Tunnel face surrounding rock rapid grading device

Abstract

The utility model relates to the technical field of tunnel face surrounding rock grading, in particular to a tunnel face surrounding rock rapid grading device which comprises a base, four supporting columns and a protection assembly, the four supporting columns are symmetrically and fixedly arranged at the top end of the base, the protection assembly comprises a limiting frame connected to the outer surfaces of the supporting columns in a sliding mode, and observation windows are embedded in the side walls of the limiting frame. A first hole groove is formed in the side wall of the limiting frame, and a bolt rod is inserted into the middle of the first hole groove. Compared with a traditional tunnel face surrounding rock grading device, the tunnel face surrounding rock grading device is provided with the protection assembly, the protection assembly comprises the limiting frame and the observation window, the limiting frame and the observation window are enclosed to be in a concentric-square shape, protection comprehensiveness is improved, and the safety of tunnel face surrounding rock grading is improved through cooperation of the plug pin rod, the first hole groove and the second hole groove. The position adjusting convenience and the mounting stability of the limiting frame and the observation window are improved, so that surrounding rock particles are prevented from being crushed and splashed, and the grading detection safety is improved.

Description

Technical Field

[0001] This utility model relates to the field of tunnel face surrounding rock classification technology, and in particular to a rapid classification device for tunnel face surrounding rock. Background Technology

[0002] Rock grading at the tunnel face is a crucial aspect of tunnel engineering. It involves assessing and classifying the stability and bearing capacity of the rock surrounding the tunnel face based on geological conditions and mechanical properties. This provides a basis for tunnel design and construction. Rock grading at the tunnel face can be achieved using a point load tester. This instrument is used to conduct point load tests on sampled rock at the tunnel face. By applying loads and measuring the rock's failure rate, relevant mechanical parameters such as uniaxial compressive strength are obtained.

[0003] Existing tunnel face rock grading devices typically use hydraulic cylinders to drive the pressing head for crushing. Due to the high pressure at the end of the pressing head, the surrounding rock breaks into pieces during crushing, which may cause particles to splash, thus affecting the safety of grading and testing. Utility Model Content

[0004] To overcome the problem that existing tunnel face rock grading devices typically use hydraulic cylinders to drive the pressing head for crushing, which results in the surrounding rock breaking into pieces due to the high pressure at the end of the pressing head, potentially causing particles to fly and affecting the safety of grading and testing.

[0005] The technical solution of this utility model is as follows: a rapid grading device for surrounding rock at the tunnel face, comprising a base, support columns, and protective components. Four support columns are symmetrically fixed at the top of the base. The protective components include a limiting frame that is slidably connected to the outer surface of the support columns. Each limiting frame has an observation window embedded in its side wall. A first slot is opened on the side wall of the limiting frame, and a pin is inserted into the middle of the first slot. Two second slots are opened on the side wall of the support column near the first slot. Each support column has a mounting base fixed at its top. A hydraulic cylinder is fixed at the bottom of the mounting base. A pressure sensor is fixed at the output end of the hydraulic cylinder, and a pressing head is fixed at the bottom end of the pressure sensor.

[0006] Furthermore, a limiting seat is fixed in the middle of the base, and a groove is opened on the surface of the limiting seat. The groove and the pressing head are located in the same vertical direction, which improves the convenience of installation and positioning.

[0007] Furthermore, the four corners of the limiting frame are provided with sliding grooves, which are respectively fitted onto the outer surface of the support column to improve the ease of movement of the limiting frame.

[0008] Furthermore, a limiting ring is engaged on the inner wall of the slide groove. The limiting ring is circular and is fitted onto the outer surface of the support column, which improves the stability of the sliding of the limiting frame.

[0009] Furthermore, two support pads are fitted at the bottom of the limit frame, both of which are U-shaped, which improves the stability of the limit frame support.

[0010] Furthermore, a magnet is snapped into the middle of the pin, and a pull ring is fixed to the end of the magnet, which improves the stability of the pin insertion.

[0011] Furthermore, the external dimensions of the pin are adapted to the internal dimensions of the first and second slots, respectively.

[0012] Furthermore, a display screen is embedded in the side wall of the mounting base, and the display screen is coupled to the hydraulic cylinder and the pressure sensor respectively. LED strips are wrapped around the side wall of the mounting base.

[0013] The beneficial effects of this utility model are:

[0014] Compared to traditional tunnel face rock grading devices, this device incorporates protective components, including a limit frame and an observation window. The limit frame and observation window are arranged in a U-shape, enhancing the overall protective coverage. The use of a pin rod, a first slot, and a second slot improves the ease of adjusting the position of the limit frame and observation window, as well as the stability of installation, thus preventing the fragmentation and splashing of surrounding rock particles and improving the safety of grading detection. Furthermore, the device includes a support pad and a limiting ring. The limiting ring, in a circular shape, is fitted onto the surface of the support column to increase frictional resistance and slow the sliding speed of the limit frame on the support column surface. The support pad provides cushioning and limiting, thereby improving the stability of the limit frame during slippage. Attached Figure Description

[0015] Figure 1 The diagram shown is a schematic representation of the overall structure of the tunnel face surrounding rock grading device of this utility model.

[0016] Figure 2 The diagram shown is a schematic representation of the support column structure of this utility model.

[0017] Figure 3 The diagram shown is a schematic representation of the protective component structure of this utility model.

[0018] Figure 4 The diagram shown is a cross-sectional view of the limiting frame of this utility model.

[0019] Figure 5 The diagram shown is a schematic representation of the pin structure of this utility model.

[0020] Explanation of reference numerals in the attached drawings: 1. Base; 2. Support column; 3. Protective component; 301. Limiting frame; 302. Observation window; 303. Slide groove; 304. First slot; 305. Support pad; 306. Limiting ring; 4. Mounting seat; 5. Display screen; 6. Hydraulic cylinder; 7. Pressure sensor; 8. Pressing head; 9. Limiting seat; 10. Groove; 11. Second slot; 12. Pin rod; 13. Magnet; 14. Pull ring. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Among the currently discovered feasible technologies, the following are described:

[0023] Classification of surrounding rock at the tunnel face is a very important task in tunnel engineering. It involves assessing and classifying the stability and bearing capacity of the rock around the tunnel face based on factors such as geological conditions and mechanical properties, so as to provide a basis for tunnel design and construction. Rock hardness is classified according to the saturated uniaxial compressive strength of the rock, such as hard rock, relatively hard rock, relatively soft rock, soft rock, and extremely soft rock.

[0024] Rock mass integrity: measured by rock mass integrity coefficient, degree of joint and fissure development, etc., can be divided into intact, relatively intact, relatively broken, broken, extremely broken, etc.; Geological structure: including the development of faults, folds and other structures, and the degree of cutting and damage to the rock mass; Groundwater conditions: groundwater volume, water pressure, softening and mudification of the rock mass, etc.

[0025] The *Highway Tunnel Design Code* (JTG3370.1—2018) classifies surrounding rock into grades I-VI, with grade I being the best and grade VI the worst. For example, grade I surrounding rock is hard rock, with an intact, massive, or thickly layered structure; grade VI surrounding rock is soft rock, with fractured or extremely fractured rock masses, including fault fracture zones and strongly weathered zones. The *Railway Tunnel Design Code* (TB10003—2016) classifies surrounding rock from grade I to grade V, with grade I being the best. For example, grade I surrounding rock refers to hard rock, with an intact, massive, monolithic structure, a saturated uniaxial compressive strength greater than 60 MPa, and a rock mass integrity coefficient greater than 0.75.

[0026] A manual point load tester is a commonly used device for testing the strength of rocks. It typically consists of a loading device, a force measuring device, and a pressure plate. The loading device usually employs a manual hydraulic pump or a screw loading mechanism, applying pressure to the pressure plate to apply a concentrated load to the rock specimen. The force measuring device is often a pressure gauge or pressure sensor, used to measure the load magnitude during the loading process. This type of tester is simple in structure and easy to operate, suitable for field and laboratory point load tests on small-sized rock specimens. For example, some manual point load testers have a maximum loading capacity of up to 50 kN and an accuracy of 0.1 kN, meeting the point load test requirements for most conventional rock specimens.

[0027] For sample preparation, representative rock samples are selected from the parent rock, ensuring that the samples are free of obvious cracks and defects. For massive rocks, they can be processed into cylindrical samples with a diameter of about 50 mm or cubic samples with a side length of 50 mm. For irregularly shaped rocks, larger portions should be selected, and the minimum sample size should be greater than 10 mm. The two ends of the sample should be ground flat to ensure that the parallelism error does not exceed 0.05 mm, so as to ensure uniform load transfer during the test.

[0028] For instrument preparation, check that all components of the load testing instrument are intact, the loading system is functioning properly, and the force gauge is calibrated and within its validity period. Select an appropriate loading head based on the size and shape of the specimen. Generally, a ball-end loading head is used for cylindrical specimens, while a flat-end loading head can be used for cubic or irregular specimens. Place the instrument on a stable workbench, turn on the power, and preheat for 10-15 minutes to allow the instrument to reach a stable working state.

[0029] Install the specimen and place it on the loading platform of the instrument, aligning the center of the specimen with the center of the loading head. For cylindrical specimens, the loading head should coincide with the axis of the specimen; for cubic or irregular specimens, the loading head should be applied to the center of the specimen as much as possible. Use clamps to firmly fix the specimen to prevent it from sliding or rotating during loading.

[0030] For the loading test, slowly and evenly rotate the loading handle to apply the load to the specimen. The loading speed should be controlled within a certain range, generally 0.5-1.0 kN / s, to avoid the specimen breaking instantly due to excessive loading speed, which would affect the accuracy of the test results. Observe the reading of the force gauge and the deformation of the specimen. When the specimen cracks or shows obvious deformation, record the maximum load value at this time. Record the maximum load value of each specimen, the dimensions of the specimen (diameter or side length), and other data.

[0031] The working principle of the point load tester is based on the failure characteristics of rock under point load. When a concentrated load is applied to a rock sample, stress concentration occurs inside the sample. As the load gradually increases, the stress inside the sample also increases. When the stress reaches the ultimate strength of the rock, the sample will fracture.

[0032] By measuring the maximum load a rock specimen withstands upon failure and considering the specimen's dimensions, its point load strength can be calculated. Point load strength is correlated with mechanical properties of rock, such as uniaxial compressive strength. Therefore, point load tests can be used to indirectly assess the strength characteristics of rock, providing crucial parameters for engineering design and construction.

[0033] Example 1

[0034] Please refer to Figures 1-5 The tunnel face surrounding rock rapid grading device includes a base 1, support columns 2, and protective components 3. Four support columns 2 are symmetrically welded to the top of the base 1 for support and limiting. All support columns 2 are smooth round rods. The protective components 3 include limiting frames 301 slidably connected to the outer surface of the support columns 2. Each limiting frame 301 has an observation window 302 embedded in its side wall. The observation window 302 is made of tempered glass for protection and to facilitate operator observation of the pressing and testing process. Sliding grooves 303 are provided at the four corners of the limiting frame 301, respectively fitted onto the outer surface of the support columns 2 to improve the ease of movement of the limiting frame 301. A first slot 304 is provided on the side wall of the limiting frame 301, with a pin 12 inserted into the center of the first slot 304. The support columns 2 are close to... Two second slots 11 are opened on the side wall of the first slot 304. The top of the support column 2 is fixed with a mounting seat 4. The bottom of the mounting seat 4 is fixed with a hydraulic cylinder 6. The output end of the hydraulic cylinder 6 is fixed with a pressure sensor 7. The bottom end of the pressure sensor 7 is fixed with a pressing head 8. The pressing head 8 is made of stainless steel and is conical to increase the pressure at the bottom. The middle of the base 1 is fixed with a limiting seat 9. The surface of the limiting seat 9 is provided with a groove 10 for the surrounding rock to be clamped and positioned. The groove 10 and the pressing head 8 are located in the same vertical direction, which improves the convenience of installation and positioning. The side wall of the mounting seat 4 is embedded with a display screen 5 to display pressure data for operators to observe and classify. The display screen 5 is coupled to the hydraulic cylinder 6 and the pressure sensor 7 respectively. The side wall of the mounting seat 4 is wrapped with a light strip to improve the lighting in the tunnel.

[0035] A limiting ring 306 is engaged on the inner wall of the slide groove 303. The limiting ring 306 is circular and is respectively sleeved on the outer surface of the support column 2, which improves the sliding stability of the limiting frame 301. Two support pads 305 are sleeved on the bottom end of the limiting frame 301. The support pads 305 are made of rubber and are U-shaped, which improves the support stability of the limiting frame 301.

[0036] A magnet 13 is snapped into the middle of the pin 12, and a pull ring 14 is fixed at the end of the magnet 13. The pull ring 14 can be magnetically attracted to the middle of the second slot 11, which improves the stability of the pin 12 insertion. The external dimensions of the pin 12 are adapted to the internal dimensions of the first slot 304 and the second slot 11, respectively.

[0037] When using the tunnel face surrounding rock grading device, first move the device to the designated location and then connect it to an external power source. The operator pulls the limiting frame 301 along the support column 2 towards the mounting base 4, exposing the limiting seat 9. The operator can then clamp the sampled surrounding rock block into the center of the groove 10, thus improving the convenience of sample installation and positioning. Next, release the limiting frame 301 and insert the pin rod 12 into the second slot 11, improving the stability of the limiting frame 301 support. This allows the limiting frame 301 and the observation window 302 to slide down under gravity and support the device. On the surface of the limiting seat 9, the operator then activates the hydraulic cylinder 6 to drive the pressure sensor 7 and the pressing head 8 to move vertically downward, so that the bottom end of the pressing head 8 is supported on the sample surface. The pressure is transmitted to the pressure sensor 7 and displayed on the surface of the display screen 5 through an electrical signal, thereby improving the efficiency of graded detection. The display screen 5, hydraulic cylinder 6, pressure sensor 7 and pressing head 8 are all existing technologies and will not be described in detail here. When the surrounding rock sample is crushed and splashed, the sample observation window 302 can prevent the fragments from splashing by supporting and limiting, thereby improving the safety of the detection process.

[0038] Considering that the limit frame 301 falls too fast, the frictional resistance is increased by the limit ring 306 to slow down the downward speed. The support pad 305 is installed, which is elastic and used to buffer and absorb shock, thereby improving the stability of the limit frame 301 supported on the surface of the limit seat 9.

[0039] Also taking into account the surface contamination and obstruction of the limit seat 9, the operator slides the limit bracket 301 to insert the pin rod 12 into another second hole slot 11, thereby locking the limit bracket 301 at the bottom of the mounting base 4, thus exposing the limit seat 9, reducing obstruction and facilitating cleaning.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rapid grading device for surrounding rock at tunnel faces, characterized in that, It includes a base (1), support columns (2) and protective components (3): four support columns (2) are symmetrically fixed at the top of the base (1). The protective components (3) include a limiting frame (301) that is slidably connected to the outer surface of the support column (2). The side wall of the limiting frame (301) is embedded with an observation window (302). The side wall of the limiting frame (301) is provided with a first slot (304). A pin rod (12) is inserted in the middle of the first slot (304). The side wall of the support column (2) near the first slot (304) is provided with two second slots (11). The top of the support column (2) is fixed with a mounting seat (4). The bottom of the mounting seat (4) is fixed with a hydraulic cylinder (6). The output end of the hydraulic cylinder (6) is fixed with a pressure sensor (7). The bottom end of the pressure sensor (7) is fixed with a pressing head (8).

2. The rapid rock grading device for tunnel face as described in claim 1, characterized in that: A limiting seat (9) is fixed in the middle of the base (1). A groove (10) is provided on the surface of the limiting seat (9). The groove (10) and the pressing head (8) are located in the same vertical direction.

3. The rapid rock grading device for tunnel face as described in claim 1, characterized in that: The four corners of the limiting frame (301) are provided with sliding grooves (303), which are respectively fitted onto the outer surface of the support column (2).

4. The rapid rock grading device for tunnel face as described in claim 3, characterized in that: Limiting rings (306) are engaged on the inner wall of the slide (303). The limiting rings (306) are circular and are respectively sleeved on the outer surface of the support column (2).

5. The rapid rock grading device for tunnel face as described in claim 3, characterized in that: The bottom end of the limiting frame (301) is fitted with two support pads (305), both of which are U-shaped.

6. The rapid rock grading device for tunnel face as described in claim 1, characterized in that: A magnet (13) is snapped into the middle of the pin (12), and a pull ring (14) is fixed to the end of the magnet (13).

7. The rapid rock grading device for tunnel face as described in claim 6, characterized in that: The external dimensions of the pin (12) are adapted to the internal dimensions of the first slot (304) and the second slot (11), respectively.

8. The rapid rock grading device for tunnel face as described in claim 1, characterized in that: The mounting base (4) has a built-in display screen (5) embedded in its side wall. The display screen (5) is coupled to the hydraulic cylinder (6) and the pressure sensor (7) respectively. The mounting base (4) has a light strip wrapped around its side wall.

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