Large indoor simulation device and method for in-situ soil layer

Abstract

The invention relates to the technical field of indoor soil body testing equipment, and provides a large indoor simulation device and method for an in-situ soil layer. The simulation device comprises a foundation slab, the foundation slab is connected with a material barrel with a measuring hole through a cooperative loading jack, the inner wall of the material barrel is provided with a flexible sleeve, and the open end of the material barrel is provided with an upper cover plate with a variable-diameter testing hole; the supporting stand columns penetrate through the upper cover plate and the foundation bottom plate and are fixed through nuts. A force sensor is arranged in the collaborative loading jack, a displacement sensor is arranged on the outer side of the collaborative loading jack, and the collaborative loading jack, the force sensor and the displacement sensor are all connected with the loading console. According to the invention, in-situ characteristics such as density and stress of an in-situ soil layer in an indoor simulation field test can be realized, and necessary equipment and technical support are provided for carrying out a calibration test of the indoor simulation field in-situ test.

Description

Technical Field

[0001] The present invention relates to the technical field of indoor soil testing equipment, and in particular to a large-scale indoor simulation device and method for in-situ soil layers. Background Technique

[0002] The statements in this part merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] At present, the static and dynamic characteristics of soil are mainly studied through indoor tests on remolded soil samples, and the corresponding characteristic parameters are determined. Indoor static and dynamic characteristic tests can simulate various external control conditions such as rich stress conditions of soil, and obtain characteristic parameters of various types of static and dynamic constitutive models of soil through systematic tests. However, it is difficult to reflect the in-situ structural characteristics of natural soil layers, and it is difficult to reliably determine the characteristic parameters of soil only by indoor tests. In-situ tests are carried out on actual soil layers, with little disturbance to the in-situ soil, and can more truly reflect the in-situ structural effect and in-situ stress state of the soil. At the same time, it can also solve the size effect problem caused by the limitation of equipment size in indoor tests. However, the test conditions of in-situ tests are relatively single and difficult to control, the test stress conditions are single, it is difficult to carry out tests under different consolidation stress states, and it is difficult to verify the complex influence relationships of various factors such as in-situ compactness (relative density).

[0004] Simulating in-situ conditions indoors, constructing soil layers that can reflect the actual on-site state, and carrying out calibration tests of in-situ tests under controllable conditions is a reasonable way to solve the problems existing in the existing single indoor remolded soil sample test and in-situ test, integrate the advantages of both, and comprehensively study and determine the static and dynamic characteristic parameters of overburden soil. Summary of the Invention

[0005] In order to solve the technical problems existing in the above background technique, the present invention provides a large-scale indoor simulation device and method for in-situ soil layers. The present invention develops a large-scale indoor simulation device for in-situ soil layers and proposes corresponding test methods for carrying out calibration tests of indoor simulated in-situ tests, which can extend single and specific on-site test conditions to different in-situ conditions, and provides the necessary equipment and technical support for reliably determining the mechanical characteristics and parameters of in-situ soil layers by combining the results of in-situ tests and indoor tests.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention provides a large-scale indoor simulation device for in-situ soil layers.

[0008] A large-scale indoor simulation device for in-situ soil layers, comprising: a base floor, on which a bucket with a measurement hole is connected by a collaborative loading jack, a flexible sleeve is arranged on the inner wall of the bucket, and an upper cover plate with a variable-diameter test hole is arranged at the open end of the bucket; a support column penetrates through the upper cover plate and the base floor and is fixed by nuts;

[0009] A force sensor is arranged inside the collaborative loading jack, a displacement sensor is arranged outside the collaborative loading jack, and the collaborative loading jack, the force sensor and the displacement sensor are all connected to a loading console.

[0010] Furthermore, a directional bearing is arranged on the support column, the directional bearing comprises a bearing bracket and a bearing, the support column passes through the bearing bracket, and the directional bearing is fastened to the support column by the bearing bracket, and the bearing is in vertical contact with the outer side wall of the bucket.

[0011] Furthermore, a variable-diameter hole with a hole bolt is arranged inside the upper cover plate, a variable-diameter hole inner bolt is arranged inside the variable-diameter hole with a hole bolt, and the centers of the variable-diameter hole inner bolt, the variable-diameter hole with a hole bolt and the bucket are coaxial.

[0012] Furthermore, the support column and the upper cover plate are fixed by a positioning nut, and the support column and the base floor are fixed by a fastening nut.

[0013] Furthermore, the flexible sleeve is also provided with an opening at a position corresponding to the opening of the bucket.

[0014] Furthermore, a plurality of groups of measurement hole bolts are arranged on the side wall of the bucket.

[0015] Furthermore, a lubricating material is smeared between the flexible sleeve and the bucket.

[0016] The second aspect of the present invention provides a large-scale indoor simulation method for in-situ soil layers.

[0017] A large-scale indoor simulation method for in-situ soil layers, applied to the large-scale indoor simulation device for in-situ soil layers described in the first aspect, comprising:

[0018] Placing a thin flexible sleeve with a lubricating material (such as vaseline, carbon powder, etc.) coated on the outer wall into the bucket and closely fitting it with the inner wall of the bucket; opening holes at corresponding positions of the flexible sleeve according to the positions of the measurement holes of the bucket;

[0019] Place the test soil materials in the bucket with measurement holes in layers according to the preset relative density. After each layer is filled, use a compaction instrument to compact it and restore the density. After one round of compaction, measure and compare whether it has been compacted to the specified height. If not, conduct the next round of compaction until it reaches the specified height to complete the compaction of one layer of soil materials. During this process, remove the corresponding measurement hole bolts at the required positions according to the test needs and arrange sensors.

[0020] Install the upper cover plate, start the collaborative loading jack through the loading console, and load the soil materials to the preset stress state according to the signal of the force sensor to complete the loading.

[0021] Conduct an indoor simulation test of in-situ testing on site.

[0022] Further, during the compaction process, manual compaction and electric compaction are respectively adopted according to the density requirements of the soil sample. When manual compaction or electric compaction is carried out, the compaction process follows the basic principle from the outside to the inside. First, ram around the inner wall of the bucket with measurement holes, and then move the compactor inward and ram the next circle along the inner diameter of the compacted track. During the compaction process, there should be partial overlap between the two compaction tracks to ensure that the compaction range is completely covered.

[0023] Further, before conducting the indoor simulation test, remove the bolts inside the variable-diameter hole or the bolt with holes in the variable-diameter hole.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] To reliably determine the mechanical properties and parameters of the soil mass by combining the results of in-situ tests on site and indoor tests, it is necessary to carry out calibration tests for indoor simulation of in-situ tests on site. The present invention has developed a large-scale indoor simulation device for in-situ soil layers and proposed corresponding test methods. The lateral deformation of the soil mass is restricted by a rigid side wall, and a vertical load is applied through a jack to simulate the in-situ stress state of the in-situ soil layer. By controlling the sample preparation method, the in-situ density of the in-situ soil layer is simulated. At the same time, the device provides variable-diameter test holes and multiple measurement holes, providing basic conditions for further carrying out indoor simulation tests of various in-situ tests. The present invention can simulate the in-situ state such as density and stress of the in-situ soil layer in indoor simulation of in-situ tests on site, providing necessary equipment and technical support for carrying out calibration tests for indoor simulation of in-situ tests on site.

[0026] The present invention is internally provided with a flexible sleeve, which is in smooth contact with the inner wall of the bucket and completely deforms in coordination with the soil materials during the test, achieving the purpose of reducing the friction between the soil materials and the bucket wall and keeping the stress state inside the soil materials as consistent as possible. Description of the Drawings

[0027] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0028] Figure 1 It is a structural diagram of a large indoor simulation device for in-situ soil layers shown in the present invention;

[0029] Figure 2 It is a detailed mechanism diagram of the upper cover plate with variable-diameter test holes shown in the present invention;

[0030] Figure 3 It is a detailed mechanism diagram of the base floor shown in the present invention;

[0031] Figure 4 It is a detailed mechanism diagram of the directional bearing shown in the present invention;

[0032] Wherein, 1. fastening nut, 2. upper cover plate, 3. variable-diameter hole with-hole bolt, 4. bolt inside the variable-diameter hole, 5. support column, 6. material bucket, 7. cooperative loading jack, 8. base floor, 9. positioning nut, 10. measuring hole bolt, 11. directional bearing, 12. force sensor, 13. displacement sensor, 14. loading console, 15. flexible sleeve, 16. bearing bracket, 17. bearing. Specific embodiments

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0034] It should be noted that the following detailed descriptions are all illustrative and are intended to provide a further description of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] In view of the fact that the in-situ structure of the in-situ soil layer mentioned in the background technology is extremely likely to be damaged due to sampling disturbance during the sampling process. The large-scale special sampling method on-site is not applicable to general projects due to its high cost. The test results of indoor remolded samples are difficult to reflect the influence of in-situ structure and are difficult to accurately reflect the physical and mechanical properties of the soil mass. The test conditions of on-site in-situ tests are single, difficult to control, and it is impossible to directly obtain the characteristic parameters of the static and dynamic constitutive model of the soil mass. Therefore, it is necessary to carry out calibration tests for indoor simulation of on-site in-situ tests, extend the single and specific on-site test conditions to different in-situ conditions, and provide necessary conditions for reliably determining the mechanical properties and parameters of the in-situ soil layer by combining on-site in-situ tests and indoor remolded sample test results. Existing indoor test devices are all special test equipment for specific tests, lacking test devices and technologies that can restore the in-situ soil state and provide basic conditions for carrying out various on-site test simulation tests, which restricts the development of indoor simulation test research on on-site in-situ tests. In order to give full play to the respective advantages of indoor and outdoor tests and reliably determine the mechanical properties and parameters of the in-situ soil layer by combining on-site in-situ tests and indoor test results, it is necessary to carry out calibration tests for indoor simulation of on-site in-situ tests, extend the single and specific on-site test conditions to different in-situ conditions, and it is necessary to develop large-scale indoor simulation devices and methods for in-situ soil layers that can restore the in-situ soil layer state. The present invention will be described in detail through several embodiments as follows:

[0037] Embodiment 1

[0038] As Figure 1 shown, this embodiment provides a large-scale indoor simulation device for in-situ soil layers. The components in the figure are respectively fastening nut 1, upper cover plate 2 with variable-diameter test holes, variable-diameter hole bolt 3, bolt inside the variable-diameter hole 4, support column 5, bucket 6 with measurement holes, cooperative loading jack 7, base plate 8, positioning nut 9, measurement hole bolt 10, directional bearing 11, force sensor 12, displacement sensor 13, loading console 14, and flexible sleeve 15.

[0039] The aperture of the test hole of the upper cover plate 2 is determined according to the test aperture requirements of the on-site in-situ test for the indoor simulation test to be carried out, and the material stiffness of the upper cover plate 2 should meet the deformation requirements during the loading process; the aperture of the measurement hole of the bucket 6 is determined according to the installation dimension requirements of the sensors to be arranged, and the bucket diameter and height of the bucket 6 are determined according to the maximum particle size of the soil material and meet the requirements of the on-site in-situ test for the indoor simulation test to be carried out; the material stiffness of the side wall of the bucket 6 should be much greater than the soil stiffness and meet the lateral deformation requirements during the loading process, and steel can be used.

[0040] The present invention determines the size of the bucket 6 according to the maximum particle size of the soil material, so that the influence of the side wall constraint on the central soil body during the loading and test process is very small, and the boundary effect can be ignored.

[0041] The side wall of the bucket 6 of the present invention is a rigid boundary with a stiffness much greater than that of the soil body, which can strictly control its own lateral deformation. The lifting of the cooperative loading jack is controlled by the loading console, and the vertical load is applied to the soil sample by the reaction force provided by the upper cover plate to restore the stress state of the soil body in the in-situ soil layer.

[0042] A thin-layer flexible casing 15 is arranged in the bucket 6, and the flexible casing 15 is closely attached to the inner wall of the bucket 6. A lubricating material (such as vaseline, carbon powder, etc.) is smeared on the outer wall of the flexible casing 15 to reduce the friction with the bucket 6. The inner wall of the flexible casing 15 is in rough contact with the soil material, and the flexible casing 15 and the soil material are completely coordinated in deformation during the test, without affecting the deformation characteristics of the soil material during the test. This method can reduce the friction between the soil material and the bucket wall and keep the stress state of the soil material inside the bucket as consistent as possible.

[0043] The detailed structures of the upper cover plate 2 and the foundation bottom plate 8 of the large-scale indoor simulation device for the in-situ soil layer are respectively as Figure 2 and Figure 3 shown. Different in-situ tests have different requirements for the aperture of the test hole. In order to meet the indoor simulation requirements of various in-situ tests, variable-diameter test holes are designed in the upper cover plate of this device, and multiple groups of variable-diameter hole-bolted bolts 3 and corresponding variable-diameter hole internal bolts 4 are used to meet the test requirements. For the aperture of the test hole required for different tests, variable-diameter hole-bolted bolts 3 and corresponding variable-diameter hole internal bolts 4 matching the aperture can be selected and installed before the test loading stage. During the test, the variable-diameter hole internal bolts 4 can be removed separately as needed, or the variable-diameter hole-bolted bolts 3 together with the variable-diameter hole internal bolts 4 can be removed to leave a test hole with the required size for in-situ test. This method can, on the basis of meeting the test opening requirements, maximize the avoidance of the unloading of the soil body load above except for the test hole position, and avoid affecting the accuracy of the subsequent test results.

[0044] The present invention uses replaceable variable-diameter hole-bolted bolts 3 and variable-diameter hole internal bolts 4, which can meet the indoor simulation test requirements of various in-situ tests. In the present invention, according to the actual working conditions, the shapes, sizes and quantities of the variable-diameter hole-bolted bolts 3, variable-diameter hole internal bolts 4 and measuring hole bolts 10 can be changed, such as using multi-layer bolted bolts. The present invention does not make any limitation here. The present invention can change the geometric form of the rib plate of the component or use a solid component instead.

[0045] The detailed structure of the directional bearing 11 of the large-scale indoor simulation device for the in-situ soil layer is as Figure 4As shown in the figure. The directional bearing 11 consists of two parts: a bearing bracket 16 and a bearing 17. During use, the support column 5 is passed through the bearing bracket 16, and the directional bearing 11 is fastened to the column 5 by means of the bearing bracket 16. The bearings 17 in all directions are in vertical contact with the material bucket 6 to ensure that the material bucket 6 does not deflect in this direction. At the same time, during the loading and unloading stages of the device, the friction between the bearing 17 and the material bucket 6 is minimized as much as possible to avoid the influence of vertical friction on the test results.

[0046] In the present invention, other directional devices can also be used to replace the directional bearing, and the present invention does not make any limitations here.

[0047] The loading device for providing the in-situ stress state for the large-scale indoor simulation device of the in-situ soil layer includes a loading console 14, a coordinated loading jack 7, a force sensor 12, and a displacement sensor 13. After setting the values of the target force and displacement on the operation interface of the loading console 14, the loading console 14 will compare the target force and target displacement with the force and displacement measured by the force sensor 12 and the displacement sensor 13, and automatically control the lifting of the coordinated loading jack 7 below the material bucket 6 with a measurement hole through the loading console 14, thereby driving the lifting of the material bucket 6 with a measurement hole; when the target force or target displacement set in the loading console 14 is equal to the force or displacement measured by the force sensor 12 and the displacement sensor 13, the coordinated loading jack 7 stops lifting and the position remains unchanged. During the loading and unloading process, a vertical load is applied to the soil sample by the upper cover plate 2 with a variable-diameter test hole, the variable-diameter hole bolt 3 therein, and the bolt inside the variable-diameter hole 4 to simulate the in-situ stress state of the soil layer.

[0048] During the loading and unloading process, multiple coordinated loading jacks 7 evenly arranged below the material bucket 6 with a measurement hole will move in coordination based on the displacement signal provided by the displacement sensor 13 to ensure that the bottom surface of the material bucket 6 with a measurement hole remains horizontal, and the moving direction of the material bucket 6 with a measurement hole always remains vertical.

[0049] The present invention adopts a loading method of coordinating the loading of multiple jacks, which can ensure that the moving direction of the material bucket always remains vertical, effectively reducing the phenomenon of uneven stress distribution in the soil layer during the loading and testing process. In the present invention, the number of jacks can be changed according to specific working conditions, such as using a single jack, or using other loading devices to replace the jack. The present invention does not make any limitations here.

[0050] The installation process of the large-scale indoor simulation device of the in-situ soil layer is as follows:

[0051] (1) Place the foundation bottom plate 8 on a site with satisfactory flatness and stiffness.

[0052] (2) Install the force sensor 12 into the coordinated loading jack 7. Place the coordinated loading jack 7 above the foundation bottom plate 8 to ensure that the top surface of the coordinated loading jack 7 is horizontal and the heights are the same.

[0053] (3) Place the bucket 6 with a measurement hole on the top surface of the collaborative loading jack 7, and require the bucket 6 with a measurement hole to be centered with the foundation bottom plate 8.

[0054] (4) Pass the support column 5 through the lower positioning nut 9 and the foundation bottom plate 8 in sequence, install the lower fastening nut 1 and tighten it. Then install the directional bearing 11 and the upper positioning nut 9 on the support column 5 in sequence. In the present invention, the directional bearing 11 is installed on the support column 5, which can effectively prevent the device from tilting during installation, loading and testing.

[0055] (5) Pass the support column 5 through the upper cover plate 2 with a variable diameter test hole, place the upper cover plate 2 with a variable diameter test hole on the upper positioning nut 9, confirm that the center positions of the upper cover plate 2 with a variable diameter test hole and the foundation bottom plate 8 are consistent, and tighten the fastening nut 1 on the upper part of the support column 5.

[0056] (6) Install the bolt 4 in the variable diameter hole into the bolt 3 with a hole in the variable diameter hole, and then install the bolt 3 with a hole in the variable diameter hole into the upper cover plate 2 with a variable diameter test hole.

[0057] (7) Tighten the measurement hole bolt 10 on the side wall of the bucket 6 with a measurement hole. In the present invention, multiple groups of symmetric measurement hole bolts 10 are arranged on the side wall of the bucket 6, and corresponding sensors can be installed and arranged according to the test requirements through the measurement holes.

[0058] (8) Install the displacement sensor 13 outside the collaborative loading jack 7.

[0059] (9) Connect the loading control console 14 to the collaborative loading jack 7, and then connect the force sensor 12 and the displacement sensor 13 to the loading control console 14.

[0060] (10) Test the loading condition of the collaborative loading jack 7 and the signals of the force sensor 12 and the displacement sensor 13 through the loading control console 14 to complete the installation.

[0061] The present invention has developed a large-scale indoor simulation device for in-situ soil layers and proposed corresponding test methods, which can realize the simulation of in-situ states such as the density and stress of in-situ soil layers in indoor simulation of field tests. At the same time, variable diameter test holes and multiple measurement holes are provided, providing basic conditions for further carrying out indoor simulation tests of various field tests.

[0062] The present invention realizes the precise control of the soil sample density through the sample preparation method combining layer-by-layer sample preparation and manual compaction and electric compaction, and can restore various soil density states from loose to dense.

[0063] Embodiment 2

[0064] This embodiment provides a large-scale indoor simulation method for an on-site in-situ soil layer, which is applied to the large-scale indoor simulation device for an in-situ soil layer described in the first embodiment, and includes:

[0065] Remove the upper fastening nut 1 and the upper cover plate 2 with the variable diameter test hole. Place a thin flexible sleeve 15 with a lubricating material (such as vaseline, carbon powder, etc.) on the outer wall in the barrel 6 and fit it tightly against the inner wall of the barrel 6. According to the position of the measuring hole of the barrel 6, a hole is opened at the corresponding position of the flexible sleeve 15.

[0066] The test soil material is loaded into the material barrel 6 with measuring holes in layers according to the preset relative density. After each layer is loaded, a compaction instrument is used for compaction, and watering is used as an aid to restore the density of the in-situ soil layer. Manual compaction or electric compaction is used according to the density requirements of the soil sample. Manual compaction is used to prepare relatively loose soil samples, and the soil is tamped using a metal compactor. Electric compaction is used to prepare relatively dense soil samples, and the soil is tamped using an electric mechanical compactor. When compacting manually or using a small electric mechanical compactor, the compaction process follows the basic principle of from the outside to the inside. First, tamp along the inner wall of the material barrel 6 with measuring holes for one circle, and then move the compactor inward to perform the next circle of compaction along the inner diameter of the compacted trajectory. During this process, it is noted that the two compaction trajectories should overlap by about 20% to ensure that the compaction range is fully covered. Repeat the above compaction process until it is compacted to the center of the material barrel 6 with measuring holes, completing a round of compaction. Measure and compare whether the soil has been compacted to the specified height. If not, repeat the above steps for the next round of compaction until the soil is compacted to the specified height, completing the compaction of a layer of soil. In this process, remove the corresponding measurement hole bolts 10 at the required position according to the test needs and arrange the sensor.

[0067] After the soil material in the material barrel 6 with the measuring hole is filled and compacted, the upper cover plate 2 with the variable diameter test hole is installed according to the hole position and aligned with the support column 5, and the upper fastening nut 1 is tightened.

[0068] According to the test requirements, appropriate bolts with holes 3 with reduced diameter holes and bolts in reduced diameter holes 4 are selected and installed on the upper cover plate 2 with reduced diameter test holes.

[0069] The cooperative loading jack 7 is started through the loading console 14, and the soil material is loaded to a preset stress state based on the signal of the force sensor 12 to complete the loading.

[0070] An indoor simulation test for in-situ testing is carried out by removing the bolt 4 in the variable-diameter hole or the bolt 3 with holes in the variable-diameter hole as needed. After removing the bolt 4 in the variable-diameter hole or the bolt 3 with holes in the variable-diameter hole, assemble the in-situ testing equipment and place it on the upper cover plate 2 with a variable-diameter test hole, so that the test soil body in the indoor simulation test of in-situ testing is located at the center of the bolt 4 in the variable-diameter hole or the bolt 3 with holes in the variable-diameter hole; carry out the simulation test according to the test operation requirements of in-situ testing and record the test data; after the test is completed, disassemble the in-situ testing equipment and reinstall the removed bolt 4 in the variable-diameter hole or the bolt 3 with holes in the variable-diameter hole on the upper cover plate 2 with a variable-diameter test hole to complete the indoor simulation test of in-situ testing.

[0071] After completing an indoor simulation test of in-situ testing, the coordinated loading jack 7 is retracted to the initial state through the loading console 14 based on the signal of the displacement sensor 13.

[0072] Remove the upper fastening nut 1 and remove the upper cover plate 2 with a variable-diameter test hole.

[0073] Remove the soil material and the flexible casing 15 in the bucket 6 with a measuring hole, remove the sensor installed on the measuring hole of the bucket 6 with a measuring hole, screw on the corresponding measuring hole bolt 10 and tighten it.

[0074] Install the upper cover plate 2 with a variable-diameter test hole in alignment with the support column 5 according to the hole position and tighten the upper fastening nut 1 to complete the shutdown.

[0075] The present invention has developed a large-scale indoor simulation device for in-situ soil layers and proposed corresponding test methods. On the premise of restoring the state of in-situ soil bodies, variable-diameter test holes and multiple measuring holes are provided, providing basic conditions for further carrying out indoor simulation tests of various in-situ tests. The indoor simulation tests of in-situ testing that can be carried out in this device include: static cone penetration test, dynamic cone penetration test, standard penetration test, vane shear test, pressuremeter test, shear wave velocity test, etc. According to the size of the test soil body and the sensor layout method required for the indoor simulation test of in-situ testing to be carried out, sensors are arranged at the measuring holes in appropriate positions, test holes of appropriate sizes are selected, and in-situ testing equipment is erected above the test holes to carry out different types of indoor simulation tests of in-situ testing.

[0076] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A large-scale indoor simulation device for in-situ soil layers, characterized in that: include: A base bottom plate, a barrel with a measuring hole is connected to the base bottom plate through a cooperative loading jack, a flexible sleeve is provided on the inner wall of the barrel, and an upper cover plate with a variable diameter test hole is provided at the open end of the barrel; a supporting column is used to penetrate the upper cover plate and the base bottom plate, and is fixed with nuts; A force sensor is arranged inside the cooperative loading jack, and a displacement sensor is arranged outside the cooperative loading jack. The cooperative loading jack, the force sensor and the displacement sensor are all connected to the loading console.

2. The large-scale indoor simulation device for in-situ soil layer according to claim 1 is characterized in that: The support column is provided with a directional bearing, which includes a bearing bracket and a bearing. The support column passes through the bearing bracket, and the directional bearing is fastened to the support column by the bearing bracket. The bearing is in vertical contact with the outer wall of the barrel.

3. The large-scale indoor simulation device for in-situ soil layer according to claim 1 is characterized in that: The upper cover plate is provided with a reducing hole with a hole bolt, and the reducing hole with a hole bolt is provided inside the reducing hole with a hole bolt. The centers of the reducing hole with a hole bolt, the center of the reducing hole with a hole bolt and the center of the barrel are coaxial.

4. The large-scale indoor simulation device for in-situ soil layer according to claim 1, characterized in that: The support columns are fixed to the upper cover plate by using positioning nuts, and the support columns are fixed to the base bottom plate by using fastening nuts.

5. The large-scale indoor simulation device for in-situ soil layer according to claim 1, characterized in that: The flexible sleeve is also provided with a hole at a position corresponding to the opening of the barrel.

6. The large-scale indoor simulation device for in-situ soil layer according to claim 1, characterized in that: A plurality of groups of measuring hole bolts are arranged on the side wall of the barrel.

7. The large-scale indoor simulation device for in-situ soil layer according to claim 1, characterized in that: Lubricating material is applied between the flexible sleeve and the barrel.

8. A large-scale indoor simulation method for in-situ soil layers, characterized in that: A large-scale indoor simulation device for the in-situ soil layer according to any one of claims 1 to 7, comprising: A thin flexible sleeve with a lubricating material coated on the outer wall is placed in the barrel and fits tightly with the inner wall of the barrel; a hole is opened at the corresponding position of the flexible sleeve according to the position of the measuring hole of the barrel; The test soil material is loaded into the material barrel with measuring holes in layers according to the preset relative density. After each layer is loaded, it is compacted using a compaction instrument to restore the density. After one round of compaction, it is measured and compared whether it has been compacted to the specified height. If not, the next round of compaction is carried out until it is compacted to the specified height, completing the compaction of one layer of soil material. During this process, the corresponding measuring hole bolts are removed at the required position according to the test needs and sensors are arranged; Install the upper cover plate, start the coordinated loading jack through the loading console, load the soil material to the preset stress state according to the signal of the force sensor, and complete the loading; Conduct indoor simulation tests for on-site in-situ testing.

9. The large-scale indoor simulation method of in-situ soil layer according to claim 8, characterized in that: The compaction process adopts manual compaction and electric compaction respectively according to the density requirements of the soil sample; when manual compaction or electric compaction is performed, the compaction process follows the basic principle of from outside to inside, first tamping along the inner wall of the barrel with measuring holes, and then moving the compactor inward to perform the next circle of compaction along the inner diameter of the compacted track. During the compaction process, the two compaction tracks should partially overlap to ensure that the compaction range is fully covered.

10. The large-scale indoor simulation method of in-situ soil layer according to claim 8, characterized in that: Before conducting indoor simulation tests, remove the bolts in the reducing holes or the bolts with holes in the reducing holes.

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