In-hole in-situ direct shear test device for fine particle tailings and use method of in-hole in-situ direct shear test device

Abstract

The invention belongs to the technical field of direct shear tests, and particularly provides an in-hole in-situ direct shear test device for fine particle tailings and a use method of the in-hole in-situ direct shear test device. The in-hole in-situ direct shear test device for the fine particle tailings comprises a counterweight support, a torsion device box, an inner frame body guide frame, an annular soil cutting hydraulic box, an outer frame body, an inner frame body, an inner frame body shear plate and an outer frame body shear plate, and the outer frame body is a cylindrical barrel. The use method of the in-hole in-situ direct shear test device for the fine particle tailings comprises the following steps: deploying a first oil pump, a second oil pump and a power supply on the ground, assembling the in-situ direct shear test device, and mounting a counterweight; the in-situ direct shear test device is tripped into the exploration drill hole; starting a first oil pump; starting a second oil pump; starting the power supply. According to the scheme, vertical stress and normal stress of soil sample shearing are applied to a tailing soil sample through balance weight and hydraulic pressure at the tailing sampling depth, and the cohesive force and the strength parameters of an internal friction angle of fine-particle tailings are objectively obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of direct shear tests, and in particular provides an in-hole in-situ direct shear test device for fine-grained tailings and a use method thereof. Background Art

[0002] Tailings are fine solid waste particles left after ore processing, which may contain harmful chemicals and heavy metals. As a high potential energy hazard source, the safe storage of tailings is the focus of national supervision. In particular, fine-grained non-ferrous metal mine tailings have the characteristics of low permeability and large deformation, which makes its strength test complicated and the stability calculation uncertain, posing a threat to the safety of tailings ponds.

[0003] In the field of geotechnical exploration, there are many types of in-situ direct shear test devices, such as the three-box full-reaction direct shear device for exploration pits, anchored type, support frame type, pneumatically driven type, columnar jointed rock in-situ direct shear test device, and portable geotechnical direct shear instrument.

[0004] For example, the PHICOMETRE type of the French APAGEO company and the deep in-situ in-hole shear test system of the Chinese patent CN108426789A both obtain shear parameters by lifting the shear soil layer, but the latter increases the normal and radial forces. The BST type in-situ soil in-hole shear tester of the American HANDY company cannot obtain the stress-strain relationship curve. Japanese patent JPH10325788A discloses a bedrock in-situ shear strength test device and method for determining the shear strength of rock after excavation. The soft rock bed drilling shear test method and device disclosed in Japanese patent JPH08285747A are similar to the PHICOMETRE system and are mainly used for soft rock. The Chinese patent CN115901491A application discloses a two-in-one drilling shear test system and method. However, these devices are not suitable for in-situ direct shear tests of strength parameters of fine-grained tailings with high water content, low permeability, easy disturbance, and easy thixotropy.

[0005] At present, the determination of fine-grained tailings strength parameters is usually carried out in the laboratory, but there are differences with the on-site strength parameters. With the refined utilization of rare metal resources, tailings particles have become finer, and existing equipment is difficult to adapt. Therefore, it is necessary to develop a new in-hole in-situ direct shear test device to improve the accuracy of fine-grained tailings strength parameters and ensure the safe design and operation of tailings ponds. Summary of the invention

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: an in-hole in-situ direct shear test device for fine-grained tailings, comprising a counterweight support, a torsion device box, an inner frame guide, an annular soil cutting hydraulic box, an outer frame, an inner frame, an inner frame shear plate and an outer frame shear plate, the outer frame is a cylindrical barrel, the annular soil cutting hydraulic box is arranged on the top of the outer frame, the inner frame is coaxially arranged inside the outer frame, and the inner frame guide coaxially penetrates the annular soil cutting hydraulic box and extends into the inner frame;

[0007] The inner frame is composed of three arc-shaped steel plates, each of which has an arc of degrees. The steel plates are fixedly connected to the inner frame guide frame through the inner frame pressure piston. The counterweight support and the torsion device box are sequentially sleeved on the inner frame guide frame from top to bottom. The torsion device box is abutted against the top surface of the annular soil cutting hydraulic box, and the torsion device box is transmission connected to the inner frame guide frame.

[0008] Furthermore, an inner frame capping plate is provided on the top of the inner frame, and the inner frame capping plate and the inner frame guide frame are coaxially arranged and welded to each other;

[0009] The lower surface of the inner frame capping plate is provided with a radial track, and the top of the steel plate is engaged with the radial track.

[0010] Furthermore, an outer frame shear plate is axially arranged on the inner side wall of the outer frame, and an inner frame shear plate is axially arranged on the outer side wall of the inner frame.

[0011] Furthermore, a counterweight is arranged above the counterweight support, and the counterweight is coaxially sleeved on the inner frame guide frame.

[0012] A method for using an in-hole in-situ direct shear test device for fine-grained tailings, the specific steps are as follows:

[0013] Step 1: deploy the first oil pump, the second oil pump and the power supply on the ground, assemble the in-situ direct shear test device, and install the counterweight;

[0014] Step 2: Lower the in-situ direct shear test device into the exploration borehole until the outer frame reaches the depth of the tailings sampling point;

[0015] Step 3: Start the first oil pump to drive the outer frame and the inner frame to cut into the tailings;

[0016] Step 4: Start the second oil pump to drive the inner frame to apply normal pressure to the tailings soil sample;

[0017] Step 5: Start the power supply to drive the inner frame to shear the tailings soil sample.

[0018] Further, in step 1, the height of the counterweight is calculated according to the following formula;

[0019] H2=(ρ 土 ·H土 ) / ρ 钢 ;

[0020] Where H2 is the height of the counterweight, ρ 钢 is the steel density of the counterweight, ρ 土 is the density of sampled tailings, H 土 Depth of the selected tailings sampling point.

[0021] Furthermore, in step 5, the relationship between the rotation angle velocity α of the inner frame and the relative displacement s between the inner frame and the tailings soil sample can be calculated by the following formula:

[0022] α=2πv 柱 / 60;

[0023] s=αd 2内 t;

[0024] Where α is the angular velocity of the inner frame, d 2内 is the outer surface radius of the inner frame, and t is the rotation time.

[0025] The beneficial effects of using the present invention are:

[0026] This scheme applies vertical stress and normal stress of shear to tailings soil samples through counterweights and hydraulics at the tailings sampling depth, conducts in-situ shear tests close to the objective stress state of the soil samples, eliminates the drawbacks of using disturbed samples in laboratory direct shear tests, and objectively obtains the strength parameters of cohesion and internal friction angle of fine-grained tailings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of an axial section of the present invention;

[0028] Figure 2 It is a schematic diagram of the connection relationship between the present invention and ground facilities;

[0029] Figure 3 It is a structural schematic diagram of the present invention;

[0030] Figure 4 An exploded view of the inner frame and associated structures of the present invention;

[0031] The reference numerals include: 1. counterweight support; 2. torsion device box; 3. inner frame guide frame; 4. annular soil cutting hydraulic box; 5. outer frame; 6. inner frame; 7. inner frame shear plate; 8. outer frame shear plate; 9. oil port; 10. counterweight; 11. hydraulic guide rod; 12. inner frame pressure piston; 13. counterweight guide rod; 14. inner frame capping plate; 15. radial track; 16. first oil pump; 17. second oil pump; 18. control power supply; 19. survey drilling. DETAILED DESCRIPTION

[0032] The present invention is described in detail below with reference to the accompanying drawings.

[0033] Embodiment 1

[0034] Reference Figure 1-Figure 4 , an in-hole in-situ direct shear test device for fine-grained tailings, comprising a counterweight support 1, a torsion device box 2, an inner frame guide 3, an annular soil cutting hydraulic box 4, an outer frame 5, an inner frame 6, an inner frame shear plate 7 and an outer frame shear plate 8, the outer frame 5 is a cylindrical barrel, the annular soil cutting hydraulic box 4 is arranged on the top of the outer frame 5, the inner frame 6 is coaxially arranged inside the outer frame 5, and the inner frame guide 3 coaxially penetrates the annular soil cutting hydraulic box 4 and extends into the inner frame 6;

[0035] The inner frame 6 is composed of three arc-shaped steel plates, each of which has an arc of 120 degrees. The steel plates are fixedly connected to the inner frame guide frame 3 through the inner frame pressure piston 12. The three inner frame pressure pistons 12 can drive the three steel plates to diffuse outward or contract inward synchronously.

[0036] The counterweight support 1 and the torsion device box 2 are sleeved on the inner frame guide frame 3 from top to bottom in sequence, the torsion device box 2 abuts against the top surface of the annular soil cutting hydraulic box 4, and the torsion device box 2 is transmission-connected with the inner frame guide frame 3;

[0037] An inner frame capping plate 14 is disposed on the top of the inner frame 6, and the inner frame capping plate 14 is coaxially disposed with the inner frame guide frame 3 and welded to each other;

[0038] A radial track 15 is provided on the lower surface of the inner frame capping plate 14 , and the top of the steel plate is engaged with the radial track 15 to limit the freedom of the steel plate.

[0039] An outer frame shear plate 8 is axially arranged on the inner side wall of the outer frame 5 , and an inner frame shear plate 7 is axially arranged on the outer side wall of the inner frame 6 .

[0040] A counterweight 10 is disposed above the counterweight support 1 , and the counterweight 10 is coaxially sleeved on the inner frame guide frame 3 .

[0041] The outer diameter of the outer frame 5 matches the diameter of the survey borehole 19;

[0042] The counterweight guide rod 13 is screwed to the inner frame guide frame 3 , and the hydraulic guide rod 11 is communicated with the oil delivery port 9 of the annular soil cutting hydraulic box 4 .

[0043] The torsion device box 2 has a built-in motor and is connected to the inner frame guide frame 3 through a transmission method such as a gear set, chain or belt. The torsion device box 2 is connected to the power supply 18 and the control system on the ground through a line. When the in-situ direct shear test device is deployed in the exploration borehole 19, the control system can control the torsion device box 2 to drive the inner frame guide frame 3 to rotate.

[0044] Preferably, the counterweight support 1, the inner frame guide frame 3, the outer frame 5, the inner frame 6, the inner frame shear plate 7 and the outer frame shear plate 8 are all made of manganese steel.

[0045] Embodiment 2

[0046] A method for using an in-hole in-situ direct shear test device for fine-grained tailings, the specific steps are as follows:

[0047] Step 1: deploy the first oil pump 16, the second oil pump 17 and the power supply 18 on the ground, assemble the in-situ direct shear test device, and install the counterweight;

[0048] Specifically, a first oil pump 16, a second oil pump 17 and a power supply 18 are deployed on the ground. Through a hydraulic oil conduit, the first oil pump 16 is connected to the annular soil cutting hydraulic box 4, the second oil pump 17 is connected to the inner frame pressure piston 12, and the power supply 18 is connected to the torsion device box 2 through a line;

[0049] Assemble the in-situ direct shear test device, and put the counterweights 10 on the hydraulic guide rods 11 and the counterweight guide rods 13 one by one;

[0050] Specifically, the height of the counterweight 10 is calculated according to the following formula:

[0051] H2=(ρ 土 ·H 土 ) / ρ 钢 ;

[0052] Where H2 is the height of the counterweight 10, ρ 钢 is the steel density of counterweight 10, ρ 土 is the density of sampled tailings, H 土 Depth of the selected tailings sampling point.

[0053] Step 2: lower the in-situ direct shear test device into the exploration borehole 19 until the outer frame 5 reaches the depth of the tailings sampling point;

[0054] Specifically, the in-situ direct shear test device is lowered into the exploration borehole 19 until the outer frame 5 reaches the depth of the tailings sampling point;

[0055] Step 3: Start the first oil pump 16, and the annular soil cutting hydraulic box 4 pushes the outer frame 5 and the inner frame 6 downward to cut into the tailings, so that the tailings fill the space between the outer frame 5 and the inner frame 6;

[0056] Step 4: Start the second oil pump 17, and the inner frame pressure piston 12 drives the inner frame 6 to expand outward, applying normal pressure to the tailings soil sample;

[0057] Step 5, start the power supply 18, the torsion device box 2 drives the inner frame 6 to rotate through the inner frame guide frame 3, and shears the tailings soil sample;

[0058] Specifically, the relationship between the rotation angle speed α of the inner frame 6 and the relative displacement s between the inner frame 6 and the tailings soil sample can be calculated by the following formula:

[0059] α=2πv 柱 / 60;

[0060] s=αd 2内 t;

[0061] Where, α is the angular velocity of the inner frame 6, d 2内 is the outer surface radius of the inner frame 6, and t is the rotation time.

[0062] Embodiment 3

[0063] Compared with the first embodiment, specifically, this embodiment takes the exploration borehole 19 with a hole diameter of 108 mm as an example, and the specific parameters of the components of the in-situ direct shear test device are as follows:

[0064] The outer diameter of the outer frame 5 is 108 mm;

[0065] The distance between the inner frame 6 and the outer frame 5 is 25 mm;

[0066] The radial track 15 has a height of 2 mm and a width of 5 mm;

[0067] The inner frame guide frame 3 is welded from a steel pipe with a wall thickness of 3mm and an outer diameter of 16mm and a steel pipe with a wall thickness of 3mm and a steel pipe with a wall thickness of 3mm and an outer diameter of 50mm;

[0068] The inner frame pressure piston 12 can apply normal stress of 25kPa, 50kPa, 75kPa and 100kPa to the soil sample;

[0069] The hydraulic guide rod 11 is a steel pipe with a wall thickness of 3 mm, a diameter of 10 mm, and a single section length of 1 mm;

[0070] The counterweight guide rod 13 is a steel pipe with a wall thickness of 3 mm and an outer diameter of 16 mm;

[0071] The counterweight is a double-hole cylinder with a height of 250 mm, made of Q235 steel, and the apertures of the two holes match the hydraulic guide rod 11 and the counterweight guide rod 13 respectively.

[0072] The survey grade is Class A. Initially, 16 boreholes were arranged 30 meters in front of the dam, with an average hole depth of 49 meters. The groundwater in the exposed range is divided into pore groundwater of artificial filling accumulation layer and bedrock fissure water. The groundwater depth is between 0.20 and 19.20 meters. According to the analysis of tailings particles, the stratum name is determined to be tailings silt. The upper tailings are in a plastic state. The cohesion and internal friction angle of the tailings soil sample are 8.8 kPa and 1.5 degrees respectively. The middle tailings are loose and slightly dense. The cohesion and internal friction angle of the tailings soil sample are 16.4 kPa and 8.8 degrees respectively.

[0073] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, many changes can be made in the specific implementation methods and application scopes based on the ideas of the present invention. As long as these changes do not deviate from the concept of the present invention, they all belong to the protection scope of the present invention.

Claims

1. An in-hole in-situ direct shear test device for fine-grained tailings, characterized in that: It includes a counterweight support, a torsion device box, an inner frame guide, an annular soil cutting hydraulic box, an outer frame, an inner frame, an inner frame shear plate and an outer frame shear plate. The outer frame is a cylindrical barrel. The annular soil cutting hydraulic box is arranged on the top of the outer frame. The inner frame is coaxially arranged inside the outer frame. The inner frame guide coaxially penetrates the annular soil cutting hydraulic box and extends into the inner frame. The inner frame is composed of three arc-shaped steel plates, each of which has an arc of degrees. The steel plates are fixedly connected to the inner frame guide frame through the inner frame pressure piston. The counterweight support and the torsion device box are sequentially sleeved on the inner frame guide frame from top to bottom. The torsion device box is abutted against the top surface of the annular soil cutting hydraulic box, and the torsion device box is transmission connected to the inner frame guide frame.

2. According to the in-hole in-situ direct shear test device of fine-grained tailings described in claim 1, it is characterized by: The inner frame is provided with an inner frame capping plate on the top, and the inner frame capping plate and the inner frame guide frame are coaxially arranged and welded to each other; The lower surface of the inner frame capping plate is provided with a radial track, and the top of the steel plate is engaged with the radial track.

3. According to the in-hole in-situ direct shear test device of fine-grained tailings as described in claim 1, it is characterized by: An outer frame shear plate is axially arranged on the inner side wall of the outer frame, and an inner frame shear plate is axially arranged on the outer side wall of the inner frame.

4. The in-hole in-situ direct shear test device for fine-grained tailings according to claim 1, characterized in that: A counterweight is arranged above the counterweight support, and the counterweight is coaxially sleeved on the inner frame guide frame.

5. A method for using an in-hole in-situ direct shear test device for fine-grained tailings, using the in-hole in-situ direct shear test device for fine-grained tailings as claimed in any one of claims 1 to 4, characterized in that: The specific steps are as follows: Step 1: deploy the first oil pump, the second oil pump and the power supply on the ground, assemble the in-situ direct shear test device, and install the counterweight; Step 2: Lower the in-situ direct shear test device into the exploration borehole until the outer frame reaches the depth of the tailings sampling point; Step 3: Start the first oil pump to drive the outer frame and the inner frame to cut into the tailings; Step 4: Start the second oil pump to drive the inner frame to apply normal pressure to the tailings soil sample; Step 5: Start the power supply to drive the inner frame to shear the tailings soil sample.

6. The method for using the in-hole in-situ direct shear test device for fine-grained tailings according to claim 5, characterized in that: In step 1, the height of the counterweight is calculated according to the following formula; H2=(ρ 土 ·H 土 ) / p 钢 ; Where H2 is the height of the counterweight, ρ 钢 is the steel density of the counterweight, ρ 土 is the density of sampled tailings, H 土 Depth of the selected tailings sampling point.

7. The method for using the in-hole in-situ direct shear test device for fine-grained tailings according to claim 5, characterized in that: In step 5, the relationship between the rotation angle velocity α of the inner frame and the relative displacement s between the inner frame and the tailings soil sample can be calculated by the following formula: α＝2πv 柱 / 60； s=αd 2内 t; Where α is the angular velocity of the inner frame, d 2内 is the outer surface radius of the inner frame, and t is the rotation time.

Images