In-hole in-situ loess collapsibility coefficient testing device and method based on cutting load method

Abstract

The invention discloses an in-hole in-situ loess collapsibility coefficient testing device and method based on a cutting load method. The in-hole cutting device comprises a first air cylinder, supporting rods are arranged on multiple side faces of the first air cylinder and correspond to the output end of the first air cylinder in position, a conductive ring is connected with a first motor, and an output shaft of a second motor is connected with a tool bit. The collapsibility coefficient testing device comprises two supporting plates which are vertically arranged in a circular ring shape, a fourth air cylinder and a bidirectional electric push rod are located in the middles of the supporting plates, the output ends of the two sides of the fourth air cylinder are connected with the supporting plates respectively, and upper and lower output shafts of the bidirectional electric push rod are connected with an upper loading unit and a lower loading unit which are of the same structure respectively. The top of the upper loading unit and the bottom of the lower loading unit are both provided with pressure plates capable of expanding in the radial direction, and the pressure plate located on the lower loading unit is provided with a plurality of radial water spraying holes. The test position is flexible, and the test result is more accurate and reliable.

Description

Technical Field

[0001] The invention belongs to the field of geotechnical engineering tests and relates to an in-hole in-situ loess collapsibility coefficient testing device and method based on a cutting load method. Background Art

[0002] Collapsible loess, when exposed to water under a certain pressure, will deform significantly and rapidly lose strength. According to my country's "Building Standard for Collapsible Loess Regions" (GB50025-2018), collapsible loess testing primarily includes indoor single- and double-line methods and on-site pit immersion methods. Field testing, which avoids the disturbance of specimens encountered in indoor testing, is widely adopted in engineering practice. In some areas of my country, the depth of self-weight collapsible loess can reach 50-60 meters. For deeply buried collapsible loess, the results of the on-site pit immersion method often deviate significantly from actual conditions due to site limitations, long testing cycles, and high water consumption. To meet the needs of engineering construction, how to quickly and accurately evaluate the collapsible properties of loess at different burial depths has become a crucial issue for ensuring the stability of urban building foundations in loess areas and the safe operation and maintenance of power transmission lines.

[0003] While some studies have proposed testing devices and methods for the collapsibility coefficient of loess in a hole, they lack accuracy and efficiency. For example, the invention patent "Direct Measurement Device for Collapsibility Coefficient in a Hole and Method for Measuring Collapsibility Coefficient of Loess (CN109238866B)" uses a single-line method, but only applies one pressure in a set of in-hole tests, which is inconsistent with the single-line method's requirement for three or more static pressure load tests. Another example is the invention patent "Device and Method for Testing Collapsibility Coefficient of Loess in a Hole (CN117647443B)" that loads an annular soil mass within a hole. However, both the jacking end and the anchoring end of the annular soil mass are deformed by the force. If the jacking distance is not accurately determined, the accuracy of the collapsibility coefficient test will be seriously affected. Clearly, there is still a lack of effective means and methods for determining the collapsibility coefficient of deep loess. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an in-situ loess collapsibility coefficient testing device and method based on the cutting load method, which has flexible testing positions and more accurate and reliable test results.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: An in-hole in-situ loess collapsibility coefficient testing device based on a cutting load method, comprising an in-hole cutting device and a collapsibility coefficient testing device; The in-hole cutting device includes a cross plate, a first cylinder, a first motor, a conductive ring, a second motor and a cutter head connected in sequence from top to bottom; support rods are provided on multiple sides of the first cylinder, the support rods correspond to the positions of the output ends of the first cylinder, the conductive ring is connected to the first motor, and the cutter head is connected to the output shaft of the second motor; The wetting coefficient testing device includes a support plate, a fourth cylinder, a bidirectional electric push rod and a pressure plate; the two support plates are arranged vertically in a circular ring, the fourth cylinder and the bidirectional electric push rod are located in the middle of the support plate, the output ends on both sides of the fourth cylinder are connected to the support plates respectively, and the upper and lower output shafts of the bidirectional electric push rod are respectively connected to the upper loading unit and the lower loading unit with the same structure, and the top of the upper loading unit and the bottom of the lower loading unit are both provided with radially expandable pressure plates, and the pressure plate located in the lower loading unit is provided with multiple radial water spray holes.

[0006] Preferably, a hanging ring is connected to the top of the cross plate.

[0007] Preferably, the support rod is L-shaped, with the short side slidingly connected to the top of the first cylinder and the long side located on the side of the first cylinder. The side of the first cylinder is provided with multiple blowing ports facing the long side of the support rod.

[0008] Preferably, the top of the conductive ring is connected to the first motor via a disc, and the cross plate and the disc are connected via two connecting rods.

[0009] Preferably, the output shaft of the second motor is vertically connected to a gear downward, the gear is engaged with two horizontal racks, and a cutter head is provided at the end of each rack.

[0010] Preferably, the two output shafts of the bidirectional electric push rod are connected to a flange, the pressure plate is arranged on the disc, the flange and the disc are connected by a connecting rod, and a radial guide rail and a radial inclined guide rail are provided at the connection between the connecting rod and the disc; Each pressure plate is composed of a plurality of large expansion plates and a plurality of small expansion plates staggered together. The plurality of large expansion plates are slidably arranged along radial guide rails, and the plurality of small expansion plates are slidably arranged along radial inclined guide rails.

[0011] Preferably, a second cylinder and a third cylinder are provided between the pressure plate and the flange, the second cylinder is connected to the plurality of large expansion plates via a connecting rod mechanism, and the third cylinder is connected to the plurality of small expansion plates via a connecting rod mechanism.

[0012] Preferably, a displacement sensor for acquiring displacement data is respectively provided on the top of the upper loading unit and the bottom of the lower loading unit.

[0013] Preferably, the water spray holes are evenly distributed around the circumference, and a plurality of water spray holes are arranged in a ring shape at equal intervals along the large expansion plate.

[0014] A method for testing the in-hole in-situ loess collapsibility coefficient of the in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method comprises the following steps: Step 1: Select a drilling location on the ground and drill a hole; Step 2: Lower the in-hole cutting device to the target depth and deploy the support rods by the first cylinder to anchor the in-hole cutting device; Step 3: Start the first motor to drive the conductive ring to rotate, and the second motor drives the cutter head to cut and form the upper and lower soil sample grooves to be tested, and retract the cutting device in the hole; Step 4: Lower the collapsibility coefficient test device to the soil sample trough and deploy the support plate via the fourth cylinder; Step 5, unfold the pressure plate; Step 6, injecting water into the sample through the water spray hole; Step 7: Use a bidirectional electric push rod to apply pressure step by step, and record the vertical displacement of the upper and lower specimens at each level of pressure; Step 8: Calculate the vertical collapsibility coefficient of loess under each level of pressure.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides an in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method. By providing an in-hole cutting device and a collapsibility coefficient testing device, it is possible to in-situ cut two annular soil sample grooves to be tested at any depth in the borehole, and utilize a radial expansion structure and a bidirectional electric push rod to apply loading force. Combined with a water spray hole to form a saturated state, it can simultaneously perform graded loading tests on samples in both the natural state and the submerged state, thereby minimizing disturbance to the loess and effectively obtaining true deformation data of the upper and lower samples. The device has a compact structure and reliable anchoring. The support rod is driven by a cylinder to achieve adaptive expansion. The pressure plate adopts a multi-stage expansion structure to improve fitting accuracy. It can efficiently complete loess collapsibility coefficient testing in complex geological environments. The test position is flexible and the disturbance is small. It is suitable for in-situ testing needs of deep collapsible loess, improving test accuracy and engineering adaptability.

[0016] Furthermore, the present invention adopts gear and rack meshing. Compared with single-knife rotary cutting, the device maintains a consistent feed rate, ensures the quality of the sample in the hole, and improves the testing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the in-hole cutting device and in-hole working diagram of the present invention; Figure 2 Schematic diagram of the collapsibility coefficient testing device and the working diagram inside the hole of the present invention; Figure 3 This is a working process diagram of the in-hole cutting device of the present invention; Figure 4This is a working process diagram of the collapsibility coefficient testing device of the present invention; Figure 5 Schematic diagram of the gear structure of the present invention; Figure 6 This is a schematic diagram of the closing and unfolding structures of the large and small display panels of the present invention; Figure 7 This is a schematic diagram of the bidirectional electric push rod structure of the present invention; Figure 8 This is a schematic diagram of the support rod structure of the in-hole cutting device of the present invention; Figure 9 It is a volume-pressure change test curve diagram of the loess in the non-water-soaked and wetted state and the soil in the water-soaked and wetted state of the present invention.

[0018] Among them: 1. lifting ring, 2. cross plate, 3. first cylinder, 31. air inlet, 32. air outlet, 4. support rod, 5. conductive ring, 6. motor, 61. first motor, 62. second motor, 7. cutter head, 8. gear; 9. support plate, 10. pressure plate, 101. large expansion plate, 102. small expansion plate, 11. bidirectional electric push rod, 12. water spray hole, 13. connecting rod, 14. side limit ring, 34. second cylinder, 35. third cylinder, 36. fourth cylinder. DETAILED DESCRIPTION

[0019] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms "installed", "connected", and "connected" should be understood in a broad sense, for example, they can be fixedly connected, detachably connected, or integrally connected; they can be mechanically connected, electrically connected, or able to communicate with each other; they can be directly connected, or indirectly connected through an intermediate medium, or they can be internally connected between two elements or an interactive relationship between two elements. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0022] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0023] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0024] The in-situ in-hole loess collapsibility coefficient testing device based on the cutting load method described in this embodiment mainly includes two parts: an in-hole cutting device and a collapsibility coefficient testing device. Each part has a compact structure and coordinated functions, and can obtain loess collapsibility coefficient data efficiently and accurately under in-situ conditions.

[0025] like Figure 1 As shown, Ⅰ is the rotating part controlled by the in-hole cutting device; Ⅱ is the knife extending part controlled by the in-hole cutting device.

[0026] like Figure 1 As shown, the in-hole cutting device is primarily used to in-situ cut two soil sample annular grooves at a predetermined depth in the hole wall for subsequent collapsibility loading tests. The in-hole cutting device includes a lifting ring 1, a cross plate 2, a first cylinder 3, a support rod 4, a conductive ring 5, a motor 6, a cutter head 7, and a gear 8.

[0027] Before operation, first lower the entire device through the lifting ring 1 to the drill hole of the predetermined depth through the rope. The lifting ring 1 is connected and fixed to the cross plate 2 through appropriate bolts. The cross plate 2 is further connected to the four support rods 4. Figure 8 As shown, the support rod 4 is L-shaped, with the short side horizontally slidingly connected to the top and bottom of the first cylinder 3, and the long side is located on the side of the first cylinder 3. Blowing ports are provided on the four sides of the first cylinder 3, and the blowing ports are set toward the long side of the support rod 4. The support rod 4 is driven by the blowing of the first cylinder 3 to expand outward, and after expansion, it supports the hole wall, thereby stably anchoring the entire in-hole cutting device to the hole wall. An air inlet 31 and an air outlet 32 ​​are provided on the first cylinder 3 for supplying air to the first cylinder 3.

[0028] The motor 6 includes a first motor 61 and a second motor 62, which are responsible for controlling the rotation of the conductive ring 5 and the extension and retraction of the cutter head 7, respectively. The first motor 61 is located below the first cylinder 3. The output shaft of the first motor 61 is vertically connected to the conductive ring 5 downward. The top of the conductive ring 5 is connected to the first motor 61 through a disc. The cross plate 2 and the disc are connected by two connecting rods. The bottom of the conductive ring 5 is connected to the second motor 62, driving the lower cutting mechanism to rotate. The cutter head 7 is controlled by the second motor 62 to extend and retract, as shown in FIG. Figure 5 As shown, the output shaft of the second motor 62 is vertically connected to the gear 8 downward, and the gear 8 is horizontally meshed with two racks. A cutter head 7 is set at the end of the rack. The gear 8 and the rack are driven to ensure a stable feed rate during the cutting process. The gear 8 and the rack are set in the bottom support shell.

[0029] After the in-hole cutting device is activated, the cutter head 7 gradually extends and begins to rotate, cutting along the hole wall. After the first soil sample groove is cut, the in-hole cutting device is lowered to the second testing position, and the above operation is repeated to cut the second soil sample groove. The entire process can be completed at any depth within the hole, maximally restoring the original state of the soil.

[0030] like Figure 2 As shown, the collapsibility coefficient testing device is used to in-situ test the collapsibility of loess in two soil sample troughs formed by cutting. It mainly includes a support plate 9, a pressure plate 10, a fourth cylinder 36, a bidirectional electric push rod 11, a water spray hole 12, a connecting rod 13, and a side limit ring 14.

[0031] like Figure 2Among them, III is the collapsibility coefficient test device under natural conditions, IV is the anchoring part of the collapsibility coefficient test device, and V is the collapsibility coefficient test device under saturated conditions.

[0032] The support plate 9 is the main structure of the wetting coefficient testing device. The two arc-shaped support plates 9 are vertically arranged in a circular ring in the middle position of the wetting coefficient testing device. The fourth cylinder 36 and the bidirectional electric push rod 11 are located in the center of the support plate 9. A connecting rod is arranged on both sides of the fourth cylinder 36 to connect with the support plate 9.

[0033] The upper and lower output shafts of the bidirectional electric push rod 11 are connected to a flange. Figure 7 As shown, the bidirectional electric push rod 11 is the power core and adopts a retractable structure to drive the two loading units of the upper natural condition sample and the lower submerged sample respectively.

[0034] The upper loading unit and the lower loading unit have the same structure, both of which are provided with a pressure plate 10 and a side limit ring 14. The pressure plate 10 is set on the disc, and the flange and the disc are connected by a connecting rod. The connection between the connecting rod and the disc is provided with a radial guide rail and a radial inclined guide rail.

[0035] The pressure plate 10 is composed of a plurality of large expansion plates 101 and a plurality of small expansion plates 102 staggered together. The large expansion plates 101 are slidably connected to the radial guide rail, and the small expansion plates 102 are slidably connected to the radial inclined guide rail. After the plurality of large expansion plates 101 and the plurality of small expansion plates 102 are retracted, the small expansion plates 102 are located above the large expansion plates 101. A small diameter circle is formed between the plurality of large expansion plates 101, and a small diameter circle is formed between the small expansion plates 102. After the plurality of large expansion plates 101 and the plurality of small expansion plates 102 are expanded, they are staggered to form a disc structure.

[0036] A second cylinder 34 and a third cylinder 35 are provided between the pressure plate and the flange. The large expansion plate 101 and the small expansion plate 102 are controlled by the second cylinder 34 and the third cylinder 35 driving the connecting rod mechanism up and down respectively. When the output shafts of the second cylinder 34 and the third cylinder 35 are extended, the connecting rod mechanism drives the large expansion plate 101 to extend along the radial guide rail, and a gap is generated between adjacent large expansion plates 101. The connecting rod mechanism drives the small expansion plate 102 to extend along the radial inclined guide rail, and the small expansion plate 102 extends between the adjacent large expansion plates 101, and the large expansion plate 101 and the small expansion plate 102 form a large diameter circle.

[0037] After the collapsibility coefficient testing device is placed in the hole, the large expansion plate 101 and the small expansion plate 102 are expanded and extended into the upper and lower soil sample grooves to be tested. The pressure plate 10 located in the upper soil sample groove to be tested is pressed against the top of the upper soil sample groove to be tested, and the top of the upper soil sample groove to be tested is the upper sample. The pressure plate 10 located in the lower soil sample groove to be tested is pressed against the bottom of the lower soil sample groove to be tested, and the bottom of the lower soil sample groove to be tested is the lower sample.

[0038] The side limit rings 14 are arranged at the top of the upper loading unit and the bottom of the lower loading unit. The side limit rings 14 are located outside the two soil sample grooves to prevent the soil samples from becoming unstable due to lateral deformation during the loading process.

[0039] The water spray holes 12 are radially arranged on the large expansion plate 101 and are used to uniformly inject water into the lower soil sample, thereby achieving annular water seepage, saturating the soil sample and effectively accelerating the saturation speed of the sample.

[0040] After the collapsibility tester is lowered to the test position, the fourth cylinder 36 deploys the support plate 9, which is then anchored to the hole wall. Subsequently, the second cylinders 34 and 35 sequentially deploy the large and small deployment plates 101 and 102, forming a complete enclosure and loading surface for the specimen.

[0041] Displacement sensors are provided on the top of the upper loading unit and the bottom of the lower loading unit.

[0042] The in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method includes the following steps when performing the in-hole in-situ loess collapsibility coefficient test: Step 1: clean the test site and select the drilling location, and use the drill rod to drill to the predetermined depth to obtain the borehole; Step 2: The in-hole cutting device is hoisted to the test position by a rope, and the first cylinder 3 is inflated to expand the support rod 4 to provide anchoring force to fix the in-hole cutting device in the hole.

[0043] Step 3: After fixing the in-hole cutting device, start the first motor 61 and the second motor 62, extend the knife to cut the soil sample groove to be tested while rotating the conductive ring 5 to form the soil sample groove to be tested, repeat the operation at a suitable position below the first soil sample groove to be tested to obtain the second soil sample groove to be tested.

[0044] Step 4: After the two soil sample grooves to be tested are cut, the cutting device in the hole is retracted.

[0045] Step 5: Use a rope to place the collapsible coefficient test device to the position of the soil sample groove to be tested. Use the fourth cylinder 36 to unfold the support plate 9 to provide sufficient anchoring force to fix the collapsible coefficient test device in the test position.

[0046] Step 6: Use the second cylinder 34 and the third cylinder 35 to unfold the large unfolding plate 101 and the small unfolding plate 102 at the top of the upper loading unit and the bottom of the lower loading unit.

[0047] Step 7: Continue to inject water at a constant flow rate to the bottom of the lower loading unit through the water spray hole 12 to soak the lower sample and observe the water level. When the water in the borehole cannot penetrate into it, the test soil layer is considered to be saturated.

[0048] Step 8: Apply a certain pressure with the bidirectional electric push rod until the vertical displacement of the sample at the pressure plate 10 changes by less than 0.10 mm in two consecutive hours. The deformation is considered stable and the vertical displacement is recorded as s. z and s z ',like Figure 9 As shown, the vertical displacement is measured by displacement sensors at the top of the upper loading unit and the bottom of the lower loading unit.

[0049] Step 9: Continue to control the bidirectional electric push rod and apply the next level of pressure until the vertical displacement of the specimen at the upper and lower expansion plate positions changes by less than 0.10 mm in two consecutive hours. The deformation is considered stable and the vertical displacement is recorded as s. z1 and s z1 ',like Figure 9 shown.

[0050] Step 10: Calculate the vertical loess collapsibility coefficient under each level of pressure:

[0051] Where: is the vertical loess collapsibility coefficient, It is the height of the sample after the saturated deformation is stable under a certain pressure level. It is the height of the sample after its natural deformation stabilizes under a certain level of pressure.

[0052] The serial numbers of the above embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0053] In the above embodiments of the present application, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0054] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only exemplary. For example, the division of the units can be a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0055] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0056] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

[0057] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this patent should not be determined with reference to the above description, but rather with reference to the preceding claims and the full scope of equivalents to which such claims are entitled. For the purpose of completeness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein from the preceding claims is not a disclaimer of such subject matter, nor should it be considered that the applicants did not consider such subject matter to be part of the disclosed inventive subject matter.

Claims

1. An in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method, characterized in that: Including in-hole cutting device and collapsibility coefficient testing device; The in-hole cutting device comprises a cross plate (2), a first cylinder (3), a first motor (61), a conductive ring (5), a second motor (62) and a cutter head (7) connected in sequence from top to bottom; multiple side surfaces of the first cylinder (3) are provided with support rods (4), the support rods (4) correspond to the positions of the output ends of the first cylinder (3), the conductive ring (5) is connected to the first motor (61), and the output shaft of the second motor (62) is connected to the cutter head (7); The collapsible coefficient testing device comprises a support plate (9), a fourth cylinder (36), a bidirectional electric push rod (11) and a pressure plate (10); the two support plates (9) are arranged vertically in a circular ring, the fourth cylinder (36) and the bidirectional electric push rod (11) are located in the middle of the support plate (9), the output ends on both sides of the fourth cylinder (36) are respectively connected to the support plate (9), the upper and lower output shafts of the bidirectional electric push rod (11) are respectively connected to an upper loading unit and a lower loading unit with the same structure, the top of the upper loading unit and the bottom of the lower loading unit are both provided with a radially expandable pressure plate (10), and a plurality of radial water spray holes (12) are provided on the pressure plate (10) located in the lower loading unit.

2. The in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method according to claim 1, characterized in that: The top of the cross plate (2) is connected with a lifting ring (1).

3. The in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method according to claim 1, characterized in that: The support rod (4) has an L-shaped structure, with a short side slidably connected to the top of the first cylinder (3), and a long side located to the side of the first cylinder (3). The side of the first cylinder (3) is provided with a plurality of blowing ports facing the long side of the support rod (4).

4. The in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method according to claim 1, characterized in that: The top of the conductive ring (5) is connected to the first motor (61) via a disc, and the cross plate (2) is connected to the disc via two connecting rods.

5. The in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method according to claim 1, characterized in that: The output shaft of the second motor (62) is vertically connected to the gear (8) downward, and the gear (8) is engaged with two horizontal racks, and a cutter head (7) is provided at the end of each rack.

6. The in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method according to claim 1, characterized in that: The two output shafts of the bidirectional electric push rod (11) are both connected to a flange, the pressure plate (10) is arranged on the disc, the flange and the disc are connected by a connecting rod, and a radial guide rail and a radial inclined guide rail are arranged at the connection between the connecting rod and the disc; Each pressure plate (10) is composed of a plurality of large expansion plates (101) and a plurality of small expansion plates (102) staggered together, the plurality of large expansion plates (101) being slidably arranged along radial guide rails, and the plurality of small expansion plates (102) being slidably arranged along radial inclined guide rails.

7. The in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method according to claim 6, characterized in that: A second cylinder (34) and a third cylinder (35) are provided between the pressure plate (10) and the flange. The second cylinder (34) is connected to the plurality of large expansion plates (101) via a connecting rod mechanism, and the third cylinder (35) is connected to the plurality of small expansion plates (102) via a connecting rod mechanism.

8. The in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method according to claim 6, characterized in that: The water spray holes (12) are evenly distributed around the circumference, and the plurality of water spray holes (12) are arranged in an annular manner at equal intervals along the large expansion plate (101).

9. The in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method according to claim 1, characterized in that: The top of the upper loading unit and the bottom of the lower loading unit are respectively provided with displacement sensors for acquiring displacement data.

10. A method for testing the in-hole in-situ loess collapsibility coefficient based on the in-hole in-situ loess collapsibility coefficient testing device based on the cutting load method according to any one of claims 1 to 9, characterized in that: The steps include: Step 1: Select a drilling location on the ground and drill a hole; Step 2: lower the in-hole cutting device to the target depth, and deploy the support rod (4) via the first cylinder (3) to anchor the in-hole cutting device; Step 3, starting the first motor (61) to drive the conductive ring (5) to rotate, and the second motor (62) drives the cutter head (7) to cut and form the upper and lower soil sample grooves to be tested, and retracting the cutting device in the hole; Step 4, lower the collapsibility coefficient test device to the soil sample trough, and unfold the support plate (9) via the fourth cylinder (36); Step 5, unfold the pressure plate (10); Step 6, injecting water into the sample through the water spray hole (12); Step 7, using a bidirectional electric push rod (11) to apply pressure step by step, and record the vertical displacement of the upper and lower samples at each pressure level; Step 8: Calculate the vertical collapsibility coefficient of loess under each level of pressure.

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