A physical model test system and method for deformation and failure of spoil dump

Abstract

The present invention provides a physical model test system and method for dumpsite deformation and failure, comprising a model dumpsite, an ice and snow layer, an image acquisition device, a distributed fiber optic monitoring device, and a loading device. The ice and snow layer is laid within the model dumpsite. The distributed fiber optic monitoring device includes multiple distributed optical fibers pre-buried within the model dumpsite to monitor strain and temperature information within the model dumpsite during the test. The image acquisition device is used to record the deformation and failure process of the model dumpsite during the test. The test system includes an ice and snow layer that simulates the dumpsite's morphology and freeze-thaw effects. The loading device applies external loads in stages, monitors external soil deformation within the dumpsite via the image acquisition device, and monitors soil strain and temperature changes within the dumpsite via the distributed fiber optic monitoring device. This system effectively simulates the external failure and deformation characteristics of the dumpsite under freeze-thaw and external loads, while also obtaining information on internal strain evolution and temperature field distribution.

Description

Technical Field

[0001] The invention belongs to the technical field of spoil dump deformation and failure model testing, and in particular relates to a spoil dump deformation and failure physical model testing system and method. Background Art

[0002] Spoil dumps are large in scale, and currently there is no universally recognized ideal theoretical model that can accurately and completely describe their failure behavior. Numerical simulation has become an effective method and means to study engineering failure problems, but simulating three-dimensional problems is often limited by computational efficiency and scale. Physical model testing, as an important research tool in rock mechanics, provides an effective means of exploring the potential failure mechanisms of complex spoil dumps, especially at a time when theoretical knowledge is still incomplete and discontinuous numerical simulation technology is immature.

[0003] Few physical model tests have examined deformation and failure of open-pit mine dumps, such as landslides and debris flows. Most studies analyze the stability of model dumps under rainfall conditions, while others focus on the selection of similar materials for physical model tests and their impact. Open-pit mine dumps in cold northern regions typically experience a freezing period lasting four to five months each year. Under the influence of freeze-thaw cycles and deadweight, collapse, uneven settlement, debris flows, and shallow landslides are common. The uneven distribution of weak planes, voids, and cracks complicates the internal structure and mechanical properties of the soil, leading to a variety of geological hazards. However, physical model tests of dumps that consider the combined effects of melting ice and snow and external loads have yet to be conducted. Furthermore, due to the large scale of dumps and environmental and technical constraints, field testing is difficult to conduct, and obtaining information on internal strain evolution is challenging. Therefore, it is imperative to provide a physical model testing system that can simultaneously monitor external deformation and failure, as well as internal strain evolution, under combined loads such as freeze-thaw and external loads, using distributed fiber optic monitoring technology.

[0004] Therefore, it is necessary to provide an improved technical solution to the above-mentioned deficiencies in the prior art. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a system and method for testing the deformation and failure physical model of a spoil dump.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A physical model test system for deformation and failure of a spoil dump, comprising:

[0008] A model dumping ground, which is formed by piling up soil and is used to simulate the shape of the dumping ground;

[0009] An ice and snow layer is laid in the model dumping ground and is located at a designed elevation of the slope of the model dumping ground;

[0010] A loading device is provided at the shoulder of the model dumping ground to apply external loads to the model dumping ground in stages;

[0011] A distributed optical fiber monitoring device, comprising a plurality of distributed optical fibers pre-buried in the model dumping ground, for monitoring strain and temperature information of the model dumping ground during the test;

[0012] An image acquisition device is used to record the deformation and destruction process of the model dump during the test.

[0013] Preferably, the model spoil dump is built in a test bench, and a substratum is poured in the test bench according to a real three-dimensional terrain, and the substratum simulates the real surface of the substratum of the spoil dump.

[0014] Preferably, baffles are provided on the test bench respectively corresponding to the left and right sides and the rear side of the model spoil field, and the baffles are made of transparent acrylic material.

[0015] Preferably, the ice and snow layer is provided at a depth of 10-20 cm below the slope of the model dumping ground;

[0016] The thickness of the ice and snow layer is 5-10 cm.

[0017] Preferably, the distributed optical fiber monitoring device comprises:

[0018] an optical fiber strain demodulator, the optical fiber strain demodulator being connected to the distributed optical fiber and being used to analyze Brillouin scattered light frequency information when strain occurs in the distributed optical fiber;

[0019] A fiber Bragg grating demodulator is connected to the distributed optical fiber and is used to calculate the temperature change of the distributed optical fiber monitoring point.

[0020] Preferably, the loading device uses weights to simulate external loads, and the weights are placed in sequence at the left, middle and right positions of the shoulder of the model spoil field.

[0021] Preferably, the image acquisition device includes a plurality of cameras to record the test images in front, behind, left, right and above of the model dumping ground throughout the entire process.

[0022] A physical model test method for deformation and failure of a spoil dump, comprising:

[0023] A model dumping ground is formed by piling up soil to simulate the dumping ground morphology, and multiple distributed optical fibers are pre-buried during the construction of the model dumping ground;

[0024] The ice and snow layer is laid at the design elevation of the model dumping site, and the model dumping site is built after the ice and snow layer is laid;

[0025] The ice and snow layer was allowed to melt, and external loads were applied in stages through a loading device to simulate the deformation and failure characteristics of the dump site under the combined effects of freeze-thaw and external loads. The deformation and failure process of the model dump site was recorded using an image acquisition device to record and analyze soil infiltration as well as uneven settlement, collapse, and debris flow that occurred during the melting of the ice and snow layer.

[0026] During the test, the strain and temperature information of the model dumping ground are monitored regularly through distributed optical fibers.

[0027] Preferably, after the initial melting of the ice and snow layer, external loads are applied in sequence at the left, middle and right positions of the shoulder of the model spoil dump, with the external load added at each level being 25 kg. Before and after the application of each graded external load, the strain information of the model spoil dump is recorded once through distributed optical fiber.

[0028] Preferably, the soil deformation characteristics of the model dumping site are determined in combination with soil strain information, the soil deformation range and depth information are delineated, and then the dangerous area of the model dumping site is delineated, and distributed optical fiber is pre-buried in the dangerous area inside the model dumping site.

[0029] Beneficial effects: The test system has a monitoring system that simulates the shape of the spoil dump and the ice and snow layer caused by freeze-thaw effects, loads external loads in stages through a loading device, monitors the deformation of the external soil of the spoil dump through an image acquisition device, and monitors the strain of the soil in the spoil dump and the change of soil temperature through a distributed optical fiber monitoring device. It can not only effectively simulate the external destruction and deformation characteristics of the spoil dump under freeze-thaw and external loads, but also obtain internal strain evolution and temperature field distribution information, greatly improving the accuracy and scientificity of the spoil dump slope destruction characteristic test under combined loads such as freeze-thaw effects, and achieving a leap in the study of the deformation and destruction characteristics of the spoil dump slope under combined loads and distributed optical fiber monitoring technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings and the accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. Among them:

[0031] Figure 1 A simplified structural diagram of the test system in a specific embodiment provided by the present invention;

[0032] Figure 2 This is a schematic diagram of the distribution of distributed optical fibers in a specific embodiment provided by the present invention.

[0033] Figure 1: Fiber optic strain demodulator; 2. Fiber Bragg grating demodulator; 3. Model dumping site; 4. Weights; 5. Ice and snow layer; 6. Substratum; 7. Image acquisition device; 8. Acrylic plate; 9. Computer host; 10. Distributed optical fiber. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0035] In the description of the present invention, the terms "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention. The terms "connected" and "connected" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a direct connection or an indirect connection through an intermediate component. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0036] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other.

[0037] like Figure 1-2As shown, a physical model test system for deformation and destruction of a spoil dump comprises a model spoil dump 3, an ice and snow layer 5, a loading device, a distributed optical fiber 10 monitoring device and an image acquisition device 7. The model spoil dump 3 is made of soil piled up and is used to simulate the shape of the spoil dump. The soil used to pile up the model spoil dump 3 is taken from the actual spoil dump, and similarity ratio calculation is performed through similarity theory to simulate the actual spoil dump in a real way, thereby improving the authenticity and effectiveness of the obtained test parameters. The ice and snow layer 5 is laid in the model spoil dump 3, and the ice and snow layer 5 should be laid evenly; or the thickness of the ice and snow layer 5 is measured based on the detection of the actual spoil dump. In the simulation, the ice and snow layer 5 is specifically located below the slope of the model spoil dump 3 and at the designed elevation of the slope of the model spoil dump 3; the loading device is arranged at the shoulder of the model spoil dump 3 to apply external loads to the model spoil dump 3 in stages, which can effectively simulate the external destruction and deformation characteristics of the spoil dump under the action of freeze-thaw and external loads. The distributed optical fiber 10 monitoring device includes multiple distributed optical fibers 10 pre-buried in the model spoil dump 3 to monitor the strain and temperature information of the model spoil dump 3 during the test; the image acquisition device 7 is used to record the changes of the model spoil dump 3 during the test.

[0038] In another optional embodiment, the model spoil dump 3 is built on a test bench, which is designed, processed and welded from stainless steel profiles. Concrete is poured into the spoil dump's underlying layer 6 (bedrock) within the test bench according to the real three-dimensional terrain. The concrete is first cured to a certain strength, and then the distributed optical fiber 10 is laid. Finally, the model soil is piled on the real three-dimensional surface, i.e., the spoil dump's underlying layer 6 (bedrock). The model's loose soil is removed using an artificial simulated rock dumper, and after the soil has been piled to a certain height, it is compacted layer by layer.

[0039] In another optional embodiment, the test bench is equipped with baffles corresponding to the left and right sides and rear of the model dump 3. Specifically, the side of the model dump 3 corresponding to the slope shoulder is the rear side, and the two side surfaces of the model dump 3 near the rear are the left and right sides. The baffles are made of a transparent material. They are composed of highly transparent acrylic panels 8. The purpose of providing highly transparent acrylic panels 8 is to facilitate the observation of uneven soil settlement, collapse, debris flow, as well as the melting of the ice and snow layer 5 and the infiltration of ice and snow water during the test.

[0040] In another optional embodiment, when the model soil is piled to 10-20 cm below the slope elevation of the designed spoil dump, an ice and snow layer 5 is laid, and the thickness of the ice and snow layer 5 is set to 5-10 cm. After the ice and snow layer 5 is laid, the subsequent soil disposal work is continued until the model spoil dump 3 is completed. According to the set test requirements, the freeze-thaw effect simulation is carried out, that is, the ice and snow layer 5 is allowed to melt, and the deformation and damage characteristics of the spoil dump caused by the combined action of the melting of the ice and snow layer 5 and the graded external load are observed and recorded, specifically including the recording and analysis of the uneven settlement, collapse, debris flow of the soil body and the ice and snow water infiltration phenomenon during the melting of the ice and snow layer 5. During the test process, the distributed optical fiber 10 is monitored every 30 minutes.

[0041] In another optional embodiment, the distributed optical fiber 10 monitoring device includes a fiber strain interrogator 1 and a fiber Bragg grating interrogator 2. The fiber strain interrogator 1 is connected to the distributed optical fiber 10 and is used to analyze the Brillouin scattered light frequency information when strain occurs in the distributed optical fiber 10. The fiber Bragg grating interrogator 2 is connected to the distributed optical fiber 10 and is used to determine the temperature change at the monitoring point of the distributed optical fiber 10. Specifically, the fiber strain interrogator 1 is called a double-ended high-precision distributed optical fiber 10 strain interrogator 1 (BOFDA); the fiber Bragg grating interrogator 2 is called a cabinet-type fiber Bragg grating interrogator 2 (FBG). The double-ended high-precision distributed optical fiber 10 strain interrogator 1 (BOFDA) and the cabinet-type fiber Bragg grating interrogator 2 (FBG) are connected to a computer host 9. The double-ended high-precision distributed optical fiber 10 strain interrogator 1 uses leading optical frequency domain scattering technology to analyze the Brillouin scattered light frequency information when optical fiber strain occurs. When the soil in the dump deforms, the frequency of the Brillouin scattered light at the relevant point in the optical fiber changes. This frequency change is linearly correlated with the axial strain of the optical fiber, which can be used to determine the strain change in the soil at the monitored location. The Fiber Bragg Grating Interrogator 2 has a built-in laser light source module, which uses the output wavelength information to determine the temperature of the monitoring point.

[0042] In another optional embodiment, a weight 4 is used in the loading device to simulate an external load. After the freeze-thaw effect has lasted for a certain period of time (2 hours), the external load is applied in stages to the left, middle and right positions of the shoulder of the model spoil field 3. During the test, the loading device applies a graded external load of 0-200kg, with each grade of external load being 25kg. Fiber optic scanning is performed before and after the application of each graded external load. Among them, when an external load of 0kg is applied, that is, when there is no external load, the soil settles under the action of freeze-thaw and deadweight. In another embodiment, the external load loading interval is 30min; the test is started 2 hours after the ice and snow layer 5 melts, the fiber optic frequency scanning step is 5MHz; the fiber optic strain test accuracy is ±2με; the maximum sampling resolution of the fiber optic is 0.05m; the fiber optic spatial resolution is 0.2m; and the fiber optic strain coefficient is 50.

[0043] In another optional embodiment, the image acquisition device 7 records the entire test process from soil piling to the end of the test during the physical model test.

[0044] The image acquisition device 7 includes multiple cameras or digital cameras, which are fixed in position to capture images of the front, back, left, right, and top of the model during the physical model test. The capture time is from the start of the physical model test soil pile to the end of the model test.

[0045] The present invention also provides a physical model test method for deformation and destruction of a spoil dump, which is mainly used in the field of physical model test of deformation and destruction of spoil dumps in cold northern regions under the action of combined loads such as freeze-thaw and external loads. The test consists of pouring the underlying layer 6 (bedrock), piling up the model soil, laying the ice and snow layer 5, performing freeze-thaw action, applying external loads in stages, all-round photography, and distributed optical fiber 10 monitoring. The method includes: forming a model spoil dump 3 by piling up soil to simulate the shape of the spoil dump, and pre-burying multiple distributed optical fibers 10 during the piling process of the model spoil dump 3; laying an ice and snow layer 5 when the model spoil dump 3 is piled up to the designed elevation, and completing the piling of the model spoil dump 3 after the ice and snow layer 5 is laid; melting the ice and snow layer 5, starting to apply external loads in stages through a loading device, and observing and recording the deformation and failure characteristics of the model spoil dump 3 caused by the combined action of the melting of the ice and snow layer 5 and the staged external loads through an image acquisition device 7, so as to record and analyze the uneven settlement, collapse, debris flow and ice and snow water infiltration of the soil during the melting of the ice and snow layer 5; during the test, the strain and temperature information of the model spoil dump 3 during the test are monitored regularly through a distributed optical fiber 10 monitoring device.

[0046] In another optional embodiment, after the initial melting of the ice and snow layer 5, specifically 2 hours after the melting of the ice and snow layer 5, the test can be started. External loads are applied to the left, middle, and right positions of the shoulder of the model dump 3, with each level of added external load being 25 kg. The loading device applies external loads of 0-200 kg in stages. Before and after applying each stage of external load, optical fiber scanning is performed to record strain and temperature information of the model dump 3 through the distributed optical fiber 10. The applied external load of 0 kg, i.e., when no external load is applied, the soil settles under the effects of freeze-thaw and deadweight.

[0047] In another optional embodiment, the distributed optical fiber 10 monitoring system can record and analyze soil strain and temperature information in the dumping area. Combined with the soil strain information, the system can determine the deformation characteristics of the model dumping area 3, delineate the deformation range and depth information, and further delineate the dangerous areas of the model dumping area 3. The internal temperature information of the dumping area can assist in explaining the deformation mechanism of the dumping area. In one embodiment, the test bench is 3000 mm long, 1500 mm wide, and 1500 mm high. The shoulder width of the constructed model dumping area 3 is no less than 600 mm, and the slope of the model dumping area 3 is preferably 30°. The optical fiber is approximately 30 cm from the boundary of the model dumping area 3. The optical fibers are arranged in two layers in the X direction, with two fibers per layer and a spacing of approximately 80 cm. In the Y direction, the optical fibers are arranged in two layers, with three fibers per layer and a spacing of approximately 45 cm. In the Z direction, the optical fibers are arranged in two layers, with a spacing of 2 fibers per layer and a spacing of 60 cm. It should be understood that the above description is merely exemplary and is not intended to be limiting in this embodiment.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A physical model test system for deformation and failure of spoil dump, characterized by: include: A model dumping ground, which is formed by piling up soil and is used to simulate the shape of the dumping ground; An ice and snow layer is laid in the model dumping ground and is located at a designed elevation of the slope of the model dumping ground; A loading device is provided at the shoulder of the model dumping ground to apply external loads to the model dumping ground in stages; A distributed optical fiber monitoring device, comprising a plurality of distributed optical fibers pre-buried in the model dumping ground, for monitoring strain and temperature information of the model dumping ground during the test; An image acquisition device, the image acquisition device is used to record the deformation and failure process of the model dump during the test; The model dump is built in a test bench, and a substratum is poured in the test bench according to a real three-dimensional terrain, and the substratum simulates the real surface of the substratum of the dump; The distributed optical fiber monitoring device comprises: an optical fiber strain demodulator, the optical fiber strain demodulator being connected to the distributed optical fiber and being used to analyze Brillouin scattered light frequency information when strain occurs in the distributed optical fiber; A fiber Bragg grating demodulator, the fiber Bragg grating demodulator is connected to the distributed optical fiber and is used to calculate the temperature change of the distributed optical fiber monitoring point; The distributed fiber optic monitoring system records and analyzes soil strain and temperature information in the dump, combines this information to determine the deformation characteristics of the model dump, delineate the deformation range and depth, and thus delineate the dangerous areas of the model dump. The optical fiber is 30 cm away from the boundary of the model dumping ground, and the optical fiber is arranged in two layers in the X direction, two layers in the Y direction, and two layers in the Z direction.

2. The spoil dump deformation and failure physical model test system according to claim 1 is characterized in that: Baffles are provided on the test bench respectively corresponding to the left and right sides and the rear side of the model spoil field, and the baffles are made of transparent acrylic material.

3. The spoil dump deformation and failure physical model test system according to claim 1 is characterized in that: The ice and snow layer is set at a depth of 10-20 cm below the slope of the model dumping site; The thickness of the ice and snow layer is 5-10 cm.

4. The spoil dump deformation and failure physical model test system according to claim 1 is characterized in that: The loading device uses weights to simulate external loads, and the weights are placed in sequence at the left, middle and right positions of the shoulder of the model spoil field.

5. The spoil dump deformation and failure physical model test system according to claim 1 is characterized in that: The image acquisition device includes a plurality of cameras, which record the test images in front, behind, left, right and above of the model dumping ground throughout the whole process.

6. A physical model test method for deformation and failure of a spoil dump, characterized in that: include: A model dumping ground is formed by piling up soil to simulate the dumping ground morphology, and multiple distributed optical fibers are pre-buried during the construction of the model dumping ground; The ice and snow layer is laid at the design elevation of the model dumping site, and the model dumping site is built after the ice and snow layer is laid; The ice and snow layer was allowed to melt, and external loads were applied in stages through a loading device to simulate the deformation and failure characteristics of the dump site under the combined effects of freeze-thaw and external loads. The deformation and failure process of the model dump site was recorded using an image acquisition device to record and analyze soil infiltration as well as uneven settlement, collapse, and debris flow that occurred during the melting of the ice and snow layer. During the test, the strain and temperature information of the model dumping ground are monitored regularly through distributed optical fibers.

7. The method for testing the deformation and failure physical model of a spoil dump according to claim 6, characterized in that: After the initial melting of the ice and snow layer, external loads were applied in sequence to the left, middle and right positions of the shoulder of the model dump site. The external load added at each level was 25 kg. Before and after the application of each graded external load, the strain information of the model dump site was recorded through distributed optical fiber.

8. The spoil dump deformation and failure physical model test method according to claim 6, characterized in that: The soil deformation characteristics of the model dumping site are determined by combining soil strain information, and the soil deformation range and depth information are delineated. Then, the dangerous area of the model dumping site is delineated, and distributed optical fiber is pre-buried in the dangerous area inside the model dumping site.

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