Method for determining disturbance stress caused by rock mass excavation

Abstract

The embodiments of the present application relate to the technical field of testing or analyzing materials by means of determining the chemical or physical properties of the materials, and in particular to a method for determining the disturbance stress of rock excavation. The method mainly includes the steps of: installing a glue layer and a strain gauge at the measuring point, injecting cement slurry at the measuring point to form a cement slurry layer in the rock mass, the strain gauge is arranged in the glue layer, and the cement slurry layer is formed between the glue layer and the rock mass; determining a correction coefficient for correcting the measured value of the strain gauge; and determining the disturbance stress of rock excavation according to the strain value of the cement slurry layer. According to the method, it is not necessary to directly install the glue layer and the strain gauge in the borehole at the measuring point of the rock mass. The stress acquisition device set by the above method has no gap with the hole wall due to the effect of the cement slurry layer, and the stress acquisition device can be effectively fixed, and the influence of the cement slurry layer is taken into account, and the measured value of the strain gauge is corrected by using the correction coefficient to make the determined disturbance stress of rock excavation more accurate.

Description

Technical Field

[0001] Embodiments of the present application relate to the technical field of testing or analyzing materials by means of determining the chemical or physical properties of the materials, and in particular, to a method for determining disturbance stress caused by rock excavation. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] In operations such as tunneling or ore mining, it is necessary to analyze the conditions of the rock mass in the excavation and mining area at any time, so as to timely understand the changes in the physical properties of the rock mass caused by external forces during the operation, and judge the safety of the working environment based on the changes. Summary of the invention

[0004] A brief overview of the present application is provided below in order to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0005] An embodiment of the present application proposes a method for determining the disturbance stress of rock excavation, which includes the following steps: S1: determining a measuring point on the rock mass; S2: installing a glue layer and a strain gauge at the measuring point, and injecting cement slurry at the measuring point to form a cement slurry layer in the rock mass, the strain gauge is arranged in the glue layer, and the cement slurry layer is formed between the glue layer and the rock mass; S3: obtaining data measured by the strain gauge; S4: determining the measurement value of the strain gauge based on the data; S5: determining a correction coefficient for correcting the measurement value of the strain gauge; S6: determining the strain value of the cement slurry layer based on the correction coefficient and the measurement value of the strain gauge; S7: determining the disturbance stress of rock excavation based on the strain value of the cement slurry layer.

[0006] According to the method provided in the embodiment of the present application, it is not necessary to directly install the glue layer and the strain gauge in the borehole at the measuring point of the rock mass. Due to the effect of the cement slurry layer, there is no gap between the stress acquisition device set by the above method and the hole wall, and the stress acquisition device can be effectively fixed. In addition, considering the influence of the cement slurry layer, the measurement value of the strain gauge is corrected by using the correction coefficient to make the determined disturbance stress of rock excavation more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to further illustrate the above and other advantages and features of the present application, the specific embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. The accompanying drawings together with the following detailed description are included in this specification and form a part of this specification. Elements with the same function and structure are represented by the same reference numerals. It should be understood that these drawings only describe typical examples of the present application and should not be regarded as limiting the scope of the present application.

[0008] Figure 1 A schematic diagram of the structure of adhesive layer-strain gauge-cement slurry layer-rock mass according to an embodiment of the present application is shown;

[0009] Figure 2 is a schematic diagram of a grouting method when the direction of the drilling hole is inclined upward according to an embodiment of the present application;

[0010] Figure 3 is a schematic diagram of a grouting method when the direction of the drilling hole is inclined downward according to an embodiment of the present application;

[0011] Figure 4 is a schematic diagram of a grouting method when the direction of the drilling hole is horizontal according to an embodiment of the present application;

[0012] Figure 5 is a diagram showing the relationship between the disturbance stress and time at the first measuring point according to an embodiment of the present application;

[0013] Figure 6 4 is a diagram showing the relationship between the disturbance stress and time at the second measuring point according to an embodiment of the present application.

[0014] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner that does not affect the reader's understanding.

[0015] Explanation of the reference numerals: 10, rock mass; 20, adhesive layer; 30, strain gauge; 40, cement slurry layer; 100, mounting pipe; 101, centering piece; 200, grouting pipe; 300, cable line; 400, exhaust pipe; 11, drilling hole. DETAILED DESCRIPTION

[0016] Exemplary embodiments of the present application will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual implementation are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the process of developing any such actual implementation in order to achieve the developer's specific goals, such as meeting those constraints related to the system and business, and these constraints may vary from implementation to implementation. In addition, it should be understood that although the development work may be very complex and time-consuming, it is only a routine task for those skilled in the art who benefit from the content of this application.

[0017] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure and / or processing steps closely related to the scheme according to the present application are shown in the accompanying drawings, while other details that are not very relevant to the present application are omitted.

[0018] The disclosure below provides a plurality of different embodiments or examples to implement the present application. In order to simplify the disclosure of the present application, the parts and methods of specific examples are described below. Of course, they are merely examples, and the purpose is not to limit the present application. In the description of the embodiments of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0019] In the prior art, a stress acquisition device is usually installed on the rock mass, and the stress of the rock mass is collected at any time by the stress acquisition device, and the change of the physical properties of the rock mass is judged by analyzing the stress. However, the inventors found that the following problems exist in using the existing stress acquisition device to monitor the stress of the rock mass: when the existing stress acquisition device is installed on the small hole of the rock mass, there is a gap between the stress acquisition device and the hole wall, which makes the stress acquisition device unable to be effectively fixed, and there is a deviation in the reliability of the strain data, resulting in distortion of the analysis of the physical properties of the rock mass based on this.

[0020] In view of the above problems, an embodiment of the present application proposes a method for determining the disturbance stress caused by rock excavation, which includes the following steps: S1: determining a measuring point on the rock mass; S2: installing a glue layer and a strain gauge at the measuring point, and injecting cement slurry at the measuring point to form a cement slurry layer in the rock mass, the strain gauge is arranged in the glue layer, and the cement slurry layer is formed between the glue layer and the rock mass; S3: obtaining data measured by the strain gauge; S4: determining the measurement value of the strain gauge based on the data; S5: determining a correction coefficient for correcting the measurement value of the strain gauge; S6: determining the strain value of the cement slurry layer based on the correction coefficient and the measurement value of the strain gauge; S7: determining the disturbance stress caused by rock excavation based on the strain value of the cement slurry layer.

[0021] According to the method provided in the embodiment of the present application, it is not necessary to directly install the glue layer and the strain gauge in the drill hole at the measuring point of the rock mass, such as Figure 1 As shown, Figure 1 The schematic diagram of the structure of the adhesive layer-strain gauge-cement slurry layer-rock mass according to the embodiment of the present application is shown. The stress acquisition device is set by the above method. Due to the effect of the cement slurry layer, there is no gap with the hole wall, the stress acquisition device can be effectively fixed, and the influence of the cement slurry layer is taken into account, and the measurement value of the strain gauge is corrected by using the correction coefficient to make the determined disturbance stress of rock mass excavation more accurate.

[0022] like Figure 1As shown, a glue layer 20 and a strain gauge 30 are installed at the measuring point of the rock mass 10 , and cement slurry is injected at the measuring point to form a cement slurry layer 40 in the rock mass. The strain gauge 30 is arranged in the glue layer 20 , and the cement slurry layer 40 is formed between the glue layer 20 and the rock mass 10 .

[0023] According to some embodiments of the present application, in step S5, the correction coefficient is determined according to the borehole diameter and the thickness of the cement slurry layer at the measuring point. The correction coefficient determined in the above manner can accurately correct the direct measurement result of the strain gauge. In addition, the determination of the borehole diameter and the thickness of the cement slurry layer is easy to implement and has high accuracy, and will not generate new interference factors.

[0024] According to some embodiments of the present application, the borehole diameter, the thickness of the cement slurry layer, and the correction coefficient satisfy the following relationship:

[0025] ;

[0026] Wherein, η represents the correction coefficient, D represents the borehole diameter, and d represents the thickness of the cement slurry layer. The correction coefficient can be further accurately determined by the above relationship.

[0027] According to some embodiments of the present application, in step S6, the correction coefficient, the measured value of the strain gauge, and the strain value of the cement slurry layer satisfy the following relationship:

[0028] ;

[0029] Where η is the correction factor, represents the strain value of the cement slurry layer, Represents the measured value of the strain gauge. Through the above relationship, under the condition of considering the influence of the cement slurry layer, the measured value of the slurry strain gauge is accurately converted into the strain value of the cement slurry layer, thereby further improving the accuracy of the disturbance stress of rock excavation.

[0030] According to some embodiments of the present application, in step S2, a hole of a predetermined size is drilled at the measuring point, and then the glue layer and the strain gauge are installed in the hole. According to the method provided in the embodiment of the present application, when it is used on site, only a large hole is drilled, for example, the hole diameter is 75~130 mm, and the glue layer and the strain gauge are placed in the large hole. Thereby, the requirements for opening holes in the prior art are overcome. For example, in the prior art, there are problems such as construction difficulties, difficulty in placing strain acquisition devices, and high bonding failure rates by drilling small holes in large holes, and operators with rich experience are required. The operation threshold is high, and improper operation directly leads to failure of monitoring stress. Using the method provided in the embodiment of the present application, especially in broken rock masses, such as coal rock masses, cement slurry can fill the cracks and form a layer of homogeneous body around the glue layer and the strain gauge, so that it can be suitable for monitoring the disturbed stress of broken rock masses.

[0031] According to some embodiments of the present application, the correction coefficient can also be determined in the following manner. In step S5, the following steps are also included: determining the measurement value of the strain gauge under the condition of no glue layer, and determining the correction coefficient based on the measurement value of the strain gauge under the condition of no glue layer and the measurement value obtained in step S4.

[0032] The measured value of the strain gauge without the adhesive layer can be determined by simulation, and then compared with the measured value obtained in step S4, and the correction coefficient can be further determined based on the comparison result of the two.

[0033] The embodiments of the present application provide the above two methods for determining the correction coefficient. However, those skilled in the art may also adopt other methods for determining the correction coefficient according to the principle and influence of the adhesive layer on strain transfer.

[0034] According to some embodiments of the present application, in step S2, the cement slurry is injected at the measuring point so that the cement slurry completely covers the adhesive layer and leaves no gap between the wall of the borehole at the measuring point. On this basis, the reliability of the above method and the accuracy of the data obtained can be provided.

[0035] In actual application, since the directions of drilling may be different, different grouting methods need to be used in the grouting process.

[0036] Figure 2 , Figure 3 as well as Figure 4 The grouting methods of different drilling methods are shown respectively, specifically, Figure 2 It is a schematic diagram of the grouting method when the direction of the drilling hole is inclined upward; Figure 3 It is a schematic diagram of the grouting method when the direction of the drilling hole is inclined downward; Figure 4 It is a schematic diagram of the grouting method when the drilling direction is horizontal.

[0037] According to an embodiment of the present application, when the adhesive layer 20 is arranged in the borehole 11, the adhesive layer 20 is placed in the borehole 11 using the mounting tube 100. Figure 2 As shown, when the direction of the borehole 11 is inclined upward, when grouting is injected into the borehole 11 , it is configured to seal the borehole 11 and inject grout into the borehole 11 using the grouting pipe 200 .

[0038] exist Figure 2In the grouting method shown, the strain gauge 30 is pre-set on the adhesive layer 20, and the adhesive layer 20 is placed in the borehole 11 using the mounting tube 100. The cable 300 extends from the mounting tube 100 out of the borehole 11 and is connected to an external data receiving and processing device (not shown in the figure). The mounting tube 100 is also provided with a centering piece 101 so that the adhesive layer 20 can be installed in a centered manner. When performing the grouting operation, the borehole 11 is first sealed, and then cement slurry is injected into the borehole 11 using the grouting tube 200. Among them, the mounting tube 100 is also used as an exhaust to discharge the gas in the borehole during the grouting process.

[0039] exist Figure 3 In the grouting method shown, the strain gauge 30 is pre-set on the adhesive layer 20, and the adhesive layer 20 is placed in the borehole 11 using the mounting tube 100. The cable 300 extends from the mounting tube 100 out of the borehole 11 and is connected to an external data receiving and processing device (not shown in the figure). The mounting tube 100 is also provided with a centering member 101 to facilitate the centering installation of the adhesive layer 20. When performing the grouting operation, the mounting tube 100 is used as a grouting tube, and cement slurry is injected into the borehole 11 through the mounting tube 100. Among them, the gas in the borehole 11 can be discharged from the borehole, and there is no need to set up an additional exhaust device for exhaust.

[0040] exist Figure 4 In the grouting method shown, the strain gauge 30 is pre-set on the adhesive layer 20, and the adhesive layer 20 is placed in the borehole 11 using the mounting tube 100. The cable 300 extends from the mounting tube 100 out of the borehole 11 and is connected to an external data receiving and processing device (not shown in the figure). The mounting tube 100 is also provided with a centering piece to facilitate the centering installation of the adhesive layer 20. When performing the grouting operation, the mounting tube 100 is used as a grouting tube, and cement slurry is injected into the borehole 11 through the mounting tube 100. Among them, it is also necessary to set an exhaust pipe 400 at the connection between the borehole 11 and the outside so that the gas in the borehole 11 can be discharged from the borehole. In addition, the orifice of the borehole 11 needs to be sealed.

[0041] In addition, in step S7, the disturbance stress of rock mass excavation is determined according to the strain value of the cement slurry layer, and those skilled in the art can calculate and determine it through existing calculation models.

[0042] Figure 5 is a diagram showing the relationship between the disturbance stress and time at the first measuring point according to an embodiment of the present application, Figure 6 4 is a diagram showing the relationship between the disturbance stress and time at the second measuring point according to an embodiment of the present application.

[0043] Figure 5 and Figure 6 According to the embodiment of the present application, different measuring points are monitored, and the obtained disturbance stress and time relationship are plotted into a curve.

[0044] in, Figure 5 Curve 1 in the figure shows the change of the disturbance stress in the x direction with time. Figure 5 Curve 2 in the figure shows the change of the disturbance stress in the y direction with time. Figure 5 Curve 3 in FIG. 3 shows the variation of the disturbance stress in the z direction with time.

[0045] Figure 6 Curve 4 in the figure shows the change of the disturbance stress in the x direction with time. Figure 6 Curve 5 in the figure shows the change of the disturbance stress in the y direction with time. Figure 6 Curve 6 in FIG. 5 shows the variation of the disturbance stress in the z direction with time.

[0046] Depend on Figure 5 and Figure 6 It can be seen that the stress field changes in the x direction (horizontal direction) are all manifested as stress reduction, and the stress field changes in the y direction (vertical direction) are manifested as stress increase. The main reason is that after excavation, the rock mass releases stress into the hole, and stress concentration occurs in the vertical direction of the rock mass. The above results are also consistent with the stress monitoring results determined by computer simulation and theoretical analysis, further verifying the reliability and accuracy of the method provided in the embodiment of the present application for disturbance stress monitoring.

[0047] Regarding the embodiments of the present application, it should also be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other to obtain new embodiments.

[0048] The above are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for determining disturbance stress of rock mass excavation, characterized in that: It includes the following steps: S1: Determine the measuring point on the rock mass; S2: installing a glue layer and a strain gauge at the measuring point, injecting cement slurry at the measuring point to form a cement slurry layer in the rock mass, wherein the strain gauge is arranged in the glue layer, and the cement slurry layer is formed between the glue layer and the rock mass; S3: Obtain the data measured by the strain gauge; S4: Determine the measurement value of the strain gauge according to the data; S5: Determine a correction coefficient for correcting the measured value of the strain gauge; S6: determining the strain value of the cement slurry layer according to the correction coefficient and the measured value of the strain gauge; S7: determining the disturbance stress of the rock mass excavation according to the strain value of the cement slurry layer; The diameter of the drill hole, the thickness of the cement slurry layer and the correction coefficient satisfy the following relationship: ； Wherein, η represents the correction coefficient, D represents the diameter of the borehole, and d represents the thickness of the cement slurry layer; In step S6, the correction coefficient, the measured value of the strain gauge, and the strain value of the cement slurry layer satisfy the following relationship: ； Wherein, η represents the correction coefficient, represents the strain value of the cement slurry layer, Indicates the measured value of the strain gauge; In step S2, cement slurry is injected at the measuring point so as to completely cover the adhesive layer and the wall of the drilled hole at the measuring point without leaving any gap.

2. The method according to claim 1, characterized in that In step S5, the correction coefficient is determined according to the diameter of the drill hole at the measuring point and the thickness of the cement slurry layer.

3. The method according to claim 1 or 2, characterized in that: In step S2, a hole of a predetermined size is drilled at the measuring point, and then the adhesive layer and the strain gauge are installed in the hole.

4. The method according to claim 1, characterized in that: When the adhesive layer is arranged in the drill hole, the adhesive layer is placed in the drill hole by using a mounting tube. When the direction of the borehole is inclined upward, when grouting is injected into the borehole, it is configured to seal the borehole and inject grout into the borehole using a grouting pipe.

5. The method according to claim 1, characterized in that When the adhesive layer is arranged in the drill hole, the adhesive layer is placed in the drill hole by using a mounting tube. When the direction of the borehole is inclined downward, when grouting is injected into the borehole, the installation pipe is used as a grouting pipe to inject grout into the borehole.

6. The method according to claim 1, characterized in that When the adhesive layer is arranged in the drill hole, the adhesive layer is placed in the drill hole by using a mounting tube. When the direction of the borehole is horizontal, when grouting is injected into the borehole, the installation pipe is used as a grouting pipe to inject grout into the borehole.

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