A deep buried high ground stress soft rock tunnel repair test model and test method

Abstract

The present application discloses a deep-buried high-ground stress soft rock tunnel repair test model and test method, comprising a test box, a similarity ratio model is placed in the test box, and a test tunnel is excavated on the similarity ratio model; at the same time, along the radial direction of the test tunnel, a rock simulation layer and a backfill layer are sequentially arranged on the outer side of the similarity ratio model, the rock simulation layer wraps the similarity ratio model, and the backfill layer wraps the rock simulation layer. At the same time, the present application also discloses a test method based on the above-mentioned test model, which will perform a secondary repair and secondary loading on the tunnel after a primary loading until the test tunnel is deformed, so as to verify whether the secondary repair scheme is feasible by observing the deformation of the test tunnel; compared with the prior art, it can effectively improve the simulation degree of the tunnel structure and the rock mass in which the tunnel is located, so as to realize the evaluation of the secondary repair scheme and improve the reliability and stability of the secondary repair support scheme.

Description

Technical Field

[0001] The present application relates to the field of geotechnical engineering technology, and in particular to a deep-buried high-in-situ stress soft rock tunnel repair test model and test method. Background Art

[0002] The forces on the tunnels of metal mines, especially those on the tunnel structures located in the deep rock mass of metal mines, are completely different from those on non-metal mines, which are mainly reflected in the hardness and deformation stability of the rock mass. In terms of rock hardness, metal mines have the characteristics of high strength of individual rock blocks, i.e. hard rock in geology, and poor overall stability of the rock mass, i.e. "soft rock" in engineering. In terms of deformation stability, with the increase of mining depth, the surrounding rock pressure is fast, the deformation is large, the duration is long, and it has obvious rheological characteristics. The above characteristics of the rock mass make it impossible for traditional support schemes to guarantee the safety of the tunnels, and the tunnel repair rate is high. There is also a lack of effective verification means to determine whether the secondary repair scheme of the tunnel can effectively guarantee the safety of the tunnel. Summary of the invention

[0003] The main purpose of this application is to provide a deep-buried high-in-situ stress soft rock tunnel repair test model and test method, aiming to solve the defect of lack of verification of tunnel repair support schemes in the prior art.

[0004] This application achieves the above objectives through the following technical solutions:

[0005] A deep buried high ground stress soft rock tunnel repair test model, comprising a model box;

[0006] A similarity ratio model, wherein the similarity ratio model is buried in the model box; a test tunnel is excavated on the similarity ratio model;

[0007] A rock mass simulation layer, the rock mass simulation layer surrounds the axis of the test tunnel and wraps it;

[0008] A backfill layer is arranged in the model box and surrounds the axis of the test tunnel, and the backfill layer wraps the rock simulation layer.

[0009] Accordingly, the present application also discloses a test method based on the above test model, comprising the following steps:

[0010] constructing a similarity ratio model of the lane according to the size parameters of the lane;

[0011] Building a test model using the similarity ratio model;

[0012] Formulate a tunnel loading scheme according to tunnel working conditions, and use the tunnel loading scheme to perform a loading test on the test model until the test tunnel is deformed;

[0013] According to the repair plan, the test tunnel that has completed the first loading is repaired to obtain the second loading test model;

[0014] The secondary loading test lane is secondary loaded according to the lane loading scheme until the secondary loading test lane is deformed.

[0015] Optionally, constructing a similarity ratio model of the repair lane according to the size parameters of the lane includes the following steps:

[0016] Acquire the size parameters of the lane, wherein the size parameters include the length, width, height and other construction parameters of the lane;

[0017] Determine the similarity ratio according to engineering requirements;

[0018] Scaling the size parameter according to the similarity ratio to obtain a model size parameter;

[0019] A similarity ratio model is produced according to the model size parameters.

[0020] Optionally, making a similarity ratio model according to the model size parameters comprises the following steps:

[0021] Obtain the compressive strength parameters of the tunnel;

[0022] Calculating an equivalent compressive strength parameter of a similarity ratio model according to the similarity ratio and the compressive strength parameter;

[0023] Formulate a number of different material ratios, and prepare at least one similarity ratio model to be verified for each of the material ratios;

[0024] Conducting compression tests on the similarity ratio models to be verified respectively, screening the similarity ratio models to be verified in combination with the equivalent compressive strength parameters, and obtaining the test material ratio;

[0025] The test material ratio is used to make a similarity ratio model that meets the model size parameters.

[0026] Optionally, using the test material ratio to make a similarity ratio model that meets the model size parameters includes the following steps:

[0027] Obtain the support plan for the roadway;

[0028] The support components involved in the support scheme are manufactured using 3D printing technology, and the support components include NPR long and short anchor cables / rods, ordinary anchor cables / rods and U-shaped arch frames;

[0029] Making support molds according to model size parameters, and installing the support components on each of the support molds respectively;

[0030] The test materials are mixed and made into fillers, which are then backfilled into each of the support moulds to make a similar ratio model.

[0031] Optionally, using the similarity ratio model to build a test model includes the following steps:

[0032] Formulate the burial plan of the testing equipment;

[0033] The blocks were made by using the test material mix;

[0034] Place a similar model in the model box, lay blocks layer by layer and tamp the soil; install the detection equipment layer by layer according to the burial plan;

[0035] Curing at room temperature and demoulding;

[0036] A tunnel is excavated on the similarity ratio model to form a test tunnel.

[0037] Optionally, the blocks are made using the test material ratio, including the following steps:

[0038] Calculate the structural parameters of the blocks according to the model size parameters;

[0039] Designing a block mold according to the structural parameters and using 3D printing technology to make the block mold;

[0040] The test material ratio is adopted to prepare fillers, and the fillers are filled into the block mold to prepare model blocks.

[0041] Optionally, a similarity ratio model is placed in a model box, blocks are laid layer by layer and the soil is filled and compacted; and the detection equipment is installed layer by layer according to the embedding method, including the following steps:

[0042] Determine the single backfill height according to the working conditions;

[0043] Lay blocks on the bottom of the model box according to the single backfill height, and then backfill and compact;

[0044] Repeat the steps of laying blocks at the bottom of the model box according to the single backfill height, and then backfilling and compacting, and burying the detection equipment in the base layer according to the embedding plan to complete the tamping operation of the base layer;

[0045] Several similar ratio models are spliced ​​and placed on the base layer according to the length of the lane;

[0046] Along the axis direction of the similarity ratio model, according to the single backfill height, blocks are laid on both sides of the similarity ratio model and backfilled and compacted;

[0047] Repeat the steps of laying blocks and backfilling and compacting on both sides of the similarity ratio model according to the single backfill height along the axis direction of the similarity ratio model, burying the detection equipment in the middle layer according to the burying plan, and completing the tamping operation of the middle layer;

[0048] According to the single backfill height, blocks are laid layer by layer on the top of the similarity ratio model and tamped until the top is sealed, and detection equipment is buried in the top layer according to the burying plan.

[0049] Optionally, a tunnel loading plan is formulated according to tunnel working conditions, including the following steps:

[0050] Acquire actual working conditions of the environment where the tunnel is located, wherein the actual working conditions include actual horizontal ground stress and actual vertical ground stress;

[0051] Convert the actual working condition according to the similarity ratio to obtain the test working condition, wherein the test working condition includes the test horizontal ground stress and the test vertical ground stress;

[0052] Set the pressure gradient and formulate a pressure scheme for the original rock stress stage in combination with the test conditions;

[0053] Determine the secondary loading simulation working condition, and formulate a pressurization plan for the secondary loading stage in combination with the pressurization gradient;

[0054] The three-stage loading simulation working conditions are determined, and the pressurization conditions of the three-stage loading are formulated in combination with the pressurization gradient.

[0055] Optionally, repairing the test model that has completed the primary loading according to the repair plan to obtain the secondary loading test model includes the following steps:

[0056] Obtaining a secondary repair scheme and a similarity ratio, and calculating secondary repair lining size parameters according to the secondary repair scheme and the similarity ratio;

[0057] Use 3D printing technology to make secondary repair lining molds that meet the secondary repair lining size parameters;

[0058] Use the secondary repair lining mold and the test material ratio to make the secondary repair lining;

[0059] The original support structure in the test model after one loading is removed;

[0060] Laying secondary repair lining in the test model tunnel;

[0061] Install support components in the tunnel according to the repair plan.

[0062] Compared with the prior art, this application has the following beneficial effects:

[0063] The test model described in the present application includes a model box, in which a similarity model of a roadway is arranged, and a test roadway is excavated on the similarity model, and a rock simulation layer is wrapped around the axis of the test roadway on the outside of the test roadway, and a backfill layer is also arranged in the model box, and the backfill layer wraps the rock simulation layer;

[0064] The application also discloses a corresponding test method, which first needs to construct a similarity ratio model of the lane according to the size parameters of the lane, use the similarity ratio model to build a test model, then formulate a lane loading plan according to the lane working conditions, and use the lane loading plan to perform a loading test on the test model until the test lane is deformed; then repair the test model that has completed the first loading according to the repair plan, obtain a second loading test model, and finally perform a loading test on the second loading test model according to the loading plan until the test lane is deformed;

[0065] In the above test process, the primary loading damage to the roadway is to simulate the damage of the roadway, that is, to simulate the actual working conditions of the repaired roadway, which is conducive to improving the accuracy and reliability of the verification of the repair support scheme; the secondary loading is to simulate the actual working conditions of the roadway after repair, and by observing various detection parameters and the actual damage of the roadway, it is judged whether the roadway repair scheme can play its due effect;

[0066] At the same time, the extrusion pressure of the rock simulation layer is calculated based on the real rock parameters and similarity ratio of the mine where the tunnel is located, thereby realizing the restoration simulation of the rock layer of the mountain where the tunnel is located;

[0067] Compared with the prior art, the present application realizes the simulation of complex tunnel structures through the proportional scaling technical solution, which reduces the test cost while ensuring the reliability and accuracy of the simulation test;

[0068] Secondly, by simulating and restoring the working conditions of the tunnel and the structure of the mountain where the tunnel is located, it is convenient for the staff to compare and observe whether the secondary repair plan can play a role, so as to judge whether it can play a role in actual support, realize the verification of the support plan, and improve the feasibility and reliability of the secondary repair tunnel support plan. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 A structural schematic diagram of a deep buried high ground stress soft rock tunnel repair test model provided in Example 1 of the present application;

[0070] Figure 2 A flow chart of a deep buried high ground stress soft rock tunnel repair test method provided in Example 2 of the present application;

[0071] Figure 3 is a diagram of the arrangement of the pressure boxes in the base layer;

[0072] Figure 4 It is the layout diagram of the pressure box in the vertical plane;

[0073] Figure numerals: 1 - model box, 2 - similarity ratio model, 3 - test tunnel, 4 - rock simulation layer, 5 - backfill layer, 6 - earth pressure box, 7 - strain brick.

[0074] The purpose, features and advantages of this application will be further described in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0075] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0076] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0077] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; 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.

[0078] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "robot coordinate system and / or m" as an example, it includes the robot coordinate system scheme, or the m scheme, or the scheme that the robot coordinate system and m satisfy at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0079] Embodiment 1:

[0080] Reference Figure 1 This embodiment is an optional embodiment of the present application, which discloses a deep-buried high-in-situ stress soft rock tunnel repair test model, including a model box 1, in which a similarity ratio model 2 is placed, and the similarity ratio model 2 is a model of the tunnel reduced according to the similarity ratio, and a test tunnel 3 is excavated on the similarity ratio model 2;

[0081] The test box is also provided with a rock simulation layer 4 and a backfill layer 5, wherein the rock simulation layer 4 is formed by aligning a plurality of blocks, and along the radial direction of the test tunnel 3, the rock simulation layer 4 is arranged on the outside of the similarity ratio model 2, and around the axial direction of the test tunnel 3, the rock simulation layer 4 wraps the similarity ratio model 2;

[0082] Along the axial direction of the test tunnel 3, the rock mass simulation layer 4 extends in sequence and wraps the entire test tunnel 3;

[0083] A backfill layer 5 is also provided in the model box 1 . The backfill layer 5 is arranged outside the rock simulation layer 4 along the radial direction of the test tunnel 3 . Meanwhile, the backfill layer 5 wraps the rock simulation layer 4 around the axial direction of the test tunnel 3 .

[0084] Embodiment 2:

[0085] Reference Figure 2 This embodiment, as an optional embodiment of the present application, discloses a metal mine soft rock tunnel repair test method, comprising the following steps:

[0086] It should be noted that in this embodiment, each step will be described through a specific example. In the above example, the tunnel is located in the deep rock mass of the metal mine. The rock mass in the above area has the characteristics of high strength of individual rock blocks, that is, hard rock in geology, and poor overall stability of the rock mass, that is, the characteristics of soft rock in engineering.

[0087] S1. constructing a similarity ratio model of the lane according to the size parameters of the lane;

[0088] S11, obtaining the size parameters of the lane, wherein the size parameters include the length, width, height and other construction parameters of the lane;

[0089] Obtaining the parameters of the lane through engineering drawings and field surveying, wherein the dimension parameters include the length, width, height and other construction parameters of the lane;

[0090] S12. Determine the similarity ratio according to the engineering requirements;

[0091] The similarity ratio is set according to the actual engineering situation. In a specific embodiment, the similarity ratio is determined to be 1:25, that is, various actual parameters are reduced by 25 times;

[0092] S13, scaling the size parameter according to the similarity ratio to obtain a model size parameter;

[0093] Retrieving the size parameters obtained in step S11, reducing the model size parameters according to a similarity ratio other than that set in step S12;

[0094] In the specific example, the size of the entire model is 1600mm*1600mm*1600mm (length*width*height of the model). Specifically, the length of the lane is 1600mm, its width is 320mm, and in the height direction, its vertical height is 320mm, and there is a semicircular arc with a radius of 100mm on the top;

[0095] S14, making a similarity ratio model according to the model size parameters.

[0096] S141, obtaining compressive strength parameters of the tunnel;

[0097] The compressive strength parameters of the tunnel need to be determined in combination with the specific conditions of the rock mass in the area where the tunnel is located and the uniaxial compressive strength of the rock obtained by indoor rock mechanics experiments;

[0098] In the specific example, the compressive strength was 100MPa obtained through indoor rock mechanics experiments;

[0099] S142, calculating an equivalent compressive strength parameter of a similarity ratio model according to the similarity ratio and the compressive strength parameter;

[0100] Since in the specific example, the similarity ratio is 1:25, the equivalent compressive strength parameter can be calculated to be 4 MPa in combination with the compressive strength in step S141;

[0101] S143, formulating a number of different material ratios, and preparing at least one similarity ratio model to be verified for each of the material ratios;

[0102] First, according to the actual situation of the project, several different material ratios are formulated, each of which contains river sand, gypsum powder, barite powder, cement, mica powder and other materials;

[0103] Combined with the similarity ratio, a similarity ratio model to be tested is made for each of the above material ratios;

[0104] S144, respectively perform a compression test on each of the similarity ratio models to be verified, screen each of the similarity ratio models to be verified in combination with the equivalent compressive strength parameter, and obtain a test material ratio;

[0105] Carry out uniaxial compressive strength test for each similarity ratio model to be tested, determine its uniaxial compressive strength parameter, select the material ratio whose uniaxial compressive strength parameter is equal to or slightly larger than the equivalent compressive strength parameter, and select one ratio from the above ratios in combination with economic conditions and other factors as the experimental material ratio.

[0106] In the specific example, the material ratios with uniaxial compressive strength parameters not less than 4MPa are selected, and then one is selected as the test material ratio in combination with comprehensive factors such as economy among the selected material ratios; that is, if there is a material ratio with uniaxial compressive strength equal to 4MPa, this is used as the test material ratio, and if there are multiple, the one with the best economy is selected as the test material ratio;

[0107] If there is no material mix with uniaxial compressive strength equal to 4MPa, the material mix closest to 4MPa is selected as the test material mix;

[0108] By calculating and proportionally reducing the above-mentioned equivalent compressive strength parameters, it can be ensured that during the actual test, the pressure on the tunnel is basically the same as the pressure in the rock mass in which it is actually located, thereby seeking a similar material ratio that is closer to the actual rock, improving the realism of the simulation test as much as possible, and thus ensuring the accuracy and reliability of the simulation test.

[0109] S145. Use the test material ratio to make a similarity ratio model that meets the model size parameters.

[0110] S1451, obtain the support plan for the tunnel;

[0111] Obtain the tunnel support plan from the engineering construction data and use the payment plan as the original support plan;

[0112] Furthermore, in order to verify the reliability of various support schemes, multiple support sections using other support structures can be set as needed, that is, along the axial direction of the tunnel, the tunnel is divided into several sections, one of which adopts the original support scheme, one of which adopts the no-support scheme, and the other end adopts other support schemes, such as the NPR long and short anchor cable / rod support scheme;

[0113] The above scheme can verify and test multiple different support schemes on one test device at the same time, effectively improving the simulation efficiency of the test and reducing the test cost;

[0114] Secondly, since there are multiple sections with different support schemes in a tunnel, and other external factors are the same, a single variable experiment is realized. Therefore, in the later observation process, the deformation characteristics and deformation amounts of different support schemes can be observed more clearly and intuitively, so as to select the optimal support scheme.

[0115] S1452. Using 3D printing technology to manufacture the support components involved in the support scheme, the support components including NPR long and short anchor cables / rods, ordinary anchor cables / rods and U-shaped arch frames;

[0116] Obtain the structural dimensions of various support components, and then calculate the corresponding mold dimensions according to the similarity ratio;

[0117] Use 3D printing technology to make support components that meet the mold size requirements, namely, NPR long and short anchor cables / rods, ordinary anchor cables / rods and U-shaped arch frames, where the ordinary anchor cables / rods are the support components involved in the original support plan, and the U-shaped arch frames correspond to the no-support plan in step S1451;

[0118] The use of 3D printing technology can not only quickly produce various support components and improve the efficiency of model production, but also effectively reduce the cost of model production.

[0119] S1453, making support molds according to the model size parameters, and installing the support components on each of the support molds respectively;

[0120] In the process of making the support mold, aluminum plate is preferably used to make the mold, and then various different support components are installed in different mold boxes respectively;

[0121] In the above steps, various support components are pre-installed, which can reduce the difficulty of installing the support components on the one hand; on the other hand, in the later backfilling process, various support components can fit more closely with the external joints, thereby more realistically simulating the actual working conditions of the support components, which is conducive to improving the realism of the simulation.

[0122] S1454. Use the test material ratio to make fillers and backfill each of the support molds to make a similar ratio model.

[0123] After the support mold is manufactured, the filler is manufactured using the test material ratio selected in step S144, and the support mold is backfilled with the filler to manufacture a similarity ratio model.

[0124] S2. Building a test model using the similarity ratio model;

[0125] S21. Develop a plan for burying the testing equipment;

[0126] Before building the similarity ratio model, it is necessary to first determine the burial scheme of various detection equipment, which includes the specific various detection sensors used, the burial positions of various detection sensors, and the burial depth relative to the tunnel;

[0127] In the specific example, the designed detection device only needs to include the pressure box, strain brick 7, etc., the burial plan and the number, burial depth and burial position of the above-mentioned equipment, and the wiring problems of various detection equipment must also be considered;

[0128] S22, using the test material ratio to make blocks;

[0129] S221, calculating structural parameters of the building blocks according to the model size parameters;

[0130] Obtaining model size parameters, and determining size parameters of the building block according to the model size parameters. In a specific example, it is determined that the width of the building block is 40 mm, the length is 200 mm, and the height is 40 mm;

[0131] S222, designing a block mold according to the structural parameters and using 3D printing technology to manufacture the block mold;

[0132] S223, using the test material ratio to make filler, and filling the filler into the block mold to make a model block.

[0133] The filler is prepared by using the test material ratio, and the filler is filled into the block mold. After drying, the mold is demoulded to obtain a model building block.

[0134] S23. Place a similar model in the model box, lay blocks layer by layer and fill and compact the soil; install the detection equipment layer by layer according to the embedding plan;

[0135] S231, determining a single backfill height according to working conditions;

[0136] First, prepare a model box according to the model size determined in step S13. In a specific example, the size of the model box is 1600mm*1600mm*1600mm;

[0137] Then, the single backfill height is determined in combination with the model size parameters. Specifically, the length of the tunnel is 1600mm, its width is 320mm, and in the height direction, its vertical height is 320mm, and there is a semicircular arc with a radius of 100mm on the top;

[0138] Therefore, in the specific example, the single backfill height is determined to be 80 mm;

[0139] S232, laying blocks at the bottom of the model box according to the single backfill height, and then backfilling and compacting;

[0140] S233, repeating the steps of laying blocks at the bottom of the model box according to the single backfill height, and then backfilling and compacting, and burying the detection equipment in the base layer according to the embedding plan, and completing the tamping operation of the base layer;

[0141] In the specific example, the bottom of the model box is taken as the reference elevation of 0 mm, and the area between the bottom of the tunnel model and the bottom of the model box is determined to be the base layer, and the thickness of the base layer is 640 mm;

[0142] Combined with the single backfill height, it can be seen that the base layer needs to be backfilled and compacted 8 times;

[0143] At the same time, determine that the soil pressure box 6 and strain brick 7 are set at 300mm, 600mm, 1000mm, 1200mm and 1400mm respectively below the central axis of the tunnel along the axial direction of the tunnel, and lead wires;

[0144] Along the height direction of the tunnel, a layer of earth pressure box 6 and strain brick 7 are buried at 320mm, 400mm, 480mm and 560mm respectively; Figure 3 As shown;

[0145] It should be pointed out that each time the tamping operation is carried out, the blocks need to be laid first, and then the gaps between the blocks need to be filled by backfilling, while ensuring that the entire soil layer is compacted;

[0146] S234, splicing a number of similar ratio models according to the length of the laneway and placing them on the base layer;

[0147] When the base layer is completed, similarity ratio models with different support components are selected according to the needs, and the similarity ratio models are spliced ​​and connected at the top of the base layer along the axis of the tunnel to construct the entire tunnel model;

[0148] S235, laying blocks on both sides of the similarity ratio model along the axis direction of the similarity ratio model according to the single backfill height and backfilling and compacting;

[0149] S236, repeating the steps of laying blocks on both sides of the similarity ratio model according to the single backfill height and backfilling and compacting along the axis direction of the similarity ratio model, burying the detection equipment in the middle layer according to the burying plan, and completing the tamping operation of the middle layer;

[0150] Taking the axis direction of the similarity ratio model as a reference line, backfilling is performed in the space on both sides of the similarity ratio model;

[0151] In the specific example, the single backfill height is 80 mm. Combined with the model size parameters, it can be seen that the backfill height of the middle layer is 320 mm, so 4 backfills are required;

[0152] First, two tampings with layer heights of 80 mm and 80 mm are carried out on both sides of the similarity ratio model, and earth pressure boxes 6 and strain bricks 7 are arranged on both sides of the similarity ratio model at an elevation of 800 mm;

[0153] Then, two tamping operations with layer heights of 80 mm and 80 mm were continued on both sides of the similarity ratio model, and earth pressure boxes 6 were arranged on both sides of the similarity ratio model at an elevation of 960 mm;

[0154] Continue to backfill twice with a height of 80 mm on both sides of the similarity ratio model, and bury the earth pressure box 6 at the corresponding elevation position;

[0155] Finally, two backfills with a height of 80 mm were carried out on both sides of the similar ratio model, and earth pressure boxes 6 were buried at the corresponding elevation positions; thus, the height of the model was raised to 1280 mm. Figure 4 ;

[0156] At this point, the tamping work of the middle layer is completed;

[0157] S237, laying blocks layer by layer on the top of the similarity ratio model according to the single backfill height and tamping until the top is sealed, and burying detection equipment in the top layer according to the burying plan.

[0158] Combined with the height of the model box, it can be known that the thickness of the top layer is 320 mm. Therefore, 4 times of tamping and filling operations, each of which is 80 mm, can reach the top of the model box, thus completing the tamping and filling operation of the top layer.

[0159] It should be noted that since the rock mass of the mountain where the metal mine tunnel is located is mainly in a diamond structure, in the block stacking process of the above steps, the blocks also need to be arranged according to the diamond cross-section to construct a rock simulation layer for simulating the mountain structure; the backfill soil in the above steps constitutes the backfill layer.

[0160] Secondly, it can be seen from the above steps that the blocks of this application are also supported by the ratio of experimental materials. The performance parameters of the above ratio are calculated from the compressive strength parameters and similarity ratios of the actual rock mass. The simulation of the mountain structure is achieved through the stacking method of the blocks and the coordination of the equivalent compressive strength parameters, thereby restoring the geological environment of the tunnel as much as possible and improving the accuracy of the test.

[0161] S24, curing at room temperature and demoulding;

[0162] Place the model box in a ventilated environment, spray water continuously for curing, and dry it in the sun for 7-10 days before removing the mold.

[0163] S25, excavating a tunnel on the similarity ratio model to form a test tunnel.

[0164] After the mold is removed, the similarity ratio model will be exposed. At this time, various testing equipment will be debugged. After the testing equipment is debugged correctly, the fillers in each similarity ratio model will be hollowed out by manual excavation, so as to build a test tunnel in the model box;

[0165] In combination with the above, it can be seen that, since various support components are pre-installed during the model making process, various fillers will fit closely with the support components during the backfilling process, thereby ensuring that the support components can work normally and improving the realism of the simulation; on the other hand, the above construction operation method can also reduce the difficulty of installing various support components and improve the efficiency of model making;

[0166] Secondly, the above method can effectively prevent the damage to the backfill layer during the installation of the support components, causing the backfill layer to collapse, thereby affecting the pressure on the tunnel during the loading process, and effectively improving the reliability of the simulation test.

[0167] S3, formulating a tunnel loading scheme according to tunnel working conditions, and using the tunnel loading scheme to perform a loading test on the test model until the test tunnel is deformed;

[0168] S31, obtaining actual working conditions of the environment where the tunnel is located, wherein the actual working conditions include actual horizontal ground stress and actual vertical ground stress;

[0169] The actual working conditions need to be determined according to the actual conditions of the rock mass where the tunnel is located. In the specific example, the mine surface elevation is 1750m, the tunnel is located near the 850m level, the burial depth is about 900m, the actual horizontal ground stress is about 34.7MPa, and the actual vertical ground stress is about 24.3MPa.

[0170] S32, converting the actual working condition according to the similarity ratio to obtain a test working condition, wherein the test working condition includes a test horizontal ground stress and a test vertical ground stress;

[0171] Combined with the similarity ratio, the test working conditions are deduced to be that the test horizontal stress is about 1.4MPa and the test vertical stress is about 1.0MPa;

[0172] S33, setting a pressurization gradient, and formulating a pressurization plan for the original rock stress stage in combination with the test working conditions;

[0173] In the specific example, the pressure gradient is determined to be 0.2MPa in combination with the actual test conditions and test working conditions, and the pressure of the pressure test is increased by 0.2MPa each time;

[0174] Since the pressure gradient is 0.2MPa, the test working conditions are that the horizontal stress is about 1.4MPa and the vertical stress is about 1.0MPa; therefore, the horizontal pressure is loaded with 7 gradients and the vertical stress is loaded with 5 stresses; each gradient stress level is stabilized for 20 minutes, and when the horizontal stress reaches 1.4MPa and the vertical stress reaches 1.0MPa, the pressure is stabilized for 6 hours, that is, the pressure of the original rock stress stage is completed;

[0175] The original rock stress stage is to increase the pressure on the roadway to the test working conditions, thereby restoring the actual working conditions of the roadway;

[0176] At the same time, during the loading process, the deformation and failure characteristics of the tunnel under the original support and NPR support under the current buried depth stress state can also be observed;

[0177] S34, determining the secondary loading simulation working condition, and formulating a pressurization scheme for the secondary loading stage in combination with the pressurization gradient;

[0178] After the original rock stress stage loading is completed, the secondary loading simulation is continued;

[0179] First, determine the secondary loading simulation working conditions, that is, the horizontal stress is loaded with 1 gradient, the vertical stress is loaded with 1 gradient, the horizontal stress reaches 1.6MPa, and the vertical stress is 1.2MPa. At this time, the simulated pressure reaches the stress level at a burial depth of 1000m. After the loading is completed, the pressure is stabilized for 6 hours, and the secondary loading is completed;

[0180] S35, determining the three-stage loading simulation working condition conditions, and formulating the pressurization conditions of the three-stage loading stage in combination with the pressurization gradient.

[0181] The three-stage loading scheme is to load horizontal stress with 2 gradients and vertical stress with 1 gradient. At this time, the horizontal stress reaches 2.0MPa and the vertical stress is 1.4MPa. The pressure stabilization time is 6 hours. At this time, the simulated pressure reaches the stress level at a burial depth of 1100m.

[0182] The tunnel was overloaded by secondary and tertiary loading. In this process, the deformation and failure characteristics of the tunnel under original support and NPR support at different buried depth stress states can be observed.

[0183] At the same time, the above-mentioned overload damage can also simulate the natural damage of rock to the tunnel, and then simulate the working conditions of the restored tunnel, thereby improving the reliability of the secondary repair verification.

[0184] S4. Repair the test model that has completed the primary loading according to the repair plan to obtain a secondary loading test tunnel;

[0185] S41, making a secondary repair lining according to the repair plan;

[0186] S411, obtaining a secondary repair plan and a similarity ratio;

[0187] The secondary repair plan mainly includes the support plan and the thickness of the thin shotcrete layer;

[0188] S412, calculating secondary repair lining size parameters according to the secondary repair scheme and similarity ratio;

[0189] According to the support scheme and similarity ratio, corresponding support components are manufactured using 3D printing technology;

[0190] The secondary repair lining size parameters are calculated based on the thickness of the thin shotcrete layer and the similarity ratio;

[0191] S413. Use 3D printing technology to make a secondary repair lining mold that meets the secondary repair lining size parameters;

[0192] S414. Use the secondary repair lining mold and the test material ratio to make the secondary repair lining.

[0193] After the model is made, the test material ratio is used to make fillers, which are then filled into the secondary repair lining mold to make the secondary repair lining;

[0194] S42, dismantling the original supporting structure in the test model after one loading;

[0195] All original supporting structures in the test model after one loading were removed;

[0196] S43, laying secondary repair lining in the tunnel of the test model;

[0197] Installing the secondary repair lining produced in step S41 into the tunnel from which the supporting structure has been removed in step S42;

[0198] S44. Install support components in the tunnel according to the repair plan.

[0199] According to the repair plan, support components are installed in different areas of the tunnel to complete the secondary repair of the tunnel.

[0200] S5. Perform secondary loading on the secondary loading test lane according to the lane loading scheme until the secondary loading test lane is deformed.

[0201] The loading scheme described in step S3 is used to complete the secondary loading of the secondary repair lane step by step, and the deformation of the lane is observed at each loading stage and the corresponding detection parameters are collected.

[0202] The effectiveness of the secondary repair plan is determined based on the actual deformation of the tunnel and the detection parameters.

[0203] Compared with the prior art, the present application realizes the simulation of complex tunnel structures through the proportional scaling technical solution, which reduces the test cost while ensuring the reliability and accuracy of the simulation test;

[0204] Secondly, by simulating and restoring the working conditions of the tunnel, the staff can compare and observe whether the secondary repair plan can play a role, so as to judge whether it can play a role in actual support, verify the support plan, and improve the feasibility and reliability of the secondary repair tunnel support plan.

[0205] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A deep buried high ground stress soft rock tunnel repair test method, including a test model, characterized in that: The test model comprises a model box (1); A similarity ratio model (2), wherein the similarity ratio model (2) is buried in the model box (1); a test tunnel (3) is excavated on the similarity ratio model (2); A rock mass simulation layer (4), the rock mass simulation layer (4) surrounds the axis of the test tunnel (3) and wraps it; A backfill layer (5), the backfill layer (5) being arranged in the model box (1) around the axis of the test tunnel (3), the backfill layer (5) wrapping the rock mass simulation layer (4); The test method comprises the following steps: constructing a similarity ratio model of the lane according to the size parameters of the lane; Building a test model using the similarity ratio model; Formulate a tunnel loading scheme according to tunnel working conditions, and use the tunnel loading scheme to perform a loading test on the test model until the test tunnel is deformed; According to the repair plan, the test tunnel that has completed the first loading is repaired to obtain the second loading test tunnel; The secondary loading test lane is secondary loaded according to the lane loading scheme until the secondary loading test lane is deformed.

2. A deep buried high ground stress soft rock tunnel repair test method according to claim 1, characterized in that: The similarity ratio model of the repaired laneway is constructed according to the size parameters of the laneway, comprising the following steps: Acquire the size parameters of the lane, wherein the size parameters include the length, width, height and other construction parameters of the lane; Determine the similarity ratio according to engineering requirements; Scaling the size parameter according to the similarity ratio to obtain a model size parameter; A similarity ratio model is produced according to the model size parameters.

3. A deep buried high ground stress soft rock tunnel repair test method according to claim 2, characterized in that: The method of making a similarity ratio model according to the model size parameters comprises the following steps: Obtain the compressive strength parameters of the tunnel; Calculating an equivalent compressive strength parameter of a similarity ratio model according to the similarity ratio and the compressive strength parameter; Formulate a number of different material ratios, and prepare at least one similarity ratio model to be verified for each of the material ratios; Conducting compression tests on the similarity ratio models to be verified respectively, screening the similarity ratio models to be verified in combination with the equivalent compressive strength parameters, and obtaining the test material ratio; The test material ratio is used to make a similarity ratio model that meets the model size parameters.

4. A deep buried high ground stress soft rock tunnel repair test method according to claim 3, characterized in that: The method of using the test material ratio to make a similarity ratio model that meets the model size parameters includes the following steps: Obtain the support plan for the roadway; The support components involved in the support scheme are manufactured using 3D printing technology, and the support components include NPR long and short anchor cables / rods, ordinary anchor cables / rods and U-shaped arch frames; Making support molds according to model size parameters, and installing the support components on each of the support molds respectively; The test materials are mixed and made into fillers, which are then backfilled into each of the support moulds to make a similar ratio model.

5. A deep buried high ground stress soft rock tunnel repair test method according to claim 1, characterized in that: The method of using the similarity ratio model to build a test model comprises the following steps: Formulate the burial plan of the testing equipment; The blocks were made by using the test material mix; Place a similar model in the model box, lay blocks layer by layer and tamp the soil; install the detection equipment layer by layer according to the burial plan; Curing at room temperature and demoulding; A tunnel is excavated on the similarity ratio model to form a test tunnel.

6. A deep buried high ground stress soft rock tunnel repair test method according to claim 5, characterized in that: The method of making blocks by using the test material ratio comprises the following steps: Calculate the structural parameters of the blocks according to the model size parameters; Designing a block mold according to the structural parameters and using 3D printing technology to make the block mold; The test material ratio is adopted to prepare fillers, and the fillers are filled into the block mold to prepare model blocks.

7. A deep buried high ground stress soft rock tunnel repair test method according to claim 5, characterized in that: The method comprises placing a similarity model in a model box, laying blocks layer by layer and filling and compacting the soil; and installing the detection equipment layer by layer according to the embedding method, including the following steps: Determine the single backfill height according to the working conditions; Lay blocks on the bottom of the model box according to the single backfill height, and then backfill and compact; Repeat the steps of laying blocks at the bottom of the model box according to the single backfill height, and then backfilling and compacting, and burying the detection equipment in the base layer according to the embedding plan to complete the tamping operation of the base layer; Several similar-ratio models are spliced ​​and placed on the blocks of the base layer according to the length of the roadway; Along the axis direction of the similarity ratio model, according to the single backfill height, blocks are laid on both sides of the similarity ratio model and backfilled and compacted; Repeat the steps of laying blocks and backfilling and compacting on both sides of the similarity ratio model according to the single backfill height along the axis direction of the similarity ratio model, burying the detection equipment in the middle layer according to the burying plan, and completing the tamping operation of the middle layer; According to the single backfill height, blocks are laid layer by layer on the top of the similarity ratio model and tamped until the top is sealed, and detection equipment is buried in the top layer according to the burying plan.

8. A deep buried high ground stress soft rock tunnel repair test method according to claim 1, characterized in that: The method of formulating a tunnel loading plan according to tunnel working conditions includes the following steps: Acquire actual working conditions of the environment where the tunnel is located, wherein the actual working conditions include actual horizontal ground stress and actual vertical ground stress; Convert the actual working condition according to the similarity ratio to obtain the test working condition, wherein the test working condition includes the test horizontal ground stress and the test vertical ground stress; Set the pressure gradient and formulate a pressure scheme for the original rock stress stage in combination with the test conditions; Determine the secondary loading simulation working condition, and formulate a pressurization plan for the secondary loading stage in combination with the pressurization gradient; The three-stage loading simulation working conditions are determined, and the pressurization conditions of the three-stage loading are formulated in combination with the pressurization gradient.

9. A deep buried high ground stress soft rock tunnel repair test method according to claim 3, characterized in that: The method of repairing the test model after the primary loading according to the repair plan to obtain the secondary loading test tunnel includes the following steps: Obtaining a secondary repair scheme and a similarity ratio, and calculating secondary repair lining size parameters according to the secondary repair scheme and the similarity ratio; Use 3D printing technology to make secondary repair lining molds that meet the secondary repair lining size parameters; Use the secondary repair lining mold and the test material ratio to make the secondary repair lining; The original support structure in the test model after one loading is removed; Laying secondary repair lining in the test model tunnel; Install support components in the tunnel according to the repair plan.

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