A detachable ring knife device special for fissured soil

Abstract

The utility model relates to a detachable ring knife device special for fissure soil, which adopts sectional structure design, realizes the axial positioning of the ring knife through the cooperation of the stepped fitting interface and the quick-release type outer buckle snap fastener. To effectively disperse stress, it is provided with a fluorine rubber stress buffer pad with a thickness of 1.5 mm and a buffer rate of greater than or equal to 80% at the port to absorb the compaction vibration energy; the inner wall of the ring knife is compounded with a low-modulus polytetrafluoroethylene layer and is provided with three axial stress release guide grooves; the inner wall of the port is designed with a 20° flared chamfer to jointly guide the smooth demolding of the soil sample and disperse stress. The ring knife body is made of high-toughness aluminum alloy with a breaking elongation of greater than or equal to 8% and a wall thickness of 1.5 mm to ensure the overall strength and anti-deformation ability. The device improves the completeness rate of fissure soil samples to more than 95%, ensures the sampling accuracy, significantly improves the test efficiency, and saves time and labor cost.

Description

Technical Field

[0001] This utility model relates to the technical field of geotechnical engineering testing equipment, specifically to a detachable ring cutter device for fractured soil. Background Technology

[0002] Fissured soils (such as residual granite soils and expansive soils) have micro-cracks within their structure, resulting in uneven structural strength and susceptibility to disturbance. This leads to significant defects in the traditional integrated ring sample preparation process. 1. Structural damage during demolding: After the soil sample dries and shrinks, the constraint force of the inner wall of the ring cutter will be concentrated at the cracks in the soil. When forcibly demolded, the cracks will expand rapidly, eventually leading to the fragmentation of the sample. Statistics show that the fragmentation rate is as high as 60% or more.

[0003] 2. Insufficient adaptability: Traditional ring cutter inner wall treatment techniques (such as polishing and coating) cannot alleviate the problem of stress concentration in cracks, and the failure is particularly obvious in cracked soil with changes in moisture content. Utility Model Content

[0004] This invention provides a detachable ring cutter device for fractured soil. The segmented structure releases demolding stress, avoids structural damage to fractured soil samples during extraction, ensures sample preparation accuracy, effectively improves testing efficiency, and saves time and labor costs.

[0005] The technical solution of this utility model is as follows: A detachable ring cutter device for fractured soil includes a separable upper ring cutter and a lower ring cutter. The upper and lower ring cutters are axially positioned and connected through a stepped interlocking interface. The stepped fitting interface is provided on the end faces of the upper and lower ring cutters, including a boss and a groove structure, with a tolerance of ±0.02mm to ensure precise alignment; A fluororubber stress buffer pad is provided at the mating surface of the stepped mating interface. The outer wall of the ring cutter is equipped with quick-release external buckles, which are three sets evenly distributed on the outer wall of the ring cutter. They are used to quickly lock and separate the upper ring cutter from the lower ring cutter. After unlocking, the radial micro-separation of the ring cutter is allowed to be ≤0.2mm. The inner wall of the ring cutter is covered with a low-modulus polytetrafluoroethylene layer, the elastic modulus of which is ≤5MPa, to buffer the shrinkage stress of the fractured soil. Three stress-relief guide grooves are evenly opened along the axial direction on the inner wall of the ring cutter.

[0006] The preferred embodiment of the detachable ring cutter device for fractured soil is that the end of the stress relief guide groove has a radius of 0.3mm, a groove width of 1mm, and a depth of 0.5mm, in order to avoid stress concentration.

[0007] The preferred embodiment of the detachable ring cutter device for fractured soil is that the ring cutter has a wall thickness of 1.5 mm and an inner diameter of 61.8 mm, which is compatible with the standard fractured soil sample size.

[0008] The preferred embodiment of the detachable ring cutter device for fractured soil is that the inner wall of the ring cutter port is provided with a 20° flared chamfer with a chamfer width of 1.5mm; used to guide the soil sample to be demolded smoothly.

[0009] The preferred embodiment of the detachable ring cutter device for fractured soil is that the ring cutter is made of high-toughness aluminum alloy with a fracture elongation of ≥8%.

[0010] The preferred embodiment of the detachable ring cutter device for fractured soil is that the fluororubber stress buffer pad has a thickness of 1.5mm and a buffering rate of ≥80%, which is used to absorb the energy of compaction vibration. Beneficial effects

[0011] This invention effectively disperses the concentrated stress on the fractured soil during demolding through a segmented structure and stress relief guide groove design, thus solving the problem of sample breakage caused by traditional ring cutter demolding.

[0012] A fluororubber stress buffer pad is placed on the ring cutter mating surface, which can absorb more than 80% of the compaction impact energy, significantly reduce the disturbance to the internal cracks of the soil during the sample preparation process, prevent the cracks from expanding further, and ensure the original structure of the sample.

[0013] The quick-release external snap-fit ​​and segmented design enable rapid assembly and separation of the ring cutter. The demolding process does not require complex equipment or forceful ejection, simplifying the operation process and greatly improving the efficiency of sample preparation and testing.

[0014] The inner diameter of the ring cutter is 61.8 mm, which is compatible with the relevant procedures for fractured soil testing in the "Standard for Geotechnical Testing Methods" (GB / T 50123-2019). It can be directly applied to the existing geotechnical testing system without changing the existing testing methods.

[0015] Actual tests show that this device can increase the integrity rate of fractured soil samples from less than 40% with traditional ring cutters to over 95%. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a ring cutter; Figure 2 This is a schematic diagram of the upper section of the ring cutter; Figure 3 This is a schematic diagram of the lower section of the ring cutter; Figure 4 This is a schematic diagram of the cross-section of the ring cutter; Figure 5This is a schematic diagram of a quick-release external buckle.

[0017] Among them, 1-upper ring cutter, 2-lower ring cutter, 3-quick-release external buckle, 4-stepped fitting interface, 5-stress relief guide groove, 6-flared chamfer. Detailed Implementation

[0018] like Figure 1-5 As shown, a detachable ring cutter device for fractured soil includes a separable upper ring cutter 1 and a lower ring cutter 2. The upper ring cutter 1 and the lower ring cutter 2 are axially positioned and connected through a stepped fitting interface 4; The stepped fitting interface is provided on the end faces of the upper ring cutter 1 and the lower ring cutter 2, including a boss and a groove structure, with a tolerance of ±0.02mm, to ensure precise alignment; A fluororubber stress buffer pad is provided at the mating surface of the stepped mating interface 4. The outer wall of the ring cutter is equipped with a quick-release external buckle 3, which is used to quickly lock and separate the upper ring cutter 1 and the lower ring cutter 2. After unlocking, the radial micro-separation of the ring cutter is allowed to be ≤0.2mm. The inner wall of the ring cutter is covered with a low-modulus polytetrafluoroethylene layer, the elastic modulus of which is ≤5MPa, to buffer the shrinkage stress of the fractured soil. Three stress-relief guide grooves are evenly opened along the axial direction on the inner wall of the ring cutter.

[0019] The stress relief guide groove 5 has a radius of 0.3mm at the end, a groove width of 1mm and a depth of 0.5mm, which is used to avoid stress concentration.

[0020] The ring cutter has a wall thickness of 1.5 mm and an inner diameter of 61.8 mm, and is compatible with standard fractured soil sample sizes.

[0021] The inner wall of the ring cutter port is provided with a 20° flared chamfer 6, with a chamfer width of 1.5mm; used to guide the soil sample to be demolded smoothly.

[0022] The ring cutter is made of high-toughness aluminum alloy with a fracture elongation of ≥8%.

[0023] The fluororubber stress buffer pad has a thickness of 1.5 mm and a buffering rate of ≥80%, and is used to absorb the energy of compaction vibration.

[0024] The sample preparation and demolding process of a detachable ring cutter device for fractured soil is as follows: 1. Sample preparation stage: Assembly: The assembling section ring cutter 1 and the lower section ring cutter 2 are precisely aligned through a stepped interlocking interface, and then the quick-release external buckle 3 is locked. Compaction: Fill the cracked soil sample in layers and compact it, controlling the compaction energy to ≤ 27 J / cm³; use the stress relief guide groove and fluororubber stress buffer pad on the inner wall of the ring cutter to disperse the energy and prevent crack propagation; 2. Demolding stage: Unlock: After the soil sample has naturally shrunk, release the quick-release outer buckle 3 to allow radial micro-separation of the ring cutter; Stress relief: Slightly rotate the upper ring cutter 1 and the lower ring cutter 2 about 10° relative to each other to completely release the residual stress by utilizing the gap of the stepped interlocking interface.

[0025] Demolding: Along the stress relief guide groove on the inner wall of the ring cutter, gently and vertically separate the upper ring cutter 1 and the lower ring cutter 2, and remove the complete soil sample without damage.

Claims

1. A detachable ring cutter device for fractured soil, characterized in that, Includes a separable upper ring cutter and a lower ring cutter; The upper and lower ring cutters are axially positioned and connected through a stepped interlocking interface. The stepped fitting interface is provided on the end faces of the upper and lower ring cutters, including a boss and a groove structure, with a tolerance of ±0.02mm to ensure precise alignment; A fluororubber stress buffer pad is provided at the mating surface of the stepped mating interface. The outer wall of the ring cutter is equipped with a quick-release external buckle to enable the upper and lower ring cutters to lock and separate quickly. After unlocking, the radial micro-separation of the ring cutter is allowed to be ≤0.2mm. The inner wall of the ring cutter is covered with a low-modulus polytetrafluoroethylene layer, the elastic modulus of which is ≤5MPa, to buffer the shrinkage stress of the fractured soil. Three stress-relief guide grooves are evenly opened along the axial direction on the inner wall of the ring cutter.

2. The detachable ring cutter device for fractured soil according to claim 1, characterized in that: The stress relief guide groove has a radius of 0.3mm at the end, a groove width of 1mm, and a depth of 0.5mm to avoid stress concentration.

3. The detachable ring cutter device for fractured soil according to claim 1, characterized in that: The ring cutter has a wall thickness of 1.5 mm and an inner diameter of 61.8 mm, and is compatible with standard fractured soil sample sizes.

4. The detachable ring cutter device for fractured soil according to claim 1, characterized in that: The inner wall of the ring cutter port is provided with a 20° flared chamfer with a chamfer width of 1.5mm; this is used to guide the soil sample to be demolded smoothly.

5. A detachable ring cutter device for fractured soil according to claim 1, characterized in that: The ring cutter is made of high-toughness aluminum alloy with a fracture elongation of ≥8%.

6. A detachable ring cutter device for fractured soil according to claim 1, characterized in that: The fluororubber stress buffer pad has a thickness of 1.5 mm and a buffering rate of ≥80%, and is used to absorb the energy of compaction vibration.

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