Grouting stress field testing method and system

Abstract

The invention relates to a grouting stress field testing method and system. The grouting stress field test system comprises the following steps: manufacturing a sample: preparing a castable according to the mechanical properties of simulated surrounding rock, reserving a grouting hole in a mold, pouring the castable into the mold, pre-embedding a distributed strain optical fiber measuring line, and enabling a part of the distributed strain optical fiber measuring line to be perpendicular to the axial direction of the grouting hole; connecting pipes are installed at the open ends of the grouting holes; mounting a grouting pump for grouting; strain data obtained by the distributed strain optical fiber measuring lines at different times are collected in the time period from grouting starting to slurry solidification, and stress data are obtained by multiplying the strain data by the elastic modulus of the sample. According to the grouting stress field testing method, the distribution characteristics of the grouting stress field generated by the grouting pressure in the surrounding rock are tested and obtained from the perspective of a laboratory, support is provided for design of parameters such as surrounding rock grouting hole parameters and grouting pressure for deep ground energy development, meanwhile, the grouting reinforcement effect is improved, and the stability of the surrounding rock is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of deep earth energy development, and in particular to a grouting stress field testing method and system. Background Art

[0002] In the deep-earth energy development industry, all broken rock tunnels and tunnels need to be reinforced by grouting. The slurry enters the cracks inside the surrounding rock and solidifies, restoring the integrity of the broken surrounding rock and forming a network skeleton, thereby increasing the strength of the surrounding rock, improving the stability of the surrounding rock and ensuring safety.

[0003] Traditional grouting methods are mostly low-pressure filling grouting. The grouting pressure is generally within 3MPa, and there are many losses during the grouting process. The pressure entering the surrounding rock is almost attenuated to 0, and the slurry only plays the role of filling cracks and solidifying reinforcement. With the increase of burial depth, the cracks are re-compacted and closed by high stress. The use of low-pressure grouting often leads to extremely limited grouting volume, which seriously affects the grouting reinforcement effect. Therefore, a high-pressure splitting grouting method is proposed, which is obviously different from low-pressure passive grouting. Under high pressure, the slurry injection volume is not only greatly increased, but also the high-value grouting pressure generates a grouting stress field inside the surrounding rock, actively squeezes the surrounding rock, and greatly improves the strength of the surrounding rock. However, the distribution law of the grouting stress field is still unclear, and there is a lack of theoretical guidance for the formulation of high-pressure grouting reinforcement design schemes. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of the present invention proposes a grouting stress field testing method, which tests and obtains the distribution characteristics of the grouting stress field generated by the grouting pressure in the surrounding rock, provides support for the design of parameters such as surrounding rock grouting hole parameters and grouting pressure, and at the same time improves the grouting reinforcement effect and ensures the stability of the surrounding rock.

[0006] An embodiment of the present invention further provides a grouting stress field testing system.

[0007] The grouting stress field testing method according to an embodiment of the present invention is characterized by comprising the following steps:

[0008] Step A, making samples:

[0009] Step A1, preparing casting material according to the mechanical properties of the simulated surrounding rock;

[0010] Step A2, preparing a mold and reserving a grouting hole in the mold;

[0011] Step A3, pouring the casting material into the mold, and burying the middle part of the distributed strain optical fiber measuring line in the casting material in the mold during the pouring process, a part of the middle part of the distributed strain optical fiber measuring line is perpendicular to the axial direction of the grouting hole, two ends of the distributed strain optical fiber measuring line extend from opposite ends of the casting material in the mold respectively, and the ends of the distributed strain optical fiber measuring line are connected to the monitoring equipment;

[0012] Step A4, after pouring, curing;

[0013] Step B: installing a connecting pipe at the open end of the grouting hole;

[0014] Step C, installing a grouting pump for grouting: installing a valve on the connecting pipe, connecting the grouting pump, the grouting pipe and the valve in sequence, then opening the valve and the grouting pump to start grouting, and closing the valve after the grouting is completed;

[0015] Step D, collecting strain data obtained by the distributed strain optical fiber measuring line at different times from the start of grouting to the solidification of the slurry, and multiplying the strain data by the elastic modulus of the sample to obtain stress data.

[0016] The grouting stress field testing method of the embodiment of the present invention tests and obtains the distribution characteristics of the grouting stress field generated by the grouting pressure in the surrounding rock from a laboratory perspective, providing support for the design of parameters such as grouting hole parameters and grouting pressure of the surrounding rock of tunnels in mining, transportation and other industries, while improving the grouting reinforcement effect and ensuring the stability of the surrounding rock.

[0017] In some embodiments, the grouting stress field testing method further includes step E, repeating steps A to D, and using different grouting pressures for grouting in step C to obtain stress data under different grouting pressures and at different times, thereby producing a grouting stress cloud map.

[0018] In some embodiments, in step A1, the casting material is prepared according to the uniaxial compressive strength of the simulated surrounding rock, so that the uniaxial compressive strength of the sample is the same as that of the simulated surrounding rock.

[0019] In some embodiments, in the axial direction of the grouting hole, the bottom of the grouting hole is at least 50 mm away from the surface of the adjacent sample, and in the radial direction of the grouting hole, the wall of the grouting hole is at least 100 mm away from the surface of the adjacent sample.

[0020] In some embodiments, the number of the grouting holes is two, and the middle of the distributed strain optical fiber measuring line is located between the two grouting holes.

[0021] In some embodiments, the grouting pump is a special test pump, and the flow rate of the grouting pump is 1-600mL / min.

[0022] In some embodiments, the middle portion of the distributed strain optical fiber measuring line is serpentine and includes multiple straight segments and multiple bent segments, the straight segments are connected to the bent segments, the straight segments extend radially along the grouting hole, multiple straight segments are parallel and spaced apart in the axial direction of the grouting hole, different straight segments correspond to different depths of the grouting hole, and the bent segment located at one end of the straight segment is adjacent to the grouting hole.

[0023] In some embodiments, in step B, the open end of the grouting hole is facing upward, sodium chloride is poured into the grouting hole, a connecting pipe with a diameter smaller than the grouting hole is placed into the grouting hole, glue is injected into the gap between the grouting hole and the connecting pipe, and after the glue solidifies, clean water is poured into the grouting hole to melt the sodium chloride, and then the sample is inverted to pour out the sodium chloride solution; and / or, a threaded section is provided on the connecting pipe, and the valve is connected to the connecting pipe by threads.

[0024] In some embodiments, step G is added between step A and step C, avoiding the grouting hole, and spraying a flexible thin spray material on the surface of the sample to seal the surface of the sample, and the spraying thickness is not less than 10 mm.

[0025] The grouting stress field testing system of the embodiment of the present invention includes a sample, a distributed strain optical fiber measuring line, a monitoring device, a connecting pipe, a grouting pump, a grouting pipe and a valve. The sample is provided with a grouting hole; the middle part of the distributed strain optical fiber measuring line is buried in the sample, and the two ends of the distributed strain optical fiber measuring line are respectively located outside the opposite ends of the sample, and a part of the middle part of the distributed strain optical fiber measuring line is perpendicular to the axial direction of the grouting hole; the distributed strain optical fiber measuring line is connected to the monitoring device; the connecting pipe is installed at the open end of the grouting hole; the grouting pump, the grouting pipe, the valve and the connecting pipe are connected in sequence.

[0026] In some embodiments, in the axial direction of the grouting hole, the bottom of the grouting hole is at least 50 mm away from the surface of the adjacent sample, and in the radial direction of the grouting hole, the wall of the grouting hole is at least 100 mm away from the surface of the adjacent sample.

[0027] In some embodiments, the middle portion of the distributed strain optical fiber measuring line is serpentine and includes a plurality of straight segments and a plurality of bent segments, the straight segment and the bent segment are connected, the straight segment extends along the radial direction of the grouting hole, a plurality of the straight segments are parallel and spaced apart in the axial direction of the grouting hole, different straight segments correspond to different depths of the grouting hole, and the bent segment located at one end of the straight segment is adjacent to the grouting hole;

[0028] In some embodiments, the number of the grouting holes is two, and the middle of the distributed strain optical fiber measuring line is located between the two grouting holes.

[0029] In some embodiments, the connecting pipe is bonded into the grouting hole.

[0030] In some embodiments, the grouting pump is a special test pump, and the flow rate of the grouting pump is 1-600mL / min.

[0031] In some embodiments, the grouting stress field testing system further includes a flexible thin spray material layer, which is arranged on the surface of the sample, and the thickness of the flexible thin spray material layer is not less than 10 mm.

[0032] The grouting stress field testing system of the embodiment of the present invention is applied to the grouting stress field testing method of the embodiment of the present invention. The grouting stress field testing system of the embodiment of the present invention is used to obtain the characteristics of the grouting stress field under different grouting pressures and at different times. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of a grouting stress field testing system according to an embodiment of the present invention;

[0034] Figure 2 Schematic diagram of the structure of a sample according to an embodiment of the present invention.

[0035] Reference numerals:

[0036] Testing system 100,

[0037] Sample 1, grouting hole 11, distributed strain optical fiber measuring line 2, straight section 21, bending section 22, monitoring equipment 3, connecting pipe 4, grouting pump 5, valve 6, grouting pipe 7. DETAILED DESCRIPTION

[0038] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0039] Please refer to the attached Figure 1 to Figure 2 , describe in detail the grouting stress field testing method and system of the embodiments of the present invention.

[0040] A grouting stress field testing system 100 according to an embodiment of the present invention comprises a sample 1, a distributed strain optical fiber measuring line 2, a monitoring device 3, a connecting pipe 4, a grouting pump 5, a grouting pipe 7 and a valve 6. The sample 1 is provided with a grouting hole 11, the middle part of the distributed strain optical fiber measuring line 2 is buried in the sample 1, the two ends of the distributed strain optical fiber measuring line 2 are respectively located outside the opposite ends of the sample 1, a part of the middle part of the distributed strain optical fiber measuring line 2 is perpendicular to the axial direction of the grouting hole 11, the distributed strain optical fiber measuring line 2 is connected to the monitoring device 3, the connecting pipe 4 is installed at the open end of the grouting hole 11, and the grouting pump 5, the grouting pipe 7, the valve 6 and the connecting pipe 4 are connected in sequence.

[0041] A grouting stress field testing system 100 according to an embodiment of the present invention is applied to a grouting stress field testing method according to an embodiment of the present invention.

[0042] A grouting stress field testing method according to an embodiment of the present invention comprises the following steps:

[0043] Step A, preparation of sample 1:

[0044] Step A1, preparing casting material according to the mechanical properties of the simulated surrounding rock;

[0045] Step A2, preparing a mold and reserving a grouting hole 11 in the mold;

[0046] Step A3, pouring the casting material into the mold, and burying the middle part of the distributed strain optical fiber measuring line 2 in the casting material in the mold during the pouring process, a part of the middle part of the distributed strain optical fiber measuring line 2 is perpendicular to the axial direction of the grouting hole 11, and the two ends of the distributed strain optical fiber measuring line 2 extend from the opposite ends of the casting material in the mold respectively, and the ends of the distributed strain optical fiber measuring line 2 are connected to the monitoring device 3;

[0047] Step A4, after pouring, curing;

[0048] Step B: Install the connecting pipe 4 at the open end of the grouting hole 11;

[0049] Step C, installing the grouting pump 5 for grouting: installing the valve 6 on the connecting pipe 4, connecting the grouting pump 5, the grouting pipe 7 and the valve 6 in sequence, and then opening the valve 6 and the grouting pump 5 to start grouting. After the grouting is completed, closing the valve 6;

[0050] Step D, collecting strain data obtained by the distributed strain optical fiber measuring line 2 at different times from the start of grouting to the solidification of the slurry, and multiplying the strain data by the elastic modulus of the sample 1 to obtain stress data.

[0051] A grouting stress field testing method according to an embodiment of the present invention prepares casting materials according to the mechanical properties of the simulated surrounding rock, so as to prepare a sample 1 having mechanical properties similar to or even identical to those of the simulated surrounding rock, thereby simulating the actual surrounding rock environment, so that the strain generated after grouting of sample 1 can reflect the actual strain of the surrounding rock after grouting.

[0052] The distributed strain optical fiber measuring line 2 is used for strain monitoring. On the one hand, the distributed strain optical fiber measuring line 2 has a small diameter and is relatively slender as a whole. It occupies a small space in the sample 1. It is not necessary to require the volume of the sample 1 to be large due to data monitoring, so that the volume of the sample 1 and the volume of the mold can be selected in a wide range, which is convenient for preparing the sample 1 and reducing the cost of the sample 1. On the other hand, the strip-shaped distributed strain optical fiber measuring line 2 can be bent, so that it is easy to arrange, so that a part of the distributed strain optical fiber can be arranged along the axis perpendicular to the grouting hole 11, so that after the sample 1 is grouted, the strain at different positions away from the grouting hole 11 can be monitored, so as to obtain strain data at different positions. It should be noted that after grouting the grouting hole 11, the strain generated diffuses to the surrounding along the radial direction of the grouting hole 11, and the diffusion has a certain range. The part of the distributed strain optical fiber perpendicular to the axial direction of the grouting hole 11 can monitor the strain data.

[0053] The open end of the grouting hole 11 is installed with a connecting pipe 4, which connects the valve 6 and the grouting pipe 7, so that the grouting hole 11 can be closed through the valve 6. After the grouting is completed and the valve 6 is closed, the grouting hole 11 is pressurized to prevent the slurry from overflowing from the open end of the grouting hole 11 and affecting the pressure of the grouting hole 11 and the strain caused after grouting.

[0054] Therefore, the grouting stress field testing method of the embodiment of the present invention tests and obtains the distribution characteristics of the grouting stress field generated by the grouting pressure in the surrounding rock from a laboratory perspective, providing support for the design of parameters such as the grouting hole 11 parameters and the grouting pressure of the surrounding rock of tunnels in mining, transportation and other industries, while improving the grouting reinforcement effect and ensuring the stability of the surrounding rock.

[0055] In some embodiments, in step A1, the casting material is prepared according to the uniaxial compressive strength of the simulated surrounding rock, so that the uniaxial compressive strength of the sample 1 is the same as that of the simulated surrounding rock. The uniaxial compressive strength of the surrounding rock is highly correlated with the strain generated after grouting of the surrounding rock. Keeping the uniaxial compressive strength of the prepared sample 1 the same as that of the simulated surrounding rock can improve the simulation degree of the sample 1 and improve the strain of the sample 1 after grouting to be close to the actual situation of the simulated surrounding rock, so that the stress data obtained by the grouting stress field test method of the embodiment of the present invention is reliable and referenceable.

[0056] For example, the surrounding rock simulated by Sample 1 is a rock layer with a uniaxial compressive strength of 20 MPa, and the raw materials of the castable include river sand, cement, gypsum and water, which are mixed and stirred to form the castable.

[0057] Specifically, in step A2, the mold size is 500mm*500mm*500mm. In step A3, during the casting process of the casting material into the mold, a grouting hole 11 is reserved, a distributed strain optical fiber measuring line 2 is buried, and a vibrator is used to vibrate the casting material to ensure the compactness of the casting.

[0058] In some embodiments, in step A, in the axial direction of the grouting hole 11, the bottom of the grouting hole 11 is at least 50 mm away from the surface of the adjacent sample 1. Figure 1 As shown, the grouting hole 11 extends in the up-down direction, the open end of the grouting hole 11 is located at the upper end, the surface of the sample 1 adjacent to the bottom of the grouting hole 11 is the bottom surface of the sample 1, and the bottom of the grouting hole 11 is at least 50 mm away from the bottom surface of the sample 1. In this way, the sealing of the bottom of the grouting hole 11 can be ensured, and the slurry is prevented from seeping out from the bottom of the hole during the grouting and solidification process, which affects the pressure of the grouting hole 11 and the strain after grouting.

[0059] In the radial direction of the grouting hole 11, the wall of the grouting hole 11 is at least 100 mm away from the surface of the adjacent sample 1, which provides at least 100 mm of development space for the strain generated by grouting, so that the strain generated after grouting into the grouting hole 11 can extend to the surrounding area without artificial constraints (restrictions), thereby making the strain closer to the actual strain of the simulated surrounding rock, further improving the reliability and reference of the stress data obtained by the grouting stress field test method of the embodiment of the present invention.

[0060] In some embodiments, in step A3, the middle portion of the distributed strain optical fiber measuring line 2 is serpentine and includes a plurality of straight segments 21 and a plurality of bent segments 22, and the straight segments 21 and the bent segments 22 are connected. The straight segment 21 extends along the radial direction of the grouting hole 11, and the plurality of straight segments 21 are parallel and spaced apart in the axial direction of the grouting hole 11. Different straight segments 21 correspond to different depths of the grouting hole 11, and the bent segment 22 at one end of the straight segment 21 is adjacent to the grouting hole 11. In other words, referring to the attached Figure 1 , multiple straight segments 21 and multiple bent segments 22 are located on the same vertical plane, the straight segments 21 at different heights (corresponding to different depths of the grouting hole 11) can monitor the deformation data of the height (depth), and the straight segments 21 extend radially along the grouting hole 11, so that the strain data along the strain development direction at the same height (depth) can be monitored, and then the strain data at different positions in the strain development direction at different depths of the grouting hole 11 can be monitored, so that the grouting stress field testing method of the embodiment of the present invention obtains more and richer stress data, further improving the reliability and reference of the stress data.

[0061] In this embodiment, there are two grouting holes 11, and the middle of the distributed strain optical fiber measuring line 2 is located between the two grouting holes 11. After grouting, the strain between the two grouting holes 11 may be superimposed, so that the distributed strain optical fiber measuring line 2 is easier to monitor the data, and it also conforms to the actual situation of grouting the crack concentration area in the surrounding rock, so that the sample 1 can simulate a more complex grouting situation, thereby further improving the reliability and reference of the stress data obtained by the grouting stress field testing method of the embodiment of the present invention.

[0062] Specifically, in this embodiment, referring to the figure, the diameter of the grouting hole 11 is 36 mm, the spacing between two grouting holes 11 is 250 mm, and the hole depth is 450 mm. The length of the straight section 21 of the distributed strain optical fiber measuring line 2 is 142 mm, and the bending radius of the bending section 22 is 12 mm.

[0063] In some other embodiments, the number of grouting holes 11 is greater than two, such as three, four or five.

[0064] Specifically, in step A4, after pouring, watering and curing are carried out for 28 days under standard environment.

[0065] In some embodiments, in step B, the open end of the grouting hole 11 is facing upward, sodium chloride is poured into the grouting hole 11, the connecting pipe 4 with a diameter smaller than the grouting hole 11 is placed into the grouting hole 11, glue is injected into the gap between the grouting hole 11 and the connecting pipe 4, and after the glue solidifies, clear water is poured into the grouting hole 11 to melt the sodium chloride, and then the sample 1 is inverted to pour out the sodium chloride solution. After the glue solidifies, an adhesive layer is formed to fix and connect the wall surface of the grouting hole 11 and the connecting pipe 4.

[0066] Sodium chloride is a fine crystalline powder with a certain volume. After being poured into the grouting hole 11, it occupies a corresponding space, can provide support for the connecting pipe 4, and facilitate the bonding of the connecting pipe 4 to the wall of the grouting hole 11 through glue. In addition, sodium chloride is soluble in water. After the installation of the connecting pipe 4 is completed, the sodium chloride can be dissolved and discharged by water without affecting the grouting process of the grouting hole 11. Therefore, in step B, the installation method of the connecting pipe 4 and the grouting hole 11 is simple, easy to operate, and low in cost, which is conducive to improving the test efficiency of the grouting stress field test method of the embodiment of the present invention and reducing the test cost.

[0067] Specifically, when sodium chloride is poured into the grouting hole 11, it stops at a distance of 50 mm from the open end of the grouting hole 11. Then, the dimension of the connecting pipe 4 in the grouting hole 11 is 50 mm.

[0068] In this embodiment, epoxy resin glue is used as glue.

[0069] Furthermore, a threaded section is provided on the connecting pipe 4, and the valve 6 is connected to the connecting pipe 4 by threads. The threaded connection is simple, convenient for installing and removing the valve 6, and has good sealing performance.

[0070] In some embodiments, step G is added between step A and step C, avoiding the grouting hole 11, spraying a flexible thin spray material on the surface of the sample 1 to seal the surface of the sample 1, and the spraying thickness is not less than 10 mm. Avoiding the grouting hole 11 means not spraying the flexible thin spray material into the grouting hole 11.

[0071] Preferably, step G is performed after step B and between step C.

[0072] A flexible thin spray material is sprayed on the surface of the sample 1 to form a flexible thin spray material layer. The flexible thin spray material layer covers the surface of the sample 1. After spraying, a closed (sealed) layer can be formed on the surface of the sample 1, thereby preventing the slurry from seeping out of the surface of the sample 1 during the process of grouting into the grouting hole 11 until the slurry solidifies, causing the grouting pressure to be relieved, thereby ensuring the grouting pressure.

[0073] The flexible thin spray material adopts polyurethane thin spray material. The particle size of polyurethane thin spray material is small, and the anti-seepage effect after spraying is good.

[0074] In some embodiments, the grouting pump 5 is a test-specific pump, and the flow rate of the grouting pump 5 is 1-600 mL / min. The flow rate of the grouting pump 5 is adjustable, so as to facilitate the control and adjustment of the grouting flow rate and ensure the smoothness and safety of the grouting process.

[0075] Specifically, the rated pressure of the grouting pump 5 is 30 MPa, the grouting material adopts micro-nano inorganic organic composite grouting material, and the initial setting time is 2 hours.

[0076] In the related art, the slurry has an obvious time effect in the surrounding rock. Therefore, in step D, data is collected at different times. From the time when the slurry is just injected to the time when the slurry solidifies, the strain data of the distributed strain optical fiber measuring line 2 is collected every 30 minutes, and the strain data is multiplied by the elastic modulus of the sample 1 to obtain the stress data.

[0077] Furthermore, the grouting stress field testing method of the embodiment of the present invention includes step E. In step E, steps A to D are repeated, and different grouting pressures are used for grouting in step C to obtain stress data under different grouting pressures and at different times, thereby making a grouting stress cloud map.

[0078] What is obtained by the step A, step B, step G, step C and step D of the grouting stress field test method of the embodiment of the present invention is the stress data at different times (every 30 minutes interval) from the time when the slurry is just injected to the time when the slurry solidifies under a certain grouting pressure. By adding step E, repeating steps A, step B, step G, step C and step D, and selecting different grouting pressures in each repetition process, it is possible to obtain stress data at different grouting pressures and at different times. Based on this data, a grouting stress cloud map is drawn using a three-dimensional drawing software, and the respective characteristics of the grouting stress field at different grouting pressures and at different times can be obtained, so that the data obtained by the grouting stress field test method of the embodiment of the present invention can be more directly displayed.

[0079] Specifically, the grouting pressure is adjusted by adjusting the flow rate of the grouting pump 5 .

[0080] Furthermore, in step E, steps A to D are repeated five times, and the grouting pressures are selected as 1MPa, 2MPa, 3MPa, 4MPa and 5MPa respectively, and according to the set target grouting pressure, the flow rate of the grouting pump 5 is adjusted and controlled to ensure that the grouting pressure of the grouting process is carried out according to the set pressure.

[0081] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0082] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0083] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0084] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0085] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0086] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A grouting stress field testing method, characterized in that: The following steps are involved: Step A, preparing a sample (1): Step A1, preparing casting material according to the mechanical properties of the simulated surrounding rock; Step A2, preparing a mold and reserving a grouting hole (11) in the mold; Step A3, casting the casting material into a mold, and during the casting process, burying the middle part of the distributed strain optical fiber measuring line (2) in the casting material in the mold, a part of the middle part of the distributed strain optical fiber measuring line (2) is perpendicular to the axial direction of the grouting hole (11), and two ends of the distributed strain optical fiber measuring line (2) extend from opposite ends of the casting material in the mold respectively, and the ends of the distributed strain optical fiber measuring line (2) are connected to the monitoring equipment (3); Step A4, after pouring, curing; Step B: installing a connecting pipe (4) at the open end of the grouting hole (11); Step C, installing a grouting pump (5) for grouting: installing a valve (6) on the connecting pipe (4), connecting the grouting pump (5), the grouting pipe (7) and the valve (6) in sequence, then opening the valve (6) and the grouting pump (5) to start grouting, and closing the valve (6) after the grouting is completed; Step D, collecting strain data obtained by the distributed strain optical fiber measuring line (2) at different times during the period from the start of grouting to the solidification of the slurry, and multiplying the strain data by the elastic modulus of the sample (1) to obtain stress data.

2. The grouting stress field testing method according to claim 1, characterized in that: The method further comprises step E, repeating steps A to D, and in step C, using different grouting pressures for grouting to obtain stress data at different grouting pressures and at different times, thereby making a grouting stress cloud map.

3. The grouting stress field testing method according to claim 1, characterized in that: In step A1, a casting material is prepared according to the uniaxial compressive strength of the simulated surrounding rock, so that the uniaxial compressive strength of the sample (1) is the same as that of the simulated surrounding rock.

4. The grouting stress field testing method according to claim 1, characterized in that: In the axial direction of the grouting hole (11), the distance between the bottom of the grouting hole (11) and the surface of the adjacent sample (1) is at least 50 mm, and in the radial direction of the grouting hole (11), the distance between the wall of the grouting hole (11) and the surface of the adjacent sample (1) is at least 100 mm; And / or, the number of the grouting holes (11) is two, and the middle of the distributed strain optical fiber measuring line (2) is located between the two grouting holes (11); And / or, the grouting pump (5) is a special pump for testing, and the flow rate of the grouting pump (5) is 1-600 mL / min.

5. The grouting stress field testing method according to claim 1, characterized in that: The middle part of the distributed strain optical fiber measuring line (2) is serpentine and comprises a plurality of straight segments (21) and a plurality of bent segments (22); the straight segment (21) and the bent segment (22) are connected; the straight segment (21) extends radially along the grouting hole (11); the plurality of straight segments (21) are parallel and spaced apart in the axial direction of the grouting hole (11); different straight segments (21) correspond to different depths of the grouting hole (11); and the bent segment (22) located at one end of the straight segment (21) is adjacent to the grouting hole (11).

6. The grouting stress field testing method according to claim 1, characterized in that: In step B, the open end of the grouting hole (11) is facing upwards, sodium chloride is poured into the grouting hole (11), a connecting pipe (4) having a diameter smaller than that of the grouting hole (11) is placed into the grouting hole (11), glue is injected into the gap between the grouting hole (11) and the connecting pipe (4), and after the glue solidifies, clean water is poured into the grouting hole (11) to melt the sodium chloride, and then the sample (1) is inverted to pour out the sodium chloride solution; and / or, a threaded section is provided on the connecting pipe (4), and the valve (6) is connected to the connecting pipe (4) by a thread.

7. The grouting stress field testing method according to claim 1, characterized in that: Between step A and step C, step G is added, avoiding the grouting hole (11), spraying a flexible thin spray material on the surface of the sample (1) to seal the surface of the sample (1), and the spraying thickness is not less than 10 mm.

8. A grouting stress field testing system (100), characterized in that: include: A sample (1), wherein the sample (1) is provided with a grouting hole (11); A distributed strain optical fiber measuring line (2), wherein the middle portion of the distributed strain optical fiber measuring line (2) is buried in the sample (1), the two ends of the distributed strain optical fiber measuring line (2) are respectively located outside the two opposite ends of the sample (1), and a portion of the middle portion of the distributed strain optical fiber measuring line (2) is perpendicular to the axial direction of the grouting hole (11); A monitoring device (3), the distributed strain optical fiber measuring line (2) being connected to the monitoring device (3); a connecting pipe (4), the connecting pipe (4) being installed at the open end of the grouting hole (11); and, A grouting pump (5), a grouting pipe (7) and a valve (6); the grouting pump (5), the grouting pipe (7), the valve (6) and the connecting pipe (4) are connected in sequence.

9. The grouting stress field testing system (100) according to claim 8, characterized in that: In the axial direction of the grouting hole (11), the distance between the bottom of the grouting hole (11) and the surface of the adjacent sample (1) is at least 50 mm, and in the radial direction of the grouting hole (11), the distance between the wall of the grouting hole (11) and the surface of the adjacent sample (1) is at least 100 mm; And / or, the middle portion of the distributed strain optical fiber measuring line (2) is serpentine and comprises a plurality of straight segments (21) and a plurality of bent segments (22), the straight segment (21) and the bent segment (22) are connected, the straight segment (21) extends radially along the grouting hole (11), the plurality of straight segments (21) are parallel and spaced apart in the axial direction of the grouting hole (11), different straight segments (21) correspond to different depths of the grouting hole (11), and the bent segment (22) located at one end of the straight segment (21) is adjacent to the grouting hole (11); And / or, the number of the grouting holes (11) is two, and the middle of the distributed strain optical fiber measuring line (2) is located between the two grouting holes (11); And / or, the connecting pipe (4) is bonded inside the grouting hole (11); And / or, the grouting pump (5) is a special pump for testing, and the flow rate of the grouting pump (5) is 1-600 mL / min.

10. The grouting stress field testing system (100) according to claim 8, characterized in that: It further comprises a flexible thin sprayed material layer, which is arranged on the surface of the sample (1), and the thickness of the flexible thin sprayed material layer is not less than 10 mm.

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