Device for monitoring width and curvature of sprayed concrete crack on large-scale structural surface in large-scale underground cavern group

Abstract

The utility model discloses a device for monitoring the crack width and curvature of sprayed concrete on a large-scale structural surface in a large-scale underground cavern group, which mainly comprises two cylindrical monitoring columns with notch grooves on column bodies and column tops, and the two monitoring columns are buried in the sprayed concrete on two sides of the large-scale structural surface through drill holes. The bottoms of the two monitoring columns are located at the junction of sprayed concrete and bed rock, drilling is carried out according to the position after the sprayed concrete is sprayed again, the bottom of a drill hole is the interface of the sprayed concrete and surrounding rock, and then the two monitoring columns are fixed in the drill hole by injecting cement paste in a pressure mode. A top notch groove of the monitoring column is a cross notch groove, a column body notch groove is an annular notch groove, an electronic or mechanical vernier caliper is used during testing, the distance between the two column body notch grooves and the distance between the column top notch grooves are measured respectively, and the root of the monitoring column can be calculated according to the distance between the column body and the column top. The change of the crack width is reflected by the change of the distance between two monitoring columns on the surface of the sprayed concrete.

Description

Technical Field

[0001] The utility model relates to the technical field of geotechnical engineering testing, in particular to a device for monitoring crack width and curvature of shotcrete at a large structural surface in a large underground cavern group. Background Art

[0002] Large structural surfaces of large underground cavern groups often experience shear dislocation under the influence of cavern excavation, causing cracks in the initial support shotcrete of the cavern. Changes in crack width and shotcrete surface curvature are effective representations of shear dislocation changes of large structural surfaces. Monitoring crack width and shotcrete surface curvature is an important measure to ensure the safe and stable construction of cavern groups. However, there is currently no monitoring device specifically used to monitor cracks in shotcrete at large structural surfaces. Based on this, this application proposes a device for monitoring crack width and curvature of shotcrete at large structural surfaces in large underground cavern groups to solve the above problems. Utility Model Content

[0003] The utility model provides a device for monitoring crack width and curvature of shotcrete at large structural surface locations in large underground cavern groups, aiming to solve the problem of monitoring crack width and curvature changes of shotcrete at large structural surface locations.

[0004] In order to solve the above problems, the following technical solutions are provided:

[0005] A monitoring device for concrete crack width and curvature comprises two groups of monitoring columns. The monitoring columns of the device are provided with column body grooves and column top grooves.

[0006] The length of the monitoring column is 40~80cm.

[0007] The diameter of the monitoring column is 3-6 cm.

[0008] The column body groove is a circular groove with a groove width of 0.2-0.3 cm and a depth of 0.2-0.3 cm.

[0009] The top groove is a cross-shaped groove with a groove width of 0.2-0.3 cm and a depth of 0.2-0.3 cm.

[0010] The spacing between the column body groove and the column top groove is 10-20 cm.

[0011] Preferably, the column top groove is a cross-shaped groove.

[0012] Preferably, the column body groove is a circular ring groove.

[0013] A device for monitoring crack width and curvature of shotcrete in large structural surfaces in large underground caverns. The column bodies and column tops of two groups of cylindrical monitoring columns are grooved. Both groups of monitoring columns are buried in the shotcrete on both sides of the large structural surface through drilling. The bottoms of the two groups of monitoring columns are located at the junction of the shotcrete and the surrounding rock. After the shotcrete is sprayed again, holes are drilled according to the positions. The bottom of the drilled holes is the interface between the shotcrete and the surrounding rock. Then, the two monitoring columns are fixed in the drilled holes by injecting cement slurry. The grooves on the top of the monitoring column are cross-shaped grooves, and the grooves on the column body are circular ring-shaped grooves. When testing, an electronic or mechanical vernier caliper is used to measure the spacing between the two column body grooves and the spacing between the column top grooves. The change in the crack width at the root of the monitoring column, that is, the change in the spacing between the two monitoring columns on the surface of the shotcrete, can be calculated based on the spacing between the column body and the column top, thereby reflecting the change in the crack width. At the same time, based on the difference in spacing between the column body and the column top grooves of the two monitoring columns during the initial measurement, as well as the distance between the column body grooves and the column top grooves, the relative angle between the two groups of monitoring columns can be calculated, indirectly indicating the change in curvature of the shotcrete surface.

[0014] Optionally, the length of the monitoring column is 40~80cm, the diameter of the monitoring column is 2~6cm, and the two monitoring columns are of equal length. The grooves on the column bodies of the two monitoring columns are circular grooves with a groove width of 0.2~0.3cm and a depth of 0.2~0.3cm. The grooves on the top of the columns are cross-shaped grooves with a groove width of 0.2~0.3cm and a depth of 0.2~0.3cm. The spacing between the column body grooves and the column top grooves is 10~20cm. After the shotcrete is completed, drilling is carried out. The two drilling positions are about 5~10cm away from the boundary of the large structural surface. The drilling depth is the junction of the shotcrete and the surrounding rock. After the monitoring column is installed, the monitoring column and the drilled hole pores are filled with high-pressure cement slurry.

[0015] Optionally, the monitoring device used is an electronic or mechanical vernier caliper. After the two bored monitoring columns are installed, the first measurement is carried out, and the average value of the spacing between the two column body grooves and the two column top grooves is used as the spacing between the two groups of monitoring columns, and the distance between the column body grooves and the interface between the monitoring columns and the shotcrete is measured; as the cavern is excavated, the spacing between the column body grooves and the column top grooves is continuously measured, and the change in the angle between the two groups of monitoring columns can be calculated based on this. At the same time, the distance between the two groups of monitoring columns and the interface between the shotcrete can be calculated. This is the new monitoring column spacing, and the difference from the initial value is the crack width. The curvature of the shotcrete can be calculated based on the angle and the monitoring column spacing.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] 1. This device has the characteristics of continuous measurement and the measured values ​​are relatively accurate.

[0018] 2. This device can be used to measure the crack width and to obtain the deformation curvature of shotcrete.

[0019] 3. Set a cross-shaped groove on the top of the column and a circular groove on the column body to facilitate measurement and positioning. At the same time, the groove size matches the measuring claw size of the mechanical or electronic vernier caliper to facilitate measurement and fixation.

[0020] 4. The device of the utility model has the advantages of convenient testing, and the test results can indirectly reflect multiple variables through calculation.

[0021] 5. The cross-shaped groove on the top of the column and the annular groove on the column body are used for measurement and positioning and for fixing the vernier caliper during measurement; the cross-shaped groove on the top of the column is used for measuring and positioning the top of the column, and the annular groove on the column body is used for measuring and positioning the column body. The groove size is 0.2~0.3cm, which matches the size of the measuring claws of the mechanical or electronic vernier caliper, making it convenient to fix the mechanical or electronic vernier caliper. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the device structure of the utility model;

[0023] Figure 2 It is a structural schematic diagram of the monitoring column 1 of the utility model;

[0024] Figure 3 It is a structural schematic diagram of the column top groove 3 of the monitoring column 1 of the utility model;

[0025] Figure 4 It is a structural schematic diagram of the column body groove 2 of the monitoring column 1 of the utility model;

[0026] Figure 5 It is a schematic diagram of the measuring principle of the device of the utility model;

[0027] Figure numerals: monitoring column 1, column body groove 2, column top groove 3, shotcrete 4, surrounding rock 5, large structural surface 6. DETAILED DESCRIPTION

[0028] In conjunction with the accompanying drawings and specific embodiments, the terms "distance" and "spacing" should be understood in a broad sense, all referring to the distance between two objects. The preferred embodiments are used for illustration in this invention, and those skilled in the art can routinely adjust the size of the detection column based on the embodiments, which falls within the scope of protection of this application.

[0029] Example 1

[0030] A device for monitoring crack width and curvature of shotcrete in large structural surfaces within large underground caverns. Figure 1As shown, it includes two groups of monitoring columns 1, two column body grooves 2, two column top grooves 3, shotcrete 4, surrounding rock 5, and large structural surface 6. The monitoring column 1 is a cylindrical structure, the two column body grooves 2 are both circular, the two column top grooves 3 are both cross-shaped, the two monitoring columns 1 are buried in the shotcrete 4 through drilling, and the bottoms of the two monitoring columns 1 are located at the junction of the shotcrete 4 and the surrounding rock 5.

[0031] The working principle of the device of the present application is as follows: a mechanical or electronic vernier caliper is used to measure the distance between the column grooves 2 and the column top grooves 3 of the two monitoring columns 1, and the distance between the column grooves 2 and the interface between the monitoring column 1 and the shotcrete 4 of a single monitoring column 1. As the cavern is excavated, the distance between the column grooves 2 and the column top grooves 3 of the two monitoring columns 1 is continuously measured. Since the distance between the column top grooves 3 and the column grooves 2 is a fixed value, the change in the angle between the two monitoring columns 1 can be calculated; at the same time, the distance between the interface between the two monitoring columns 1 and the shotcrete 4 can be calculated, and the difference from the initial value is the crack width. At the same time, the curvature of the shotcrete 4 can be calculated based on the angle and the distance between the interface between the two monitoring columns 1 and the concrete. The utility model is convenient to measure, and the measurement method can calculate multiple monitoring quantities. It is very suitable for monitoring the crack width and curvature changes of the shotcrete 4 in the large structural surface 6.

[0032] In the initial state, the two groups of monitoring columns 1 are arranged in parallel, and the angle is 0°. The distance between the bottom holes of the two groups of monitoring columns 1 is measured by a mechanical or electronic vernier caliper as L3; the length of the monitoring column 1 is measured as L7, the distance between the column grooves 2 of the two groups of monitoring columns 1 is measured as L2, and the distance between the column top grooves 3 of the two groups of monitoring columns 1 is measured as L1.

[0033] Before the cracks appeared, the initial average distance between the two groups of monitoring columns 1 was:

[0034] L 初 =(L2 初 +L1 初 ) / 2

[0035] As indicated Figure 5 In this embodiment, when cracks appear in the shotcrete 4, the final average distance between the two groups of monitoring columns 1 is

[0036] L 末 =(L2 末 +L1 末 ) / 2

[0037] Crack width 2×L6=L 末 -L 初

[0038] A mechanical or electronic vernier caliper measures the distance L5 between the column body groove 2 and the column top groove 3 of two monitoring columns 1, sin θ=L6 / L5, and the angle between the two groups of monitoring columns 1 is 2θ.

[0039] 2θ = 2 × arc sin (L6 / L5)

[0040] The angle change of a single monitoring column 1 is θ, then the angle between the two groups of monitoring columns 1 is 2θ, and the distance between the two groups of monitoring columns 1 and the interface of the shotcrete 4 is L3. Since sin θ=L3 / (2×L4), it can be calculated that L4=L3 / (2×sin θ). Therefore, taking the intersection of the two groups of monitoring columns 1 as the center of the circle, the distance from the center of the circle to the column top groove 3 is the radius R, R=L7+L4. According to the curvature calculation formula in the prior art, it is concluded that the curvature of the circle with an angle of 2θ and a radius of R is 1 / R, that is, the curvature of the shotcrete 4 is 1 / R.

[0041] Example 2

[0042] A device for monitoring crack width and curvature of shotcrete in large structural surfaces within a large underground cavern group. Figure 2~Figure 4 As shown, it includes two groups of cylindrical monitoring columns 1, the length of the monitoring columns 1 is 40~80cm, the diameter D1 of the monitoring columns 1 is 4cm, and the two groups of monitoring columns 1 are completely identical and of equal length; each group of monitoring columns 1 is also provided with a column body groove 2 and a column top groove 3; the column body groove 2 is a circular ring groove around the cylindrical monitoring column 1, the column body groove 2 has a depth D2 of 0.2~0.3cm, and a width W1 of 0.2~0.3cm, and the column top groove 3 is a cross-shaped groove at the top of the cylindrical monitoring column 1, the groove depth D3 is 0.2~0.3cm, and the width W2 is 0.2~0.3cm. The spacing between the column body groove 2 and the column top groove 3 is 15cm. After the shotcrete 4 is completed, two cylindrical monitoring columns 1 are drilled. The two drilling positions are about 5 to 10 cm away from the boundary of the large structural surface 6. The drilling depth is the junction of the shotcrete 4 and the surrounding rock 5. After the monitoring column 1 is installed, the monitoring column 1 and the drilled hole pores are filled with high-pressure cement slurry.

[0043] Both groups of monitoring columns 1 are circular, with a flat pier on the top and a cross-shaped groove on the flat pier; the column groove 2 of the monitoring column 1 is circular; the monitoring column 1 is buried in the shotcrete 4 through drilling, the drilling depth is the junction of the shotcrete 4 and the surrounding rock 5, and is fixed with high-pressure cement slurry during installation.

[0044] After the cylindrical monitoring columns 1 are installed, the first distance measurement is performed. The distance between the column body grooves 2 of the two groups of monitoring columns 1 and the distance between the column top grooves 3 of the two groups of monitoring columns 1 are measured respectively, and the average value of the two is used as the initial value of the distance between the two monitoring columns 1.

[0045] At the same time, the column grooves 2 of the two monitoring columns 1 and the distance between the monitoring column 1 and the concrete interface are measured respectively, and the average of the two results is used as the column grooves 2 of the monitoring column 1 and the distance between the monitoring column 1 and the concrete interface. The measuring tool is an electronic or mechanical vernier caliper, and then continuous monitoring is carried out as the cavern is excavated. According to the difference between the average values ​​of the spacing between the two groups of column grooves 2 and the spacing between the two groups of column top grooves 3 in the initial and final states, and the distance L5 between the column grooves 2 and the column top grooves 3 of a single monitoring column 1, the change in the angle between the two monitoring columns 1 is calculated, so as to reflect the change in the crack width and curvature of the shotcrete 4 at the position of the large structural surface 6 during the cavern excavation process, and indirectly reflect the shear dislocation of the large structural surface 6 during the cavern excavation process.

[0046] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be modified and varied in various ways. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for monitoring crack width and curvature of shotcrete on large structural surfaces in large underground caverns, characterized in that: The monitoring columns (1) include two groups of monitoring columns (1), each of which is provided with a column body groove (2) and a column top groove (3). The column body groove is a circular groove with a width of 0.2-0.3 cm and a depth of 0.2-0.3 cm. The column top groove is a cross-shaped groove with a groove width of 0.2-0.3 cm and a depth of 0.2-0.3 cm.

2. A device for monitoring crack width and curvature of shotcrete on large structural surfaces in large underground caverns according to claim 1, characterized in that: The monitoring column (1) has a length of 40 to 80 cm.

3. The device for monitoring crack width and curvature of shotcrete on large structural surfaces in large underground caverns according to claim 1, characterized in that: The diameter of the monitoring column (1) is 3 to 6 cm.

4. A device for monitoring crack width and curvature of shotcrete at large structural surfaces in large underground caverns according to claim 1, characterized in that: The distance between the column body groove (2) and the column top groove (3) is 10 to 20 cm.

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