A tunnel test device and test method for simulating stick-slip initiation of near-fault ground motion of a normal fault

Abstract

The application provides a tunnel test device for simulating stick-slip initiation near-fault ground motion of a normal fault, which comprises at least two groups of interval arranged explosion assemblies, a baffle, a tunnel model, a model box and a first simulated stratum, a second simulated stratum and a third simulated stratum assembled in the model box. The model box is provided with an opening, the baffle is clamped at the opening position to block the second simulated stratum; the side of the second simulated stratum far from the opening is higher than the side of the second simulated stratum close to the opening, and separates the first simulated stratum and the third simulated stratum; the tunnel model passes through the first simulated stratum, the second simulated stratum and the third simulated stratum; the explosion assembly is arranged below the tunnel model; the explosion assembly is provided with a first lead wire, an explosive and a driven block for detonating the explosive, the driven block is arranged in the second simulated stratum and connected with the explosive, and the side of the explosive far from the driven block is connected with the model box through the first lead wire.

Description

Technical Field

[0001] This invention relates to the field of similar model testing technology for tunnel seismic response, and in particular to a tunnel testing device for simulating near-fault seismic motion induced by normal fault stick-slip. Background Technology

[0002] Similarity model testing, as one of the main methods for tunnel research and analysis, is widely used in tunnel seismic resistance and disaster prevention research and testing due to its stronger intuitiveness and realism compared to numerical simulation methods. Currently, the commonly used tunnel seismic response model testing method is the shaking table test. This involves placing the tunnel in a model box, then placing the model box on a shaking table, vibrating the table in a predetermined direction, and then observing the tunnel's deformation and damage effects. Because the shaking table is a single platform, the vibration direction and velocity of the strata particles inside the model box are similar. The essence of the shaking table test is to simulate the uniform vibration process of vertically incident seismic waves, i.e., the tunnel experiencing far-field ground motion. However, in the most dangerous seismic response of tunnels crossing seismogenic faults, the ground motion is essentially a near-field ground motion. The seismic mechanism of near-field ground motion is that the strata generate fault creep under tectonic stress. Due to the long-term creep of the seismogenic fault, energy accumulates at the fault, eventually leading to fault stick-slip. Under stick-slip action, fault rupture promotes the occurrence of ground motion and permanent displacement of the surface. The location where the fault ruptures is the epicenter of the earthquake caused by the stick-slip action of the active fault.

[0003] At this point, the seismic waves are not incident perpendicularly, but are scattered from the point source to the surrounding area. This non-uniform near-field motion differs from the shaking table tests currently used to simulate far-field ground motion. Traditional shaking table tests cannot effectively simulate the source mechanism of non-uniform ground motion caused by stick-slip action of active faults. It is obviously unreasonable to use traditional shaking table tests to study the seismic response of tunnels under near-fault ground motion. Summary of the Invention

[0004] The main technical problem to be solved by the present invention is to provide a tunnel test device for simulating near-fault ground motion caused by normal fault stick-slip. It can simulate the earthquake generation mechanism of near-fault ground motion caused by normal fault stick-slip, so that the test results of the surface displacement and elastic wave generated by it on the tunnel are more realistic.

[0005] To address the aforementioned technical problems, this invention provides a tunnel testing device for simulating near-fault ground motion induced by stick-slip of a normal fault. The device includes at least two sets of spaced-apart explosive components, a baffle, a tunnel model, a model box, and a first, second, and third simulated strata assembled within the model box. The model box has an opening, and the baffle is engaged at the opening to seal the second simulated stratum. The side of the second simulated stratum furthest from the opening is higher than the side closest to the opening, and separates the first and third simulated strata. The tunnel model traverses the first, second, and third simulated strata. The explosive components are positioned below the tunnel model. Each explosive component includes a first lead, an explosive, and a driven block for detonating the explosive. The driven block is located within the second simulated stratum and connected to the explosive. The side of the explosive furthest from the driven block is connected to the model box via the first lead.

[0006] In a preferred embodiment, the talc layer is further included; the talc layer is disposed between the first simulated formation and the second simulated formation, and between the third simulated formation and the second simulated formation.

[0007] In a preferred embodiment, a filter layer is further included, laid between the tunnel model and the explosive assembly, the filter layer being interrupted at the location of the talc layer.

[0008] In a preferred embodiment: the opening is located at the lower end of the side wall of the model box, and the cross-section of the opening is adapted to the cross-section of the second simulated stratum.

[0009] In a preferred embodiment: it further includes a C-shaped plate fixed to the outer edge of the opening; the model box has an outwardly convex platform, the outwardly convex platform and the C-shaped plate enclosing to form a channel for the baffle to slide; the baffle slides within the channel to displace the second simulated stratum.

[0010] In a preferred embodiment, an energy-absorbing layer is further included; the energy-absorbing layer is attached to the inner wall surface of the model box.

[0011] In a preferred embodiment: the sensitivity of the explosive components decreases sequentially from bottom to top.

[0012] In a preferred embodiment: the explosive assembly is further provided with a second lead, and the driven block is connected to the explosive through the second lead; the explosive is arranged in the second simulated stratum on the side close to the first simulated stratum.

[0013] In a preferred embodiment: when the deformation stiffness of the second lead is consistent, the detonation sensitivity of the explosive decreases sequentially from bottom to top; when the detonation sensitivity of the explosive is consistent, the deformation stiffness of the second lead decreases sequentially from bottom to top.

[0014] The main technical problem to be solved by this invention is to provide a test method for a tunnel test device that simulates near-fault ground motion induced by stick-slip of a normal fault, comprising the following steps:

[0015] Step 1: Connect one end of the first lead wire to the model box; fill the first simulated stratum to the installation position of the filter layer in the model box, and ensure the tension of the first lead wire during filling;

[0016] Step 2: Fill the model box with the second simulated stratum up to the installation position of the filter layer; during filling, install and configure the explosive assembly in the second simulated stratum;

[0017] Step 3: Fill the model box with the third simulated stratum up to the installation position of the filter layer, and then lay the filter layer;

[0018] Step 4: Fill the filter layer with the first, second, and third simulated geological layers up to the tunnel model installation position, and then place the tunnel model.

[0019] Step 5: Fill the tunnel model with the first, second, and third simulated geological layers until the model box is full, and then let it stand still.

[0020] Step 6: Pull the outer baffle until the explosives detonate sequentially; observe the experimental results after the model box vibration stops.

[0021] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0022] 1. This invention provides a tunnel test device for simulating near-fault ground motion induced by stick-slip of a normal fault. First, multiple simulated strata are arranged inside a model box, and an opening is made on the side wall of the model box. A second simulated stratum is sealed by a baffle. Then, multiple explosive components are spaced apart in the simulated strata from bottom to top, positioned below a filter layer. The filter layer is located below the tunnel model. When the baffle is pulled open and slid outwards, the second simulated stratum, under the influence of gravity and without the baffle support, slides downwards towards the opening, simultaneously displacing a driven block. The driven block pulls the explosives, triggering an explosion. Because the sensitivity of the explosive components decreases from bottom to top, the explosions are always triggered sequentially from the bottom of the simulated strata upwards, conforming to the earthquake process of a stick-slip earthquake on a normal fault. After the explosives detonate, elastic waves are generated inside the model box. These elastic waves pass through the filter layer from bottom to top. The filter layer filters out high-frequency components while retaining low-frequency components, simulating real seismic waves, ultimately affecting the location of the tunnel model, causing the tunnel model to vibrate. The experimental setup reasonably simulates the seismogenic mechanism of near-fault earthquakes under normal fault stick-slip action, making the experimental results of the resulting surface displacement and elastic waves on the tunnel more realistic.

[0023] 2. This invention provides a tunnel test device for simulating near-fault ground motion caused by stick-slip of a normal fault. A C-shaped plate is welded onto the convex platform of the model box, so that the baffle, the C-shaped plate and the convex platform enclose a closed space. When the baffle is pulled open to allow it to slide, the sudden outflow of the second simulated stratum can be prevented, thereby improving the stability of the test.

[0024] 3. This invention provides a tunnel test device for simulating near-fault ground motion caused by stick-slip of a normal fault. It does not require a shaking table and can control the dislocation of the second simulated stratum by sliding the baffle outward. The test cost is greatly reduced compared with the traditional shaking table test. Attached Figure Description

[0025] Figure 1 This is a front view of the experimental apparatus described in preferred embodiment 1 of the present invention;

[0026] Figure 2 This is a top view of the experimental apparatus described in preferred embodiment 1 of the present invention;

[0027] Figure 3 This is a side view of the test apparatus described in preferred embodiment 1 of the present invention;

[0028] Figure 4 for Figure 1 Sectional view along line AA;

[0029] Figure 5 for Figure 4 A magnified view of a section at point A in the middle;

[0030] Figure 6This is a schematic diagram of the structure of the explosion assembly in the preferred embodiment 1 of the present invention. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed", "equipped", "sleeved / connected", "connected", etc., should be interpreted broadly. For example, "connection" can be a wall-mounted 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 a connection within two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0034] Example 1

[0035] refer to Figures 1-6This embodiment provides a tunnel test device for simulating near-fault ground motion induced by stick-slip of a normal fault. It includes at least two sets of spaced-apart explosive components 1, baffles 2, a tunnel model 3, a model box 4, and a first simulated stratum 5, a second simulated stratum 6, and a third simulated stratum 7 assembled within the model box 4. The model box 4 has an opening 41, and the baffles 2 are engaged at the opening 41 to seal the second simulated stratum 6. The side of the second simulated stratum 6 furthest from the opening 41 is higher than the side closest to the opening 41, and separates the tunnel from the... The tunnel model 3 passes through the first simulated stratum 5, the second simulated stratum 6, and the third simulated stratum 7; the explosive assembly 1 is installed below the tunnel model 3; the explosive assembly 1 is provided with a first lead wire 1-1, an explosive 1-2, and a driven block 1-3 for detonating the explosive 1-2. The driven block 1-3 is arranged in the second simulated stratum 6 and connected to the explosive 1-2. The side of the explosive 1-2 away from the driven block 1-3 is connected to the model box 4 through the first lead wire 1-1.

[0036] More specifically, in this embodiment, the tunnel test device for simulating near-fault ground motion caused by stick-slip of a normal fault includes at least two sets of spaced explosive components 1, baffles 2, tunnel models 3, C-shaped plates 11, model boxes 4, and a first simulated stratum 5, a second simulated stratum 6, and a third simulated stratum 7 assembled in the model boxes 4. The simulated strata are composed of river sand, quartz sand, and fly ash as the main materials, waste engine oil and petroleum jelly as the binding materials, and barite powder and diatomaceous earth as auxiliary materials, mixed in a certain proportion to form a stratum-like material.

[0037] The model box 4 has an opening 41, which is elongated. A baffle 2 is engaged at the opening 41 to block the second simulated stratum 6. The opening 41 is located at the lower end of the side wall of the model box 4, and its cross-section is adapted to the cross-section of the second simulated stratum 6. A C-shaped plate 11 is welded to the outer edge of the opening 41. The model box 4 has a protruding platform 42, which, together with the C-shaped plate 11, forms a channel for the baffle 2 to slide. The baffle 2 slides within the channel to displace the second simulated stratum 6. The first simulated stratum 5 is in contact with the second simulated stratum 6, with the interface being a fault plane; the second simulated stratum 6 is in contact with the third simulated stratum 7. The first simulated stratum 5 and the third simulated stratum 7 are fixed strata, while the second simulated stratum 6 is a movable stratum. The second simulated stratum 6 is set at a large dip angle and gradually transitions to horizontal from top to bottom. The side of the second simulated stratum 6 furthest from the opening 41 is higher than the side of the second simulated stratum 6 closest to the opening 41, and separates the first simulated stratum 5 and the third simulated stratum 7. When the baffle 2 is pulled outwards, the second simulated stratum 6, affected by gravity and losing the support of the baffle 2, slides downwards, causing permanent displacement of the strata and surface. The downward sliding of the second simulated stratum 6 conforms to the stick-slip fault state of a normal fault. In this embodiment, the model box 4 serves as a bearing container, forming a closed space together with the C-shaped plate 11 and the baffle 2. The tunnel model 3 traverses the first simulated stratum 5, the second simulated stratum 6, and the third simulated stratum 7, and has a certain burial depth.

[0038] The explosive components 1 are arranged at intervals from bottom to top in the simulated strata. Specifically, the explosive components 1 are installed below the tunnel model 3. The explosive components 1 are provided with a first lead wire 1-1, a second lead wire 1-4, an explosive 1-2, and a driven block 1-3 for detonating the explosive 1-2. The driven block 1-3 is arranged in the second simulated stratum 6 and connected to the explosive 1-2. The side of the explosive 1-2 away from the driven block 1-3 is connected to the model box 4 through the first lead wire 1-1. The driven block 1-3 is located in the second simulated stratum 6 and is constrained by the soil. When the second simulated stratum 6 slides down, it follows the movement of the second simulated stratum 6. In this embodiment, the sensitivity of the explosive components 1 decreases sequentially from bottom to top. Further, the driven block 1-3 is connected to the explosive 1-2 through the second lead wire 1-4; the explosive 1-2 is arranged in the second simulated stratum 6 on the side closer to the first simulated stratum 5. When the deformation stiffness of the second leads 1-4 is consistent, the detonation sensitivity of explosive 1-2 decreases sequentially from bottom to top; when the detonation sensitivity of explosive 1-2 is consistent, the deformation stiffness of the second leads 1-4 decreases sequentially from bottom to top. The explosive 1-2 is a pull-sensitive explosive. In this embodiment, the tunnel test device simulating near-fault ground motion induced by normal fault stick-slip further includes a talc layer 8, a filter layer 9, an energy-absorbing layer 10, and a support 12. A talc layer 8 of a certain thickness is arranged between the first simulated stratum 5 and the second simulated stratum 6, and between the third simulated stratum 7 and the second simulated stratum 6. The talc layer 8 helps the second simulated stratum 6 slide downwards more effectively. The filter layer 9 is laid between the tunnel model 3 and the explosive component 1. It can be understood that the explosive component 1, the filter layer 9, and the tunnel model 3 are arranged sequentially from bottom to top within the model box 4. The filter layer 9 can filter out high-frequency components and retain low-frequency components. The filter layer 9 is broken at the location of the talc layer 8. An energy-absorbing layer 10 of a certain thickness is attached to the inner wall of the model box 4. The energy-absorbing layer 10 is made of a flexible energy-absorbing material, including but not limited to: polyurethane foam, polyethylene foam, silicone, corrugated cardboard, and shock-absorbing rubber. In this embodiment, the flexible energy-absorbing material is not limited to the above-listed items. The bracket 12 is used to fix the model box 4. The bracket 12 is disposed on the outer wall of the model box 4, with a certain number of brackets 12 on each side wall. One end of the bracket 12 is connected to the outer wall of the model box 4, and the other end is fixed to the ground.

[0039] It is worth noting that this embodiment also provides a test method for the tunnel test device for simulating near-fault ground motion induced by normal fault stick-slip, comprising the following steps:

[0040] Step 1: Complete the welding of the protruding platform 42 and C-shaped plate 11 of the model box 4; place the model box 4 on a horizontal surface and fix it to the ground using the bracket 12. Position the baffle 2 at the opening 41, flush with the side wall of the model box 4, to complete the overall closure of the model box 4.

[0041] Step 2: Set an energy-absorbing layer 10 of a certain thickness on the inner wall of the model box 4;

[0042] Step 3: Connect one end of the first lead wire 1-1 to the model box 4 in sequence; then fill the first simulated stratum 5 to the filter layer 9 from bottom to top, keeping the first lead wire 1-1 taut during filling;

[0043] Step 4: Lay the talc layer 8 between the first simulated stratum 5 and the second simulated stratum 6;

[0044] Step 5: Install and deploy the driven block 1-3, the second lead wire 1-4, and the explosive 1-2 in sequence at each location;

[0045] Step 6: Fill the second simulated stratum 6 to the filter layer 9 from bottom to top. When filling, keep the second lead wire 1-4 horizontal and keep the driven block 1-3 facing the fault.

[0046] Step 7: Lay the talc layer 8 between the second simulated stratum 6 and the third simulated stratum 7;

[0047] Step 8: Fill the installation positions from bottom to top, from the third simulated stratum 7 to the filter layer 9;

[0048] Step 9: Lay the filter layer 9; then continue to fill the first simulated stratum 5, the second simulated stratum 6 and the third simulated stratum 7 on top of the filter layer 9 until the tunnel model 3 is installed.

[0049] Step 10: Place tunnel model 3; then continue to fill the first simulated stratum 5, the second simulated stratum 6 and the third simulated stratum 7 on top of tunnel model 3 until model box 4 is full;

[0050] Step 11: Let the test device stand for a certain period of time to allow the state of each part in the model box 4 to stabilize.

[0051] Step 12: Pull out the baffle 2 according to the test requirements until the explosives 1-2 are detonated in sequence; observe the experimental results after the vibration of the model box 4 stops.

[0052] The above description is merely a preferred embodiment of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention by those skilled in the art within the scope of the technology disclosed in the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A tunnel testing device for simulating near-fault ground motion induced by stick-slip of a normal fault, characterized in that, The device includes at least two sets of spaced-apart explosive components, baffles, a tunnel model, a model box, and a first, second, and third simulated geological layer assembled within the model box. The model box has an opening, and the baffles are engaged at the opening to seal the second simulated geological layer. The side of the second simulated geological layer furthest from the opening is higher than the side closest to the opening, and this separations the first and third simulated geological layers. The tunnel model traverses the first, second, and third simulated geological layers. The explosive components are positioned below the tunnel model. Each explosive component includes a first lead, an explosive material, and a driven block for detonating the explosive material. The driven block is located within the second simulated geological layer and connected to the explosive material. The side of the explosive material furthest from the driven block is connected to the model box via the first lead. The sensitivity of the explosive components decreases sequentially from bottom to top. The device also includes a filter layer laid between the tunnel model and the explosive components.

2. The tunnel test device for simulating near-fault ground motion induced by normal fault stick-slip as described in claim 1, characterized in that, It also includes a talc layer; the talc layer is arranged between the first simulated stratum and the second simulated stratum, and between the third simulated stratum and the second simulated stratum.

3. The tunnel test device for simulating near-fault ground motion induced by stick-slip of a normal fault according to claim 2, characterized in that, The filter layer breaks at the location of the talc layer.

4. The tunnel test device for simulating near-fault ground motion induced by stick-slip of a normal fault according to claim 1, characterized in that, The opening is located at the lower end of the side wall of the model box, and the cross-section of the opening is adapted to the cross-section of the second simulated stratum.

5. The tunnel test device for simulating near-fault ground motion induced by stick-slip of a normal fault according to claim 4, characterized in that, It also includes a C-shaped plate fixed to the outer edge of the opening; the model box has an outwardly protruding platform, the outwardly protruding platform and the C-shaped plate enclosing to form a channel for the baffle to slide; the baffle slides within the channel to displace the second simulated stratum.

6. The tunnel test device for simulating near-fault ground motion induced by normal fault stick-slip as described in claim 1, characterized in that, It also includes an energy-absorbing layer; the energy-absorbing layer is attached to the inner wall of the model box.

7. The tunnel test device for simulating near-fault ground motion induced by stick-slip of a normal fault according to claim 1, characterized in that, The explosive assembly is further provided with a second lead wire, and the driven block is connected to the explosive through the second lead wire; the explosive is arranged in the second simulated stratum on the side close to the first simulated stratum.

8. The tunnel test device for simulating near-fault ground motion induced by stick-slip of a normal fault according to claim 7, characterized in that, When the deformation stiffness of the second lead is consistent, the detonation sensitivity of the explosive decreases from bottom to top.

9. A test method for a tunnel test apparatus as described in claim 3 for simulating near-fault ground motion induced by normal fault stick-slip, characterized in that, Includes the following steps: Step 1: Connect one end of the first lead wire to the model box; fill the first simulated stratum to the installation position of the filter layer in the model box, and ensure the tension of the first lead wire during filling; Step 2: Fill the model box with the second simulated stratum up to the installation position of the filter layer; during filling, install and configure the explosive assembly in the second simulated stratum; Step 3: Fill the model box with the third simulated stratum up to the installation position of the filter layer, and then lay the filter layer; Step 4: Fill the filter layer with the first, second, and third simulated geological layers up to the tunnel model installation position, and then place the tunnel model. Step 5: Fill the tunnel model with the first, second, and third simulated geological layers until the model box is full, and then let it stand still. Step 6: Pull the outer baffle until the explosives detonate sequentially; observe the experimental results after the model box vibration stops.

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