Vacuum stirring and soil sample preparation integrated intelligent device and method

Abstract

The application discloses a kind of vacuum stirring and soil sample preparation integrated intelligent device and method, including stirring device, consolidation sample preparation device, vacuum pumping device, intelligent control system.Stirring device is used to stir soil sample into uniform mud;Consolidation sample preparation device is used to prepare remolded soil sample;Vacuum pumping device ensures that the internal environment of overall test is in vacuum state;Intelligent control system realizes intelligent staged loading to consolidate soil sample in stages.The beneficial effects of the scheme provided by the application are that: by vacuum pumping device, ensure that mud is in vacuum state during stirring and transportation to consolidation sample preparation device, effectively reduce the air content in remolded soil sample, in the process of soil sample consolidation forming, the pore water pressure and effective stress of soil sample are calculated in real time by means of intelligent control system, the degree of consolidation is accurately controlled, the load size is accurately controlled intelligently, automatic staged loading is realized, complete soil sample consolidation settlement curve can be obtained, and soil test is carried out in detail.

Description

Technical Field

[0001] This invention relates to the field of indoor testing technology in geotechnical engineering, specifically to an integrated device for vacuum mixing and soil sample preparation with intelligent control of consolidation pressure. Background Technology

[0002] Undisturbed soils, having undergone long-term soil deposition or geological changes, possess significant in-situ characteristics, such as structure and overconsolidation. To quantitatively describe the structure of undisturbed soils, parallel remolded soil tests are often conducted for quantitative and qualitative analysis. The accuracy of the results of remolded soil-related test studies is inevitably based on good soil sample preparation. Therefore, how to prepare high-quality soil samples is very important.

[0003] Common methods for preparing reconstituted soil samples include compaction, impact sampling, and pressure sampling. Soil samples obtained through compaction and impact sampling often suffer from inconsistent density, poor continuity, and poor uniformity due to repeated dynamic compaction, failing to meet the homogeneity requirements of unit tests. Soil samples obtained through pressure sampling have small volumes, failing to meet the size requirements of triaxial tests. Therefore, for cohesive soils, soil sample preparation often involves first preparing the cohesive soil into a slurry, and then consolidating it under static pressure with an overburden load. The key aspects of this process are: 1. How to remove air bubbles from the slurry; 2. How to accurately control the overburden load; 3. How to determine the degree of consolidation of the soil sample to judge whether the preparation is complete. To solve these key problems and prepare high-quality soil samples to provide excellent experimental materials for indoor experimental research, the inventors have proposed an integrated vacuum mixing and soil sample preparation device with intelligent control of consolidation pressure. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an integrated device for vacuum mixing and soil sample preparation with intelligent control of consolidation pressure.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] An integrated vacuum mixing and soil sample preparation device with intelligent control of consolidation pressure is characterized by integrating the mixing device and the consolidation sample preparation device into one unit. With the help of a vacuum pump, it can complete the two tasks of mud mixing and transportation to the consolidation sample preparation device in a vacuum environment. With the help of the intelligent control system, it can acquire the pore water pressure and effective stress data of the soil sample in real time, accurately control the degree of consolidation of the soil sample under graded loads, realize automatic graded loading, and obtain complete soil sample consolidation settlement curves, thus realizing intelligent and precise geotechnical testing.

[0007] A working method for an integrated vacuum mixing and soil sample preparation device with intelligent control of consolidation pressure, the process of which is as follows:

[0008] First, close the connecting valve (14) between the mixing device and the consolidation device, pour the mud into the mixing device, cover the top cover of the mixing tank (2), close the air inlet valve (5) of the mixing device, connect the vacuum pump (28) to the air extraction valve (4) of the mixing device, open the air extraction valve (4) of the mixing device, start the vacuum pump (28) to start vacuuming, and at the same time start the mixer motor (7) to drive the mixer (8) to mix the mud. When the mud is mixed evenly and no bubbles emerge, the vacuum mixing of the mud is completed. Close the vacuum pump (28) and close the air extraction valve (4) of the mixing device.

[0009] Then, use steel screws (21) to fix the top cover (10) of the consolidation tank onto the consolidation tank (9), and close the drain valve (16) on the consolidation tank (9); connect the vacuum pump (28) to the air extraction valve (26) of the top cover (10) of the consolidation tank, start the vacuum pump (28) to begin vacuuming, and extract the air from the consolidation tank (9). Once the inside of the consolidation sample preparation device is in a vacuum state, open the connecting valve (14) so ​​that the mud flows into the consolidation sample preparation device from the stirring device under vacuum. Then close the connecting valve (14) and open the air inlet valve (27);

[0010] Finally, the top cover (10) of the consolidation bucket is replaced with the loading system (11). A permeable stone, a porous drainage loading plate (19), and a pressure rod (20) are placed on top of the soil sample in sequence. The loading device (11) is connected to the consolidation bucket (9) using steel screws (25). Then, the drainage valve (26) under the consolidation bucket (9) is opened, and the air pressure valve (22) is opened. The consolidation pressure is loaded by air pressure. During the preparation of the soil sample, the signal processing system (30) is in working condition. The specific operation of the signal processing system (30) is as follows: it receives the data signals from the pore water pressure sensor (32) and the pressure sensor (33), and obtains the effective stress in the soil sample through the data processing of the signal processing system (30). It judges the degree of consolidation of the soil sample under the consolidation stress. If the consolidation is completed (judgment standard: effective stress = consolidation stress), the intelligent control air pump (31) increases the air pressure and automatically loads to the next level of consolidation stress to realize automatic graded loading consolidation. If the consolidation is not completed, it waits for the consolidation to be completed before performing the above operation. Once the soil sample has consolidated, the soil sample preparation is complete. A soil sample with clear consolidation stress and low air content can be obtained, and a complete soil sample consolidation settlement curve can be acquired.

[0011] An integrated device for vacuum mixing and soil sample preparation with intelligent control of consolidation pressure, characterized in that it includes a mixing device, a consolidation sample preparation device, a vacuum device, and an intelligent control system.

[0012] The stirring device is used to stir the mud;

[0013] The consolidation and sampling device is used to prepare soil samples;

[0014] The vacuum device ensures that the mixing device and the solidification and sample formation device are in a vacuum state during the mixing and transportation of the mud.

[0015] The intelligent control system enables intelligent graded loading to consolidate soil samples in stages.

[0016] The stirring device includes a stirring tank (1), a stirring tank top cover (2), and a connecting pipe (3). The stirring tank (1) is used to stir the mud. The connecting pipe (3) is located in the middle of the stirring tank (1). The uniformly stirred mud flows into the solidification and sample formation device through the connecting pipe (3). Two air valves are symmetrically installed on the stirring tank top cover (2). One is a stirring device air extraction valve (4) for vacuuming, and the other is a stirring device air inlet valve (5) for connecting to the atmosphere. The center of the stirring tank top cover (2) is a motor positioning frame (6), and the motor (7) is placed on the motor positioning frame (6). The upper part of the stirrer (8) is connected to the motor (7). After the motor (7) is started, it drives the stirrer (8) to rotate to stir the mud.

[0017] The consolidation sampling device includes a consolidation bucket (9), a top cover (10) of the consolidation bucket, and a loading system (11). A connecting pipe (12) is located in the upper middle part of the consolidation bucket (9) and is used to connect the stirring device and the consolidation sampling device. The connecting pipe (12) has a fixing collar (13) and a connecting valve (14). The fixing collar (13) is used to fix the connecting pipe (3) of the stirring device and the connecting pipe (12) of the consolidation sampling device. The connecting valve (14) controls the flow of mud from the stirring device into the consolidation bucket (9). A permeable stone (15) is placed at the bottom of the consolidation bucket (9), and a drain valve (16) is placed on the bottom side wall as a drainage channel for soil sample consolidation. A rubber sealing ring (17) is placed in the annular groove at the top of the consolidation bucket (9) to ensure that the inside of the consolidation bucket (9) is not connected to the atmosphere when vacuuming. The loading system (11) includes a top cover (18). The structure includes a porous drainage loading plate (19), a pressure rod (20), a steel screw (21), a pneumatic valve (22), and a pneumatic pipe (23). The pressure rod (20) is connected to the porous drainage loading plate (19), passes through the top cover (18), and is connected to the top of the pneumatic pipe (23). The pneumatic pressure is applied to the pressure rod (20) through the pneumatic pipe (23) to apply pressure to the porous drainage loading plate (19) to consolidate the soil sample. The pressure can be controlled by the pneumatic valve (22). The top cover (10) of the consolidation bucket includes a cover plate (24), a steel screw (25), an air extraction valve (26), and an air inlet valve (27). The top cover (10) of the consolidation bucket is fixed to the consolidation bucket (9) using the steel screw (25). The air extraction valve (26) and the air inlet valve (27) are arranged symmetrically. The air extraction valve (26) is connected to the vacuum pump (28) for vacuuming, and the air inlet valve (27) is connected to the external atmosphere.

[0018] Further optimization involves a vacuum device that ensures the mixing device and the solidification device are in a vacuum state during the mixing and transportation of the mud, including a vacuum pump (28) and an air extraction pipe (29); the vacuum pump (28) is located below the mixing tank (1), and the air extraction pipe (29) connects the vacuum pump (28) to the air extraction valve (4) and the air extraction valve (26) of the mixing device, and is used to remove air from the mixing device and the solidification device.

[0019] Further optimization involves the intelligent control system used for intelligent and precise control of the load during soil sample preparation. This system includes a signal processing system (30), an air pump (31), a pore water pressure sensor (32), and a pressure sensor (33). The pore water pressure sensor (32) is located in the middle of the side wall of the consolidation bucket (9), and its pore water pressure data is u. It is used to measure the pore water pressure in the soil sample. The pressure sensor (33) is located below the pore water pressure sensor (32) and is used to measure the overburden stress of the soil sample. Its pressure data is σ. The signal processing system (30) receives the data signals from the pore water pressure sensor (32) and the pressure sensor (33). After data processing by the signal processing system (30), it controls the next operation.

[0020] The control algorithm of the signal processing system (30) is as follows:

[0021] Step 1

[0022] Step 1.1: Set the staged loading pressure increment Δσ ′ The final target pressure value σ v ;

[0023] Step 1.2: Issue the data collection command;

[0024] Step 1.3: Collect pore water pressure data u and pressure data σ using pore water pressure sensor (32) and pressure sensor (33), and store them in real time;

[0025] Step 1.4: Calculate the effective stress σ ′ =σ-u, and store in real time; output σ ′ Provided to step 3;

[0026] Step 1.5: If σ ′ If ≠σ, then return to step 1.3;

[0027] If σ ′ =σ, proceed to the next step;

[0028] Step 1.6: If σ ′ ≠σ v Control the air pressure to increase the air pressure increment σ ′ Then return to step 1.3;

[0029] If σ ′ =σ v Then the consolidation is complete.

[0030] Step 2:

[0031] Step 2.1:

[0032] Step 2.1.1: Input the dry soil mass m weighed before soil sample preparation. s The specific gravity of soil particles G obtained from data (such as survey reports, etc.) s ;

[0033] Step 2.1.2: Calculate the volume V of soil particles s ;

[0034] Step 2.2:

[0035] Step 2.2.1: Manually measure the soil sample diameter R and height H;

[0036] Step 2.1.2: Calculate the total soil volume V;

[0037] Step 2.3: Calculate the void ratio e = (VV) s ) / V s Output e is provided to step 3;

[0038] Step 3: Plot the consolidation settlement curve e-σ ′ .

[0039] Further restrictions:

[0040] This invention is applicable to soil sample preparation and, by way of example and not limitation, has the following beneficial effects compared to existing technologies:

[0041] 1. The present invention, through a vacuum device, a stirring device, and a consolidation device, can ensure that the mud is in a vacuum state during the stirring and transportation to the consolidation device, effectively reducing the air content in the prepared soil sample and improving the quality level of the prepared soil sample.

[0042] 2. The present invention achieves high-efficiency drainage and consolidation through the upper and lower drainage channels of the consolidation sample device, which greatly shortens the test time.

[0043] 3. This invention achieves intelligent and precise geotechnical testing through an intelligent control system, which can acquire the pore water pressure and effective stress of soil samples in real time, accurately control their degree of consolidation, and realize automatic graded loading, thereby reducing the time and labor costs of the test. At the same time, it can obtain complete soil sample consolidation and settlement curves to grasp the basic mechanical properties of the soil sample. Attached Figure Description

[0044] Figure 1 This is the overall northeast isometric side view of the invention;

[0045] Figure 2 This is a southwest isometric side view of the stirring device of the present invention;

[0046] Figure 3 This is a southwest isometric perspective view of the stirring device of the present invention;

[0047] Figure 4 This is a front cross-sectional view of the stirring device of the present invention;

[0048] Figure 5 This is a northeast isometric side view of the consolidation sample-forming device of the present invention;

[0049] Figure 6 This is a southwest isometric side view of the consolidation barrel of the consolidation sample-forming device of the present invention;

[0050] Figure 7 This is a front perspective view of the consolidation barrel of the consolidation sample-forming device of the present invention;

[0051] Figure 8 This is a southwest isometric side view of the top cover of the consolidation barrel of the consolidation sample-forming device of the present invention.

[0052] Figure 9 This is a northeast isometric side view of the loading device of the consolidation sample forming apparatus of the present invention;

[0053] Figure 10 This is a northeast isometric side view of the vacuum pumping device of the present invention;

[0054] Figure 11 Schematic diagram of the intelligent control system;

[0055] Figure 12 Schematic diagram of intelligent control algorithm.

[0056] Explanation of reference numerals in the attached figures:

[0057] Mixing tank (1), mixing tank top cover (2), connecting pipe (3), mixing device exhaust valve (4), mixing device air inlet valve (5), motor positioning frame (6), motor (7), agitator (8), consolidation tank (9), consolidation tank top cover (10), loading system (11), connecting pipe (12), fixing collar (13), connecting valve (14), permeable stone (15), drain valve (16), rubber sealing ring (17). 7), top cover (18), perforated drainage loading plate (19), pressure rod (20), steel screw (21), air pressure valve (22), air pressure pipe (23), cover plate (24), steel screw (25), air extraction valve (26), air inlet valve (27), vacuum pump (28), air pipe (29), signal processing system (30), air pump (31), pore water pressure sensor (32), pressure sensor (33). Detailed Implementation

[0058] The technical solution of the integrated vacuum mixing and remolded soil preparation device for intelligent control of consolidation pressure provided by the present invention will be further described below with reference to specific embodiments and accompanying drawings. The advantages and features of the present invention will become clearer from the following description.

[0059] It should be noted that the embodiments of the present invention have preferred implementability but are not intended to limit the present invention in any way. The technical features or combinations of technical features described in the embodiments of the present invention should not be considered isolated; they can be combined with each other to achieve better technical effects. The scope of the preferred embodiments of the present invention may also include other implementations, and this should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0060] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of exemplary embodiments may have different values.

[0061] The accompanying drawings of this invention are all in a very simplified form and use non-precise proportions, intended only to facilitate and clarify the illustration of the embodiments of this invention, and are not intended to limit the implementation of this invention. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effects and objectives achieved by this invention, should fall within the scope of the technical content disclosed in this invention. Furthermore, the same reference numerals appearing in the various drawings of this invention represent the same features or components and can be applied to different embodiments.

[0062] like Figure 1 As shown, this invention is an integrated device for vacuum mixing and soil sample preparation with intelligent control of consolidation pressure. Its features include a mixing device, a consolidation sample preparation device, a vacuum device, and an intelligent control system. The mixing device is used to mix the mud and includes a mixing tank (1), a mixing tank top cover (2), and a connecting pipe (3). The consolidation sample preparation device is used to prepare soil samples and includes a consolidation tank (9), a consolidation tank top cover (10), and a loading system (11). The vacuum device ensures that the mixing device and the consolidation sample preparation device are in a vacuum state during the mixing and transportation of the mud, and includes a vacuum pump (28) and an air pipe (29). The intelligent control system realizes intelligent graded loading to consolidate the soil sample in stages and includes a signal processing system (30), an air pump (31), a pore water pressure sensor (32), and a pressure sensor (33).

[0063] like Figure 2As shown, the stirring device is used to stir mud and includes a stirring tank (1), a stirring tank top cover (2), and a connecting pipe (3).

[0064] like Figure 3 As shown, two air valves are symmetrically installed on the top cover (2) of the mixing tank. One is the air extraction valve (4) of the mixing device used for vacuuming, and the other is the air inlet valve (5) of the mixing device connected to the atmosphere.

[0065] like Figure 4 As shown, the mixing tank (1) is used to mix mud. The connecting pipe (3) is located in the middle of the mixing tank (1). The uniformly mixed mud flows into the solidification and sample forming device through the connecting pipe (3). The center of the top cover (2) of the mixing tank is the motor positioning frame (6), and the motor (7) is placed on the motor positioning frame (6). The upper part of the stirrer (8) is connected to the motor (7). After the motor (7) is started, it drives the stirrer (8) to rotate to mix the mud.

[0066] like Figure 5 As shown, the consolidation sampling device is used to prepare soil samples and includes a consolidation bucket (9), a consolidation bucket top cover (10), and a loading system (11);

[0067] like Figure 6 As shown, the connecting pipe (12) is located in the upper middle part of the consolidation tank (9) and is used to connect the stirring device and the consolidation sample forming device. The connecting pipe (12) has a fixing collar (13) and a connecting valve (14). The fixing collar (13) is used to fix the connecting pipe (3) of the stirring device and the connecting pipe (12) of the consolidation sample forming device. The connecting valve (14) controls the flow of mud from the stirring device into the consolidation tank (9). A rubber sealing ring (17) is placed in the annular groove at the top of the consolidation tank (9) to ensure that the inside of the consolidation tank (9) is not connected to the atmosphere when vacuuming.

[0068] like Figure 7 As shown, a permeable stone (15) is placed at the bottom of the consolidation bucket (9), and a drainage valve (16) is located on the bottom side wall as a drainage channel for soil sample consolidation.

[0069] like Figure 8 As shown, the top cover (10) of the consolidation tank includes a cover plate (24), steel screws (25), a vacuum valve (26), and an air inlet valve (27). The top cover (10) of the consolidation tank is fixed to the consolidation tank (9) using steel screws (25). The vacuum valve (26) and the air inlet valve (27) are arranged symmetrically. The vacuum valve (26) is connected to a vacuum pump (28) for vacuuming, and the air inlet valve (27) is connected to the external atmosphere.

[0070] like Figure 9As shown, the loading system (11) includes a top cover (18), a porous drainage loading plate (19), a pressure rod (20), a steel screw (21), a pneumatic valve (22), and a pneumatic pipe (23). The pressure rod (20) is connected to the porous drainage loading plate (19), passes through the top cover (18), and is connected to the pneumatic pipe (23) at the top. The air pressure is applied to the pressure rod (20) through the pneumatic pipe (23) to consolidate the soil sample on the porous drainage loading plate (19). The pressure can be controlled by the pneumatic valve (22).

[0071] like Figure 10 As shown, the vacuum device ensures that the mixing device and the solidification device are in a vacuum state during the mixing and transportation of the mud, including a vacuum pump (28) and an air extraction pipe (29); the vacuum pump (28) is located below the mixing tank (1), and the air extraction pipe (29) connects the vacuum pump (28) to the air extraction valve (4) and the air extraction valve (26) of the mixing device, and is used to remove air from the mixing device and the solidification device.

[0072] like Figure 11 As shown, the intelligent control system is used to intelligently and precisely control the load during the soil sample preparation process, including a signal processing system (30), an air pump (31), a pore water pressure sensor (32), and a pressure sensor (33); the pore water pressure sensor (32) is arranged in the consolidation tank (9) (as shown). Figure 5 The middle part of the side wall (shown) is used to measure the pore water pressure in the soil sample, and the pore water pressure data is u; the pressure sensor (33) is arranged below the pore water pressure sensor (32) and is used to measure the overburden stress of the soil sample, and the pressure data is σ; the signal processing system (30) receives the data signals from the pore water pressure sensor (32) and the pressure sensor (33), and after data processing, controls the next operation. The specific work of the signal processing system (30) is as follows: receiving the data signals from the pore water pressure sensor (32) and the pressure sensor (33), obtaining the effective stress in the soil sample after data processing, judging the degree of consolidation of the soil sample under the consolidation pressure, if consolidation is completed (judgment standard: effective stress = overburden stress), then the intelligent control air pump (31) increases the air pressure and automatically loads to the next level of consolidation pressure to realize automatic graded loading consolidation; if consolidation is not completed, then wait for consolidation to be completed before performing the above operation.

[0073] like Figure 12 As shown, the control algorithm of the signal processing system (30) is as follows:

[0074] Step 1

[0075] Step 1.1: Set the staged loading pressure increment Δσ ′ The final target pressure value σ v ;

[0076] Step 1.2: Issue the data collection command;

[0077] Step 1.3: Collect pore water pressure data u and pressure data σ using pore water pressure sensor (32) and pressure sensor (33), and store them in real time;

[0078] Step 1.4: Calculate the effective stress σ ′ =σ-u, and store in real time; output σ ′ Provided to step 3;

[0079] Step 1.5: If σ ′ If ≠σ, then return to step 1.3;

[0080] If σ ′ =σ, proceed to the next step;

[0081] Step 1.6: If σ ′ ≠σ v Control the air pressure to increase the air pressure increment σ ′ Then return to step 1.3;

[0082] If σ ′ =σ v Then the consolidation is complete.

[0083] Step 2:

[0084] Step 2.1:

[0085] Step 2.1.1: Input the dry soil mass m weighed before soil sample preparation. s The specific gravity of soil particles G obtained from data (such as survey reports, etc.) s ;

[0086] Step 2.1.2: Calculate the volume V of soil particles s ;

[0087] Step 2.2:

[0088] Step 2.2.1: Manually measure the soil sample diameter R and height H;

[0089] Step 2.1.2: Calculate the total soil volume V;

[0090] Step 2.3: Calculate the void ratio e = (VV) s ) / V s Output e is provided to step 3;

[0091] Step 3: Plot the consolidation settlement curve e-σ ′ .

[0092] When using this device: First, close the connecting valve (14) between the mixing device and the consolidation device, pour the mud into the mixing device, cover the top cover (2) of the mixing tank, close the air inlet valve (5) of the mixing device, connect the vacuum pump (28) to the air extraction valve (4) of the mixing device, open the air extraction valve (4) of the mixing device, start the vacuum pump (28) to start vacuuming, and at the same time start the agitator motor (7) to drive the agitator (8) to mix the mud. When the mud is mixed evenly and no bubbles emerge, the mud vacuum mixing is completed. Close the vacuum pump (28) and close the air extraction valve (4) of the mixing device. Then, use steel screws (21) to fix the top cover (10) of the consolidation tank on the consolidation tank (9), and close the drain valve (16) on the consolidation tank (9). Connect the vacuum pump (28) to the air extraction valve (26) of the top cover (10) of the consolidation tank, start the vacuum pump (28) to start vacuuming, and extract the air from the consolidation tank (9). When the consolidation sample preparation device is in a vacuum state, open the connecting valve (14) to allow the mud to flow from the mixing device into the consolidation sample preparation device under vacuum. Then close the connecting valve (14) and open the air inlet valve (27); finally, replace the top cover (10) of the consolidation bucket with the loading system (11), and place the permeable stone, the porous drainage loading plate (19), and the pressure rod (20) on top of the soil sample in sequence, and use steel screws (25) to connect the loading device (11) to the consolidation bucket (9); then open the drainage valve (26) below the consolidation bucket (9), open the air pressure valve (22), and load the consolidation pressure through air pressure. During the preparation of the soil sample, the signal processing system (30) receives signals from the pore water pressure sensor (32) and the pressure transmitter. After calculation, the data signal from sensor (33) controls the next operation. The specific work of signal processing system (30) is as follows: receiving data signals from pore water pressure sensor (32) and pressure sensor (33), obtaining the effective stress in the soil sample through data processing, judging the degree of consolidation of the soil sample under the consolidation pressure, if consolidation is completed (judgment standard: effective stress = overlying stress), then intelligently controlling air pump (31) to increase air pressure, automatically loading to the next level of consolidation pressure, realizing automatic graded loading consolidation; if consolidation is not completed, then waiting for consolidation to be completed before performing the above operation. Once the soil sample is consolidated, the soil sample preparation is completed, and a soil sample with a clear consolidation pressure and low air content can be obtained, and a complete soil sample consolidation settlement curve can be obtained.

[0093] This invention is applicable to soil sample preparation. Compared with existing technologies, and as an example rather than a limitation, it has the following beneficial effects: By using a vacuum device, a stirring device, and a consolidation device, the mud can be kept in a vacuum state during stirring and transportation to the consolidation device, effectively reducing the air content in the prepared soil sample and improving its quality. The upper and lower drainage channels of the consolidation device achieve efficient drainage and consolidation, significantly shortening the test time. The intelligent control system enables intelligent and precise geotechnical testing, allowing real-time acquisition of pore water pressure and effective stress in the soil sample, accurate control of its degree of consolidation, and automatic graded loading, reducing test time and labor costs. Simultaneously, it can obtain complete soil sample consolidation settlement curves, allowing for a grasp of the basic mechanical properties of the soil sample.

[0094] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the invention in any way. Any changes or modifications made by those skilled in the art based on the above-disclosed technical content should be considered as equivalent and valid embodiments, and all fall within the scope of protection of the present invention.

Claims

1. An integrated device for vacuum mixing and soil sample preparation with intelligent control of consolidation pressure, characterized in that: Includes a stirring device, a solidification and sample preparation device, a vacuum device, and an intelligent control system; The stirring device is used to stir mud, including a stirring tank (1), a stirring tank top cover (2), and a connecting pipe (3). The consolidation sampling device is used to prepare soil samples and includes a consolidation bucket (9), a consolidation bucket top cover (10), and a loading system (11). The vacuum device ensures that the inside of the mixing device and the solidification device is in a vacuum state during the mixing and transportation of the mud, including a vacuum pump (28) and an air pipe (29). The intelligent control system realizes intelligent graded loading to consolidate the soil sample in stages, including a signal processing system (30), an air pump (31), a pore water pressure sensor (32), and a pressure sensor (33). The pore water pressure sensor (32) is arranged in the middle of the side wall of the consolidation bucket (9) to measure the pore water pressure in the soil sample. The pore water pressure data is u. The pressure sensor (33) is arranged below the pore water pressure sensor (32) to measure the overburden stress of the soil sample. The pressure data is u. The signal processing system (30) receives data signals from the pore water pressure sensor (32) and the pressure sensor (33), and after data processing by the signal processing system (30), controls the next operation. The control algorithm of the signal processing system (30) is as follows: Step 1 Step 1.1: Set the tiered loading pressure increment Final pressure target value ; Step 1.2: Issue the data collection command; Step 1.3: Collect pore water pressure data u and pressure data u using pore water pressure sensor (32) and pressure sensor (33). And store in real time; Step 1.4: Calculate the effective stress And store in real time; output Provided to step 3; Step 1.5: If If so, return to step 1.3; Step 1.6: If Let's move on to the next step; like Control air pressure to increase air pressure increment Then return to step 1.3; like Then the consolidation is complete; Step 2: Step 2.1: Step 2.1.1: Enter the dry soil mass weighed before soil sample preparation. The specific gravity of soil particles obtained from the data ; Step 2.1.2: Calculate soil particle volume ; Step 2.2: Step 2.2.1: Manually measure the soil sample diameter R and height H; Step 2.1.2: Calculate the total soil volume V; Step 2.3: Calculate the void ratio Output Provided to step 3; Step 3: Plot the consolidation settlement curve .

2. The integrated device for intelligent control of consolidation pressure and vacuum mixing and soil sample preparation according to claim 1, characterized in that: The mixing tank (1) is used to mix mud. The connecting pipe (3) is moved to the middle of the mixing tank (1). The uniformly mixed mud flows into the solidification and sample forming device through the connecting pipe (3). Two air valves are symmetrically installed on the top cover (2) of the mixing tank. One is the vacuum valve (4) of the mixing device for vacuuming, and the other is the air inlet valve (5) of the mixing device for connecting to the atmosphere. The center of the top cover (2) of the mixing tank is the motor positioning frame (6), and the motor (7) is placed on the motor positioning frame (6). The upper part of the agitator (8) is connected to the motor (7). After the motor (7) is started, it drives the agitator (8) to rotate to stir the mud.

3. The integrated device for intelligent control of consolidation pressure and vacuum mixing and soil sample preparation according to claim 1, characterized in that: The connecting pipe (12) is located in the upper middle part of the consolidation bucket (9) and is used to connect the stirring device and the consolidation sample forming device. The connecting pipe (12) has a fixing collar (13) and a connecting valve (14). The fixing collar (13) is used to fix the connecting pipe (3) of the stirring device and the connecting pipe (12) of the consolidation sample forming device. The connecting valve (14) controls the channel through which the mud flows from the stirring device into the consolidation bucket (9). A permeable stone (15) is placed at the bottom of the consolidation bucket (9). There is a drain valve (16) on the bottom side wall as a drainage channel for soil sample consolidation. A rubber sealing ring (17) is placed in the annular groove at the top of the consolidation bucket (9) to ensure that the inside of the consolidation bucket (9) is not connected to the atmosphere when vacuuming. The loading system (11) includes a top cover (18), a porous drainage loading plate (19), and a pressure plate. The pressure rod (20), steel screw, air pressure valve (22), and air pressure pipe (23) are connected to the porous drainage loading plate (19), pass through the top cover (18), and are connected to the air pressure pipe (23) at the top. The air pressure is applied to the pressure rod (20) through the air pressure pipe (23) to apply pressure to the porous drainage loading plate (19) to consolidate the soil sample. The pressure can be controlled by the air pressure valve (22). The top cover (10) of the consolidation bucket includes a cover plate (24), steel screw, air extraction valve (26), and air inlet valve (27). The top cover (10) of the consolidation bucket is fixed to the consolidation bucket (9) using steel screw. The air extraction valve (26) and the air inlet valve (27) are arranged symmetrically. The air extraction valve (26) is connected to the vacuum pump (28) for vacuuming. The air inlet valve (27) is connected to the external atmosphere.

4. The integrated device for intelligent control of consolidation pressure and vacuum mixing and soil sample preparation according to claim 1, characterized in that: The vacuum pump (28) is located below the mixing tank (1). The air pipe (29) connects the vacuum pump (28) to the air extraction valve (4) and air extraction valve (26) of the mixing device, and is used to extract the air from the mixing device and the solidification sample device.

5. An operation method for an integrated vacuum mixing and soil sample preparation device with intelligent control of consolidation pressure, characterized in that: First, close the connecting valve (14) between the mixing device and the consolidation device, pour the mud into the mixing device, cover the top of the mixing tank (2), close the air inlet valve (5) of the mixing device, connect the vacuum pump (28) to the air extraction valve (4) of the mixing device, open the air extraction valve (4) of the mixing device, start the vacuum pump (28) to start vacuuming, and at the same time start the stirrer motor (7) to drive the stirrer (8) to stir the mud. When the mud is stirred evenly and no bubbles emerge, the vacuum stirring of the mud is completed. Then, close the vacuum pump (28) and close the air extraction valve (4) of the mixing device. Then, use steel screws to fix the top cover (10) of the consolidation tank onto the consolidation tank (9), and close the drain valve (16) on the consolidation tank (9); connect the vacuum pump (28) to the air extraction valve (26) of the top cover (10) of the consolidation tank, start the vacuum pump (28) to start vacuuming, and extract the air from the consolidation tank (9); when the inside of the consolidation sample preparation device is in a vacuum state, open the connecting valve (14) so ​​that the mud flows from the stirring device into the consolidation sample preparation device in a vacuum environment; then close the connecting valve (14) and open the air inlet valve (27). Finally, the top cover (10) of the consolidation bucket is replaced with a loading system (11). A permeable stone, a porous drainage loading plate (19), and a pressure rod (20) are placed on top of the soil sample in sequence. The loading system (11) is then connected to the consolidation bucket (9) using steel screws. The drainage valve (16) below the consolidation bucket (9) is then opened, and the air pressure valve (22) is opened. Consolidation pressure is applied via air pressure during soil sample preparation. During this process, the signal processing system (30) receives data signals from the pore water pressure sensor (32) and the pressure sensor (33). After data processing by the signal processing system (30), the next operation is controlled. The specific work of 30) is as follows: receive the data signals from the pore water pressure sensor (32) and the pressure sensor (33), obtain the effective stress in the soil sample through data processing, determine the degree of consolidation of the soil sample under the consolidation pressure, if the consolidation is completed, the judgment criteria are met: effective stress = overlying stress, then the intelligent control air pump (31) increases the air pressure and automatically loads to the next level of consolidation pressure to achieve automatic graded loading consolidation; if the consolidation is not completed, wait for the consolidation to be completed and perform the above operation; when the soil sample is consolidated, the soil sample preparation is completed, and a soil sample with clear consolidation pressure and low air content can be obtained, and a complete soil sample consolidation settlement curve can be obtained.

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