Research on the device and method for studying the influencing factors of water migration rate in sandy conglomerate surrounding rock

Abstract

The present application relates to a kind of experimental device for studying the influencing factor of water transport rate of sandstone surrounding rock, the experimental device includes base, multifunctional container, three microwave moisture sensors, three micro-pressure transmitters, high-density electrical instrument and data collector.Multifunctional container is equipped with cover and base fence;The front end of base fence is equipped with sample support vertical plate, and the front of sample support vertical plate is equipped with sensor fixed column;Multifunctional container is square hole, and square hole is equipped with sealing buckle;Sealing buckle is inserted with rock sample in contact with square hole;Rock sample is equipped with three sensor layout ports, and is sleeved with three electrode fixed frame, and electrode fixed frame is equipped with copper screw with electrode line;Electrode line is connected with high-density electrical instrument;Three micro-pressure transmitters are in contact with rock sample;Rock sample is uniformly distributed with a plurality of platinum resistance on one side.At the same time, the present application also discloses test method.The present application can realize the influence degree of water transport rate in rock sample under the action of different factors.

Description

Technical Field

[0001] This invention relates to the field of rock and soil cultural relic protection, and in particular to experimental apparatus and methods for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks. Background Technology

[0002] Under the influence of both natural and human factors, grotto temples suffer from various ailments, including cracks, collapses, efflorescence, blisters, and weathering of murals and statues, seriously threatening their long-term preservation and safe use. Water, as one of the most significant factors contributing to these ailments, exhibits varying mechanisms of water damage across different grottoes due to regional geological and climatic conditions. Therefore, the threat posed by water transport to the cliff faces, murals, and statues of grotto temples has long been a challenging problem in the field of grotto temple conservation.

[0003] After water infiltrates into the soil and rock mass, the thickness of the water film around the solid particles gradually increases under microscopic forces such as van der Waals forces. Some air is trapped inside the soil and rock mass, providing the necessary conditions for the formation of pore gas pressure. However, the internal gas pressure not only affects water infiltration but also hinders water migration. Furthermore, temperature changes affect the viscosity, density, and surface tension of water, thereby influencing matrix potential, solute potential, and water kinetic parameters. Under the influence of temperature gradients, water tends to migrate towards areas of lower temperature, and the migration rate increases with increasing temperature. Therefore, temperature gradient is one of the main controlling factors for water migration. There is a certain correlation between matrix potential and water content in unsaturated soil and rock masses. Water in the soil and rock mass migrates from areas of high water content to areas of low water content under the influence of matrix potential energy. The greater the gradient of matrix potential energy, the stronger the driving force for water migration, and the greater the amount of water migrated.

[0004] Therefore, changes in external factors such as rainfall, solar radiation, temperature, and air pressure can cause any one or more factors that maintain the water vapor balance in the soil or rock mass to change, such as temperature, air pressure, or matrix suction. This will disrupt the original balance and cause water to migrate.

[0005] Therefore, focusing on the changes in external factors such as rainfall, temperature, and air pressure, and simulating and analyzing the impact of these changes on the rate of water transport within rock samples is of great significance for comprehensively exploring the water transport patterns of the surrounding rock of grottoes during rainfall and for preventing water damage. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an experimental device with a simple structure and convenient operation for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks.

[0007] Another technical problem to be solved by the present invention is to provide an experimental method for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks.

[0008] To address the aforementioned problems, the present invention provides an experimental apparatus for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks. The apparatus comprises a base, a multifunctional container placed on the base, three microwave humidity sensors, three micro-pressure transmitters, a high-density electrical resistivity meter, and a data acquisition unit. The multifunctional container has a cover plate with an outer rim on its top. Base railings are provided on both sides of the multifunctional container, with the bottom of the railings fixed to the base. A sample support plate is provided at the front end of each base railing on both sides, and a sensor fixing column is provided on the front of the sample support plate. Triangular fixing plates connected to the sample support plate are provided on both sides of the sensor fixing column. The multifunctional container faces the sample support plate. A square hole is opened in the lower middle part of one side of the housing, and a sealing buckle is provided on the square hole. A rock sample is inserted into the sealing buckle and contacts the square hole. The bottom surface of the rock sample contacts the back of the frontmost sample support plate. The rock sample has three sensor placement ports and three electrode fixing frames are fitted on it. The electrode fixing frames have copper screws with electrode wires inside. The electrode wires are connected to the high-density electrical resistivity meter. Each of the sensor placement ports has a microwave humidity sensor. The ends of the three micro-pressure transmitters are in contact with the rock sample. Several platinum resistance thermometers are evenly distributed on one side of the rock sample, which is parallel to the base fence. The micro-pressure transmitters, the microwave humidity sensors, and the platinum resistance thermometers are respectively connected to the data acquisition unit.

[0009] The height of the base fence is lower than the height of the sample support plate, and the height of the sample support plate is lower than the height of the sensor fixing column.

[0010] The area of ​​the square hole is smaller than the cross-sectional area of ​​the rock sample.

[0011] The sealing buckle is filled with microcrystalline wax at the point where it contacts the rock sample.

[0012] The rock sample was covered with waterproof tape on all four sides.

[0013] One of the sensor placement openings is located on the upper part of the bottom surface of the rock sample, and one of the three electrode fixing frames is located on the upper side of the rock sample between each pair of the three electrode fixing frames.

[0014] The three electrode fixing frames are respectively set at 2cm, 10cm and 18cm along the longitudinal section of the rock sample.

[0015] Five holes with a spacing of 2 cm are made on each of the four sides of each electrode fixing frame, and the inner walls of the holes are threaded. Each hole is equipped with a copper screw. The tip of the copper screw is in contact with the surface of the rock sample, and the head of the screw is connected to one end of the electrode wire. The other end of the electrode wire is connected to the high-density electrical resistivity instrument.

[0016] One of the three micro-pressure transmitters is located in the arc-shaped groove at the top of the sensor fixing column, and each of the three electrode fixing frames has a micro-pressure transmitter on its upper side between each pair of rock samples.

[0017] An experimental method for studying the factors influencing the rate of water transport in sandstone and conglomerate surrounding rocks includes the following steps:

[0018] (1) Sample selection:

[0019] The rock samples were dried and their basic parameters were determined.

[0020] (2) Sample installation:

[0021] The rock sample is sealed by wrapping it with waterproof tape and cutting a pre-cut opening for sensor installation using a round blade. One end of the rock sample is placed tightly against the square hole of the multi-functional container, and the gap between the rock sample and the sealing buckle is sealed with microcrystalline wax. Two micro-pressure transmitters and two microwave humidity sensors are placed side by side at equal intervals on the top of the horizontal plane of the rock sample, and one micro-pressure transmitter and one microwave humidity sensor are placed on each exposed end of the rock sample. Six platinum resistance thermometers are placed at equal intervals on one side of the rock sample. The data monitored by the micro-pressure transmitters, microwave humidity sensors, and platinum resistance thermometers are collected and stored by a data acquisition device. The copper screws on the electrode fixing frame are tightened, and the electrode fixing frame is installed at 2cm, 10cm, and 18cm along the longitudinal section of the rock sample and connected to the high-density electrical resistivity meter for monitoring.

[0022] (3) Set the temperature of the entire enclosed space to the required temperature for the test, and proceed to the next step after the temperature stabilizes.

[0023] (4) Loading process:

[0024] Standard sand is filled into a multifunctional container, and rainfall gradient supply is achieved by changing the moisture content of the standard sand.

[0025] Alternatively, a salt water dish containing different saturated salt solutions and a temperature and humidity sensor can be placed inside a multifunctional container to control the relative humidity gradient;

[0026] Alternatively, after sealing the square hole of the multi-functional container with glass, pure water can be filled into the multi-functional container. At the same time, an electric kettle and a temperature sensor can be placed into the multi-functional container through the open cover. The water temperature can be controlled by the electric kettle and the thermal switch, thereby achieving a temperature gradient.

[0027] Alternatively, a multi-functional container can be sealed, with an opening in the cover plate to connect to an air pump, and an air pressure gradient can be achieved through the air pump and a pressure gauge;

[0028] (5) Data collection:

[0029] The data acquisition device collects data every 1 minute, and the high-density electrical resistivity meter collects resistivity values ​​on three resistivity profiles every 2 hours.

[0030] (6) Results analysis.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. In this invention, by setting up a multifunctional container, a microwave humidity sensor, three micro-pressure transmitters, an electrode fixing frame, and a platinum resistance thermometer, the influence of external rainfall, temperature, relative humidity, and air pressure factors on the rate of water transport in a rock sample under individual action can be simulated and studied.

[0033] 2. The present invention has a simple structure and is easy to operate. Attached Figure Description

[0034] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0035] Figure 1 This is a schematic diagram of the test apparatus and monitoring system of the present invention.

[0036] Figure 2 This is a diagram of the experimental apparatus of the present invention.

[0037] Figure 3 This is a schematic diagram showing the deployment locations of the monitoring sensors in this invention.

[0038] Figure 4 This is a schematic diagram showing the location of the resistivity profile in this invention.

[0039] Figure 5 This is a schematic diagram showing the electrode point layout in this invention.

[0040] Figure 6 This is a schematic diagram of the electrode fixing frame structure in this invention.

[0041] In the figure: 1—base; 2—base railing; 3—multifunctional container; 4—outer edge; 5—cover plate; 6—sealing buckle; 7—sensor fixing column; 8—sample support plate; 9—triangular fixing plate; 10—rock sample; 11—electrode fixing frame; 12—copper screw; 13—microwave humidity sensor; 14—micro pressure transmitter; 15—platinum resistance thermometer. Detailed Implementation

[0042] like Figures 1-6As shown, an experimental setup for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks is presented. The experimental setup includes a base 1, a multifunctional container 3 placed on the base 1, three microwave humidity sensors 13, three micro pressure transmitters 14, a high-density electrical resistivity meter, and a data acquisition unit.

[0043] The multifunctional container 3 has a cover plate 5 with an outer edge 4 on its top; the multifunctional container 3 has a base railing 2 on each side, and the bottom of the base railing 2 is fixed to the base 1; the front end of the base railing 2 on both sides has a sample support plate 8, and the front of the sample support plate 8 has a sensor fixing column 7; the sides of the sensor fixing column 7 have triangular fixing plates 9 connected to the sample support plate 8; a square hole is opened in the lower middle part of one side of the box of the multifunctional container 3 facing the sample support plate 8, and a sealing buckle 6 is provided on the square hole; a rock sample 10 is inserted into the sealing buckle 6 and contacts the square hole. The bottom surface of the rock sample 10 is in contact with the back of the frontmost sample support plate 8; the rock sample 10 is provided with three sensor placement ports and three electrode fixing frames 11 are fitted on it. The electrode fixing frames 11 are provided with copper screws 12 with electrode wires; the electrode wires are connected to the high-density electrical resistivity meter; each sensor placement port is provided with a microwave humidity sensor 13; the ends of the three micro pressure transmitters 14 are in contact with the rock sample 10; several platinum resistance thermometers 15 are evenly distributed on one side of the rock sample 10 parallel to the base fence 2; the micro pressure transmitters 14, microwave humidity sensors 13 and platinum resistance thermometers 15 are respectively connected to the data acquisition unit.

[0044] Wherein: the height of the base fence 2 is lower than the height of the sample support plate 8, and the height of the sample support plate 8 is lower than the height of the sensor fixing column 7.

[0045] The area of ​​the square hole is smaller than the cross-sectional area of ​​rock sample 10.

[0046] The sealing buckle 6 is filled with microcrystalline wax at the junction with the rock sample 10 to ensure a seal.

[0047] Waterproof tape was applied to all four sides of the rock sample 10 for sealing.

[0048] One of the sensor placement openings is located on the upper part of the bottom surface of the rock sample 10, and one of the three electrode fixing frames 11 is located on the upper side of the rock sample 10 between each pair.

[0049] The three electrode fixing frames 11 are respectively set at 2cm, 10cm and 18cm along the longitudinal section of the rock sample 10.

[0050] Five holes with a spacing of 2 cm are made on the four sides of each electrode fixing frame 11, and the inner walls of the holes are threaded. A copper screw 12 is installed in each hole. The tip of the copper screw 12 is in contact with the surface of the rock sample 10, and the head of the screw is connected to one end of the electrode wire. The other end of the electrode wire is connected to the high-density electrical resistivity instrument.

[0051] One of the three micro-pressure transmitters 14 is located in the arc-shaped groove at the top of the sensor fixing column 7, and a micro-pressure transmitter 14 is respectively located on the upper side of the rock sample 10 between each pair of the three electrode fixing frames 11.

[0052] The spacing between each pair of platinum resistance thermometers 15 is 3 cm, so that a surface temperature monitoring line is arranged in the horizontal direction of the rock sample 10.

[0053] The base 1 is cut from an acrylic sheet; the multi-functional container 3 is made of a custom acrylic sheet and sealed with glass glue, and is fixed to the base 1 with acrylic glue, and the base railing 2 is glued to both sides for reinforcement.

[0054] A high-density resistivity meter is used to monitor resistivity; a data acquisition unit collects and stores the data obtained by the micro-pressure transmitter 14, microwave humidity sensor 13 and platinum resistance thermometer 15. The data acquisition unit can be a CR1000X data acquisition unit.

[0055] The multifunctional container 3 provides a space to simulate changes in environmental factors such as rainfall, temperature, relative humidity and air pressure. By controlling the state within the space of the multifunctional container 3, the influencing factors of water transport in rock samples, including the gradients of rainfall, temperature, relative humidity and air pressure, can be controlled.

[0056] The main factors affecting the rate of water transport within rock samples are changes in rainfall, temperature, relative humidity, and air pressure.

[0057] One influencing factor is the simulation of rainfall effects: After rainfall acts on the soil and rock mass, it causes the water content of the soil and rock mass to increase. Therefore, the rainfall gradient is converted into a standard sand gradient supply with different water contents. A multifunctional container 3 is filled with standard sand with a certain water content to simulate sand and soil materials in the actual environment. Water can seep into the horizontally placed rock sample 10 through the square hole in the lower part of the multifunctional container 3, and the rainfall gradient supply is achieved by changing the water content of the standard sand.

[0058] The second influencing factor, relative humidity, was simulated: relative humidity at different gradients was controlled by placing salt water dishes containing different saturated salt solutions inside the multifunctional container 3.

[0059] The third influencing factor is temperature. The square hole on the upright plate of the multifunctional container 3 is sealed with glass. Pure water is filled into the multifunctional container 3. The temperature of the water is controlled by a hot water heater and a thermal switch, thereby controlling the temperature of one end of the sample.

[0060] The fourth influencing factor is the simulation of air pressure: the top of the multifunctional container 3 is sealed, the gap between the rock sample 10 and the sealing buckle 6 is sealed to prevent gas from entering the rock sample 10, and the water tank cover 5 is opened to connect to the air pump. The air pressure change in the chamber is controlled by the air pump and pressure gauge.

[0061] Therefore, the experimental method for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks includes the following steps:

[0062] (1) Sample selection:

[0063] Rock sample 10 was dried and its basic parameters were determined;

[0064] (2) Sample installation:

[0065] The rock sample 10 is sealed by wrapping it with waterproof tape, and the sensor installation opening is reserved by cutting with a round blade. One end of the rock sample 10 is tightly attached to the square hole of the multifunctional container 3, and the gap between the rock sample 10 and the sealing buckle 6 is sealed with microcrystalline wax. Two micro pressure transmitters 14 and two microwave humidity sensors 13 are arranged side by side at equal intervals on the top of the horizontal plane of the rock sample 10, and one micro pressure transmitter 14 and one microwave humidity sensor 13 are set at each of the exposed ends of the rock sample 10. Six platinum resistance thermometers 15 are arranged at equal intervals on one side of the rock sample 10. The data monitored by the micro pressure transmitters 14, microwave humidity sensors 13 and platinum resistance thermometers 15 are collected and stored by the data acquisition device. The copper screws 12 on the electrode fixing frame 11 are tightened, and the electrode fixing frame 11 is installed at 2cm, 10cm and 18cm along the longitudinal section of the rock sample 10 and connected to the high-density electrical resistivity meter for monitoring.

[0066] (3) Set the temperature of the entire enclosed space to the required temperature for the test, and proceed to the next step after the temperature stabilizes.

[0067] (4) Loading process:

[0068] Standard sand is filled into the multifunctional container 3, and the rainfall gradient supply is achieved by changing the moisture content of the standard sand.

[0069] Alternatively, a salt water dish containing different saturated salt solutions and a temperature and humidity sensor can be placed inside the multifunctional container 3 to control the relative humidity gradient;

[0070] Alternatively, after sealing the square hole of the multifunctional container 3 with glass, pure water can be filled into the multifunctional container 3. At the same time, the electric kettle and temperature sensor can be placed into the multifunctional container 3 through the open cover 5. The water temperature can be controlled by the electric kettle and the thermal switch, thereby achieving a temperature gradient.

[0071] Alternatively, the multifunctional container 3 can be sealed, and the cover plate 5 can be opened to connect to an air pump, so that the air pressure gradient can be achieved through the air pump and pressure gauge;

[0072] (5) Data collection:

[0073] The data acquisition device collects data every 1 minute, and the high-density electrical resistivity meter collects resistivity values ​​on three resistivity profiles every 2 hours.

[0074] (6) Results analysis.

[0075] The monitoring data from the micro-pressure transmitter 14, the microwave humidity sensor 13, and the platinum resistance thermometer 15, along with the monitoring data from the high-density electrical resistivity meter on three resistivity profiles, can be used to obtain the changes in air pressure, moisture content, and temperature over time at different locations on the surface of the rock sample 10, as well as the changes in moisture content over time at the three profiles of the rock sample 10. Dividing the distance between the profiles by the time of water transport gives the rate of water transport within the rock sample.

Claims

1. An experimental apparatus for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks, characterized in that: The test apparatus includes a base (1), a multifunctional container (3) placed on the base (1), three microwave humidity sensors (13), three micro pressure transmitters (14), a high-density electrical resistivity meter, and a data acquisition unit; the top of the multifunctional container (3) is provided with a cover plate (5) with an outer edge (4); the two sides of the multifunctional container (3) are respectively provided with base railings (2), the bottom of which is fixed to the base (1); the front end of the base railings (2) on both sides is provided with a sample support plate (8), and the front of the sample support plate (8) is provided with a sensor fixing column (7); the sensor fixing column is provided with a sensor fixing column (7). The column (7) has triangular fixed plates (9) on both sides connected to the sample support plate (8); the multifunctional container (3) facing the sample support plate (8) has a square hole in the lower middle part of one side of the box, and a sealing buckle (6) is provided on the square hole; the sealing buckle (6) is inserted with a rock sample (10) in contact with the square hole, and the bottom surface of the rock sample (10) is in contact with the back of the frontmost sample support plate (8); the rock sample (10) has three sensor placement ports and is fitted with three electrode fixing frames (11), and the electrode fixing frames (11) are equipped with copper screws with electrode wires ( 12); the electrode wire is connected to the high-density electrical resistivity meter; each of the sensor mounting ports is equipped with a microwave humidity sensor (13); the ends of the three micro-pressure transmitters (14) are in contact with the rock sample (10); several platinum resistance thermometers (15) are evenly distributed on one side of the rock sample (10) parallel to the base fence (2); the micro-pressure transmitters (14), the microwave humidity sensor (13) and the platinum resistance thermometers (15) are respectively connected to the data acquisition unit; one of the sensor mounting ports is located on the upper part of the bottom surface of the rock sample (10), and the three electrode fixing frames ( 11) Each of the rock samples (10) between each pair is provided with a micro pressure transmitter (14); one of the three micro pressure transmitters (14) is provided in the top arc groove of the sensor fixing column (7); each of the three electrode fixing frames (11) between each pair of rock samples (10) is provided with a micro pressure transmitter (14); the multifunctional container (3) provides space to simulate changes in environmental factors such as rainfall, temperature, relative humidity and air pressure. By controlling the state in the space of the multifunctional container (3), the influencing factors of water transport in the rock sample, including the gradient of rainfall, temperature, relative humidity and air pressure, can be controlled.

2. The experimental apparatus for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks as described in claim 1, characterized in that: The height of the base fence (2) is lower than the height of the sample support plate (8), and the height of the sample support plate (8) is lower than the height of the sensor fixing column (7).

3. The experimental apparatus for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks as described in claim 1, characterized in that: The area of ​​the square hole is smaller than the cross-sectional area of ​​the rock sample (10).

4. The experimental apparatus for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks as described in claim 1, characterized in that: The sealing buckle (6) is filled with microcrystalline wax at the junction with the rock sample (10).

5. The experimental apparatus for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks as described in claim 1, characterized in that: The rock sample (10) has waterproof tape on all four sides.

6. The experimental apparatus for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks as described in claim 1, characterized in that: The three electrode fixing frames (11) are respectively set at 2cm, 10cm and 18cm along the longitudinal section of the rock sample (10).

7. The experimental apparatus for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks as described in claim 1, characterized in that: Each of the electrode fixing frames (11) has 5 holes at 2cm intervals on its four sides, and the inner walls of the holes are threaded. Each hole is equipped with a copper screw (12). The tip of the copper screw (12) is in contact with the surface of the rock sample (10), and the head of the screw is connected to one end of the electrode wire. The other end of the electrode wire is connected to the high-density electrical resistivity instrument.

8. An experimental method for studying the influencing factors of water transport rate in sandstone and conglomerate surrounding rocks using the apparatus described in claim 1, comprising the following steps: (1) Sample selection: The rock sample (10) was dried and its basic parameters were determined; (2) Sample installation: The rock sample (10) is sealed by wrapping it with waterproof tape and cutting out the sensor installation opening with a round blade. One end of the rock sample (10) is placed close to the square hole of the multi-functional container (3), and the gap between the rock sample (10) and the sealing buckle (6) is sealed with microcrystalline wax. Two micro pressure transmitters (14) and two microwave humidity sensors (13) are arranged side by side at equal intervals on the top of the horizontal plane of the rock sample (10), and one micro pressure transmitter is installed at each of the exposed ends of the rock sample (10). (14) and a microwave humidity sensor (13); six platinum resistance thermometers (15) are set at equal intervals on one side of the rock sample (10); the data monitored by the micro pressure transmitter (14), microwave humidity sensor (13) and platinum resistance thermometer (15) are collected and stored by the data acquisition device; tighten the copper screws (12) on the electrode fixing frame (11), install the electrode fixing frame (11) at 2cm, 10cm and 18cm along the longitudinal section of the rock sample (10), and connect it to the high-density electrical resistivity meter for monitoring; (3) Set the temperature of the entire enclosed space to the required temperature for the test, and proceed to the next step after the temperature stabilizes. (4) Loading process: Standard sand is filled into a multifunctional container (3), and the rainfall gradient supply is achieved by changing the moisture content of the standard sand. Alternatively, a salt water dish containing different saturated salt solutions and a temperature and humidity sensor can be placed in a multifunctional container (3) to control the relative humidity gradient; Alternatively, after sealing the square hole of the multifunctional container (3) with glass, pure water is filled into the multifunctional container (3). At the same time, the immersion heater and temperature sensor are placed into the multifunctional container (3) through the open cover (5). The water temperature is controlled by the immersion heater and the thermal switch, thereby achieving a temperature gradient. Alternatively, the multifunctional container (3) can be sealed, and the cover plate (5) can be opened to connect to the air pump, so that the air pressure gradient can be achieved through the air pump and the pressure gauge; (5) Data collection: The data acquisition device collects data every 1 minute, and the high-density electrical resistivity meter collects resistivity values ​​on three resistivity profiles every 2 hours. (6) Results analysis.

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