CN115420662A - A kind of experiment method of inclined hole high pressure water pressure - Google Patents

Abstract

The invention discloses an inclined hole high-pressure water-pressing experimental method, which adopts the technical scheme that: the method comprises the following steps: s1, installing experimental equipment: constructing an inclined hole pressurized-water test device by adopting a single-hole sectional pressurized-water mode, drilling a hole in a clean water forward circulation mode, placing a water stop plug at a test layer section after the drilling reaches a test design depth to serve as a physical water-blocking boundary, and fixing an upper water stop plug and a lower water stop plug by a perforated pipe and connecting the upper water stop plug and the lower water stop plug with a water inlet pipe; a flowmeter and a pressure gauge are arranged at the water inlet pipe for real-time monitoring and acquisition; s2, checking the air tightness of the water stop plug and the water inlet pipe; s3, performing a water pressing experiment; the invention develops the application of the inclined hole high-pressure water-pressurizing test and the research on the permeability characteristic of the rock mass under the action of high permeability pressure, has important guiding significance for underground space engineering design and safe production, and has more accurate result of calculating the permeability parameter of the rock and soil through the experimental method.

Description

A kind of experiment method of inclined hole high pressure water pressure

technical field

The invention belongs to the technical field of civil engineering, and in particular relates to an experimental method for high-pressure water pressure in inclined holes.

Background technique

In recent years, with the rapid development of my country's economic construction and the continuous improvement of engineering technology, underground space projects such as tunnels, underground oil depots, energy storage power stations, and civil air defense projects have been developed and utilized on a large scale, especially for high-depth pressure-bearing caverns. The application is more and more extensive. In underground engineering, the surrounding rock of caverns often needs to withstand high internal water pressure and aerodynamic pressure. Literature ^[3] The pressure in the cavern of a medium-pressure gas storage power station can reach 10Mpa. The sealing pressure reached 0.125Mpa. While high seepage pressure meets the needs of engineering operation, it also poses a huge threat to the seepage stability of underground cavern rock mass. When the pressurized water seal pressure of the middle hole of Jinping I Hydropower Station reached 0.456Mpa, the water seal ruptured and released the pressure; the Guangzhou Pumped Storage Power Station caused the structure to split and seep water due to the excessive hydraulic gradient, and the water seepage amounted to 32L/s.

As a new type of survey technology, inclined hole drilling has a wide range of exploration and can effectively identify unfavorable geological bodies such as faults, fractured zones, and karst caves in special and complex sections and key locations. High-pressure water pressure test is an important means to reveal the permeability of rock formations. At present, conventional straight-hole high-pressure water pressure tests are mainly used. The inclined-hole high-pressure water pressure test can effectively prove the permeability characteristics of rock mass and reduce the workload of drilling operations. According to the "Water Conservancy and Hydropower Engineering Borehole Pressurized Water Test Regulations SL31-2003", the calculation of the permeability coefficient of rock mass with low water permeability under the turbulent flow state adopts the laminar flow formula, and the permeability coefficient can only be obtained approximately. In actual engineering, as the pressure increases, the water flow state around the borehole will change to a nonlinear flow, and even induce hydraulic fracturing, that is, the indentation flow will increase significantly. If the linear flow formula continues to be used for calculation, the calculated results of rock and soil permeability parameters will be too small. Therefore, the application of inclined hole high-pressure water pressure test and the study of the permeability characteristics of rock mass under high seepage pressure have important guiding significance for underground space engineering design and safe production.

Contents of the invention

The object of the present invention is to provide a kind of inclined hole high-pressure water pressure experiment method, in order to solve the problem raised in the above-mentioned background technology.

In order to achieve the above object, the present invention provides the following technical solutions: a method for experimenting with high-pressure water pressure in inclined holes, comprising the following steps:

S1. Install experimental equipment: use the single-hole segmental pressurized water mode to build an inclined-hole pressurized water test device. The borehole is drilled in a positive circulation of clean water. After drilling reaches the test design depth, place a water stopper in the test layer. As a physical water blocking boundary, the upper water stopper and the lower water stopper are fixed with flower tubes and connected to the water inlet pipe; flow meters and pressure gauges are installed at the water inlet pipes for real-time monitoring and collection;

S2. Check the airtightness of the water stopper and the water inlet pipe: inflate the water stopper. After reaching the design pressure, stop the air supply and observe the change of the pressure gauge. If the air pressure remains constant or changes within the design range, it means that the water stopper is airtight. The tightness is good; keep the pressure of the water stopper constant, start to press the water, make the water pressure of the test section reach a constant value, place a water pressure recorder on the upper part of the water stopper and observe the change of the water pressure, if there is no change or the change is within Design range, indicating that the water inlet pipe is well sealed;

S3. Pressed water test: The pressurized water test should be carried out at a pressure not lower than the third level, and not lower than five stages. The pressure of the test section is set at 0.3-1.0Mpa. When the inflow flow has no continuous increase trend, and the difference between the maximum and minimum flow readings for 5 consecutive times is less than 10% of the final value or reaches 1L/min, enter the next stage of pressure. Considering the pipe loss pressure, the pressure of each test section is according to the formula ( 1) Calculate:

P=P _p +P _z -P _s (1);

Among them, P is the pressure of the test section; P _p is the pressure of the pressure gauge indicating gauge; P _z is the water column pressure from the center of the pressure gauge to the groundwater level; P _s is the pipe loss pressure.

Preferably, the stratum lithology of the test interval in the S1 is mainly granite, the joints and fissures are relatively developed, and the integrity of the core is average.

Preferably, the drilling inclination angle in S1 is 45°, and the hole diameter is 75mm.

Preferably, in said S1, a 45mm caliber water stopper is placed in the test interval.

Preferably, in S1, when the upper water stopper and the lower water stopper are fixed with flower tubes and connected to the water inlet pipe, raw tape and waterproof tape are used to wrap the joints.

Preferably, in said S3, if the burial depth of the test section is 122.00-131.40m, it is carried out according to five-level pressure and nine stages, and the pressure indicated by the five-level pressure gauge is P1=0.2Mpa, P2=0.5Mpa, P3=0.8 Mpa, P4=1.1Mpa, P5=1.4Mpa, press water according to nine stages of pressure: P1-P2-P3-P4-P5-P4-P3-P2-P1.

Preferably, in said S3, during the test, when the water pressure is adjusted, the outlier value of the sudden change of the flow value detected by the flow meter at the water inlet is eliminated.

Preferably, after the S3, the process curve of the pressure water test is drawn and analyzed.

Compared with prior art, the beneficial effect of the present invention is:

The present invention has carried out the application of inclined hole high-pressure water pressure test and the study of the permeability characteristics of rock mass under the action of high osmotic pressure, which has important guiding significance for underground space engineering design and safe production. Through the experimental method of the present invention, the calculation of rock The results for soil permeability parameters are more accurate.

Description of drawings

Fig. 1 is a structural diagram of the experimental device of the present invention;

Fig. 2 is the pressure-flow change curve diagram of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

Please refer to Fig. 1 and Fig. 2, the present invention provides a kind of technical scheme: a kind of inclined hole high-pressure water pressure test method, comprises the following steps:

S1. Install experimental equipment: use the single-hole segmental pressurized water mode to build an inclined-hole pressurized water test device. The borehole is drilled in a positive circulation of clean water. After drilling reaches the test design depth, place a water stopper in the test layer. As a physical water blocking boundary, the upper water stopper and the lower water stopper are fixed with flower tubes and connected to the water inlet pipe; flow meters and pressure gauges are installed at the water inlet pipes for real-time monitoring and collection;

S2. Check the airtightness of the water stopper and the water inlet pipe: inflate the water stopper. After reaching the design pressure, stop the air supply and observe the change of the pressure gauge. If the air pressure remains constant or changes within the design range, it means that the water stopper is airtight. The tightness is good; keep the pressure of the water stopper constant, start to press the water, make the water pressure of the test section reach a constant value, place a water pressure recorder on the upper part of the water stopper and observe the change of the water pressure, if there is no change or the change is within Design range, indicating that the water inlet pipe is well sealed;

S3. Pressed water test: The pressurized water test should be carried out at a pressure not lower than the third level, and not lower than five stages. The pressure of the test section is set at 0.3-1.0Mpa. When the inflow flow has no continuous increase trend, and the difference between the maximum and minimum flow readings for 5 consecutive times is less than 10% of the final value or reaches 1L/min, enter the next stage of pressure. Considering the pipe loss pressure, the pressure of each test section is according to the formula ( 1) Calculate:

P=P _p +P _z -P _s (1);

Among them, P is the pressure of the test section; P _p is the pressure of the pressure gauge indicating gauge; P _z is the water column pressure from the center of the pressure gauge to the groundwater level; P _s is the pipe loss pressure.

Among them, the stratum lithology of the S1 middle test interval is mainly granite, with well-developed joints and fissures, and the integrity of the core is average.

Wherein, the drilling inclination angle in S1 is 45°, and the hole diameter is 75mm.

Among them, in the S1, a 45mm diameter water stopper is placed in the test section.

Wherein, in S1, when the upper water stopper and the lower water stopper are fixed with flower tubes and connected to the water inlet pipe, raw tape and waterproof tape are used to wrap the joints.

Wherein, in the above-mentioned S3, if the burial depth of the test section is 122.00-131.40m, proceed according to the five-level pressure and nine stages, and the indicated pressure of the five-level pressure gauge is P1=0.2Mpa, P2=0.5Mpa, P3=0.8Mpa , P4=1.1Mpa, P5=1.4Mpa, press water according to the nine stages of P1-P2-P3-P4-P5-P4-P3-P2-P1.

Wherein, in the above S3, during the test, when the water pressure is adjusted, the abnormal value of the sudden change of the flow value detected by the flow meter at the water inlet is eliminated.

Wherein, after the S3, the process curve of the pressure water test is drawn and analyzed.

Among them, the present invention has carried out the application of inclined hole high-pressure water pressure test and the study of the permeability characteristics of rock mass under the action of high osmotic pressure, which has important guiding significance for underground space engineering design and safe production. Through the experimental method of the present invention, The results of calculation of soil permeability parameters are more accurate.

Example 2

Please refer to Fig. 1 and Fig. 2, the present invention provides a technical solution: a method of high-pressure water pressure test with inclined hole. , The basic principle of the pressurized water device is shown in Figure 1. The stratum lithology of the test interval is mainly granite, with well-developed joints and fissures, and the integrity of the core is average. The borehole is drilled by clear water positive circulation, the drilling inclination angle is 45°, and the hole diameter is 75mm. After drilling to the test design depth, place a 45mm diameter water stopper in the test layer as a physical water blocking boundary; the upper and lower water stoppers are fixed with flower tubes and connected to the water inlet pipe, and the joints are all made of raw tape, Waterproof tape is wrapped to prevent high-pressure water seepage outside the test layer to the greatest extent; flow meters and pressure gauges are installed at the water inlet pipes for real-time monitoring and collection; in order to prevent the wear of the air pipes caused by friction between the air pipe and the upper rock wall during the placement and recovery of equipment in the hole In this test, the trachea crossing is carried out in the water inlet pipe.

After the installation of the equipment is completed, it is necessary to check the airtightness of the water stop plug and the water inlet pipe. The specific steps are: (1) Inflate the water stop plug. After reaching the design pressure, stop the air supply and observe the change of the pressure gauge. If the air pressure remains constant or The change is very small, indicating that the airtightness of the water stopper is good; (2) Keep the pressure of the water stopper constant, and start to press the water, so that the water pressure of the test section is at a certain constant value. Place a water pressure recorder on the upper part of the upper water stopper to observe the change of water pressure. If the change is not large, it means that the water inlet pipe is well sealed.

Although it has been according to the specification, the pressure water test should be carried out according to three pressure levels and five stages, and the pressure of the test section should be set at 0.3-1.0Mpa. Considering that the burial depth of the test section is relatively deep, the pressure of the test section should be appropriately increased and the test stages should be increased. Therefore, this test is carried out according to five pressure levels and nine stages. Taking a certain section of test inclined hole B as an example, the depth of the test section is 122.00-131.40m, and the pressure indicated by the five-stage pressure gauge is P1=0.2Mpa, P2=0.5Mpa, P3=0.8Mpa, P4=1.1Mpa, P5= 1.4Mpa, press water according to nine stages of pressure: P1-P2-P3-P4-P5-P4-P3-P2-P1. The recording frequency of pressurized water flow rate is 1 time/min. When the pressurized flow rate has no continuous increase trend and the difference between the maximum and minimum flow readings for 5 consecutive times is less than 10% of the final value (or 1L/min), the next stage can be entered pressure. Considering the pipe loss pressure, the pressure of each test section is calculated according to formula (1):

P=P _p +P _z -P _s (1);

Among them, P is the pressure of the test section; P _p is the pressure of the pressure gauge indicating gauge; P _z is the water column pressure from the center of the pressure gauge to the groundwater level; P _s is the pipe loss pressure.

The above embodiments have shown and described the embodiments of the present invention. For those skilled in the art, it can be understood that various changes, modifications, Alternatives and modifications, the scope of the present invention is defined by the appended claims and their equivalents.

Claims (8)

1. An inclined hole high-pressure water pressing experimental method is characterized in that: the method comprises the following steps:

s1, installing experimental equipment: constructing an inclined hole water pressurizing test device by adopting a single-hole sectional water pressurizing mode, drilling a hole in a clean water positive circulation mode, placing a water stop plug at a test layer section after the drilling reaches a test design depth to serve as a physical water blocking boundary, and fixing an upper water stop plug and a lower water stop plug by a perforated pipe and connecting the upper water stop plug and the lower water stop plug with a water inlet pipe; installing a flowmeter and a pressure gauge at the water inlet pipe for real-time monitoring and acquisition;

s2, checking the air tightness of the water stop plug and the water inlet pipe: inflating the water stop plug, stopping air supply after the design pressure is reached, observing the change of a pressure gauge, and if the air pressure is kept constant or the change is within the design range, indicating that the air tightness of the water stop plug is good; keeping the pressure of the water stop plug constant, starting water pressing to enable the water pressure of the test section to be at a certain constant value, placing a water pressure recorder on the upper portion of the upper water stop plug, observing the change of the water pressure, and if the water pressure is not changed or the change is in a design range, indicating that the sealing performance of the water inlet pipe is good;

s3, water pressing experiment: the water pressing test is carried out according to the pressure not lower than three stages and not lower than five stages, the pressure of the test stage is set to be 0.3-1.0 Mpa, the recording frequency of the water pressing flow is 1 time/min, when the pressing flow has no continuous increasing trend and the maximum and minimum difference of continuous 5 times of flow readings is less than 10 percent of the final value or reaches 1L/min, the pressure of the next stage is entered, the pipe loss pressure is considered, and the pressure of each stage of the test stage is calculated according to the formula (1):

P＝P _p +P _z -P _s (1)；

wherein P is the pressure of the test section; p is _p Indicating gauge pressure for the pressure gauge; p _z The water column pressure from the center of the pressure gauge to the ground water level; p is _s The tube loss pressure.

2. The inclined hole high-pressure water pressing experimental method according to claim 1, characterized in that: in the S1, the lithology of the stratum of the tested layer section is mainly granite, joints and cracks are relatively developed, and the integrity of a rock core is general.

3. The inclined hole high-pressure water pressing experimental method according to claim 1, characterized in that: and the drilling inclination angle in the S1 is 45 degrees, and the aperture is 75mm.

4. The inclined hole high-pressure water pressing experimental method according to claim 1, characterized in that: and a water stop plug with the diameter of 45mm is placed in the test layer section in the S1.

5. The inclined hole high-pressure water pressing experimental method according to claim 1, characterized in that: and in the S1, when the upper water stop plug and the lower water stop plug are fixed by a perforated pipe and connected with a water inlet pipe, the joints are wound by raw adhesive tapes and waterproof adhesive tapes.

6. The inclined-hole high-pressure water-pressing experimental method as claimed in claim 1, characterized in that: in the step S3, if the burial depth of the test section is 122.00 to 131.40m, the test is performed according to five-level pressure and nine stages, the indication pressure of the five-level pressure gauge is respectively P1=0.2Mpa, P2=0.5Mpa, P3=0.8Mpa, P4=1.1Mpa and P5=1.4Mpa, and the water is pressurized according to nine stage pressures of P1-P2-P3-P4-P5-P4-P3-P2-P1.

7. The inclined hole high-pressure water pressing experimental method according to claim 1, characterized in that: and in the S3, in the test process, when the water pressure is regulated, the abnormal value of the sudden change of the flow value detected by the flow meter at the water inlet is eliminated.

8. The inclined-hole high-pressure water-pressing experimental method as claimed in claim 1, characterized in that: and S3, drawing a curve of the pressurized water test process and analyzing.

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