High-pressure preparation method of consolidated silt at bottoms of rivers, lakes and reservoirs

Abstract

The invention relates to a high-pressure preparation method of river, lake and reservoir bottom consolidated silt. The high-pressure preparation method of the river, lake and reservoir bottom consolidated sediment comprises the following steps: (1) preparing a sample; (2) filling a settling vat; (3) pressurizing the settling vat; (4) measuring after pressure relief; the device can simulate an underwater pressure environment to make a sample, so that the consolidated silt can be repeatedly used, the sampling frequency of the consolidated silt is reduced, and the sampling cost of the consolidated silt is further reduced; and the prepared sample can be put into an experiment in the first time, so that the change of consolidated silt is reduced, the accuracy and reliability of an experiment result are ensured, and scientific researchers are helped to carry out accurate judgment.

Description

Technical Field

[0001] The present invention relates to the technical field of sediment settlement research, and particularly to a method for preparing consolidated sediment at the bottom of rivers, lakes and reservoirs under high pressure. Background Art

[0002] Consolidated sediment refers to the sediment in the deposits that are compacted, aggregated and cemented together at the bottom of rivers, lakes and reservoirs. This consolidated sediment often exhibits hard physical properties. Experiments on such consolidated sediment help to understand and control sediment deposition and erosion problems in areas such as rivers, lakes and reservoirs, and to show the structure, properties and erodibility of the sediment bed. The conventional method for obtaining consolidated sediment is to use the method of collecting sediment columns, that is, using a mechanical device to extract consolidated sediment from the bottom of the sediment bed. This method of collecting sediment columns usually requires renting a boat to transport the mechanical device directly above the collection point, and then sinking the mechanical device to the bottom to collect the consolidated sediment. After lifting the mechanical device with the collected consolidated sediment, taking out the consolidated sediment, it needs to be segmented for easy storage and stored separately in a sealed and refrigerated manner to retain the representativeness of the consolidated sediment as much as possible. Using the method of collecting sediment columns will consume a lot of manpower and material resources, and during the process of transporting and storing the consolidated sediment to the laboratory, there will still be changes in its properties, losing accuracy and representativeness; when the consolidated sediment is transported from underwater to above water, the environmental pressure changes, and the consolidated sediment will undergo chemical changes and changes in density; during the long-term storage and transportation process of the consolidated sediment, water will inevitably evaporate and be lost, and the chemical changes and density changes will cause qualitative changes from quantitative changes, which will have an adverse impact on the experimental results; the change in the properties of the consolidated sediment will lead to deviations in the experimental results and mislead the judgment of scientific researchers; therefore, each time the consolidated sediment is used, it is necessary to implement the method of collecting sediment columns, which consumes a lot of manpower and material resources, and the collected consolidated sediment cannot be experimented immediately, and the consolidated sediment is very easy to change, and it is difficult to ensure the accuracy and reliability of the experimental results, which is not conducive to scientific researchers to make judgments. Summary of the Invention

[0003] The purpose of the present invention is to solve the above problems and provide a method for preparing consolidated sediment at the bottom of rivers, lakes and reservoirs under high pressure.

[0004] The technical solution of the present invention is: a method for preparing consolidated sediment at the bottom of rivers, lakes and reservoirs under high pressure includes the following steps:

[0005] ① Sample preparation

[0006] The soil sample and water are mixed in a certain mass ratio; the soil sample is sediment sampled on-site at the bottom of a river, lake or reservoir; the soil sample can be reused, which can greatly reduce the sampling times of consolidated sediment, thereby reducing the sampling cost of consolidated sediment; the mixture is stirred with a stirrer until there is no residual water on the surface of the soil sample, which can ensure that the soil sample and water are fully mixed to form a sample; the sample has a similar composition to the sediment sampled at the bottom of a river, lake or reservoir at the first time;

[0007] ②Filling the sedimentation barrel

[0008] The samples are added into several groups of sedimentation barrels; each group of sedimentation barrels corresponds to an underwater pressure of a water depth; the water depth is the depth of the bottom of the river, lake or reservoir; the underwater pressure is the same as the pressure at the bottom of the river, lake or reservoir; each group of sedimentation barrels includes several sedimentation barrels; within the same group, the sedimentation barrels are numbered one by one; each number corresponds to a pressurization day; within the same group, the pressurization days of each sedimentation barrel are different; the bottom of the sedimentation barrel is closed, and the top is detachably and tightly connected with a top cover; the sample is added from the top of the sedimentation barrel; the sedimentation barrel is provided with an equal-diameter cavity, and the cavity depth is H; the top cover is provided with a pressurization valve, a pressure gauge and a pilot-operated check valve; the outlet of the pilot-operated check valve is The port is connected to the inside of the sedimentation barrel; when the internal air pressure of the sedimentation barrel is greater than the external atmospheric pressure, the gas inside the sedimentation barrel will not be discharged from the outlet of the pilot check valve; remove the top cover; pour the sample into each sedimentation barrel; when the top of the sample is at a certain distance from the top of the sedimentation barrel, smooth the top of the sample in the sedimentation barrel until the top of the smoothed sample is a fixed distance h from the top of the sedimentation barrel; generally, the fixed distance h is 50 cm; fill the sedimentation barrel with water; there is water above the sample, so that the pressure of the high-pressure airflow can be stably and evenly applied to the sample to simulate the sedimentation process; then install the top cover airtightly on the top of the sedimentation barrel;

[0009] ③Pressure of sedimentation barrel

[0010] Take out a group of sedimentation barrels; the sedimentation barrels in the group are uniformly fed with high-pressure airflow of the same pressure; the pressurizing valves of each sedimentation barrel in the group are connected to the high-pressure air circuit; the high-pressure air circuit is connected to the high-pressure airflow; the air pressure of the high-pressure airflow is equivalent to the underwater pressure of the corresponding water depth of the sedimentation barrels in this group; the high-pressure airflow enters the sedimentation barrel through the pressurizing valve; the pressurizing valve can control the on and off of the high-pressure airflow; the control air circuit is connected to the control airflow; the pilot control port of the pilot check valve is connected to the control air circuit; once the pilot control port enters the control airflow, the inlet and outlet of the pilot check valve are connected; the high-pressure gas in the sedimentation barrel will be discharged outward through the pilot check valve to achieve pressure relief of the sedimentation barrel; therefore, when opening the high-pressure air circuit, the control air circuit needs to be closed; open all the pressurizing valves of the sedimentation barrels in this group to allow the high-pressure gas to pass into each sedimentation barrel, providing a stable and uniform high pressure for the sedimentation barrel;

[0011] ④Measurement after pressure relief

[0012] Each number corresponds to the pressurization days of a sedimentation bucket; after the sedimentation bucket is pressurized for a sufficient number of days, the corresponding sedimentation bucket is depressurized; the depressurization process is to first close the pressurization valve and then introduce a control air flow into the pilot check valve; the pilot check valve realizes remote depressurization, improving the safety of the depressurization operation;

[0013] Then open the top cover and measure the distance h from the top of the sample to the top of the sedimentation bucket ’ ; From this, it can be known that for the underwater pressure at the same water depth, the degree of compaction of the consolidated sediment under different days of pressurization; the calculation formula for the degree of compaction of the consolidated sediment is Take samples from the samples in each sedimentation bucket and measure the dry unit weight;

[0014] ⑤ Conduct experiments on the remaining groups of sedimentation buckets

[0015] Take out the remaining groups of sedimentation buckets, adjust the pressure of the high-pressure air flow in the high-pressure gas path, and proceed according to steps ③ and ④.

[0016] Preferably, in step ①, samples are taken from the top, bottom, and middle of the sample, and the dry unit weights are measured respectively; compare the three measured dry unit weight values; this can test the uniformity of the sample; when the three measured dry unit weight values are similar, the top, bottom, and middle of the sample are uniform.

[0017] Preferably, in steps ② and ④, before injecting water into the sedimentation bucket, measure the distances from the center and the four sides of the top of the sample to the top of the sedimentation bucket: h 中心 、h 1 、h 2 …; Calculate the standard value of the distance from the top of the sample to the top of the sedimentation bucket according to the statistical principle; the standard value calculated in this way is relatively more accurate, which is beneficial to ensuring the accuracy of the experimental results.

[0018] Preferably, the process of measuring the dry unit weight of the sample includes the following steps:

[0019] S 1 Sample the sample

[0020] Level the soil surface at the top of the sample; vertically and steadily press the core cutter into the sample; the volume of the core cutter is V; generally, the volume of the core cutter is 100 cm 3When pressing the core cutter, it is strictly prohibited to shake the core cutter left and right to ensure the density inside the core cutter; after the sample emerges from the upper end of the core cutter, dig out the samples around the core cutter, and then take out the core cutter and the sample carried by the core cutter; use a soil shaving knife to shave off the excess samples at the upper and lower ends of the core cutter to align the sample with the upper and lower ends of the core cutter to avoid interfering with the accuracy of the final calculation; place the filter paper in step ① under the core cutter, and use the bottom cover to seal the lower end of the core cutter under the filter paper; cover the upper end of the core cutter with a sealing cover; the sealing cover, bottom cover, and filter paper seal the sample inside the core cutter; wipe off the samples on the periphery of the core cutter.

[0021] S 2 Dry and weigh the sample

[0022] Weigh the container in the constant temperature oven and record it as m 1 ; Spread the sample in the core cutter evenly on the container in the constant temperature oven; put the container with the sample into the constant temperature oven for heating and drying for 6 - 8 h to ensure that the moisture in the sample is completely discharged; after the sample and the container cool down, weigh the sample and the container and record it as m 2 ; Calculate that the dry unit weight of the sample is

[0023] Furthermore, the process of measuring the water content of the sample:

[0024] In step S 1 Before sampling the sample, measure the gross weight;

[0025] Weigh the core cutter, filter paper, sealing cover and bottom cover and record it as m 毛 ; The filter paper, sealing cover and bottom cover match the core cutter;

[0026] In step S 2 After drying the sample, measure the tare weight

[0027] Weigh the core cutter, the sample inside the core cutter, the filter paper, the sealing cover and the bottom cover and record it as m 皮 ; Thus, it can be known that the net weight of the sample m 净 = m 皮 - m 毛 ;

[0028] Calculate that the water content of the sample is

[0029] Furthermore, during the drying of the sample in step S 2 The sample in the core cutter is spread evenly in the container with a thickness of 2 - 3 cm to ensure that the moisture in the sample in the container is completely discharged.

[0030] Preferably, in step ①, the mixing weight ratio of soil sample and water is 6:1.

[0031] Furthermore, the container is made of steel mesh, enabling moisture to drain outwards from the bottom of the sample through the steel mesh.

[0032] Preferably, the top cover in step ② has a flange structure; a top flange ring corresponding to and mating with this flange structure is provided at the top end of the sedimentation barrel; this flange structure is connected to the top flange ring through a bolt connector; the flange connection structure between the top cover and the top flange ring is a common airtight connection structure.

[0033] Furthermore, a flange cover is detachably and airtightly connected to the bottom of the sedimentation barrel in step ②; a bottom flange ring corresponding to the flange cover is provided at the bottom end of the sedimentation barrel; this flange cover is connected to the bottom flange ring through a bolt connector; the flange connection structure between the flange cover and the bottom flange ring is a common airtight connection structure.

[0034] Preferably, in step ③, within the same group, all the pressure valves are connected to the high-pressure gas path through the same pressure regulator, and the pilot control ports of each pilot check valve are respectively connected to the control gas path through independent manual pressure valves; the pressure regulator can adjust the high-pressure gas flow in the high-pressure gas path to introduce high-pressure gas flows of the same pressure into the sedimentation barrels in the same group; each pilot check valve is individually controlled through an independent manual pressure valve to facilitate the sequential pressure relief of each sedimentation barrel within the same group.

[0035] The beneficial effects of the present invention are as follows: The method for high-pressure preparation of consolidated sediment at the bottom of rivers, lakes, and reservoirs of the present invention has the following advantages:

[0036] (1) The present invention can simulate the underwater pressure environment to make samples, enabling the repeated use of consolidated sediment, reducing the sampling times of consolidated sediment, and thus reducing the sampling cost of consolidated sediment; moreover, the samples produced can be put into experiments immediately, reducing the changes in consolidated sediment and ensuring the accuracy and reliability of experimental results, helping scientific researchers to make accurate judgments;

[0037] (2) In step ① of the present invention, samples are also taken from the top, bottom, and middle of the sample, and the dry unit weight is measured respectively; by comparing the three measured dry unit weight values, the uniformity of the sample is inspected; Description of the Drawings

[0038] Figure 1 is a flowchart of the method for high-pressure preparation of consolidated sediment at the bottom of rivers, lakes, and reservoirs of the present invention;

[0039] Figure 2 is a flowchart of measuring the dry unit weight of the sample of the present invention;

[0040] Figure 3 is the front view of the equipment supporting the method for high-pressure preparation of consolidated sediment at the bottom of rivers, lakes, and reservoirs of the present invention;

[0041] Figure 4 is Figure 3A-A cross-sectional view;

[0042] Figure 5 is Figure 4 B-B cross-sectional view;

[0043] Figure 6 is a statistical table of experimental data of different soil samples under a water pressure of 100 m;

[0044] Figure 7 is a relationship diagram between the dry unit weight of different soil samples and the deposition duration;

[0045] Figure 8 is a change curve of the difference in dry unit weight, moisture content and deposition duration of HY41 soil sample;

[0046] Figure 9 is a change curve of the dry unit weight of HY12 soil sample consolidated under different pressures;

[0047] Figure 10 is the physical object of the equipment used in the high-pressure preparation method of consolidated sediment at the bottom of rivers, lakes and reservoirs of the present invention Figure 1 ;

[0048] Figure 11 is the physical object of the equipment used in the high-pressure preparation method of consolidated sediment at the bottom of rivers, lakes and reservoirs of the present invention Figure 2 ;

[0049] Figure 12 is the physical object of the equipment used in the high-pressure preparation method of consolidated sediment at the bottom of rivers, lakes and reservoirs of the present invention Figure 3 ;

[0050] Figure 13 is the physical object of the equipment used in the high-pressure preparation method of consolidated sediment at the bottom of rivers, lakes and reservoirs of the present invention Figure 4 ;

[0051] wherein HY12, HY22, HY30, HY36, HY41 respectively refer to different soil samples;

[0052] In the figure: 1. Settlement bucket, 11. Top flange ring, 12. Bottom flange ring, 13. Hanging plate, 2. Top cover, 31. Pressurizing valve, 32. Pressure gauge, 33. Pilot check valve, 34. Pressure relief valve, 4. Flange cover, 51. Upper sealing ring, 52. Lower sealing ring, 6. Bracket, 61. U-shaped clamp, 62. Manual pressure valve, 63. Pressure regulating valve, 7. Water receiving tank. Specific implementation mode

[0053] Example 1: Refer to Figures 1-3 , a high-pressure preparation method for consolidated sediment at the bottom of rivers, lakes and reservoirs includes the following steps:

[0054] ① Sample production

[0055] The soil sample and water are mixed in a certain mass ratio; the soil sample is sediment sampled on-site at the bottom of a river, lake or reservoir; the soil sample can be reused, which can greatly reduce the sampling times of consolidated sediment, thereby reducing the sampling cost of consolidated sediment; the mixture is stirred with a stirrer until there is no residual water on the surface of the soil sample, which can ensure that the soil sample and water are fully mixed to form a sample; the sample has a similar composition to the sediment sampled at the bottom of a river, lake or reservoir at the first time;

[0056] ②Filling sedimentation barrel 1

[0057] Add samples into several groups of sedimentation barrels 1; each group of sedimentation barrels 1 corresponds to an underwater pressure of a water depth; the water depth is the depth of the bottom of the river, lake or reservoir; the underwater pressure is the same as the pressure at the bottom of the river, lake or reservoir; each group of sedimentation barrels 1 includes several sedimentation barrels 1; in the same group, the sedimentation barrels 1 are numbered one by one; each number corresponds to a pressurization day; in the same group, the pressurization days of each sedimentation barrel 1 are different; the bottom of the sedimentation barrel 1 is closed, and the top is detachably and tightly connected with a top cover 2; the sample is added from the top of the sedimentation barrel 1; the sedimentation barrel 1 is provided with an equal-diameter cavity, and the cavity depth is H; the top cover 2 is provided with a pressurization valve 31, a pressure gauge 32 and a pilot-operated check valve 33; the pilot-operated check valve 3 The outlet of 3 is connected to the inside of the sedimentation barrel 1; when the internal air pressure of the sedimentation barrel 1 is greater than the external atmospheric pressure, the gas inside the sedimentation barrel 1 will not be discharged from the outlet of the pilot check valve 33; remove the top cover 2; pour the sample into each sedimentation barrel 1; when the top of the sample is at a certain distance from the top of the sedimentation barrel 1, smooth the top of the sample in the sedimentation barrel 1 until the top of the smoothed sample is a fixed distance h from the top of the sedimentation barrel 1; generally, the fixed distance h is 50 cm; fill the sedimentation barrel 1 with water; there is water above the sample so that the pressure of the high-pressure airflow can be stably and evenly applied to the sample to simulate the sedimentation process; then install the top cover 2 to the top of the sedimentation barrel 1 in a sealed manner;

[0058] ③Pressure of sedimentation tank 1

[0059] Take out a group of sedimentation barrels 1; the sedimentation barrels 1 within this group are uniformly supplied with high-pressure airflows at the same pressure; connect the pressure valves 31 of each sedimentation barrel 1 in this group to the high-pressure air path; this high-pressure air path is connected to the high-pressure airflow; the air pressure of this high-pressure airflow is equivalent to the underwater pressure corresponding to the water depth of this group of sedimentation barrels 1; the high-pressure airflow enters the sedimentation barrel 1 through the pressure valve 31; the pressure valve 31 can control the on-off of this high-pressure airflow; this control air path is connected to the control airflow; connect the pilot control port of the pilot check valve 33 to the control air path; once the control airflow enters the pilot control port, the inlet and outlet of the pilot check valve 33 are connected; the high-pressure gas in the sedimentation barrel 1 will be discharged outward through the pilot check valve 33, realizing the pressure relief of the sedimentation barrel 1; therefore, when opening the high-pressure air path, it is necessary to close the control air path; open all the pressure valves 31 of this group of sedimentation barrels 1 to allow the high-pressure gas to enter each sedimentation barrel 1, providing stable and uniform high pressure for the sedimentation barrel 1.

[0060] ④Measurement after pressure relief

[0061] Each number corresponds to the pressurization days of a sedimentation barrel 1; after the sedimentation barrel 1 is pressurized for a sufficient number of days, the corresponding sedimentation barrel 1 is pressure-relieved; the pressure relief process is to first close the pressure valve 31 and then introduce the control airflow into the pilot check valve 33; the pilot check valve 33 realizes remote pressure relief, improving the safety of the pressure relief operation.

[0062] Then open the top cover 2 and measure the distance h from the top of the sample to the top of the sedimentation barrel 1. ’ ; Thus, it can be known the compaction degree of the consolidated sediment under different days of pressurization at the underwater pressure of the same water depth; the calculation formula for the compaction degree of the consolidated sediment is Take samples from the samples in each sedimentation barrel 1 and measure the dry unit weight.

[0063] ⑤Conduct experiments on the remaining groups of sedimentation barrels 1

[0064] Take out the remaining groups of sedimentation barrels 1, adjust the pressure of the high-pressure airflow in the high-pressure air path, and proceed according to steps ③ and ④.

[0065] Compared with the prior art, the present invention can simulate the underwater pressure environment to produce samples, enabling the consolidated sediment to be repeatedly used, reducing the sampling times of the consolidated sediment, and thus reducing the sampling cost of the consolidated sediment; and the produced samples can be put into experiments immediately, reducing the change of the consolidated sediment, ensuring the accuracy and reliability of the experimental results, and helping scientific researchers to make accurate judgments.

[0066] In step ①, take samples from the top, bottom, and middle of the sample and measure the dry unit weight respectively; compare the three measured dry unit weight values; this can test the uniformity of the sample; when the three measured dry unit weight values are almost the same, the top, bottom, and middle of the sample are all uniform and consistent.

[0067] In steps ② and ④, before filling water into the sedimentation bucket 1, measure the distances from the center and the four surrounding points at the top of the sample to the top of the sedimentation bucket 1 respectively: h 中心 , h 1 , h 2 …; Calculate the standard value of the distance from the top of the sample to the top of the sedimentation bucket 1 according to the statistical principle; The standard value calculated in this way is relatively more accurate, which is conducive to ensuring the accuracy of the experimental results.

[0068] The process of measuring the dry unit weight of the sample includes the following steps:

[0069] S 1 Sampling the sample

[0070] Level the soil surface at the top of the sample; Vertically and steadily press the core cutter into the sample; The volume of the core cutter is V; Generally, the volume of the core cutter is 100 cm 3 ; When pressing the core cutter, it is strictly prohibited to shake the core cutter left and right to ensure the density inside the core cutter; After the sample emerges from the upper end of the core cutter, dig out the sample around the core cutter, and then take out the core cutter and the sample carried by the core cutter; Use a soil shaving knife to shave off the excess samples at the upper and lower ends of the core cutter to align the sample with the upper and lower ends of the core cutter to avoid interfering with the accuracy of the final calculation; Place the filter paper in step ① under the core cutter, and use the bottom cover to seal the lower end of the core cutter under the filter paper; Cover the upper end of the core cutter with a sealing cover; The sealing cover, bottom cover, and filter paper seal the sample inside the core cutter; Wipe off the sample on the outside of the core cutter;

[0071] S 2 Drying and weighing the sample

[0072] Weigh the container in the constant temperature oven, denoted as m 1 ; Spread the sample in the core cutter evenly on the container in the constant temperature oven; Put the container with the sample into the constant temperature oven for heating and drying for 6 - 8 h to ensure that the moisture in the sample is completely discharged; After the sample and the container cool down, weigh the sample and the container, denoted as m 2 ; Calculate the dry unit weight of the sample as

[0073] The process of measuring the water content of the sample:

[0074] Before sampling the sample in step S 1 Measure the gross weight;

[0075] Weigh the core cutter, filter paper, sealing cover and bottom cover, denoted as m 毛 ; The filter paper, sealing cover and bottom cover match the core cutter;

[0076] After drying the sample in step S 2 Measure the tare weight

[0077] Weigh the core cutter, the sample inside the core cutter, the filter paper, the top cover, and the bottom cover, and record it as m. 皮 ; Thus, it can be known that the net weight of the sample is m 净 = m 皮 - m 毛 ;

[0078] It is calculated that the water content of the sample is

[0079] In step S 2 During the drying of the sample, the sample in the core cutter is laid flat in the container with a thickness of 2 - 3 cm to ensure that the moisture in the sample in the container is completely discharged.

[0080] In step ①, the mixing weight ratio of the soil sample and water is 6:1.

[0081] The container is made of a steel mesh, so that the moisture at the bottom of the sample can also be discharged outward through the steel mesh.

[0082] Example 2: Refer to Figures 3-5 , Example 2 is basically the same as Example 1, and the same parts will not be elaborated again. The differences are as follows: The top cover 2 in step ② is of a flange structure; a top flange ring 11 corresponding to and matching with this flange structure is provided at the top of the sedimentation barrel 1; this flange structure is connected to the top flange ring 11 through a bolt connector; the flange connection structure between the top cover 2 and the top flange ring 11 is a common airtight connection structure.

[0083] A flange cover 4 is detachably and airtightly connected to the bottom of the sedimentation barrel 1 in step ②; a bottom flange ring 12 corresponding to the flange cover 4 is provided at the bottom end of the sedimentation barrel 1; this flange cover 4 is connected to the bottom flange ring 12 through a bolt connector; the flange connection structure between the flange cover 4 and the bottom flange ring 12 is a common airtight connection structure; in this way, the bottom end of the sedimentation barrel 1 can be opened, facilitating the removal of the consolidated sediment in the sedimentation barrel 1.

[0084] An upper sealing ring 51 is provided between the top cover 2 and the top flange ring 11; a lower sealing ring 52 is provided between the flange cover 4 and the bottom flange ring 12; the upper sealing ring 51 and the lower sealing ring 52 respectively enhance the airtight performance at the top and bottom ends of the sedimentation barrel 1.

[0085] A pressure relief valve 34 is also installed on the top cover 2 as an alternative for pressure relief; when the pilot check valve 33 fails, the pressure relief valve 34 can be manually operated to relieve the pressure of the sedimentation barrel 1.

[0086] The same group of sedimentation barrels 1 are hung side by side on the bracket 6; hanging plates 13 are symmetrically provided on both sides of the sedimentation barrel 1; the bracket 6 is provided with a U-shaped clamp 61 corresponding to and matching with the hanging plates 13; the hanging plates 13 are clamped into this U-shaped clamp 61, which can simplify the disassembly and installation process of the sedimentation barrel 1 and the bracket 6.

[0087] Below the support 6 is provided with a water receiving tank 7; the water receiving tank 7 corresponds to the hanging position of the sedimentation barrel 1; in this way, when the flange cover 4 is opened, the water receiving tank 7 can catch the excess water in the sedimentation barrel 1 to keep the laboratory clean.

[0088] Within the same group, all the pressure valves 31 are connected to the high-pressure gas path through the same pressure regulating valve 63, and the pilot control ports of the respective pilot check valves 33 are respectively connected to the control gas path through independent manual pressure valves 62; the pressure regulating valve 63 can adjust the high-pressure air flow in the high-pressure gas path and introduce high-pressure air flow with the same pressure into the sedimentation barrels 1 of the same group; the respective pilot check valves 33 are individually controlled through the independent manual pressure valves 62 so that the sedimentation barrels 1 within the same group can be depressurized in sequence.

[0089] According to the above solution, the inventor set up multiple sampling points in the section of the Yellow River from Tongguan to Sanmenxia, collected different soil samples and brought them to the laboratory for experiments; different sampling points were numbered differently; among them, the longitude and latitude coordinates of the HY12 sampling point are (111.184134, 34.796563), the longitude and latitude coordinates of the HY22 sampling point are (110.965580, 34.698570), the longitude and latitude coordinates of the HY30 sampling point are (110.751117, 34.644120), the longitude and latitude coordinates of the HY36 sampling point are (110.479943, 34.599409), and the longitude and latitude coordinates of the HY41 sampling point are (110.287307, 34.609599); the samples collected at each sampling point are also named after the sampling point number in the laboratory and are dried before the experiment.

[0090] During the experiment, the inventor grouped the sedimentation barrels 1 according to the water depths of 20m, 50m, 100m, and 150m; after calculating the underwater pressures of 20m, 50m, 100m, and 150m, the high-pressure air flow with the corresponding pressure was input to each group; each group was numbered according to the pressurization days of 1 day, 2 days, 3 days, 4 days, 5 days, 7 days, 10 days, 14 days, 18 days, 22 days, 26 days, and 30 days and experiments were carried out respectively; the data obtained from the experiments: moisture content, dry unit weight, and density were statistically analyzed.

Claims

1. A high pressure preparation method for consolidating sediment at the bottom of a river, lake or reservoir, characterized in that: The following steps are involved: ①Sample production Mix the soil sample and water according to a certain mass ratio; The mixture is stirred with a stirrer until there is no residual water on the surface of the soil sample to form a sample; ②Filling the sedimentation barrel Add samples into several groups of sedimentation barrels; each group of sedimentation barrels corresponds to an underwater pressure of a water depth; each group of sedimentation barrels includes several sedimentation barrels; in the same group, the sedimentation barrels are numbered one by one; the bottom of the sedimentation barrel is closed, and the top is detachably and tightly connected with a top cover; the sedimentation barrel is provided with an equal-diameter cavity, and the cavity depth is H; the top cover is provided with a pressurizing valve, a pressure gauge and a pilot check valve; the outlet of the pilot check valve is connected to the inside of the sedimentation barrel; remove the top cover; pour the sample into each sedimentation barrel; when the top of the sample is at a certain distance from the top of the sedimentation barrel, smooth the top of the sample in the sedimentation barrel until the top of the smoothed sample is a fixed distance h from the top of the sedimentation barrel; fill the sedimentation barrel with water; and then install the top cover tightly to the top of the sedimentation barrel; ③Pressure of sedimentation barrel Take out a group of sedimentation barrels; connect the pressurizing valves of each sedimentation barrel of the group with the high-pressure gas circuit; the high-pressure gas circuit connects the high-pressure gas flow; the gas pressure of the high-pressure gas flow is equivalent to the underwater pressure of the corresponding water depth of the sedimentation barrel of the group; the control gas circuit connects the control gas flow; connect the pilot control port of the pilot check valve with the control gas circuit; open the high-pressure gas circuit and close the control gas circuit; open all the pressurizing valves of the sedimentation barrel of the group to allow the high-pressure gas to pass into each sedimentation barrel; ④Measurement after pressure relief Each number corresponds to the number of days that a sedimentation barrel is pressurized. After the sedimentation barrel is pressurized for a sufficient number of days, the sedimentation barrel with the corresponding number is depressurized. The depressurization process is to first close the pressurization valve and then introduce a control air flow into the pilot check valve. Then open the top cover and measure the distance h from the top of the sample to the top of the sedimentation bucket. ’ ; From this, we can know that the density of consolidated sediment under the same water depth and different days of pressure application; the calculation formula for the density of consolidated sediment is Take samples from each settling barrel and measure the dry bulk density; ⑤ Experiment on the remaining settling buckets Take out the remaining settling barrels, adjust the pressure of the high-pressure airflow in the high-pressure air circuit, and proceed according to steps ③ and ④.

2. The high pressure preparation method for consolidating sediment at the bottom of a river, lake or reservoir according to claim 1, characterized in that: In step ①, samples are taken from the top, bottom and middle of the sample, and the dry bulk density is measured respectively; and the three measured dry bulk density values ​​are compared.

3. The high pressure preparation method for consolidating sediment at the bottom of a river, lake or reservoir according to claim 1, characterized in that: In steps ② and ④, measure the distance from the center and periphery of the top of the sample to the top of the sedimentation barrel: h 中心 , h1, h2…; the standard value of the distance from the top of the sample to the top of the sedimentation barrel is calculated based on statistical principles.

4. The high pressure preparation method for consolidated sediment at the bottom of a river, lake or reservoir according to claim 1 or 2, characterized in that: The process of measuring the dry bulk density of the sample includes the following steps: S1 Sampling Sample Shovel the soil surface on the top of the sample; press the knife ring vertically and steadily into the sample; the volume of the knife ring is V; when pressing the knife ring, it is strictly forbidden to shake the knife ring left and right; after the sample emerges from the upper end of the knife ring, dig out the samples around the knife ring, and then take out the knife ring and the sample it carries; use a soil cutter to cut off the excess sample at the upper and lower ends of the knife ring, so that the sample and the knife ring are aligned up and down; put the filter paper in step ① under the knife ring, and use the bottom cover under the filter paper to seal the lower end of the knife ring; cover the upper end of the knife ring with a cap; wipe off the sample outside the knife ring; S2 dries and weighs the sample Weigh the container of the constant temperature oven, record it as m1; spread the sample in the ring knife onto the container of the constant temperature oven; put the container with the sample into the constant temperature oven and heat and dry it for 6 to 8 hours; after the sample and the container are cooled, weigh them, record it as m2; calculate the dry bulk density of the sample as 5. The high pressure preparation method for consolidating sediment at the bottom of a river, lake or reservoir according to claim 4, characterized in that: Procedure for measuring the moisture content of a sample: Before sampling the sample in step S1, measuring the gross weight; Weigh the weight of the ring knife, filter paper, cover and bottom cover, record as m 毛 ; The filter paper, cover and bottom cover match the ring knife; After drying the sample in step S2, measure the tare weight. Weigh the knife ring, the sample inside the knife ring, the filter paper, the cover and the bottom cover, and record it as m 皮 ; From this we can know that the net weight of the sample is m 净 =m 皮 -m 毛 ; The calculated water content of the sample is 6. The high pressure preparation method for consolidating sediment at the bottom of a river, lake or reservoir according to claim 4, characterized in that: In step S2 of drying the sample, the sample in the ring knife is spread out in the container to a thickness of 2 to 3 cm.

7. The high pressure preparation method for consolidating sediment at the bottom of a river, lake or reservoir according to claim 1, characterized in that: In step ①, the mixing weight ratio of the soil sample and water is 6:

1.

8. The high pressure preparation method for consolidating sediment at the bottom of a river, lake or reservoir according to claim 4, characterized in that: Steel mesh is used as the container.

9. The high pressure preparation method for consolidating sediment at the bottom of a river, lake or reservoir according to claim 1, characterized in that: The top cover in step ② is a flange structure; a top flange ring corresponding to and matching the flange structure is provided at the top of the sedimentation barrel; the flange structure is connected to the top flange ring through a bolt connection.

10. The high pressure preparation method for consolidating sediment at the bottom of a river, lake or reservoir according to claim 1, characterized in that: In step ③, in the same group, all the pressurizing valves are connected to the high-pressure gas circuit through the same pressure regulating valve, and the pilot control ports of each pilot check valve are connected to the control gas circuit through independent manual pressure valves.

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