Underground explosion pressure test system and test method

Abstract

The invention provides an underground explosion pressure test system and test method, relates to the technical field of pressure tests, and solves the technical problems that the workload of an underground explosion pressure test is large and a sensor is easy to damage. The underground explosion pressure test system comprises an explosion device, at least one first unit, at least one second unit and a control device located on the ground, and the explosion device, the first units and the second units are all electrically connected with the control device; the first unit comprises a first sensor and a first pipe, and a wire of the first sensor penetrates through the first pipe to be electrically connected with the control device. The second unit comprises a second sensor and a second pipe, and a wire of the second sensor penetrates through the second pipe and is electrically connected with the control device; the first sensing surface of the first sensor directly faces the explosive device, and the second sensing surface of the second sensor faces the explosive device. The test system is high in test efficiency, and the sensor is not easy to damage.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure testing, and in particular to an underground explosion pressure testing system and a testing method. Background Art

[0002] Studying the propagation of stress waves in underground rock and soil is of great significance to the explosive mining of minerals. Field test is an important means of studying explosion stress in rock and soil. Therefore, a reasonable underground explosion pressure test system is an indispensable technical prerequisite and material guarantee for the above research.

[0003] In the related art, the buried depth of the sensor used to measure stress waves is the same as that of the explosives. Specifically, the sensor is pre-buried at a certain distance from the explosives. In the tunnel dug within the range where the sensor needs to be buried, multiple sensors are placed at selected measuring points along the horizontal extension direction of the tunnel, and the wires are connected to the outside of the pit along the side wall. After that, the original soil is backfilled, and the sensor position is fixed by backfilling layer by layer, and the backfill layer is compacted. After the test is completed, the sensors in the rock and soil must be removed by excavation. The experimental workload is large, and the sensors may be damaged due to operational reasons, making it difficult to reuse the expensive sensors. Summary of the invention

[0004] The purpose of the present invention is to provide an underground explosion pressure test system and test method to solve the technical problems of large workload and easy damage of sensors in underground explosion pressure test.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides an underground explosion pressure test system, comprising an explosion device located in rock soil, at least one first unit, at least one second unit and a control device located above the ground, wherein the explosion device, the first unit and the second unit are all electrically connected to the control device;

[0007] The first unit includes a first sensor and a first tube, and a wire of the first sensor passes through the first tube and is electrically connected to the control device;

[0008] The second unit includes a second sensor and a second tube, and a wire of the second sensor passes through the second tube and is electrically connected to the control device;

[0009] The first sensing surface of the first sensor faces the explosive device, and the second sensing surface of the second sensor faces the explosive device laterally.

[0010] According to at least one embodiment of the present invention, the control device includes a data collector, and the data collector is electrically connected to the explosive device, the first sensor, and the second sensor respectively.

[0011] According to at least one embodiment of the present invention, the first unit corresponds to the second unit one by one.

[0012] According to at least one embodiment of the present invention, the horizontal distance between the first unit and the explosive device and the corresponding horizontal distance between the second unit and the explosive device are the same.

[0013] According to at least one embodiment of the present invention, a line connecting the first unit and the corresponding second unit passes through the center of the explosive device.

[0014] According to at least one embodiment of the present invention, when there are plural first units and second units, the horizontal distances between each first unit and the explosive device are different, and each first unit is evenly spaced along the circumference of the explosive device.

[0015] According to at least one embodiment of the present invention, the number of the first units and the second units at the same horizontal distance from the explosive device is plural and are evenly distributed along the circumference of the explosive device.

[0016] According to at least one embodiment of the present invention, the first pipe includes a plurality of detachably connected first pipe segments, and the second pipe includes a plurality of detachably connected second pipe segments.

[0017] According to at least one embodiment of the present invention, the length of the first tube and the length of the second tube are both greater than the burial depth of the explosive device.

[0018] In a second aspect, the present invention further provides an underground explosion pressure test method, which uses the test system described in the first aspect to conduct the test.

[0019] Among the one or more technical solutions provided in the exemplary embodiments of the present invention, at least one of the following beneficial effects can be achieved.

[0020] The underground explosion pressure test system provided by the exemplary embodiment of the present invention uses a drill to drill a hole in the rock and soil, and places the explosive device in the center hole, while the first sensor and the second sensor are directly placed in the corresponding measuring holes through the first tube and the second tube, and compacted by backfilling soil. Compared with the prior art that uses the form of excavating tunnels, the workload of excavation and backfilling is reduced. At the same time, the form of using steel pipes (first pipe and second pipe) to drive the corresponding sensors can be easily taken out from the borehole, for example, the sensor tooling is mechanically hoisted out through the steel pipe, and there is no need to perform large excavation to recover the used sensors, and it is not easy to damage the sensors. Furthermore, the drilling method is not limited by depth, and the explosion stress wave test can be carried out at a hole depth of tens of meters to hundreds of meters, which expands the test range of stress waves.

[0021] Furthermore, the steel pipe of the exemplary embodiment of the present invention serves as a pipe of the sensor to lead the wire out of the ground and connect it to the control device, so that the steel pipe can protect the wire and avoid violent movement of rock and soil caused by explosion, which may cause damage to the buried wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings illustrate exemplary embodiments of the present invention and together with the description serve to explain the principles of the present invention, and these drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification;

[0023] Figure 1 is a schematic structural diagram of a test system according to an embodiment of the present invention;

[0024] Figure 2 is an isometric structural diagram of a first unit according to an embodiment of the present invention;

[0025] Figure 3 is a schematic cross-sectional structural diagram of a first unit according to an embodiment of the present invention;

[0026] Figure 4 is an isometric structural schematic diagram of a second unit according to an embodiment of the present invention;

[0027] Figure 5 is a schematic cross-sectional structural diagram of a second unit according to an embodiment of the present invention;

[0028] Figure 6 is a schematic diagram of a second packaging plate and an explosion stress wave according to an embodiment of the present invention;

[0029] Figure 7 is a peak stress fitting curve of the first sensor and the second sensor according to an embodiment of the present invention;

[0030] Figure 8 is a schematic diagram of the arrangement of the first unit and the second unit according to an embodiment of the present invention;

[0031] Fig. 9 is a schematic diagram of the arrangement of a first unit and a second unit according to another embodiment of the present invention;

[0032] Fig.10 Schematic diagram of the structure of a steel pipe according to an embodiment of the present invention.

[0033] Figure numerals: 11, first packaging plate; 111, first surface; 12, first tube; 121, open-cell foam plastic; 122, wire mesh; 123, fluororubber layer; 13, third tube; 14, first sensing surface; 21, second packaging plate; 211, guide part; 22, second tube; 24, second sensing surface, 30, control device. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] In the related technology, model test methods are often used in stress wave testing in underground rock and soil, and pressure sensors are directly buried for measurement. The main problems are as follows: most of the barrel-shaped models are filled with rock and soil to be tested to simulate the underground rock and soil environment. The cylindrical model structure is generally not more than 10m, which limits the test range of stress waves; and directly burying pressure sensors requires large-scale excavation, which is a lot of work, and they are unprotected. The hard rock blocks in the medium can easily damage the sensor wires, and the pressure sensor is easy to deviate from the original measurement point during the burial process, and the accuracy of stress wave testing cannot be guaranteed.

[0036] Figure 1 Schematic diagram of the structure of the test system according to the embodiment of the present invention. Figure 1 As shown, a center hole and two measuring holes with the same hole depth are drilled in the rock, wherein the distances between the two measuring holes and the center hole are the same.

[0037] In one example, a typical flat terrain is selected in the test field, and a measuring hole is drilled from the ground downward using a deep hole drill bit, and its diameter is sufficient to accommodate the first unit and the second unit. The distance between the measuring hole and the center hole is the same, so that the measured first stress value and the second stress value can be stress waves of the same intensity generated by the explosion center, and then it can be determined whether the first stress value is accurate.

[0038] In practical applications, the depths of the two measuring holes may be slightly greater than the depth of the central hole, so that there is room for adjustment of the positions of the first sensing surface 14 and the second sensing surface 24 .

[0039] Figure 2 is an isometric structural diagram of a first unit according to an embodiment of the present invention; Figure 3 is a schematic cross-sectional structural diagram of a first unit according to an embodiment of the present invention; Figure 4 is an isometric structural schematic diagram of a second unit according to an embodiment of the present invention; Figure 5 Schematic diagram of the cross-sectional structure of the second unit according to an embodiment of the present invention. Figure 2-Figure 5 As shown, the explosive device is placed in the central hole, and the first unit and the second unit are placed in two measuring holes respectively; wherein the first sensing surface 14 and the edge of the guide portion 211 away from the second tube 22 are both arranged opposite to the explosive device.

[0040] The first sensor and the second sensor can be placed at the bottom of the measuring hole respectively through the first tube 12 and the second tube 22. Specifically, the first tube 12 and the second tube 22 are adjusted so that the first sensing surface 14 of the first sensor faces the explosion center, while the second sensing surface 24 of the second sensor faces the explosion center, that is, the sharp edge of the guide portion 211 that is away from the second tube 22 faces the explosion center.

[0041] Exemplarily, the first tube 12 and the second tube 22 are adjusted so that the center point of the first sensing surface 14 of the first sensor, the center point of the second sensing surface 24 of the second sensor and the center point of the explosive device are located on the same horizontal plane.

[0042] The measuring hole is then backfilled with the in-situ soil. During this process, the soil pit is compacted several times with a long stick so that the rock and soil density after backfilling is similar to that before drilling.

[0043] From the above, it can be seen that the depth of burying the explosive device by drilling is not limited. Even the stress wave generated by a large-yield explosion can eliminate the influence of ground reflection on the test results, reduce the error of the experiment, and obtain a more accurate explosion stress size. The depth of the center hole can be set to exceed the critical no-effect burial depth.

[0044] Compared with excavating tunnels for burial, the test method of the exemplary embodiment of the present invention not only saves a lot of backfilling work, but also can be applied to the accurate measurement of stress waves generated by large-yield explosions.

[0045] The above explosive device can generate a stress wave that propagates in a spherical shape, for example, it can be used to detonate a small or large equivalent charge, for example, a charge of several thousand kilograms. The test method can be applied to the detonation of a charge with a large equivalent at a great burial depth, and the burial depth and the test range can both reach tens of meters.

[0046] In some embodiments, the depth of the borehole is determined based on the critical no-effect burial depth. Specifically, in order to eliminate the influence of ground reflection on the test results, reduce the experimental error, and obtain a more accurate magnitude of the explosion stress on the surface of the protective structure, the charge hole depth designed in the experiment should exceed the corresponding critical no-effect burial depth. For rock and soil media, the critical no-effect burial depth is determined by formula 1:

[0047] h l =kQ 1 / 3 , Formula 1;

[0048] Among them, h l is the critical no-effect burial depth, in m, Q is the equivalent TNT charge, in kg, and for rock and soil media, k is taken as 0.8 m kg -1 / 3 For example, for a 1kg TNT charge, when its charge is buried more than h l (0.8m), then the stress generated by the charge explosion will all act on the rock and soil, making the test results more accurate.

[0049] When selecting the range of the first sensor and the second sensor, it is necessary to select according to the experimental conditions. First, a preliminary stress peak estimation is required according to the experimental conditions, and then the sensor range is selected according to the estimation result. Here, in order to better adapt to the geotechnical testing environment, the first sensor and the second sensor can use quartz sensors with stable sensitivity. The stress peak estimation in geotechnical can be obtained according to formula 2:

[0050] σ r =A·Z -n , formula 2;

[0051] Among them, σ r is the test pressure, A and n are the stress wave attenuation coefficient and attenuation index respectively. Proportional distance Z = R / Q 1 / 3 , unit is m·kg -1 / 3 The reference values ​​of A and n in different media are shown in Table 1.

[0052] Table 1 Stress wave attenuation coefficient and attenuation index in different media

[0053]

[0054] like Figure 2 and Figure 3 As shown, the first unit includes a first sensor, a first tube 12 and a first packaging board 11 disposed at the bottom end of the first tube 12 , and a first surface 111 of the first packaging board 11 has a first opening for exposing the first sensing surface 14 of the first sensor.

[0055] In practical applications, the first sensor is packaged in the first packaging board 11, and its first sensing surface 14 is exposed through the first opening provided on the first surface 111 of the first packaging board 11, so as to receive and sense stress waves. Exemplarily, the first sensor may be a pressure sensor, optionally a quartz sensor, which has stable sensitivity. The wire of the first sensor may extend from the ground through the first tube 12 to be connected to a data acquisition device. The first tube 12 may drive the first packaging board 11 to extend into the corresponding borehole, so as to bury the first sensor in the borehole in a predetermined orientation, and may also protect the wire of the first sensor to prevent hard rock and soil from damaging the wire of the first sensor, resulting in damage to the insulation layer, excessive signal noise, or even cutting off the wire of the first sensor and failing to detect a signal.

[0056] Exemplarily, the top of the first packaging board 11 is arranged at the bottom of the first tube 12, and the first opening is located at a position close to the bottom of the first surface 111 of the first packaging board 11, and the first opening is consistent with the shape and size of the first sensing surface 14 of the first sensor, for example, it can be circular. The first sensing surface 14 is located below the first tube 12 and away from the first tube 12, which can reduce the reflection of the stress wave by the first tube 12 and affect the accuracy of the first sensor in acquiring data.

[0057] In one example, the first unit further includes a third tube 13 , both ends of which are respectively vertically connected to the bottom end of the first tube 12 and the top end of the first packaging plate 11 , and the first opening is close to the bottom end of the first packaging plate 11 .

[0058] like Figure 2 As shown, the third tube 13 and the first packaging board 11 are arranged in an L shape, and the third tube 13 and the first tube 12 are also arranged in an L shape. The third tube 13 can be regarded as a cantilever so that the first tube 12 and the first sensor are separated by a certain distance in the horizontal direction, and the first sensing surface 14 of the first sensor is close to the bottom end of the first packaging board 11, that is, there is a certain distance between the first sensing surface 14 and the first tube 12 in both the vertical direction and the horizontal direction. The reflection of the stress wave by the first tube 12 minimizes the interference to the data of the first sensor.

[0059] When the third tube 13 is connected to the first tube 12, the wire of the first sensor can pass through the third tube 13 and the first tube 12 to reach the ground.

[0060] Exemplarily, the bottom end of the first tube 12 may be closed or open without affecting the protection of the wires therein.

[0061] In one example, the first packaging board 11 is made of a material that matches the wave impedance of rock and soil, such as nylon, PVC plastic, etc., which can reduce the impact on the first sensor, thereby reducing experimental errors and more accurately measuring the forward pressure of the explosion.

[0062] like Figure 4 and Figure 5 As shown, the second unit provided by the exemplary embodiment of the present invention includes a second tube 22 and a second packaging plate 21 vertically arranged at the bottom end of the second tube 22, the second packaging plate 21 has two second surfaces distributed along the first direction, the axial direction of the second tube 22 is perpendicular to the first direction, and one second surface has a second opening for exposing the second sensing surface 24 of the second sensor; the second packaging plate 21 has a guide portion 211 surrounding the second sensing surface 24, and the thickness of the guide portion 211 gradually becomes thinner along the direction away from the second sensing surface 24.

[0063] The second packaging plate 21 and the second tube 22 are arranged in an L shape, and the axial direction of the second tube 22 can be perpendicular to the second surface, that is, the first direction is a vertical direction. Figure 4 As shown, the axial direction of the second tube 22 may also be parallel to the second surface, that is, the first direction is a horizontal direction.

[0064] A second opening is formed on one of the two opposite second surfaces of the second packaging board 21 to expose the second sensing surface 24 of the second sensor packaged in the second packaging board 21 , and the wire of the second sensor can extend out of the ground through the second tube 22 .

[0065] The second opening is disposed at a position of the second packaging plate 21 away from the second tube 22 , which can minimize the influence of the stress wave reflected by the second tube 22 on the stress measurement accuracy of the second sensor.

[0066] A guide portion 211 is formed at one end of the second packaging plate 21 away from the second tube 22. The guide portion 211 is a pancake-shaped structure that is thick in the middle and thin at the edges, and surrounds part of the circumference of the second opening. When it is fixed in the drilled hole, the edge of the guide portion 211 faces the explosive device. Since its edge is sharp and gradually thickens in the middle, the stress wave can propagate unimpeded to the second opening, that is, the second sensing surface 24 of the second sensor, so that the influence of the shape of the second packaging plate 21 itself on the stress wave is minimized, thereby improving the measurement accuracy of the second sensor.

[0067] In one example, the material of the second packaging board 21 is the same as that of the first packaging board 11 , the shape and size of the second opening is the same as that of the first opening, and the shape and thickness of the second tube 22 is the same as that of the first tube 12 , which are not described in detail here.

[0068] The first sensing surface 14 of the first sensor can face the explosive device directly, and can measure the positive stress of the stress wave; the second sensing surface 24 of the second sensor can face the explosive device laterally, and can measure the lateral stress of the stress wave. Figure 6 As shown, Figure 6 is a schematic diagram of a second packaging board and an explosion stress wave according to an embodiment of the present invention.

[0069] Under the action of blast stress wave, there is a certain relationship between normal stress and lateral stress in rock and soil, as described below:

[0070] A. Rock and soil present elastic stress state under the action of explosion stress.

[0071] Under the elastic state, the rock and soil present a triaxial stress state due to the explosion stress. The explosion stress σ at a point in the rock and soil is r It can be divided into three normal stress components and six shear stress components. The nine components are arranged according to certain rules, as shown in Formula 3.

[0072]

[0073] When the explosion stress reaches the second sensor, Figure 6 As shown, since the second sensing surface 24 of the second sensor is placed perpendicular to the explosion center, the three-dimensional stress only has normal stress on each surface element, and the shear stress is equal to 0. Formula 3 can be rewritten as Formula 4:

[0074]

[0075] The stress data recorded by the second sensor is σ perpendicular to the second sensing surface. zz The time course curve.

[0076] It should be noted that the stress waves tested by the first sensor and the second sensor are generated by the same explosive device, that is, the normal stress obtained by the first sensor is the explosion stress σ r Therefore, in the actual test process, the lateral stress σ 侧 will always be less than the normal stress σ 正 , both satisfy formula 5.

[0077] σ zz =σ 侧 =σ r μ = σ 正 ·μ, formula 5;

[0078] Where μ is the Poisson's ratio of rock and soil.

[0079] Thus, the ratio of normal stress to lateral stress can be obtained, which satisfies Equation 6.

[0080]

[0081] B. Rock and soil are in a fluid state under the action of explosion stress.

[0082] Formula 3 can be rewritten as Formula 7:

[0083]

[0084] σ m is the stress in each direction, and the magnitudes in the three directions are equal. In the fluid state, the stress recorded by the first sensor and the second sensor are both volume stresses, so we get formula 8:

[0085]

[0086] Thus, the ratio of normal stress to lateral stress can be obtained, which satisfies Equation 9.

[0087]

[0088] In the rock and soil explosion test, the rock and soil medium in the vicinity of the explosive is in a fluid state, and the rock and soil medium in the far area is in an elastic state. From the above, we can get formula 10:

[0089]

[0090] In the rock and soil explosion test, the normal stress and the lateral stress obtained by the first sensor and the second sensor have a ratio between [1,1 / μ], where μ can give an accurate value of the Poisson's ratio through on-site rock and soil survey.

[0091] In one example, the first tube 12 of the exemplary embodiment of the present invention includes a plurality of first tube segments, and the second tube 22 includes a plurality of second tube segments, and threads are provided at both ends of each first tube segment, so that the plurality of first tube segments can be assembled to form the first tube 12 according to the actual needs of the hole depth; threads are provided at both ends of each second tube segment, so that the plurality of second tube segments can be assembled to form the second tube 22 according to the actual needs of the hole depth. Exemplarily, the plurality of first tube segments and the plurality of second tube segments can be fixed in the form of sleeves, so that the length can be flexibly adjusted, increasing the flexibility and practicality of the test.

[0092] Exemplarily, the first unit of the exemplary embodiment of the present invention further includes a first rubber tube, and the second unit further includes a second rubber tube.

[0093] In practical applications, the wire of the first sensor is passed through the first rubber tube, and the first rubber tube is fixed at the central axis of the first tube 12; the wire of the second sensor is passed through the second rubber tube, and the second rubber tube is fixed at the central axis of the second tube 22. The rubber tube can not only further protect the sensor wire, but also reduce the transmission of vibration and impact. In the steel pipe, the sensor wire is fixed in the center of the pipe to avoid direct contact between the sensor wire and the steel pipe, thereby reducing wear and damage.

[0094] Furthermore, after the explosive device is activated, the data acquisition device acquires the first stress value of the first sensor and the second stress value of the second sensor through the corresponding wires. The control device determines whether the first stress value is an accurate stress value based on the ratio of the first stress value to the second stress value measured at the same explosion center distance.

[0095] When the ratio of the first stress value to the second stress value is 1 to 1 / μ, it means that the first stress value is accurate, so the first stress value is stored; when it is not in the above range, it means that the first stress value is difficult to accurately reflect the actual stress value, and the data is discarded.

[0096] In some embodiments, there are two forms of arrangement of the first unit and the second unit, that is, the method of determining the circumferential distribution measuring points of the explosion center. To avoid the influence of mutual occlusion of measuring points on the sensor, the measuring holes are circumferentially distributed around the central hole at a certain angle.

[0097] In some embodiments, the first unit corresponds to the second unit one-to-one.

[0098] In some embodiments, the horizontal distance between the first unit and the explosive device and the horizontal distance between the corresponding second unit and the explosive device are the same.

[0099] In one example, a line between a first unit and a corresponding second unit passes through the center of the explosive device.

[0100] In some embodiments, when there are multiple first units and second units, the horizontal distances between each first unit and the explosive device are different, and each first unit is evenly spaced along the circumference of the explosive device.

[0101] In one example, the number of the first unit and the second unit having the same horizontal distance from the explosive device are both plural and are evenly distributed along the circumference of the explosive device.

[0102] Solution 1: Arrange a first sensor and a second sensor at the same radial distance from the explosion center, such as Figure 8 As shown, Figure 8 2 is a schematic diagram of the arrangement of the first unit and the second unit according to an embodiment of the present invention.

[0103] When three or more control experiments are set up for a charge of a certain mass in the test, in order to reduce the test workload, this scheme is selected for arrangement, that is, a first sensor and a second sensor are arranged respectively at a radial distance, so that the normal stress and lateral stress at a radial distance are obtained, and the accuracy of the experimental results is judged based on the proportional relationship between the first stress value and the second stress value.

[0104] In scheme 1, two measuring points are used for each radial distance, where measuring points B1, B3, and B5 use the first unit, and B2, B4, and B6 use the second unit. The sensors at the same radial distance are 180° apart in the circumferential direction, and at different radial distances are 60° apart in the circumferential direction.

[0105] Solution 2: Arrange two first sensors and two second sensors at the same radial distance from the explosion center, such as Fig. 9 As shown, Fig. 9 FIG. 4 is a schematic diagram of arrangement of a first unit and a second unit according to another embodiment of the present invention.

[0106] When only one or two groups of experiments are set up for a charge of a certain mass in the test, in order to obtain more experimental data, scheme 2 is selected for arrangement, that is, two first sensors and two second sensors are arranged at a radial distance, so that the normal stress and lateral stress at a radial distance are obtained, and the accuracy of the experimental results is judged according to the proportional relationship between the first stress value and the second stress value.

[0107] In scheme 2, 4 measuring points are used for each radial distance, among which measuring points B1, B3, B5, B7, B9, and B11 use the first unit, and B2, B4, B6, B8, B10, and B12 use the second unit. The sensors at the same radial distance are 90° apart along the circumferential direction, and at different radial distances, the sensors are 30° apart along the circumferential direction.

[0108] Fig.10 Schematic diagram of the structure of a steel pipe according to an embodiment of the present invention. Fig.10 As shown, the first tube 12 and the second tube have the same structure. The structure of the first tube 12 is taken as an example for description below. The outer surface of the first tube 12 has a layer of buffering energy-absorbing material, such as open-cell foam plastic 121, with a thickness between 5 mm and 10 mm. The open-cell foam plastic 121 is fixed to the corresponding steel pipe using tape or special adhesive to avoid displacement during the explosion. A layer of wire mesh 122 is wrapped around the outside of the open-cell foam plastic 121. The wire mesh 122 should have sufficient strength and density to effectively block large particles and rocks generated by the explosion. The wire mesh 122 is fixed to the outside of the open-cell foam plastic 121 with a strap to ensure that it is not easy to fall off or move under the impact of the explosion. The mesh size is selected to be able to filter large rocks but allow stress waves to pass.

[0109] The outer layer of the wire mesh 122 also has a fluororubber layer 123, which can reduce the mutual constraints between the first tube 12 and the soil, so that the first tube 12 can deform freely with the movement of the soil during the explosion. It can effectively absorb the shock wave generated by the explosion, reduce the direct transmission of the impact force, and thus reduce the interference with the measurement results. The thickness of the fluororubber layer 123 is between 10mm and 20mm to ensure that it will not break instantly under the impact of the explosion. In this way, when the explosion wave acts on the rock and soil near the sensor, due to the high elasticity of the fluororubber, it will deform first and move with the rock and soil, reducing the impact of the first tube 12 on the overall test. The thickness of the entire first tube 12 is about 20mm to 35mm.

[0110] In some embodiments, the wall thickness of the first tube 12 is 2 mm, the surface of the first tube 12 is hot-dip galvanized, and an epoxy resin coating is added outside the hot-dip galvanized layer to further enhance the wear resistance and corrosion resistance of the first tube 12 and improve its own rust resistance and corrosion resistance.

[0111] The length of the first pipe section is unified to 2m, and 15mm long threads are processed at both ends, and waterproof sealing materials (such as fluororubber sealing rings) are applied to prevent the intrusion of moisture and soil. This is to facilitate the connection between the first pipe sections and the threading of the wires. At the same time, according to different burial depth requirements, the connection length of the first pipe is adjusted to ensure the flexibility and practicality of the experimental device. The second pipe section is the same as the first pipe section, and will not be repeated here.

[0112] For example, the first tube and the second tube are reserved with a suitable length above the ground to facilitate identification and recovery of the tooling after the experiment. Obvious identification marks are set on the reserved part above the ground, using color identification or labels, so that the experimenters can quickly locate and identify.

[0113] In some embodiments, the control device 30 includes a collection device, etc., which are all located on the ground to make the test results more accurate and reliable. Furthermore, the installation of the first unit and the second unit is also completed on the ground to ensure that the sensors buried in the soil can work normally and ensure the smooth progress of the experiment. After the experiment is over, it is only necessary to use a mechanical connection between the first pipe and the second pipe above the ground to hoist out the sensor tooling, without the need for large excavation to recover the used sensors.

[0114] Specifically, the stress wave of the explosive device is equivalent to the stress wave generated by 1kg TNT. The center hole is 1.6m deep, and the sensors are arranged in the arrangement method of scheme 2, and a set of peak stresses are measured.

[0115] Figure 7 is a peak stress fitting curve of the first sensor and the second sensor according to an embodiment of the present invention. Figure 7 As shown, the peak stress σ measured by the first sensor Band the peak stress σ measured by the second sensor F Fitting is performed to obtain Equation 11 and Equation 12 respectively.

[0116] σ B =0.188Z -2.44 , formula XI;

[0117] σ F =0.123Z -2.26 , formula twelve.

[0118] Where Z is the proportional distance in m·kg -1 / 3 .

[0119] As shown in Equation 11 and Equation 12, the peak stress of the stress wave and the proportional distance satisfy the exponential decay law of theoretical calculation in the engineering manual, that is, both the first sensor and the second sensor can accurately measure the stress wave in the rock and soil.

[0120] The exemplary embodiment of the present invention also provides an underground explosion pressure test method, which uses the test system of the above embodiment to perform the test. Specifically, it includes:

[0121] A center hole and two measuring holes with the same hole depth are drilled in the rock soil, wherein the two measuring holes are at the same distance from the center hole;

[0122] The explosive device is placed in the central hole, and the first unit and the second unit are placed in the two measuring holes respectively; wherein the first sensing surface and the edge of the guide part away from the second pipe are both arranged opposite to the stress wave generator;

[0123] A first stress value of a first sensor and a second stress value of a second sensor are collected; when the ratio of the first stress value to the second stress value is 1 to 1 / μ, the first stress value is stored; otherwise, the first stress value is discarded; wherein μ is the Poisson's ratio of the rock and soil.

[0124] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. An underground explosion pressure test system, characterized in that: The device comprises an explosive device, at least one first unit, at least one second unit and a control device located above the ground, wherein the explosive device, the first unit and the second unit are all electrically connected to the control device; The first unit includes a first sensor and a first tube, and a wire of the first sensor passes through the first tube and is electrically connected to the control device; The second unit includes a second sensor and a second tube, and a wire of the second sensor passes through the second tube and is electrically connected to the control device; The first sensing surface of the first sensor faces the explosive device, and the second sensing surface of the second sensor faces the explosive device laterally.

2. The test system according to claim 1, characterized in that: The control device comprises a data collector, and the data collector is electrically connected to the explosive device, the first sensor and the second sensor respectively.

3. The test system according to claim 2, characterized in that: The first unit corresponds to the second unit one by one.

4. The test system according to claim 3, characterized in that: The horizontal distances between the first unit and the explosive device and the corresponding horizontal distances between the second unit and the explosive device are the same.

5. The test system according to claim 4, characterized in that: A line connecting the first unit and the corresponding second unit passes through the center of the explosive device.

6. The test system according to claim 5, characterized in that: When there are plural first units and plural second units, the horizontal distances between each first unit and the explosive device are different, and each first unit is evenly spaced along the circumference of the explosive device.

7. The test system according to claim 4, characterized in that: The number of the first units and the second units at the same horizontal distance from the explosive device is plural and evenly distributed along the circumference of the explosive device.

8. The test system according to any one of claims 1 to 7, characterized in that: The first tube includes a plurality of detachably connected first tube segments, and the second tube includes a plurality of detachably connected second tube segments.

9. The test system according to claim 8, characterized in that: The length of the first tube and the length of the second tube are both greater than the burial depth of the explosive device.

10. An underground explosion pressure test method, characterized in that: The test is carried out using the test system described in any one of claims 1 to 9.

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