CN111707521A - Large-scale cylindrical loess remolding sample preparation equipment with controllable initial conditions and sample preparation method - Google Patents
Large-scale cylindrical loess remolding sample preparation equipment with controllable initial conditions and sample preparation method Download PDFInfo
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- CN111707521A CN111707521A CN202010746995.1A CN202010746995A CN111707521A CN 111707521 A CN111707521 A CN 111707521A CN 202010746995 A CN202010746995 A CN 202010746995A CN 111707521 A CN111707521 A CN 111707521A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
Abstract
The invention discloses large-scale cylindrical loess remolding sample preparation equipment with controllable initial conditions and a method thereof. Through the combination of the sample preparation cylinder and the auxiliary cylinder, in the sample preparation process, the required remolded loess sample can be calculated in advance according to the volume of the sample preparation cylinder, so when the sample preparation is carried out by utilizing the calculated mass, the mass and the volume are known, and the dry density rho is further enabled to be knowndAnd the water content omega is controllable.
Description
Technical Field
The invention belongs to the technical field of geotechnical engineering subject soil property testing, and particularly relates to large-scale cylindrical loess remolded sample preparation equipment and method with controllable initial conditions.
Background
China remolded loess plateau gully vertically and horizontally, along with the development of urbanization, the remolded loess project of flat mountain city building is carried out on partial regions. When remolding loess is used for backfilling, the original structure of the remolding loess is strongly disturbed, and the site engineering geology and hydrogeology conditions are reproduced. Therefore, the foundation soil body is easy to be collapsed in a large range and unevenly settled under external load, so that the building is cracked, even the foundation fails, the building collapses, and further disasters are caused. Therefore, the method has important practical significance for carrying out geotechnical test on the remolded loess to obtain basic physical indexes and strength deformation rules of the remolded loess, and further applying the remolded loess to engineering construction of a remolded loess fill area.
At present, in the existing sample preparation equipment for large-sized soil columns (the diameter is 25-30 times of the diameter of a cutting ring, and the height is 3-5 times of the height of the cutting ring), a device for controlling and measuring water discharged in the sample preparation process and a sample preparation volume with a determined volume are not available, the initial conditions such as the dry density and the water content of a loess remolded sample cannot be controlled, and the preparation of the loess remolded sample in a test is not uniform, so that the reliability of a test result is difficult to guarantee.
In the indoor geotechnical test, the remolded loess sample prepared by the small-sized cutting ring has smaller size, and the physical index consistency of the prepared same batch of samples cannot be ensured due to the obvious anisotropy of the remolded loess, so that the test result is influenced by the size effect; in addition, due to the small size of the sample, the ring knife boundary effect further influences the test result. Moreover, the integrity of the prepared remolded sample cannot be observed due to the fact that the side edge of the cutting ring is not transparent; finally, a matched counterforce device is not arranged when the sample is prepared by the cutting ring, and the preparation of the remolded loess sample with high dry density is difficult.
To sum up, the current loess remolded sample preparation has the following disadvantages: firstly, in a large soil column test, initial conditions such as dry density, water content and the like cannot be controlled in a sample preparation process; secondly, the loess remolded sample prepared by the cutting ring is greatly influenced by the boundary effect and the size effect; thirdly, because the cutting ring is opaque, the manufactured loess remolded sample cannot be controlled to be uniform and complete. And fourthly, it is difficult to prepare loess remolded samples having a large dry density.
Disclosure of Invention
The invention provides large-scale cylindrical loess remolded sample preparation equipment with controllable initial conditions and a sample preparation method, which solve the problems that the initial conditions cannot be controlled in the existing large-scale soil column test and uniform sample preparation is difficult.
In order to achieve the purpose, the large-scale cylindrical loess remolding sample preparation equipment with controllable initial conditions comprises a counter-force base, a barrel body and a pressure plate, wherein a pressurizing device for applying pressure to the pressure plate is installed on the counter-force base, the sample preparation barrel is fixed on the counter-force base, the barrel body comprises a sample preparation barrel and an auxiliary barrel fixed on the sample preparation barrel, and the pressurizing device applies pressure to remolded loess in the barrel body through the pressure plate during sample preparation;
the upper end of the reaction frame base is provided with a groove, the groove is used for placing a first permeable stone or a base plate, the sample making cylinder is positioned on the groove, the side wall of the groove is provided with a first diversion trench, and the outlet of the first diversion trench is provided with a first drainage switch; the pressure plate lower extreme is provided with second permeable stone or backing plate, seted up the second guiding gutter on the pressure plate, first drainage switch is installed in the exit of second guiding gutter.
Further, a sealing ring is arranged between the sample preparation cylinder and the auxiliary cylinder.
Furthermore, the upper end of the pressure plate is provided with steel balls, the pressing end of the pressing device is provided with an auxiliary part, the lower end of the auxiliary part is provided with a hemispherical pressure groove, and the pressure groove is used for containing the tops of the steel balls.
Furthermore, the sample preparation cylinder and the auxiliary cylinder are both made of organic transparent glass.
Furthermore, the inner diameters of the sample preparation cylinder and the auxiliary cylinder are both 300mm-350mm, the height of the sample preparation cylinder is 200 mm-250 mm, and the height of the auxiliary cylinder is 50mm-100 mm.
Furthermore, a reaction column is fixed on the reaction base, an external thread is arranged on the upper portion of the reaction column, the upper portion of the reaction column is in threaded connection with the reaction beam, and the pressurizing device is installed on the reaction beam.
Further, the pressurizing device is a servo jack.
A sample preparation method based on the large-scale cylindrical loess remolding sample preparation equipment with controllable initial conditions comprises the following steps:
step 1, taking dried remolded loess with mass m, wherein m is rhod×V，ρdDry density of remolded loess sample for target is rhodV is the volume of the sample preparation cylinder;
step 3, sealing the remolded loess prepared in the step 2, and then placing the remolded loess into a moisturizer for standing to ensure that the moisture in the remolded loess is uniformly distributed;
step 5.1, placing the first base plate into a groove of the back pressure base, and closing the first drainage switch; placing a part of remolded loess into the sample preparation cylinder, then placing a second base plate on the remolded loess in the sample preparation cylinder, then placing a pressure plate on the second base plate, starting a pressurizing device, enabling the pressurizing device to apply pressure to the remolded loess through the pressure plate until the remolded loess is pressed to one N part of the sample preparation cylinder, and resetting the pressurizing device; shaving the surface of the remolded loess;
and 5.2, sequentially adding the remaining N-1 parts of remolded loess into the barrel, compacting to M of N, wherein M is the number of remolded loess which is already put into the barrel, and compacting the remolded loess to the top of the sample preparation barrel after the last part of remolded loess is put into the barrel, wherein the loess in the sample preparation barrel is the target loess sample.
A sample preparation method based on the large-scale cylindrical loess remolding sample preparation equipment with controllable initial conditions comprises the following steps:
step 1, taking dried remolded loess with mass m, wherein m is rhod×V，ρdDry density of remolded loess sample for target is rhodV is the volume of the sample preparation cylinder;
step 3, sealing the remolded loess prepared in the step 2, and then placing the remolded loess into a moisturizer for standing to ensure that the moisture in the remolded loess is uniformly distributed;
step 5.1, putting the first permeable stone into a groove of the back pressure base, opening a first drainage switch, and putting the measuring cylinder at an outlet of the first drainage switch;
step 5.2, putting a part of remolded loess into the sample preparation cylinder, then placing a second permeable stone on the remolded loess in the sample preparation cylinder, opening a second drainage switch on a pressure plate, then placing the pressure plate on the first permeable stone, starting a pressurizing device, enabling the pressurizing device to apply pressure on the remolded loess through the pressure plate until the remolded loess is pressed to one N part of the sample preparation cylinder, collecting water discharged by the first drainage switch and the first drainage switch, resetting the pressurizing device, and scraping hair on the surface of the remolded loess;
and 5.2, sequentially adding the rest N-1 parts of remolded loess into the barrel, compacting to M of N, wherein M is the number of remolded loess which is already put into the barrel, collecting water discharged by the first drainage switch and the first drainage switch, compacting the remolded loess to the top of the sample preparation barrel after the last part of remolded loess is put into the barrel, and at the moment, obtaining the target loess sample as the loess in the sample preparation barrel.
Compared with the prior art, the invention has at least the following beneficial technical effects: through the combination of the sample preparation cylinder and the auxiliary cylinder, in the sample preparation process, the required remolded loess sample can be calculated in advance according to the volume of the sample preparation cylinder, so when the sample preparation is carried out by utilizing the calculated mass, the mass and the volume are known, and the dry density rho is further enabled to be knowndControllable and can control the water content w of remolded sample by closing the drainage switch。
Further, the invention controls the initial condition of sample preparation through the permeable stone and the drainage switch.
Furthermore, the volume of the glass cylinder is far larger than that of the cutting ring, so that the volume of the loess remolded sample can be increased, and the influence of the boundary effect and the size effect on the loess remolded sample can be effectively reduced.
Furthermore, the large transparent glass barrel can effectively reduce the boundary effect and the size effect on the remolded sample and is beneficial to observing whether the prepared loess remolded sample is uniform and complete.
Furthermore, the upper end of the pressure plate is provided with steel balls, the pressing end of the pressing device is provided with an auxiliary part, the lower end of the auxiliary part is provided with a hemispherical pressure groove, the pressure groove is used for containing the upper part of the steel balls, and the lower end face of the servo jack is contacted with the steel balls to provide uniform pressure for the pressure plate.
Furthermore, a reaction column is fixed on the reaction base, an external thread is arranged on the upper portion of the reaction column, the upper portion of the reaction column is in threaded connection with the reaction beam, and the pressurizing device is installed on the reaction beam. When the jack footage is not enough, can adjust the interval between reaction roof beam and the reaction base through the external screw thread.
Furthermore, the loess remolded sample with larger dry density can be easily manufactured through a servo jack pressurizing device.
The method of the invention achieves the control of the initial condition by manufacturing the soil sample and changing the drainage mode, namely the dry density rho of the remolded loess sample manufactured by the methoddAnd the water content omega is known, when the remolded loess sample prepared by the method is subjected to seepage test or strength test and the like, the dry density rho can be measureddAnd the water content omega is used as a known quantity and is not required to be measured again, so that the test efficiency is improved. Therefore, the defects of the conventional loess remolded sample can be effectively overcome, and the method has important significance for large-scale soil column tests, determination and research of properties of the loess remolded sample and remolded loess engineering.
Drawings
FIG. 1 is a schematic view of the apparatus of the present invention.
In the drawings: 1. reaction base, 2, system appearance section of thick bamboo, 3, an auxiliary cylinder, 4, pressure plate, 5, reaction column, 6, servo jack, 71, first permeable stone, 72, second permeable stone, 81, first drainage switch, 82, second drainage switch, 91, first sealing washer, 92, second sealing washer, 10, steel ball, 11, remold the loess appearance, 12, first connecting portion, 13, second connecting portion, 14, third connecting portion, 15, auxiliary member, 17, reaction beam.
Detailed Description
In order to make the objects and technical solutions of the present invention clearer and easier to understand. The present invention will be described in further detail with reference to the following drawings and examples, wherein the specific examples are provided for illustrative purposes only and are not intended to limit the present invention.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified. In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Referring to fig. 1, a large-scale cylindrical loess remolding sample preparation device with controllable initial conditions comprises a sample preparation cylinder 2, an auxiliary cylinder 3, a first permeable stone 71, a second permeable stone 72, a reaction base 1, a reaction column 5, a reaction beam 17, a servo jack 6, a pressure plate 4 and a measuring cylinder. Firstly, a sample preparation cylinder 2 is placed on a counter-force base 1, then a pressure plate 4 is placed in the sample preparation cylinder 2, and a servo jack 6 is used for pressurizing to prepare a remolded soil sample. The sample preparation cylinder 2 and the auxiliary cylinder 3 are both made of organic transparent glass and are provided with scales. The servo jack 6 is a DYG50-100 large-tonnage hydraulic jack of Yuli group.
The sample preparation cylinder 2 is a cylindrical transparent glass cylinder with an upper opening and a lower opening, the diameter of the cylinder is 300mm, the height of the cylinder is 200mm, and the cylinder can guarantee that the stress is uniform to a great extent when a next test is carried out, so that the sample preparation cylinder accords with the actual situation. The system appearance section of thick bamboo 2 upper end outwards extends has the first connecting portion 12 that the width is 35mm, and the lower extreme outwards extends has the second connecting portion 13 that the width is 35mm, and first connecting portion 12 is used for system appearance section of thick bamboo 2 to be connected with supplementary section of thick bamboo 3, and first connecting portion 12 also can make the convenient stack and the removal of a system appearance section of thick bamboo 2, and second connecting portion 13 and bolt and nut cooperation are with system appearance section of thick bamboo 2 and reaction base 1 fixed connection. Annular grooves for mounting the second sealing ring 92 are formed in the upper end of the first connecting portion 12 and the lower end of the second connecting portion 13, the upper portion of the second sealing ring 92 is located in the annular groove in the first connecting portion 12, and the lower portion of the second sealing ring 92 is located in the annular groove in the lower end of the second connecting portion 13.
The upper and lower open-ended barrel of supplementary section of thick bamboo 3, diameter 300mm, height 50mm, supplementary transparent glass section of thick bamboo upper and lower both ends have the third connecting portion 14 of width 35 mm. All set up 16 screw holes that the interval equals on first connecting portion 12, second connecting portion 13 and the third connecting portion 14, screw hole and screw nut cooperation will make a kind section of thick bamboo 2 and be connected with supplementary section of thick bamboo 3, or will make a kind section of thick bamboo 2 and fix on reaction base 1.
The counter-force base 1 is made of rigid materials and is formed by fixedly connecting two cubes arranged up and down, the side length of the cube below is 380mm, and the height of the cube is 60 mm; the side length of the cube located above is 450mm, and the height is 40 mm. Offer the circular recess that is used for placing first permeable stone 71 on the reaction base 1, the diameter of recess is 310mm, has first circular shape sealing washer 91 at the recess inner wall, and first permeable stone 71 up end flushes with the up end of reaction base 1, and reaction base 1 is used for placing system appearance section of thick bamboo 2 to provide a level and smooth face, make the loess of preparation remold a kind bottom surface and level. The sample preparation barrel 2 is placed right above the first permeable stone 71, a first diversion trench communicated with the groove is formed in the counter-force base 1, and a drainage pipe and a first drainage switch 8 are installed at the outlet of the first diversion trench.
The total four reaction columns 5 are made of rigid materials and are respectively arranged on the left and the right, the length of each reaction column 5 is 700mm, the diameter of each reaction column is 30mm, the distance between the left and the right is 400mm, and the distance between the front and the back is 6mm, and the reaction columns are used for connecting the reaction beams 17 and the reaction base 1. The upper portion of the reaction column 5 is provided with an external thread, the reaction column 5 is fixedly connected with the reaction beam 17 through the external thread and a bolt, and when the jack is insufficient in footage, the distance between the reaction beam 17 and the reaction base 1 can be adjusted through the external thread.
The pressure plate 4 is made of a rigid material and has a truncated cone shape, the diameter of the bottom of which is 300mm and the height of which is 45mm, which are the same as the diameter of the sample preparation cylinder 2. The center of the top of the pressure plate 4 is provided with a containing groove with the diameter of 60mm and the depth of 5mm, the containing groove is used for containing a steel ball 10 and preventing the pressurizing process from generating bias voltage, the length of the four sides of the containing groove is equal to the diameter of the steel ball 10, and the height of the groove is equal to the radius of the steel ball 10. The pressure plate 4 is provided with a second diversion trench, the outlet of the second diversion trench is provided with a pipeline, the pipeline is provided with a second drainage switch 82, and after the pressure of the servo jack 6 in the soil sample is borne, water in the loess can be discharged through the second diversion trench and the pipeline.
The diameter of the first permeable stone 71 is 300mm and is placed in the groove of the base, and the diameter of the second permeable stone 72 is 300mm and is placed between the auxiliary cylinder 3 and the pressure plate 4. Both the first and second permeable stones 71 and 72 are used for drainage.
The servo jack 6 is an oil jack, the end part of a piston rod of the oil jack is fixed with an auxiliary piece 15, the lower part of the auxiliary piece 15 is provided with a hemispherical pressure groove matched with the steel ball 10, and the diameter of the pressure groove is the same as that of the steel ball 10.
The measuring cylinder is used for collecting moisture discharged in the pressurizing process.
The preparation of loess remolded samples by two methods under two different initial conditions is described below.
The method comprises the following steps: when the dry density is controlled to be rhodMainly, a drainage method is adopted, and the method comprises the following steps:
step 1, soil screening. Selecting a screen with the diameter of 0.02mm, and screening the remolded loess by using the screen for later use.
And 3, water distribution. Remolded loess A remolded loess having a water content of omega% was prepared. According to mWater (W)The mass m of distilled water required to be added was calculated as m × ω%Water (W)。
And 4, standing. And (4) wrapping the remolded loess prepared in the step (3) by using a preservative film, sealing, and then placing into a moisture-keeping device for standing for 8 hours to ensure that the moisture in the remolded loess is uniformly distributed.
And 5, coating vaseline. Vaseline is evenly coated on the inner wall of the sample preparation cylinder 2 to reduce the friction force in the pressurizing process.
And 6, mounting the auxiliary barrel 3. The second sealing ring 92 and the auxiliary cylinder 3 are placed on the sample preparation cylinder 2, the open holes of the sample preparation cylinder 2 and the auxiliary cylinder 3 are aligned, and the two are tightly connected and fixed by screws and nuts.
And 7, preparing a sample. The first permeable stone 71 and the first sealing ring 91 are placed in the groove of the back pressure base 1, namely right below the sample preparation cylinder 2, the first drainage switch 81 is opened, and the measuring cylinder is placed below the first drainage switch 81. Dividing the remolded loess with the prepared water content into three parts, wherein each part is composed of
And 8, preparing a sample. Firstly, the first remolded loess is put into the sample preparation cylinder 2, then the second permeable stone 72 is placed on the remolded loess 11 in the sample preparation cylinder 2, the second drainage switch 82 on the pressure plate 4 is opened, the other measuring cylinder is placed at the water outlet of the second drainage switch 82, and then the pressure plate 4 is placed on the second permeable stone 72 in the glass cylinder. And starting the servo jack 6, enabling the servo jack 6 to descend to the position that the lower end face of the servo jack is contacted with the steel ball 10, providing uniform pressure for the pressure plate 4 by contacting the lower end face of the servo jack 6 with the steel ball 10, continuously pressurizing, compacting the remolded loess 11 to one third of the sample preparation cylinder 2 through the pressure plate 4, and collecting water discharged by the drainage switch. Then, the servo jack 6 is closed, the pressure plate 4 is taken down after the servo jack is restored to the original position, the remolded loess 11 is scraped with a scraper to remove the hair on the surface, and the remolded loess boundaries which are put twice are reduced; putting a second portion of remolded loess 11 into the sample preparation cylinder 2, then placing a second porous stone 72 on the pressure plate 4 and the remolded loess in the sample preparation cylinder 2, then placing the pressure plate 4 on the second porous stone 72 of the sample preparation cylinder 2, uniformly pressurizing the pressure plate 4 by starting the servo jack 6 to compact the remolded loess 11 to two thirds of the glass cylinder, collecting water discharged by the drainage switch, then closing the servo jack 6 to recover the original position, then taking down the pressure plate 4, and scraping the surface of the remolded loess 11 by a scraper; finally, remolding loess 11 in the third part is put into the sample preparation cylinder 2, then the second permeable stone 72 is placed on remolding loess in the pressure plate 4 and the glass cylinder, then the pressure plate 4 is placed on the second permeable stone 72 in the sample preparation cylinder 2, then the pressure plate 4 is uniformly pressurized by starting the servo jack 6, the remolding loess 11 is compacted to the top end of the transparent glass cylinder, meanwhile, water discharged by the first drainage switch and the second drainage switch is collected by the measuring cylinder, the servo jack 6 is closed to restore the original position and take down the pressure plate 4, the auxiliary cylinder 3 is detached, and the large-scale cylindrical remolding loess sample is obtained. Note that: and (3) observing the side wall of the sample preparation cylinder 2 in real time, and if the remolded loess 11 is layered in the pressing process, preparing the sample again.
Step 9, calculating the water content omega of the prepared large-scale cylindrical loess remolded sample1% of the total weight of the composition. The mass of water collected by the weighing cylinder is m1According to the formula
The water content of the prepared large cylindrical loess remolded sample can be calculated to be omega1。
The second method comprises the following steps: when the water content ratio omega is mainly controlled, a non-drainage method is adopted, and the steps are as follows:
step 1, soil screening. Selecting a screen with the diameter of 0.02mm, and screening a certain amount of remolded loess by using the screen for later use.
And 3, water distribution. Preparing a loess remolded sample with the water content of omega%. According to mWater (W)The mass of distilled water required to be added was calculated as m × ω%.
And 4, standing. And (4) wrapping the remolded loess prepared in the step (3) by using a preservative film, sealing, and then placing into a moisture-keeping device for standing for 8 hours to ensure that the moisture in the remolded loess is uniformly distributed.
And 5, coating vaseline. Vaseline is evenly coated on the inner wall of the sample preparation cylinder 2 to reduce the friction force in the pressurizing process.
And 6, mounting the auxiliary barrel 3. The auxiliary cylinder 3 is placed on the sample preparation cylinder 2, the openings of the two glass cylinders are aligned, and the two glass cylinders are tightly connected through screws and nuts.
And 7, preparing a sample. A water-tight first pad is placed in the recess and the first drain switch 81 is closed. Dividing the remolded loess into three parts, wherein each part is composed of
And 8, preparing a sample. Firstly, remoulding loess is put into the sample preparation cylinder 2, then a water-tight second backing plate is placed on the remoulding loess 11 in the sample preparation cylinder 2, the second drainage switch 82 is closed, and then the pressure plate 4 is placed on the second backing plate in the glass cylinder. And starting the servo jack 6, so that the bottom of the servo jack 6 is lowered to be in contact with the steel ball 10, the bottom of the servo jack 6 is in contact with the steel ball 10, uniform pressure is provided for the pressure plate 4, and the remolded loess 11 is pressed to one third of the sample preparation cylinder 2 by continuously pressurizing through the pressure plate 4. Then, the servo jack 6 is closed, the pressure plate 4 is taken down after the servo jack is restored to the original position, and the surface of the remolded loess 11 is shaved by a scraper; placing a part of remolded loess into the glass cylinder, then placing a second backing plate on the remolded loess 11 in the sample preparation cylinder 2, then placing the pressure plate 4 on the second backing plate, uniformly pressurizing the pressure plate 4 by starting the servo jack 6 to compact the remolded loess 11 to two thirds of the position of the glass cylinder, then closing the servo jack 6, taking down the pressure plate 4 after restoring the original position, and scraping the remolded loess 11 with a scraper to remove the surface; finally, the last remolded loess 11 is placed into the glass cylinder, then the second backing plate is placed on the remolded loess 11 in the glass cylinder, the pressure plate 4 is placed on the second backing plate in the glass cylinder, then the remolded loess 11 is compacted to the top of the sample preparation cylinder 2 by uniformly pressurizing the pressure plate 4 by starting the servo jack 6, the servo jack 6 is closed to restore the original position and take down the pressure plate 4, and the auxiliary transparent glass cylinder is removed. In this step, the side wall of the sample preparation cylinder 2 is observed in real time, and if the remolded loess 11 is layered in the pressing process, the sample preparation is carried out again.
The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.
Claims (9)
1. The large-scale cylindrical loess remolding sample preparation equipment with the controllable initial condition is characterized by comprising a counter-force base (1), a barrel body and a pressure plate (4), wherein a pressurizing device for applying pressure to the pressure plate (4) is installed on the counter-force base (1), a sample preparation barrel (2) is fixed on the counter-force base (1), the barrel body comprises a sample preparation barrel (2) and an auxiliary barrel (3) fixed on the sample preparation barrel (2), and during sample preparation, the pressurizing device applies pressure to remolded loess in the barrel body through the pressure plate (4);
a groove is formed in the upper end of the reaction frame base (1), the groove is used for placing a first permeable stone (71) or a base plate, the sample preparation cylinder (2) is located on the groove, a first flow guide groove is formed in the side wall of the groove, and a first drainage switch (81) is installed at the outlet of the first flow guide groove; the lower end of the pressure plate (4) is provided with a second permeable stone (72) or a backing plate, a second diversion trench is formed in the pressure plate (4), and a first drainage switch (81) is installed at an outlet of the second diversion trench.
2. The large-scale cylindrical loess remolding sample preparation equipment with controllable initial conditions as claimed in claim 1, wherein a sealing ring is arranged between the sample preparation barrel (2) and the auxiliary barrel (3).
3. The initial condition-controllable large-scale cylindrical loess remolding sample preparation equipment according to claim 1, wherein steel balls (10) are arranged at the upper end of the pressure plate (4), an auxiliary part is arranged at the pressing end of the pressing device, a hemispherical pressure groove is formed at the lower end of the auxiliary part, and the pressure groove is used for accommodating the tops of the steel balls (10).
4. The initial condition-controllable large-sized cylindrical loess remolding sample preparation device as claimed in claim 1, wherein the sample preparation barrel (2) and the auxiliary barrel (3) are both made of organic transparent glass.
5. The large-scale cylindrical loess remolding sample preparation device with controllable initial conditions as claimed in claim 1, wherein the inner diameters of the sample preparation cylinder (2) and the auxiliary cylinder (3) are both 300mm-350mm, the height of the sample preparation cylinder (2) is 200-250mm, and the height of the auxiliary cylinder (3) is 50mm-100 mm.
6. The initial condition controllable large-scale cylindrical loess remolding sample preparation equipment according to claim 1, wherein a reaction column (5) is fixed on the reaction base (1), an external thread is arranged on the upper part of the reaction column (5), the upper part of the reaction column (5) is in threaded connection with a reaction beam (17), and the pressurizing device is installed on the reaction beam (17).
7. The initial condition-controllable large-sized cylindrical loess remolding sampling apparatus as claimed in claim 1, wherein the pressurizing means is a servo jack.
8. A sample preparation method of large cylindrical loess remolding sample preparation equipment based on the initial condition controllable in claim 1, characterized by comprising the following steps:
step 1, taking dried remolded loess with mass m, wherein m is rhod×V，ρdDry density of remolded loess sample for target is rhodV is the volume of the sample preparation cylinder (2);
step 2, according to mWater (W)Calculating the mass of the required added distilled water as m × omega%, and preparing a loess remolded sample with the water content of omega%;
step 3, sealing the remolded loess prepared in the step 2, and then placing the remolded loess into a moisturizer for standing to ensure that the moisture in the remolded loess is uniformly distributed;
step 4, dividing the remolded loess after standing into N parts, wherein each part is composed of
Step 5, sample preparation, comprising the following steps:
step 5.1, placing the first base plate into a groove of the back pressure base (1), and closing the first drainage switch (81); putting a part of remolded loess into the sample preparation cylinder (2), then placing a second base plate on the remolded loess (11) in the sample preparation cylinder (2), then placing a pressure plate (4) on the second base plate, starting a pressurizing device, enabling the pressurizing device to apply pressure to the remolded loess (11) through the pressure plate (4) until the remolded loess (11) is pressed to one part of N of the sample preparation cylinder (2), and resetting the pressurizing device; shaving the surface of the remolded loess (11);
and 5.2, sequentially adding the remaining N-1 parts of remolded loess into the barrel, compacting to M of N, wherein M is the number of remolded loess which is already put into the barrel, and compacting the remolded loess (11) to the top of the sample preparation barrel (2) after the last part of remolded loess is put into the barrel, wherein the loess in the sample preparation barrel (2) is the target loess sample.
9. A sample preparation method based on the large cylindrical loess remolding sample preparation equipment with controllable initial conditions, which is characterized by comprising the following steps of:
step 1, taking dried remolded loess with mass m, wherein m is rhod×V，ρdDry density of remolded loess sample for target is rhodV is the volume of the sample preparation cylinder (2);
step 2, according to mWater (W)Calculating the mass of the required added distilled water as m × omega%, and preparing a loess remolded sample with the water content of omega%;
step 3, sealing the remolded loess prepared in the step 2, and then placing the remolded loess into a moisturizer for standing to ensure that the moisture in the remolded loess is uniformly distributed;
step 4, dividing the remolded loess after standing into N parts, wherein each part is composed of
Step 5, sample preparation, comprising the following steps:
step 5.1, putting the first permeable stone (71) into a groove of the back pressure base (1), opening a first drainage switch (81), and putting the measuring cylinder at an outlet of the first drainage switch (81);
step 5.2, putting a part of remolded loess into a sample preparation cylinder (2), then placing a second permeable stone on the remolded loess (11) in the sample preparation cylinder (2), opening a second drainage switch (82) on a pressure plate (4), then placing the pressure plate (4) on a second permeable stone (72), starting a pressurizing device, applying pressure to the remolded loess (11) through the pressure plate (4) until the remolded loess (11) is pressed to one part of N of the sample preparation cylinder (2), collecting water discharged by a first drainage switch (81) and the first drainage switch (81), resetting the pressurizing device, and scraping the surface of the remolded loess (11);
and 5.2, sequentially adding the remaining N-1 parts of remolded loess into the barrel, compacting to M of N, wherein M is the number of remolded loess put into the barrel, collecting water discharged by the first drainage switch (81) and the first drainage switch (81), and compacting the remolded loess (11) to the top of the sample preparation barrel (2) after the last part of remolded loess is put into the barrel, wherein the loess in the sample preparation barrel (2) is the target loess sample.
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