Multi-angle rotating extra-high core wall dam gravel-doped clay tensile-fracture test device

Abstract

The invention discloses a multi-angle rotating ultra-high core wall dam gravel-doped clay tensile-fracture test device which comprises a mold assembly, two groups of adjusting assemblies and two groups of loading assemblies, a dumbbell-shaped cavity is formed in the mold assembly body and is used for preparing and bearing a test soil test piece; the two sets of adjusting assembly bodies are distributed on the two sides of the mold assembly body in a central symmetry mode, each adjusting assembly body comprises a rotatable semicircular disc and a semicircular disc track, the rotatable semicircular discs are coaxially embedded in the inner sides of the semicircular disc tracks, and the semicircular disc tracks are movably connected with the rotatable semicircular discs; and the end part of the mold assembly body is embedded into the inner side of the semicircular disc track and is detachably connected through a mold fixing bolt. The front loading assembly, the front assembly body, the rear loading assembly, the rear assembly body and the mold assembly body are used in cooperation, the operation process is convenient and rapid, the device can be suitable for a uniaxial tensile test, a tensile fracture test, a shear fracture test, a tension-shear fracture test and a compression-shear fracture test at the same time, and the application range is remarkably widened.

Description

Technical Field

[0001] This invention relates to the field of geotechnical testing technology, and in particular to a tensile-fracture testing device for gravelly clay mixed with ultra-high core wall dams that rotates at multiple angles. Background Technology

[0002] With the increasing number of earth-rock dams, dam body cracks have gradually become one of the more common safety hazards in earth-rock dam projects. These cracks can be divided into shell cracks and core wall cracks, encompassing longitudinal cracks on the dam crest, transverse cracks on both banks, and hydraulic splitting cracks in the core wall. Core wall cracks can seriously affect the integrity of the core wall and reduce its seepage resistance. Earth-core rockfill dams such as Infiernillo (148.0m) in Mexico, La Grande 2 (156.0m) in Canada, Cougar (158.0m) in the United States, Masjed E. Leyman (177.0m) in Iran, and Maoergai (147.0m) in my country all experienced relatively serious core wall cracks within a short period of water impoundment. Hydraulic splitting cracks in the core wall, once penetrating the entire core, can create seepage channels, threatening the safety of the project. For example, approximately seven years after the first impoundment of water, seepage channels appeared at the bottom of the earthen core wall of Iran's Bidvaz earthen core dam (66.0m high); Norway's Hyttejuvet narrow-core rockfill dam (93.0m high) developed hydraulic splitting cracks that ran through the entire core wall during impoundment; and the Teton Dam in the United States collapsed due to hydraulic splitting cracks. In investigations of approximately 1300 accidents involving about 270 large reservoirs in my country, about 39% of earth-rock dams experienced accidents due to cracking issues. Statistics show that cracking problems existed in all types of earth-rock dams—low, medium, high, and extra-high—during 1-10 years of operation after construction. These findings demonstrate the prevalence and severity of soil cracking problems in earth-rock dam projects both domestically and internationally, especially since cracks in the earthen core wall directly affect the success or failure of the project and must be given sufficient attention.

[0003] Therefore, although my country's current theory and technology for constructing high earth-core dams are relatively mature, the problem of dam body cracking still exists, such as the core wall cracks in the Maergai earth-core dam. The essence of core wall cracking is shear failure, tensile failure, or a combination of shear and tensile failure that occurs when the stress and strain borne by the soil exceeds its tensile or shear strength. Meanwhile, gravelly clay is the main material for ultra-high core dams, and studying the tensile and fracture characteristics of gravelly clay is of great significance for the construction of ultra-high core dams. Therefore, it is necessary to develop an experimental device that can comprehensively study the tensile-fracture characteristics of gravelly clay.

[0004] Existing testing equipment is generally limited to measuring tensile strength and fracture toughness at fixed angles. When the tensile direction is consistent with the length direction of the test soil specimen, uniaxial tensile strength and tensile fracture toughness can be measured. When the tensile direction is perpendicular to the test soil specimen, shear fracture toughness can be measured, but compression-shear and tension-shear fracture toughness cannot be measured.

[0005] Therefore, it is necessary to study a multi-angle rotating tensile-fracture test device for gravelly clay in ultra-high core wall dams. This device can be used to conduct tensile strength tests as well as fracture toughness tests, and to measure the compressive-shear and tensile-shear fracture toughness at each angle within the range of 0 to 90°, so as to improve the research on the fracture characteristics of gravelly clay under the influence of loading forces in different directions. Summary of the Invention

[0006] To address the aforementioned shortcomings, this invention provides a multi-angle rotating tensile-fracture testing device for gravelly clay in ultra-high core wall dams. This device can simultaneously measure the fracture characteristics and uniaxial tensile characteristics of the soil. When the length direction of the test soil specimen is 0° relative to the loading direction, uniaxial tensile tests and opening fracture (Type I fracture) tests can be performed on the test soil specimen. When the length direction of the test soil specimen is within the range of 0 to 90° relative to the loading direction, slip fracture (Type II fracture), tear fracture (Type III fracture or tensile shear fracture), and compression shear fracture tests can be performed on the test soil specimen, thus overcoming the deficiencies mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A multi-angle rotating tensile-fracture test device for gravelly clay-filled ultra-high core wall dams includes a mold assembly, two sets of adjustment assemblies, and two sets of loading components. The mold assembly has a dumbbell-shaped cavity inside, which is used to prepare and support the test soil specimens; Two sets of adjustment assemblies are centrally symmetrically distributed on both sides of the mold assembly. The adjustment assembly includes a rotatable semi-disc and a semi-disc track. The rotatable semi-disc is coaxially embedded in the inner side of the semi-disc track, and the semi-disc track is movably connected to the rotatable semi-disc. The end of the mold assembly is embedded in the inner side of the semi-disc track and is detachably connected by a mold fixing bolt. Two sets of loading components are symmetrically distributed on both sides of the mold assembly. The loading components include left and right sliding rods, square short sliding arms, front and rear sliding rods, square control arms and control arm bases. The top of the control arm base is provided with a control arm groove. The square control arm slides in the inner side of the control arm groove, and a drive unit is provided in the control arm groove. The top of the square short sliding arm overlaps with the outer end of the semi-circular track's large arm. The bottom of the square short sliding arm overlaps with the top of the square control arm. The left and right sliding rods pass through the large arm of the track and the square short sliding arm. The front and rear sliding rods pass through the square short sliding arm and the control arm. The left and right sliding rods are perpendicular to the front and rear sliding rods. The semi-circular track and the square short sliding arm are both slidably engaged with the left and right sliding rods. The square short sliding arm and the square control arm are both slidably engaged with the front and rear sliding rods. An electric lock is installed inside the main arm of the track, the square short sliding arm and the square control arm. The locking pin of the electric lock is movably engaged with the outside of the left and right sliding rods or the front and rear sliding rods.

[0008] Preferably, the rotatable semi-disc is configured as a semi-circular disc structure, and the outer end of the arc side of the rotatable semi-disc matches the inner end of the arc side of the semi-disc track. A rotatable semi-disc insert ball is embedded in the outer end of the arc side of the rotatable semi-disc, a semi-disc fixing hole is opened at the outer end of the upper surface of the rotatable semi-disc, and a semi-disc locking hole is opened at the inner end of the upper surface of the rotatable semi-disc.

[0009] Preferably, the semi-circular track is a quarter-circle arc track structure, and a disc track slide is provided at the inner end of the arc of the semi-circular track. The disc track slide is set as an arc-shaped tubular "C"-shaped track. The outer end of the arc of the rotatable semi-circular disk is embedded in the disc track slide, and the inner diameter of the "C"-shaped track is adapted to the outer diameter of the ball embedded in the semi-circular disk, so that the ball embedded in the semi-circular disk slides in the disc track slide. The through holes at the end of the large arm of the disc track corresponding to the left and right sliding rods are set as disc track sliding holes. The upper end of the semi-circular disc track is provided with a disc track locking hole. Multiple diamond-shaped holes are linearly arrayed inside the disc track locking hole, and a disc track pin is movably inserted into the diamond-shaped hole. The outer diameter of the disc track pin matches the inner diameter of the fixed hole of the semi-circular disc.

[0010] Preferably, the mold assembly includes a mold fixing bolt, a front loading mold, a rear loading mold, a mold semi-clamp, a mold semi-circular groove, a side connecting wing plate, a mold middle bottom plate, and a mold template plate. The mold fixing bolt is a flat-headed stud with threads and a cross-shaped cutter. The front loading mold and the rear loading mold have an axisymmetrically distributed groove structure. Mold semi-clamps are provided on the outer sides of both the front loading mold and the rear loading mold. Mold semi-circular grooves are provided on opposite sides of the front loading mold and the rear loading mold. A side connecting wing plate is detachably installed between two opposite mold semi-circular grooves. A mold middle bottom plate is located at the bottom center of the mold assembly. Mold semi-clamps are also provided on the sides of the side connecting wing plate and the mold middle bottom plate. A mold template plate is located at the top of the mold assembly.

[0011] Preferably, the side connecting wing plate includes a wing plate vertical cylinder, a wing plate vertical cylinder hole, a wing plate long bolt, and a wing plate seam plate. The wing plate vertical cylinder is provided on both the front and rear sides of the side connecting wing plate. The wing plate vertical cylinder matches the inner diameter of the mold semi-circular groove. The wing plate vertical cylinder has a wing plate vertical cylinder hole, and the wing plate long bolt is threaded into the wing plate vertical cylinder hole.

[0012] Preferably, a T-shaped groove is provided on one side of the side connecting wing plate, and a wing plate seam plate is movably inserted into the T-shaped groove, wherein the outer diameter of the wing plate seam plate matches the inner diameter of the T-shaped groove.

[0013] Preferably, one end of the wing plate seam plate is flush with the outer wall of the side connecting wing plate, and the two sides of the mold template plate that matches the internal cavity of the mold assembly are set to be closed.

[0014] Preferably, one end of the wing plate seam plate extends to connect to the outer wall of the wing plate, and the mold template plate that matches the internal cavity of the mold assembly has slots reserved on both sides, and the slots match the ends of the wing plate seam plate.

[0015] Preferably, the number of semi-disc embedded balls on each rotatable semi-disc is set to five, and when the rotatable semi-disc is rotated, at least two semi-disc embedded balls are located in the disk track slide rail; The number of fixed holes on each rotatable semi-disc is set to six, and the multiple fixed holes on the semi-disc are spaced apart from the multiple semi-disc embedded balls.

[0016] Preferably, the number of semi-disc locking holes on each semi-disc track is set to four, corresponding one-to-one with the mold semi-clamps that need to be inserted into the rotatable semi-disc; The number of diamond-shaped holes on each rotatable semicircular disk is set to ninety. Multiple diamond-shaped holes are connected end to end and stacked in sequence, so that the mold assembly can be adjusted at any angle within the range of 1 to 90°.

[0017] The present invention has the following beneficial effects: This testing apparatus, consisting of a front loading component, a front assembly, a rear loading component, a rear assembly, and a mold assembly, is easy and quick to operate. Using this apparatus, uniaxial tensile and fracture tests on soil specimens can be performed simultaneously. The angle between the loading force and the soil specimen is used as the testing factor, allowing testing of soil specimens at each angle within the range of 0 to 90°. When performing uniaxial tensile tests, the soil specimen is seamless and a single piece. When performing tensile fracture, shear fracture, tension-shear, and compression-shear fracture tests, the soil specimen has pre-fabricated seams on one or both sides. Uniaxial tensile and tensile fracture tests can be performed when the loading force is at 0° to the soil specimen; shear fracture tests can be performed when the loading force is at 90°; and tension-shear and compression-shear fracture tests can be performed when the loading force is at 1–89°. This significantly expands the applicability of the apparatus. Attached Figure Description

[0018] Figure 1 A three-dimensional view of the overall structure of the experimental device (in its combined state) provided by the present invention.

[0019] Figure 2 This is a schematic diagram of the distribution structure of the two sets of rotatable semi-discs and semi-disc tracks in this invention.

[0020] Figure 3 This is a schematic diagram of the mold assembly in this invention.

[0021] Figure 4 A schematic diagram of the mold assembly of the experimental device provided by the present invention.

[0022] Figure 5 This is a schematic diagram of the structure of the middle connecting wing plate provided in Embodiment 1 of the present invention.

[0023] Figure 6 This is a schematic diagram of the structure of the middle connecting wing plate provided in Embodiment 2 of the present invention.

[0024] Figure 7 This is a schematic diagram of the structure of the mold template (seamless) provided in Embodiment 1 of the present invention.

[0025] Figure 8 This is a schematic diagram of the mold template (with seams) provided in Embodiment 2 of the present invention.

[0026] Figure 9 A schematic diagram of the loading force and uniaxial tensile test of the test soil specimen (at an angle of 0°) is shown.

[0027] Figure 10 A schematic diagram of a tensile fracture test of a soil specimen (at an angle of 0°) under applied force is shown.

[0028] Figure 11 A schematic diagram of the shear fracture test of the soil specimen (at an angle of 90°) under load is shown.

[0029] Figure 12 The diagram shows the load applied to the tensile-shear or compression-shear fracture test of the soil specimen (at an angle of 75°).

[0030] Figure 13 The diagram shows the loading force and the tensile-shear or compression-shear fracture test of the test soil specimen (at an angle of 60°).

[0031] Figure 14 The diagram shows the loading force and the tensile-shear or compression-shear fracture test of the test soil specimen (at an angle of 45°).

[0032] Figure 15 The diagram shows the load applied to the tensile-shear or compression-shear fracture test of the soil specimen (at an angle of 30°).

[0033] Figure 16The diagram shows the load applied to the tensile-shear or compression-shear fracture test of the soil specimen (at an angle of 15°).

[0034] Figure 17 A schematic diagram illustrating the process of using the experimental apparatus provided by this invention for conducting experiments.

[0035] In the picture: 1. Rotatable semi-circular disk; 11. Semi-circular disk with embedded ball; 12. Semi-circular disk with fixed hole; 13. Semi-circular disk with locking hole; 2. Semi-circular track; 21. Track sliding hole; 22. Track boom; 23. Track slide rail; 24. Track locking hole; 25. Track pin; 3. Mold assembly; 31. Mold fixing bolt; 32. Front loading mold; 33. Rear loading mold; 34. Mold semi-clamp; 35. Mold semi-circular groove; 36. Side connecting wing plate; 361. Wing plate vertical cylinder; 362. Wing plate vertical cylinder hole; 363. Wing plate long bolt; 364. Wing plate seam plate; 37. Mold base plate; 38. Mold template; 4. Test soil specimen; 5. Left and right sliding rods; 6. Square short sliding arm; 7. Front and rear sliding rods; 8. Square control arm; 9. Control arm groove; 10. Control arm base. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0037] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0038] like Figures 1 to 4 As shown, a multi-angle rotating tensile-fracture test apparatus for ultra-high core wall dams with gravel-mixed clay includes... The mold assembly 3 has a dumbbell-shaped cavity inside for preparing and supporting the test soil specimen 4. As a mold for making the test soil specimen 4, the test soil specimen 4 can be made by means of compaction or static compaction. In the embodiments provided in this application, the mold assembly 3 is a cuboid alloy structure with a square overall exterior. The prepared test soil specimen 4 can be with prefabricated seams or without prefabricated seams.

[0039] Two adjustment assemblies are provided, symmetrically distributed on both sides of the mold assembly 3. Each adjustment assembly includes a rotatable semi-circular disk 1 and a semi-circular disk track 2. The rotatable semi-circular disk 1 is coaxially embedded inside the semi-circular disk track 2, and the semi-circular disk track 2 is movably connected to the rotatable semi-circular disk 1. The overall adjustment assembly has a semi-circular structure. Rotating the rotatable semi-circular disk 1 along the inner arc trajectory of the semi-circular disk track 2 can change the loading force and the angle of the test soil specimen 4 during the test. The end of the mold assembly 3 is embedded inside the semi-circular disk track 2 and is detachably connected by a mold fixing bolt 31. A groove is opened on the inner side of the semi-circular disk track 2, and the inner diameter of the groove matches the outer diameter of the end of the mold assembly 3.

[0040] Two loading components are provided, symmetrically distributed on both sides of the mold assembly 3. Each loading component includes left and right sliding rods 5, a square short sliding arm 6, a front and rear sliding rod 7, a square control arm 8, and a control arm base 10. The top of the control arm base 10 has a control arm groove 9, and the square control arm 8 slides within the control arm groove 9. A drive unit is provided within the control arm groove 9, allowing the square control arm 8 to move along the length of the control arm groove 9. The drive unit can be a linear motor, with its moving slide connected to the control arm base 10. When the linear motor is working, it drives the square control arm 8; when the linear motor is not working, the square control arm 8 is self-locking. The top of the square short sliding arm 6 overlaps with the outer end of the circular arc of the semi-circular track 2, and the bottom of the square short sliding arm 6 overlaps with the top of the square control arm 8. The left and right sliding rods 5 pass through the track arm 22 and the square short sliding arm 6, and the front and rear sliding rods 7 pass through the square short sliding arm 6 and the square control arm 8. The left and right sliding rods 5 and the front and rear sliding rods 7 are arranged perpendicularly. The two sets of loading components jointly connect and support the connection structure of the two sets of adjustment assemblies and the mold assembly 3, and adjust the position of the two sets of adjustment assemblies. In the embodiment provided in this application, the track arm 22 is a cubic columnar structure; the square short sliding arm 6 and the square control arm 8 are both cuboid beam structures; the left and right sliding rods 5 and the front and rear sliding rods 7 are cylindrical aluminum alloy rod structures with a length of 200 mm and a diameter of 20 mm.

[0041] The semi-circular track 2 and the square short sliding arm 6 are both slidably engaged with the left and right sliding rods 5. The square short sliding arm 6 and the square control arm 8 are both slidably engaged with the front and rear sliding rods 7. An electric lock is installed inside the main arm 22 of the track, the square short sliding arm 6, and the square control arm 8. The locking pin of the electric lock is movably engaged with the outside of the left and right sliding rods 5 or the front and rear sliding rods 7. The electric lock is used to fix the relative positions of the semi-circular track 2, the square short sliding arm 6, and the square control arm 8 when they are adjusted to the appropriate position. Specifically, by controlling the retraction of the locking pin of the electric lock at the top of the square short sliding arm 6, the inner diameter of the through hole at the end of the square short sliding arm 6 is enlarged, allowing the square short sliding arm 6 to slide left and right along the left and right sliding rods 5. Similarly, by controlling the retraction of the locking pin of the electric lock at the bottom of the square short sliding arm 6, the square short sliding arm 6 can slide back and forth along the front and rear sliding rods 7. By controlling the extension of the locking pins of multiple electric locks and abutting against the outer walls of the left and right sliding rods 5 and the front and rear sliding rods 7, the relative position of the square short sliding arm 6 with the left and right sliding rods 5 and the front and rear sliding rods 7 can be fixed. Likewise, after the square control arm 8 slides back and forth along the front and rear sliding rods 7, the relative position of the square control arm 8 with the front and rear sliding rods 7 can also be fixed by the electric lock.

[0042] Furthermore, in the above technical solution, the rotatable semi-circular disk 1 is configured as a semi-circular disc structure. The outer end of the arc side of the rotatable semi-circular disk 1 matches the inner end of the arc side of the semi-circular disk track 2. A rotatable semi-circular disk ball 11 is embedded in the outer end of the arc side of the rotatable semi-circular disk 1. A semi-circular disk fixing hole 12 is opened at the outer end of the upper surface of the rotatable semi-circular disk 1, and a semi-circular disk locking hole 13 is opened at the inner end of the upper surface of the rotatable semi-circular disk 1. In this embodiment, the number of semi-circular disk fixing holes 12 is set to multiple, and the multiple semi-circular disk fixing holes 12 are evenly distributed on the outer end of the arc side of the rotatable semi-circular disk 1. The semi-circular disk fixing holes 12 are diamond-shaped holes that do not penetrate at the lower end, and their inner diameter is adapted to the outer diameter of the disk track pin 25. After the rotatable semi-disc 1 slides to the target angle in the semi-disc track 2, the track pin 25 can pass through the track locking hole 24 and be inserted into the semi-disc fixing hole 12 to fix the relative position of the rotatable semi-disc 1 and the semi-disc track 2 and prevent them from sliding relative to each other. The semi-disc locking hole 13 is a square groove with its upper surface slightly lower than the upper surface of the rotatable semi-disc 1. The center of the groove has a circular threaded hole, the inner diameter of which is adapted to the outer diameter of the mold fixing bolt 31.

[0043] Furthermore, in the above technical solution, the semi-circular track 2 is a quarter-circular arc track structure. The inner end of the arc of the semi-circular track 2 is provided with a disc track slide 23. The disc track slide 23 is set as an arc-shaped tubular "C"-shaped track. The outer end of the arc of the rotatable semi-circular disk 1 is embedded in the disc track slide 23. The inner diameter of the "C"-shaped track is adapted to the outer diameter of the semi-circular disk embedded ball 11, so that the semi-circular disk embedded ball 11 slides in the disc track slide 23. Multiple semi-circular disk embedded balls 11 are evenly distributed on the outer end of the arc of the rotatable semi-circular disk 1, so that the semi-circular disk embedded balls 11 slide in the disc track slide 23, realizing that the loading force and the angle of the test soil specimen 4 can be arbitrarily changed within the range of 0~90°. The semi-circular embedded ball 11 is a smooth, rigid sphere with a diameter slightly larger than the thickness of the rotatable semi-circular disk 1. After being embedded in the rotatable semi-circular disk 1, the upper, lower, and outer ends of the arc of the rotatable semi-circular disk 1 are exposed, with the majority of it embedded inside the rotatable semi-circular disk 1, preventing it from falling out. The semi-circular embedded ball 11 can slide in the disk track slide rail 23, ensuring the stability of the semi-circular embedded ball 11 during its sliding process in the semi-circular disk track 2.

[0044] The end of the disc track arm 22, corresponding to the through hole of the left and right sliding rods 5, is set as a disc track sliding hole 21. When the left and right sliding rods 5 are inserted into the disc track sliding hole 21, the disc track arm 22 can slide along the length of the left and right sliding rods 5. The disc track arm 22 has a built-in electric lock, which can be adjusted by pressing a button when it slides to an appropriate position to fix the relative position of the two. The upper end of the semi-circular disc track 2 has a disc track locking hole 24. Multiple diamond-shaped holes are linearly arranged inside the disc track locking hole 24. Disc track pins 25 are movably inserted into the diamond-shaped holes. The outer diameter of the disc track pins 25 matches the inner diameter of the semi-circular disc fixed hole 12. The disc track pins 25 are set as diamond-shaped cylinders, and the inner diameter of each hole is adapted to the outer diameter of the disc track pins 25. When the rotatable semi-disc 1 slides to the target angle in the semi-disc track 2, the track pin 25 can pass through the track locking hole 24 and be inserted into the semi-disc fixing hole 12 to fix the relative position of the rotatable semi-disc 1 and the semi-disc track 2 and prevent them from sliding relative to each other.

[0045] Furthermore, in the above technical solution, the mold assembly 3 includes a mold fixing bolt 31, a front loading mold 32, a rear loading mold 33, a mold semi-clamp 34, a mold semi-circular groove 35, a side connecting wing plate 36, a mold middle bottom plate 37, and a mold template plate 38. The mold fixing bolt 31 is a flat-headed bolt with threads and a cross-shaped cutter. The front loading mold 32 and the rear loading mold 33 are axially symmetrically distributed groove structures. Mold semi-clamps 34 are provided on the outer sides of the front loading mold 32 and the rear loading mold 33. Mold semi-circular grooves 35 are opened on the opposite sides of the front loading mold 32 and the rear loading mold 33. A side connecting wing plate 36 is detachably installed between the two opposite mold semi-circular grooves 35. A mold middle bottom plate 37 is located at the bottom center of the mold assembly 3. Mold semi-clamps 34 are also provided on the sides of the side connecting wing plate 36 and the mold middle bottom plate 37. A mold template plate 38 is located at the top of the mold assembly 3.

[0046] The mold fixing bolt 31 can be screwed into the semi-circular disk locking hole 13 and the mold half-clamp 34, which can be connected to form the mold assembly 3 or to connect the mold assembly 3 and the rotatable semi-circular disk 1, fixing their relative positions. The mold half-clamp 34 is a square block with a circular threaded hole in the center, located on the outer perimeter of the front loading mold 32 and the rear loading mold 33, the side of the side connecting wing plate 36, and the side of the mold bottom plate 37. Its inner diameter is compatible with the outer diameter of the mold fixing bolt 31. The mold semi-circular groove 35 is a cylindrical groove with a built-in thread at the bottom, which can be used to initially fix the relative position of the side connecting wing plate 36 with the front loading mold 32 and the rear loading mold 33. The side connecting wing plate 36 is a rectangular high-strength plate structure that can connect the front loading mold 32, the rear loading mold 33, and the mold bottom plate 37, fixing their relative positions. The mold bottom plate 37 is a plate structure at the bottom center of the mold assembly 3, which can bear the weight of the middle part of the test soil specimen 4 during the sample preparation process. The mold template 38 slides into the inner cavity of the mold assembly 3.

[0047] The dimensions of the mold half-buckles 34 around the front loading mold 32 and the rear loading mold 33 are adapted to the semi-circular disc retaining holes 13, and they can be respectively inserted into the semi-circular disc retaining holes 13. The thickness is consistent with the depth of the groove in the semi-circular disc retaining hole 13, and the inner diameter is consistent with the outer diameter of the mold fixing bolt 31. When the mold half-buckles 34 are inserted into the semi-circular disc retaining holes 13, they can be tightly connected with a smooth surface without protrusions. The mold fixing bolt 31 is then screwed into the mold half-buckles 34 and the semi-circular disc retaining holes 13 from top to bottom to fix their relative positions.

[0048] The mold half-buckles 34 on the side of the side connecting wing plate 36 and the bottom plate 37 of the mold can overlap each other. The mold fixing bolts 31 are screwed into the mold half-buckles 34 of the side connecting wing plate 36 and the bottom plate 37 of the mold from top to bottom to fix the relative position of the side connecting wing plate 36 and the bottom plate 37 of the mold.

[0049] Furthermore, in the above technical solution, the side connecting wing plate 36 includes a wing plate vertical cylinder 361, a wing plate vertical cylinder hole 362, a wing plate long bolt 363, and a wing plate seam plate 364. The side connecting wing plate 36 has wing plate vertical cylinders 361 on both its front and rear sides. The wing plate vertical cylinder 361 matches the inner diameter of the mold semi-circular groove 35. The wing plate vertical cylinder 361 has a wing plate vertical cylinder hole 362, and the wing plate long bolt 363 is threaded into the wing plate vertical cylinder hole 362. The wing plate vertical cylinder hole 362 is a threaded hole with internal threads at the center of the wing plate vertical cylinder 361. The wing plate long bolt 363 is a slender screw, and its external threads are compatible with the threads of the wing plate vertical cylinder hole 362 and the internal threads of the mold semi-circular groove 35, used to fix the relative positions of the side connecting wing plate 36, the front loading mold 32, and the rear loading mold 33. After the wing plate vertical cylinder 361 is inserted into the semi-circular groove 35 of the mold, the long bolt 363 of the wing plate is screwed in from top to bottom, which can further fix the relative positions of the side connecting wing plate 36, the front loading mold 32 and the rear loading mold 33.

[0050] like Figures 1 to 6 As shown, a T-shaped groove is provided on one side of the side connecting wing plate 36, and a wing plate seam plate 364 is movably inserted into the T-shaped groove. The outer diameter of the wing plate seam plate 364 matches the inner diameter of the T-shaped groove. The side connecting wing plate 36 is a replaceable T-shaped structure, divided into two types: wing plate seam plates 364 that cannot be prefabricated and wing plate seam plates 364 that can be prefabricated. One end of the wing plate seam plate 364 that cannot be prefabricated is flush with the outer wall of the side connecting wing plate 36; one end of the wing plate seam plate 364 that can be prefabricated extends from the outer wall of the side connecting wing plate 36.

[0051] As one embodiment of the wing seam plate 364, such as Figure 5 and Figure 7 As shown, one end of the wing plate seam plate 364 is flush with the outer wall of the side connecting wing plate 36, and the mold template plate 38, which matches the internal cavity of the mold assembly 3, is closed on both sides. After the wing plate seam plate 364, which cannot be prefabricated, is inserted into the middle position of the side connecting wing plate 36, the inner side of the mold is flush with the inner side of the mold of the side connecting wing plate 36.

[0052] As another embodiment of the wing seam plate 364, such as Figure 6 and Figure 8 As shown, one end of the wing joint forming plate 364 extends out of the outer wall of the side connecting wing plate 36. The mold template 38, which matches the internal cavity of the mold assembly 3, has slots pre-reserved on both sides, and the slots match the end of the wing joint forming plate 364. After the wing joint forming plate 364, which can prepare prefabricated joints, is inserted into the middle position of the side connecting wing plate 36, a thin plate structure will protrude from the inner side of the mold, which facilitates the preparation of prefabricated joints on the side of the test soil specimen 4.

[0053] The mold template 38 matches the wing joint plate 364, and is also divided into two categories: those that can prepare precast joints and those that cannot. The mold template 38 that can prepare precast joints has gaps on both sides of the middle section, allowing the protruding thin plate structures on the sides of the wing joint plate 364 to pass through the middle sides of the mold template 38. The dimensions of the protruding thin plate structures on the sides of the wing joint plate 364 can be customized according to experimental needs, and they can appear unpaired, and can be replaced when studying the effects of different precast joint widths, different precast joint depths, and single / double-sided precast joints on the mechanical properties of gravelly clay.

[0054] In the embodiments provided in this application, the depth of the thin plate structure protruding from the side of the wing plate seam plate 364 is preferably 3mm and the thickness is preferably 3mm; correspondingly, the seam depth of the side of the mold template 38 is preferably 3.5mm and the thickness is preferably 3.5mm.

[0055] Furthermore, in the above technical solution, the number of semi-disc embedded balls 11 on each rotatable semi-disc 1 is set to five, and when the rotatable semi-disc 1 is rotated (i.e. at any adjustable angle), at least two semi-disc embedded balls 11 are located in the disk track slide rail 23.

[0056] The number of fixed holes 12 on each rotatable semi-disc 1 is set to six, and the multiple fixed holes 12 on the semi-discs are spaced apart from the multiple embedded balls 11 on the semi-discs.

[0057] Furthermore, in the above technical solution, the number of semi-disc locking holes 13 on each semi-disc track 2 is set to four, which correspond one-to-one with the mold semi-clamps 34 that need to be inserted into the rotatable semi-disc 1.

[0058] The number of diamond-shaped holes on each rotatable semicircular disk 1 is set to ninety. Multiple diamond-shaped holes are connected end to end and stacked, allowing the mold assembly 3 to be adjusted at any angle within the range of 1~90°. Figures 9 to 16 As shown, this invention provides schematic diagrams of embodiments for uniaxial tensile testing and fracture tests under several loading forces in different directions. Each hole corresponds to a rotatable semi-disc 1 rotating at an angle of 1°, allowing the loading force and the angle of the test soil specimen 4 to be arbitrarily selected within the range of 0~90°.

[0059] Specifically, during the uniaxial tensile test, the angle between the applied force and the test soil specimen 4 is 0°, the applied force moves in the opposite direction, and there are no prefabricated seams on both sides of the test soil specimen 4. The placement and rotation of the entire mold are as follows: Figure 9 As shown.

[0060] When conducting a tensile fracture test, the angle between the applied force and the test soil specimen 4 is 0°, the applied force moves in the opposite direction, and the test soil specimen 4 has prefabricated seams on both sides. The overall placement and rotation of the mold are as follows: Figure 10 As shown.

[0061] When conducting a shear fracture test, the applied force is at a 90° angle to the test soil specimen 4, and the applied forces move in opposite directions. The test soil specimen 4 has prefabricated seams on both sides. The overall placement and rotation of the mold are as follows: Figure 11 As shown.

[0062] When conducting a tensile-shear fracture test, the angle between the applied force and the test soil specimen 4 is 1~89°, the applied force moves in the opposite direction, and the test soil specimen 4 has prefabricated joints on both sides. Taking 75°, 60°, 45°, 30°, and 15° as examples, the placement and rotation positions of the entire mold are as follows: Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 As shown.

[0063] When conducting a compression-shear fracture test, the angle between the applied force and the test soil specimen 4 is 1~89°, the applied force moves in opposite directions, and there are pre-fabricated joints on both sides of the test soil specimen 4. Taking 75°, 60°, 45°, 30°, and 15° as examples, the placement and rotation positions of the entire mold are as follows: Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 As shown.

[0064] The testing apparatus provided by this invention can meet the requirements of uniaxial tensile testing, tensile fracture testing, shear fracture testing, tension-shear fracture testing, and compression-shear fracture testing, depending on actual needs.

[0065] like Figure 17 In the figure, the structural layout (a) shows the initial assembly of the two sets of loading components and the two sets of adjustment assemblies.

[0066] Structural layout (b) shows the state of sliding the rotatable semi-disc 1, adjusting it to the target angle, and fixing the rotatable semi-disc 1 and the semi-disc track 2 based on structural layout (a).

[0067] Structural layout (c) shows the state of the relative position of the mold assembly 3 (test soil specimen 4 without prefabricated joints) and the two sets of adjustment assemblies, based on structural layout (b), with fine-tuning of the two sets of loading components.

[0068] Structural layout (d) shows the state in which the mold assembly 3 is connected and fixed to the two sets of adjustment assemblies based on structural layout (c).

[0069] Structural layout (e) shows the state of removing the side connecting wing plates 36 on both sides of the mold assembly 3 and the bottom mold plate 37 at the bottom, based on structural layout (d).

[0070] Structural layout (f) shows the state of the test after opening the control arm base 10, setting all stress and displacement values ​​to zero, based on structural layout (e).

[0071] Structural layout (g) shows the state of the relative position of the mold assembly 3 (test soil specimen 4 with prefabricated joints) and the two sets of adjustment assemblies, based on structural layout (b), with fine-tuning of the two sets of loading components.

[0072] The structural layout (h) shows the state in which the mold assembly 3 is connected and fixed to the two sets of adjustment assemblies based on the structural layout (g).

[0073] Structural layout (i) shows the state after removing the side connecting wing plates 36 on both sides of the mold assembly 3 and the bottom mold plate 37 at the bottom, based on structural layout (h).

[0074] Structural layout (j) shows the state of the test after opening the control arm base 10, setting all stress and displacement values ​​to zero, based on structural layout (i).

[0075] S1. Plan the test conditions and generate the test plan table.

[0076] Using gravelly clay with a 30% gravel content as the research object, the corresponding optimum moisture content was 10.34%, and the maximum dry density was 2.16 g / cm³. 3 The effects of different types of loading forces, presence or absence of precast joints, precast joint depth, precast joint thickness, and the angle between the loading force and the length of the test soil specimen 4 on the mechanical properties of gravelly clay were investigated. The experimental scheme is shown in Table 1.

[0077] Table 1. Test Scheme for Gravel-Infused Clay with 30% Gravel Content Test Name Types of applied loading forces Precast joints Precast joint depth (mm) Precast joint thickness (mm) Angle (°) between the applied force and the length direction of the test soil specimen. Uniaxial tensile test pull none 0 0 0 Tensile fracture test pull Unilateral and bilateral 1、3、5 1、3、5 0 Shear fracture test pressure Unilateral and bilateral 1、3、5 1、3、5 90 Tension-shear fracture test pull Unilateral and bilateral 1、3、5 1、3、5 10、20、30、40、50、60、70、80 Compression-shear fracture test pressure Unilateral and bilateral 1、3、5 1、3、5 10、20、30、40、50、60、70、80 Furthermore, for the experimental factors in the table, in addition to using the given experimental levels, experimental levels can be added through interpolation and other methods. For example, the more levels there are of the precast joint depth, precast joint thickness, and angle between the loading force and the length direction of the test soil specimen 4, the more comprehensive the research conclusions can be obtained. However, the more levels there are, the more tests are required. Therefore, it is necessary to comprehensively consider factors such as the test cycle and test cost.

[0078] The depth of the precast joint to be studied can be increased to the following levels: 2mm, 4mm, etc.

[0079] The thickness of the precast joint to be studied can be increased to the following levels: 2mm, 4mm, etc.

[0080] The angle between the load to be studied and the length direction of the test soil specimen 4 can be increased to the following levels: 5°, 15°, 25°, 35°, 45°, 55°, 65°, 75°, 85°, etc.

[0081] Furthermore, each set of tests under each operating condition needs to be repeated three times in parallel. The results of the three parallel tests are then averaged. The difference between the parallel test data and the average value should be within 5% to ensure the accuracy of the results. If the difference between the parallel test data and the average value exceeds 5%, the data needs to be discarded and the corresponding parallel test needs to be added again.

[0082] S2, in Figure 17 (a) Initial assembly of two sets of loading components and two sets of adjustment assemblies. Place the control arm base 10 on a flat surface. Insert a square control arm 8 into the control arm slide groove 9 inside the front control arm base 10 and connect it to the drive unit inside the control arm slide groove 9. Assemble the square control arm 8, front and rear sliding rods 7, square short sliding arm 6, and left and right sliding rods 5 in the order of bottom to top, and initially fix the relative positions of the components. Connect the semi-circular track 2 to the left and right sliding rods 5, and insert the rotatable semi-circular disk 1 into the semi-circular track 2 to initially fix the relative positions of the components.

[0083] S3, in Figure 17 (b) Adjust the positions of the pre-loaded and post-loaded components.

[0084] Slide the rotatable semi-disc 1 and find the semi-disc fixed hole 12 through the disc track locking hole 24. After sliding to the target angle, pass the disc track pin 25 from top to bottom through the disc track locking hole 24 and the semi-disc fixed hole 12 to fix the relative position of the rotatable semi-disc 1 and the semi-disc track 2.

[0085] Furthermore, when conducting different tests, the target relative angle between the rotatable semi-circular disk 1 and the semi-circular disk track 2, whether the test soil specimen 4 has a precast joint, and the direction of the loading force are all different, as detailed below: (1) When performing a uniaxial tensile test, the angle between the loading force and the test soil specimen 4 is 0°, that is, the rotatable semi-disc 1 is slid so that the semi-disc embedded ball 11 at the central axis of the rotatable semi-disc 1 and the length direction of the disk track arm 22 are in a straight line. At this time, the loading force moves in the opposite direction, and there are no prefabricated joints on both sides of the test soil specimen 4.

[0086] (2) When performing a tensile fracture test, the angle between the loading force and the test soil specimen 4 is 0°, i.e., the rotatable semi-disc 1 is slid so that the central axis of the rotatable semi-disc 1 and the length direction of the disk track arm 22 are in a straight line. At this time, the loading force moves in the opposite direction, and there are prefabricated joints on both sides of the test soil specimen 4.

[0087] (3) When conducting a shear fracture test, the angle between the applied force and the test soil specimen 4 is 90°. This means that, based on the fact that the central axis of the rotatable semi-disc 1 is aligned with the length direction of the disk track arm 22, the rotatable semi-disc 1 is slid clockwise, causing its central axis to rotate 90° clockwise and become perpendicular to the length direction of the disk track arm 22. At this time, the applied forces move in opposite directions, and there are prefabricated joints on both sides of the test soil specimen 4.

[0088] (4) When conducting a tensile-shear fracture test, the angle between the applied force and the test soil specimen 4 is 1~89°. This means that, based on the central axis of the rotatable semi-circular disk 1 being aligned with the length direction of the disk track arm 22, the rotatable semi-circular disk 1 is slid clockwise, causing its central axis to rotate clockwise by 1~89°, forming an acute angle with the length direction of the disk track arm 22. At this time, the applied force moves in the opposite direction, and there are prefabricated joints on both sides of the test soil specimen 4.

[0089] (5) When conducting a compression-shear fracture test, the angle between the applied force and the test soil specimen 4 is 1~89°. This means that, based on the central axis of the rotatable semi-circular disk 1 being aligned with the length direction of the disk track arm 22, the rotatable semi-circular disk 1 is slid clockwise, causing its central axis to rotate clockwise by 1~89°, forming an acute angle with the length direction of the disk track arm 22. At this time, the applied forces move in opposite directions, and there are prefabricated joints on both sides of the test soil specimen 4.

[0090] S4. Before the test, assemble the mold assembly 3 and prepare the test soil specimen 4.

[0091] Assemble mold assembly 3: Place the front loading mold 32, the mold base plate 37, and the rear loading mold 33 on the ground in front-to-back order. Insert the front and rear wing plate vertical cylinders 361 of the side connecting wing plates 36 into the mold semi-circular grooves 35 on the front loading mold 32 and the rear loading mold 33 respectively for initial fixation. Then, screw the wing plate long bolts 363 into the wing plate vertical cylinder holes 362 on the four wing plate vertical cylinders 361 respectively to fix the front loading mold 32, the two left and right side connecting wing plates 36, and the rear loading mold 33. Screw the mold fixing bolts 31 from top to bottom into the mold semi-clamps 34 on the side of the side connecting wing plates 36 and the mold semi-clamps 34 on the side of the mold base plate 37 to fix the two side connecting wing plates 36 and the mold base plate 37.

[0092] Selecting a suitable flange seam plate 364: Based on the test conditions selected in the test plan table, select a suitable flange seam plate 364 and insert it into the T-shaped space in the middle of the side connecting flange 36. There are two types of flange seam plates 364 available: flange seam plates 364 that cannot be prefabricated and flange seam plates 364 that can be prefabricated. The former has no thin plate structure on the side, while the latter has a thin plate structure protruding from the side. The latter with a thin plate structure protruding from the side has various options in terms of depth and thickness.

[0093] Furthermore, different flange joint plates 364 need to be selected for different test types. When a uniaxial tensile test of gravelly clay is required, two flange joint plates 364 that cannot be prefabricated can be selected; when tensile, shear, tension-shear, and compression-shear fracture tests of gravelly clay are required, two flange joint plates 364 that can be prefabricated or one flange joint plate 364 that cannot be prefabricated and one flange joint plate 364 that can be prefabricated can be selected. Furthermore, the side connecting wing plate 36 can have a thin plate structure protruding from the side, with a depth of 1mm, 2mm, 3mm, 4mm, or 5mm and a thickness of 1mm, 2mm, 3mm, 4mm, or 5mm.

[0094] Preparation of test soil specimen 4: Based on the selected type of side connecting wing plate 36, select a suitable mold to make sample plate 38 and prepare test soil specimen 4 in layers.

[0095] Furthermore, before preparing the test soil specimen 4, lubricating oil needs to be applied to the inside of the mold assembly 3 to ensure that the side connecting wing plate 36 and the bottom plate 37 of the mold can be removed smoothly, and to reduce disturbance to the test soil specimen 4.

[0096] Select a mold template 38 that matches the cross-section of the inner cavity of the mold assembly 3, compact the gravelly clay, and form a test soil specimen 4.

[0097] Furthermore, different molds 38 need to be selected for different test types. When a uniaxial tensile test of gravelly clay is required, a mold 38 with no gaps on both sides of the middle can be selected; when tensile, shear, tension-shear, and compression-shear fracture tests of gravelly clay are required, a mold 38 with gaps on both sides of the middle can be selected, or a mold 38 with no gaps on one side of the middle and a gap on the other side can be selected.

[0098] Furthermore, the depth of the side gap in the middle of the mold template 38 can be 1.5mm, 2.5mm, 3.5mm, 4.5mm, or 5.5mm, and the thickness can be 1.5mm, 2.5mm, 3.5mm, 4.5mm, or 5.5mm.

[0099] When selecting the wing joint plate 364, which cannot be prefabricated, the subsequent test process is as follows: Figure 17 (c) to Figure 17 As shown in (f), when selecting the wing joint plate 364 that can prepare prefabricated joints, as follows: Figure 17 (g) to Figure 17 As shown in (j).

[0100] S5, in Figure 17 (c) or Figure 17 (g) Fine-tune the two sets of loading components and adjust the relative position of the mold assembly 3 and the two sets of adjustment assemblies.

[0101] Based on the test type and required loading force in the test plan table, and the test angle of the test soil specimen 4, the relative positions of the disc track arm 22, the square short sliding arm 6, the square control arm 8, the left and right sliding rods 5, and the front and rear sliding rods 7 are adjusted to adjust the relative positions of the two sets of adjustment assemblies and the mold assembly 3. After adjustment, the inner diameter of the holes on the disc track arm 22, the square short sliding arm 6, and the square control arm 8 is reduced by controlling the electric lock button, thereby fixing the two sets of loading components.

[0102] S6, in Figure 17 (d) or Figure 17 (h) Connect and fix the mold assembly 3 to the two sets of adjustment assemblies.

[0103] Insert the mold half-buckles 34 on the front loading mold 32 and the rear loading mold 33 into the semi-disc locking holes 13 on the rotatable semi-disc 1 respectively; screw the mold fixing bolts 31 into the mold half-buckles 34 and the semi-disc locking holes 13 from top to bottom to fix the mold assembly 3 to the two rotatable semi-discs 1 at the front and rear.

[0104] Furthermore, the mold fixing bolts 31 required for connecting the mold assembly 3 are preferably eight, four for fixing the mold assembly 3 to the front rotatable semi-circular disk 1, and four for fixing the mold assembly 3 to the front rotatable semi-circular disk 1.

[0105] S7, in Figure 17 (e) or Figure 17 (i) Remove the side connecting wing plates 36 on both sides of the mold assembly 3 and the bottom plate 37 of the mold at the bottom.

[0106] Unscrew the mold half-clamp 34 on the side of the side connecting wing plate 36 and the mold fixing bolt 31 on the side of the mold half-clamp 34 on the side of the mold bottom plate 37, and gently remove the mold bottom plate 37; unscrew the wing plate long bolts 363 on both sides of the side connecting wing plate 36 that are screwed into the wing plate vertical cylinder hole 362, and gently remove the side connecting wing plates 36 on both sides by lifting.

[0107] Furthermore, when removing the side connecting wing plates 36 on both sides, do not shake the side connecting wing plates 36, otherwise it will disturb the test soil specimen 4 and affect the subsequent test results.

[0108] S8, in Figure 17 (f) or Figure 17 (j) In this case: Open the control arm base 10, reset all stress and displacement values ​​to zero, and conduct the test.

[0109] Furthermore, when conducting uniaxial tensile tests, tensile fracture tests, and tensile-shear fracture tests, the front and rear control arm bases 10 control the two sets of adjusting assemblies to move in opposite directions, applying tensile force to the test soil specimen 4; when conducting shear fracture tests and compression-shear fracture tests, the front and rear control arm bases 10 control the two sets of adjusting assemblies to move in opposite directions, applying compressive force to the test soil specimen 4.

[0110] After generating the test protocol table, the required tests will differ, and the test methods will vary accordingly: During the uniaxial tensile test, the loading force and the test angle of the test soil specimen 4 are fixed at 0°; a wing plate jointing plate 364 that cannot be prefabricated is selected; a mold plate 38 with no gaps on both sides of the middle is selected; and a control arm base 10 is set to control the back-to-back movement of the two sets of adjustment assemblies to apply tension to the test soil specimen 4.

[0111] During the tensile fracture test, the loading force and the test angle of the soil specimen 4 are fixed at 0°. A single-sided or double-sided precast joint is selected. When a single-sided precast joint is selected, a flange joint plate 364 that cannot be precast on one side is selected, and a flange joint plate 364 that can be precast on the other side is selected. When a double-sided precast joint is selected, flange joint plates 364 that can be precast on both sides are selected, and the depth and thickness of the flange joint plates 364 are as similar as possible. The flange joint plates 364 that can be precast have multiple options for different depths (1mm, 3mm, 5mm) and thicknesses (1mm, 3mm, 5mm). A corresponding mold template 38 is selected based on the flange joint plate 364. A control arm base 10 is set to control the two sets of adjusting assemblies to move in opposite directions, applying tension to the soil specimen 4.

[0112] During the shear fracture test, the loading force and the test angle of the soil specimen 4 are fixed at 90°. A single-sided or double-sided precast joint is selected. When a single-sided precast joint is selected, a flange joint plate 364 that cannot be precast on one side is selected, and a flange joint plate 364 that can be precast on the other side is selected. When a double-sided precast joint is selected, flange joint plates 364 that can be precast on both sides are selected, and the depth and thickness of the flange joint plates 364 are as similar as possible. The flange joint plates 364 that can be precast have multiple options for different depths (1mm, 3mm, 5mm) and thicknesses (1mm, 3mm, 5mm). A corresponding mold template 38 is selected based on the flange joint plate 364. A control arm base 10 is set to control the two sets of adjusting assemblies to move towards each other, applying tension to the soil specimen 4.

[0113] During the tensile-shear fracture test, the loading force and the test angle of the test soil specimen 4 were fixed at 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°, and multiple tests were conducted. The choice between single-sided and double-sided precast joints was made. When a single-sided precast joint was chosen, a flange joint plate 364 that could not be used to create a precast joint was selected on one side, and a flange joint plate 364 that could be used to create a precast joint was selected on the other side. When a double-sided precast joint was chosen, flange joint plates 364 that could be used to create a precast joint were selected on both sides, and the depth and thickness of the flange joint plates 364 were made as similar as possible. The wing plate jointing plate 364, which can prepare prefabricated joints, has multiple options for different depths (1mm, 3mm, 5mm) and thicknesses (1mm, 3mm, 5mm); the corresponding mold is selected to make the template plate 38 according to the wing plate jointing plate 364; the control arm base 10 is set to control the back-to-back movement of the two sets of adjustment assemblies to apply tension to the test soil specimen 4.

[0114] During the compression-shear fracture test, the loading force and the test angle of the test soil specimen 4 were fixed at 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°, and multiple tests were conducted. The choice between single-sided and double-sided precast joints was made. When a single-sided precast joint was chosen, a flange joint plate 364 that could not be used to create a precast joint was selected on one side, and a flange joint plate 364 that could be used to create a precast joint was selected on the other side. When a double-sided precast joint was chosen, flange joint plates 364 that could be used to create a precast joint were selected on both sides, and the depth and thickness of the flange joint plates 364 were made as similar as possible. The wing plate jointing plate 364, which can prepare prefabricated joints, has multiple options for different depths (1mm, 3mm, 5mm) and thicknesses (1mm, 3mm, 5mm); the corresponding mold is selected to make the template plate 38 according to the wing plate jointing plate 364; the control arm base 10 is set to control the two sets of adjusting assemblies to move towards each other and apply tension to the test soil specimen 4.

[0115] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A multi-angle rotating tensile-fracture test apparatus for gravelly clay-filled ultra-high core wall dams, characterized in that: include The mold assembly (3) has a dumbbell-shaped cavity inside, which is used to prepare and support the test soil specimen (4). Two adjustment assemblies are provided, which are centrally symmetrically distributed on both sides of the mold assembly (3). Each adjustment assembly includes a rotatable semi-circular disk (1) and a semi-circular disk track (2). The rotatable semi-circular disk (1) is coaxially embedded in the inner side of the semi-circular disk track (2), and the semi-circular disk track (2) is movably connected to the rotatable semi-circular disk (1). The end of the mold assembly (3) is embedded in the inner side of the semi-circular disk track (2) and is detachably connected by a mold fixing bolt (31). The loading components are set to two, and the two loading components are symmetrically distributed on both sides of the mold assembly (3). The loading components include left and right sliding rods (5), square short sliding arms (6), front and rear sliding rods (7), square control arms (8) and control arm bases (10). The top of the control arm base (10) is provided with a control arm groove (9). The square control arm (8) is slidably fitted inside the control arm groove (9), and a drive unit is provided inside the control arm groove (9). The top of the square short sliding arm (6) overlaps with the disk track arm (22) at the outer end of the arc of the semi-circular disk track (2). The bottom of the square short sliding arm (6) overlaps with the top of the square control arm (8). The left and right sliding rods (5) pass through the disk track arm (22) and the square short sliding arm (6). The front and rear sliding rods (7) pass through the square short sliding arm (6) and the square control arm (8). The left and right sliding rods (5) and the front and rear sliding rods (7) are set perpendicularly. The semi-circular track (2) and the square short sliding arm (6) are both slidably engaged with the left and right sliding rods (5), and the square short sliding arm (6) and the square control arm (8) are both slidably engaged with the front and rear sliding rods (7). An electric lock is provided inside the large arm (22) of the track, the square short sliding arm (6) and the square control arm (8), and the locking pin of the electric lock is movably engaged with the outside of the left and right sliding rods (5) or the front and rear sliding rods (7).

2. The multi-angle rotating tensile-fracture test device for ultra-high core wall dams with gravel-mixed clay as described in claim 1, characterized in that: The rotatable semi-circular disk (1) is configured as a semi-circular disc structure, and the outer end of the arc side of the rotatable semi-circular disk (1) matches the inner end of the arc side of the semi-circular disk track (2). A rotatable semi-circular disk ball (11) is embedded in the outer end of the arc side of the rotatable semi-circular disk (1). A semi-circular disk fixing hole (12) is opened at the outer end of the upper surface of the rotatable semi-circular disk (1), and a semi-circular disk locking hole (13) is opened at the inner end of the upper surface of the rotatable semi-circular disk (1).

3. The multi-angle rotating tensile-fracture test device for ultra-high core wall dams with gravel-mixed clay as described in claim 2, characterized in that: The semi-circular track (2) is a quarter-circular arc track structure. The inner end of the semi-circular track (2) is provided with a disc track slide (23). The disc track slide (23) is set as an arc-shaped tubular "C"-shaped track. The outer end of the arc side of the rotatable semi-circular disc (1) is embedded in the disc track slide (23), and the inner diameter of the "C"-shaped track is adapted to the outer diameter of the semi-circular disc embedded ball (11), so that the semi-circular disc embedded ball (11) slides in the disc track slide (23). The through hole at the end of the large arm (22) of the disc track corresponding to the left and right sliding rods (5) is set as a disc track sliding hole (21). The upper end of the semi-circular disc track (2) is provided with a disc track locking hole (24). Multiple diamond-shaped holes are linearly arrayed inside the disc track locking hole (24), and a disc track pin (25) is movably inserted into the diamond-shaped hole. The outer diameter of the disc track pin (25) matches the inner diameter of the semi-circular disc fixed hole (12).

4. The multi-angle rotating tensile-fracture test device for ultra-high core wall dams with gravel-mixed clay according to claim 3, characterized in that: The mold assembly (3) includes a mold fixing bolt (31), a front loading mold (32), a rear loading mold (33), a mold semi-clamp (34), a mold semi-circular groove (35), a side connecting wing plate (36), a mold bottom plate (37), and a mold template plate (38). The mold fixing bolt (31) is a flat-headed bolt with threads and a cross-shaped cutter. The front loading mold (32) and the rear loading mold (33) are axially symmetrically distributed groove structures located on the outer sides of the front loading mold (32) and the rear loading mold (33). All are provided with mold half buckles (34), and mold semicircular grooves (35) are provided on the opposite sides of the front loading mold (32) and the rear loading mold (33). A side connecting wing plate (36) is detachably installed between the two opposite mold semicircular grooves (35). A mold bottom plate (37) is located at the bottom middle of the mold assembly (3). Mold half buckles (34) are also provided on the sides of the side connecting wing plate (36) and the mold bottom plate (37). A mold template plate (38) is located at the top of the mold assembly (3).

5. The multi-angle rotating tensile-fracture test device for ultra-high core wall dams with gravel-mixed clay according to claim 4, characterized in that: The side connecting wing plate (36) includes a wing plate vertical cylinder (361), a wing plate vertical cylinder hole (362), a wing plate long bolt (363), and a wing plate seam plate (364). The side connecting wing plate (36) is provided with wing plate vertical cylinders (361) on both the front and rear sides. The wing plate vertical cylinder (361) matches the inner diameter of the mold semi-circular groove (35). The wing plate vertical cylinder (361) has a wing plate vertical cylinder hole (362). The wing plate long bolt (363) is threaded into the wing plate vertical cylinder hole (362).

6. The multi-angle rotating tensile-fracture test device for ultra-high core wall dams with gravel-mixed clay according to claim 5, characterized in that: A T-shaped groove is provided on one side of the side connecting wing plate (36), and a wing plate seam plate (364) is movably inserted into the T-shaped groove. The outer diameter of the wing plate seam plate (364) matches the inner diameter of the T-shaped groove.

7. The multi-angle rotating tensile-fracture test device for ultra-high core wall dams with gravel-mixed clay according to claim 6, characterized in that: One end of the wing plate seam plate (364) is flush with the outer wall of the side connecting wing plate (36), and the mold template plate (38) that matches the internal cavity of the mold assembly (3) is set to be closed on both sides.

8. The multi-angle rotating tensile-fracture test device for ultra-high core wall dams with gravel-mixed clay according to claim 6, characterized in that: One end of the wing plate seam plate (364) extends out to connect to the outer wall of the wing plate (36). The mold template plate (38) that matches the internal cavity of the mold assembly (3) has slots reserved on both sides, and the slots match the ends of the wing plate seam plate (364).

9. The multi-angle rotating tensile-fracture test device for ultra-high core wall dams with gravel-mixed clay according to claim 3, characterized in that: The number of semi-disc inserts (11) on each rotatable semi-disc (1) is set to five, and when the rotatable semi-disc (1) is rotated, at least two semi-disc inserts (11) are located in the disk track slide rail (23); The number of semi-disc fixed holes (12) on each rotatable semi-disc (1) is set to six, and the multiple semi-disc fixed holes (12) are spaced apart from the multiple semi-disc embedded balls (11).

10. The multi-angle rotating tensile-fracture test device for ultra-high core wall dams with gravel-mixed clay according to claim 4, characterized in that: The number of semi-disc locking holes (13) on each semi-disc track (2) is set to four, corresponding one-to-one with the mold semi-clamps (34) that need to be inserted into the rotatable semi-disc (1); The number of rhomboid holes on each rotatable semi-circular disk (1) is set to ninety. Multiple rhomboid holes are connected end to end and stacked in sequence, so that the mold assembly (3) can be adjusted at any angle within the range of 1~90°.

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