the water discharge test device for the self-flowing borehole in the bedrock confined aquifer according to claim 5, characterized in that: Step S4 specifically includes: S41: converting the relationship between the discharge flow rate Q and the pressure gauge reading into the relationship between the discharge flow rate Q and the drop depth s of the pressure-converted dynamic water level, and compiling a Qs relationship curve; converting the relationship between the pressure gauge reading and the measurement time t when the discharge flow rate Q is fixed into the relationship between the drop depth s of the pressure-converted dynamic water level and lg(t), and compiling a s and lg(t) relationship curve; S42: When the relationship curve of Qs is a straight line or close to a straight line, the confined aquifer is a steady flow; otherwise, the confined aquifer is an unsteady flow; S43: Construct permeability coefficient calculation formulas corresponding to steady flow and unsteady flow respectively, and calculate the permeability coefficient of the confined aquifer.

8. The test method for the water discharge test device of the bedrock confined aquifer gravity borehole according to claim 7, characterized in that: When the relationship curve of Qs approaches a straight line change, an approximate straight line of the relationship curve of Qs is obtained by interpolation.

9. The test method for the water discharge test device of the bedrock confined aquifer gravity borehole according to claim 8, characterized in that: The calculation formula for the permeability coefficient of the confined aquifer when it is a steady flow includes: When the drilled hole is a complete hole, the permeability coefficient K is: When the drilled hole is an incomplete hole, the permeability coefficient K is: Among them, Q is the discharge flow rate, s is the drop in dynamic water level converted from pressure, M is the thickness of the confined water aquifer, L is the length of the confined water aquifer; r is the radius of the discharge hole; and R is the impact radius.

10. The test method of the water discharge test device for the self-flowing borehole in the bedrock confined aquifer according to claim 9, characterized in that: The calculation formula of the permeability coefficient K of the confined aquifer when it is an unsteady flow is: Where W(u) is the well function; S is the water release coefficient of the confined water aquifer; u is the water supply degree of the aquifer; When u﹤0.01, the permeability coefficient K is: Among them, S1 and S2 are the ordinate values ​​of two points on the relationship curve between s and lg(t) that are close to the straight line segment, and t1 and t2 are the abscissa values ​​corresponding to S1 and S2 in the relationship curve between s and lg(t).

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