Landslide model test device and method based on sliding surface simulation based on electromagnetic principle

Abstract

A landslide model test device and method based on electromagnetic sliding surface simulation includes a U-shaped slide; the U-shaped slide is provided with multiple screw holes, and electromagnets are installed at the screw holes via adjusting screws, and the adjusting screws are used to adjust the height of the electromagnets; the sliding plate includes a panel, the bottom of the panel is provided with support legs, the support legs are provided with horizontal guide rods, and the horizontal guide rods are provided with rollers; the structure of the reference plate includes the structure of the sliding plate, and the panel of the reference plate is provided with latch holes, and the side of the panel is provided with force transmission plates; the U-shaped slide includes a slide base and side wings, and the side wings are provided with latch holes, and the latch holes are connected to the latch holes by latches; the lower end of the side wing is detachably provided with a support structure, and the support structure is provided with a pressure sensor, and the position of the pressure sensor is adapted to the position of the force transmission plate. The present invention can simulate and control slope angles ranging from 8.530-67.220, and can achieve overall or zoned adjustment of the shear strength of the sliding surface of the landslide model.

Description

Technical Field

[0001] The invention belongs to the field of landslide model test devices, and in particular relates to a landslide model test device and method for adjusting shear strength parameters of a landslide sliding surface based on electromagnetic force simulation of normal pressure on the sliding surface. Background Art

[0002] The stability of landslides has become a major concern in the field of geological disaster prevention and control. How and under what conditions landslides become unstable requires in-depth research. Model testing is a key method for studying landslide stability. Many researchers have conducted in-depth research on landslide model tests, primarily using frame-type model tests and centrifuge model tests. Frame-type model tests are further divided into two-dimensional and three-dimensional landslide model tests. However, due to the high equipment and testing costs associated with three-dimensional and centrifuge model tests, researchers currently primarily use small two-dimensional model frames to study landslide stability.

[0003] The stability of landslides is mainly controlled by the internal shear strength of the sliding zone soil and external factors such as external loads, human activities or earthquake disturbances. There are two ways to start the slide of the landslide test model: one is to reduce the shear strength of the sliding zone of the landslide model, and the other is to increase the external load of the landslide model. The technical problems are:

[0004] 1. Currently, rainfall is often applied to reduce the shear strength of landslide rock and soil and increase the deadweight of the landslide. For water-related landslides, reservoir water level fluctuations are often increased to study their stability. This method is effective in studying the effects of rainfall and reservoir water on landslide stability. However, when studying the instability conditions of landslides, the instability initiation and destruction process is difficult to control artificially, and this impact on landslide stability is difficult to quantitatively describe.

[0005] 2. Some people increase the downward inclination angle of the landslide body by raising the back side of the model frame to simulate the application of gravity load to the landslide model, thereby increasing the downward force of the landslide body and determining the downward inclination angle of the landslide body when the landslide model becomes unstable. However, considering the rollover risk of the model frame itself and the limited stroke of the jack, this angle raising is generally controlled at about 5 degrees. The study of landslide stability by raising the angle often has great limitations.

[0006] 3. Some people use heat-sensitive materials to simulate weak interlayers and control the shear strength of weak interlayers by laying electric heating tapes (tubes). However, temperature also affects the physical and mechanical properties of the surrounding media outside the sliding zone soil, and it is impossible to achieve zoning control and adjustment considering the shear strength of the sliding zone soil. Summary of the Invention

[0007] In view of the technical problems existing in the background technology, the present invention provides a landslide model test device and method based on electromagnetic principle sliding surface simulation. Multiple sets of steel plates are used to slide on a U-shaped slideway equipped with a small electromagnet to simulate the unstable movement of the sliding surface. The electromagnetic force between the electromagnet and the steel plate is adjusted by adjusting the working current of the electromagnet, that is, the normal pressure of the sliding friction is adjusted, thereby adjusting the friction force of the sliding surface. This is equivalent to simulating the change in the friction coefficient (shear strength) of the sliding surface under the condition of unchanged sliding body thickness (unchanged normal pressure) in the model test. It can realize the overall or zoned adjustment of the shear strength of the sliding surface of the landslide model.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] A landslide model test device based on electromagnetic principle sliding surface simulation includes a U-shaped slide, a reference plate and multiple sliding plates; the U-shaped slide is provided with multiple screw holes, and electromagnets are installed at the screw holes through adjusting screws, and the adjusting screws are used to adjust the height of the electromagnets;

[0010] The sliding plate includes a panel, a support leg is provided at the bottom of the panel, a horizontal guide rod is provided on the support leg, and a roller is provided on the horizontal guide rod;

[0011] The structure of the reference plate includes the structure of the sliding plate. In addition, second latch holes are provided at both ends of the panel of the reference plate, and a force transmission plate is provided on the side of the panel.

[0012] The U-shaped slide includes a slide base plate and side wings, and the side wings are provided with a first pin hole, the first pin hole is adapted to the second pin hole, and the first pin hole and the second pin hole are connected by a pin; a supporting structure is detachably provided at the lower end of the side wing, and a pressure sensor is provided on the supporting structure, and the position of the pressure sensor is adapted to the position of the force transmission plate.

[0013] In a preferred solution, a bolt hole is provided at the lower end of the side wing, and the bolt hole is connected to the supporting structure through an adjusting bolt.

[0014] In a preferred solution, the width of the panel is the same as the width of the U-shaped slide, the height of the support legs is greater than the height of the side wings; and the bottom of the support legs is arc-shaped.

[0015] In a preferred solution, the U-shaped slideway is made of stainless steel, and the reference plate and the sliding plate are both made of ordinary low-carbon steel.

[0016] In a preferred embodiment, the test method of the landslide model test device based on electromagnetic principle sliding surface simulation comprises the following steps:

[0017] Step 1: Make the slide bed: Use clay to compact and make the slide bed and its sliding surface;

[0018] Step 2: The shape of the U-shaped slide is made according to the sliding surface, and the U-shaped slide is placed on the sliding surface to ensure full contact between the two;

[0019] Step 3: Weigh all reference plates and sliding plates; fix the electromagnets at multiple screw holes on the bottom of the slide base plate;

[0020] Step 4: Place the reference plate on the U-shaped slide, adjust the adjustment screw of the electromagnet to ensure that the electromagnet is in full contact with the reference plate, and install the latch to fix the reference plate;

[0021] Step 5: Install other electromagnets and sliding plates on the slide base from bottom to top, and adjust the adjustment screws of the electromagnets to ensure that the electromagnets are in full contact with the sliding plates. After multiple sliding plates are installed, the installation of the entire sliding surface is completed.

[0022] Step 6: Install the retaining structure: Fix the retaining structure to the end of the U-shaped slideway through the adjusting bolts and bolt holes. Adjust the tightness of the adjusting bolts to ensure that the pressure sensor contacts the force transmission plate and generates a value slightly greater than zero, and reset the pressure sensor value.

[0023] Step 7: Unplug the pin, wait for the pressure sensor value to stabilize, and then record the sensor value. Based on the weight of the reference plate and all sliding plates, as well as the slope angle of the slope on which the reference plate and sliding plates are located, calculate the sliding friction coefficient of the reference plate, sliding plate, and U-shaped slideway.

[0024] Step 8: Re-insert the latch and remove the retaining structure; make a sliding body on the sliding surface;

[0025] Step 9: n electromagnets are grouped together and connected in parallel to an adjustable DC power supply. Each electromagnet is controlled separately by its own independent adjustable power supply, and the power line is led out from the upper end of the U-shaped slide.

[0026] Step 10: Reinstall the retaining structure and adjust the tightness of the bolts to ensure that the pressure sensor is in contact with the force transmission plate and produces a value slightly greater than zero, and clear the pressure sensor data;

[0027] Step 11: All electromagnets are powered on and adjusted to the rated voltage state. The plug is pulled out, and the pressure sensor value is recorded after it stabilizes. By adjusting the electromagnet voltage of different steel plates, the pressure sensor value adjusted for the shear strength of the sliding surface can be obtained, or the voltage of all electromagnets is synchronously adjusted to the same value to obtain the pressure sensor value under different shear strengths of the sliding surface. The safety factor of the slope at different slope angles and the shear strength of the critical unstable sliding surface can be obtained. The sensitivity of the shear strength changes in different partitions of the sliding surface to the stability of the landslide can also be obtained, and the key blocks for controlling the stability of the landslide can be obtained.

[0028] This patent can achieve the following beneficial effects:

[0029] The present invention simulates the sliding surface of a landslide by using multiple sets of steel plates sliding on stainless steel tracks equipped with small electromagnets. The electromagnetic force between the electromagnets and the steel plates adjusts the normal pressure between them, thereby varying the friction coefficient between them and simulating the shear strength of the sliding surface. The present invention can simulate and control slope angles ranging from 8.53° to 67.22°, and can adjust the shear strength of the sliding surface of the landslide model, both overall and in sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0031] Figure 1 This is a schematic elevation diagram of a landslide model test according to the present invention;

[0032] Figure 2 A schematic diagram of the three-dimensional structure of the U-shaped slide of the present invention;

[0033] Figure 3 This is a schematic diagram of the three-dimensional structure of the U-shaped slideway, the reference plate and the sliding plate combined in the present invention;

[0034] Figure 4 This is a front view of the retaining structure of the present invention;

[0035] Figure 5 This is a schematic diagram of the three-dimensional structure of the reference plate of the present invention;

[0036] Figure 6 It is a schematic diagram of the three-dimensional structure of the sliding plate and the subsequent plate of the present invention.

[0037] In the figure: slider bed 1, slider 2, U-shaped slide 3, reference plate 4, sliding plate 5, slide base plate 6, side wing 7, screw hole 8, bolt hole 9, first latch hole 10, supporting structure 11, adjustment bolt 12, pressure sensor 13, latch 14, second latch hole 15, force transmission plate 16, horizontal guide rod 17, support leg 18, panel 19, insulating paint 20. DETAILED DESCRIPTION

[0038] Example 1:

[0039] The preferred solution is Figures 1 to 6 As shown, a landslide model test device based on electromagnetic principle sliding surface simulation includes a U-shaped slide 3, a reference plate 4 and multiple sliding plates 5, both of which are steel plates; a plurality of screw holes 8 are provided on the U-shaped slide 3, and electromagnets are installed at the screw holes 8 through adjusting screws, and the adjusting screws are used to adjust the height of the electromagnets;

[0040] The sliding plate 5 includes a panel 19, a support leg 18 is provided at the bottom of the panel 19, a horizontal guide rod 17 is provided on the support leg 18, and a roller is provided on the horizontal guide rod 17;

[0041] The structure of the reference plate 4 includes the structure of the sliding plate 5. In addition, second pin holes 15 are provided at both ends of the panel 19 of the reference plate 4, and a force transmission plate 16 is provided on the side of the panel 19.

[0042] The U-shaped slide 3 includes a slide base plate 6 and a side wing 7. The side wing 7 is provided with a first pin hole 10, which is adapted to the second pin hole 15. The first pin hole 10 and the second pin hole 15 are connected by a pin 14. The lower end of the side wing 7 is detachably provided with a supporting structure 11, and the supporting structure 11 is provided with a pressure sensor 13. The position of the pressure sensor 13 is adapted to the position of the force transmission plate 16.

[0043] The test model consists of a slider bed 1, a sliding body 2, a U-shaped slide 3, a reference plate 4, multiple sliding plates 5, a cylindrical electromagnet, and multiple sets of 24V adjustable transformer power supplies. The slider bed 1 is formed by clay piling or concrete casting, and the sliding body 2 is formed by layering the model material. The test simulation technology of these two parts is not included in the present invention. The U-shaped slide 3 can be made into a broken line shape or rolled into an arc shape according to the shape requirements of the sliding surface of the model test. It consists of three parts: a smooth stainless steel slide base plate 6, side wings 7 on both sides perpendicular to the base plate, and a support structure 11. The lower end of the side wings is provided with two bolt holes 9 for fixing the support structure 11 and two first pin holes 10 for fixing the reference plate 4. The lower end of the side wing 7 is provided with a bolt hole 9, which is connected to the support structure 11 by an adjustment bolt 12.

[0044] The panel 19 is the same width as the U-shaped slide 3 and 8mm thick. The support legs 18 are taller than the side wings 7; their bottoms are curved. Four stainless steel rollers are connected to the horizontal guide rod 17. There are four support legs 18. The front and rear sides of the panel 19 are coated with insulating varnish 20. The curved steel support legs 18 are slightly taller than the U-shaped slide 3. The U-shaped slide 3 of this invention is made of stainless steel, while the base plate 4 and the sliding plate 5 are made of ordinary low-carbon steel.

[0045] The cylindrical electromagnet can be a small DC suction cup electromagnet (such as Xingda XDA series electromagnet, the specific model can be selected according to the specific situation of the model test), connected to the slide base plate (6) through an adjustable bolt, and the cylindrical electromagnet is powered by a 24V adjustable transformer power supply.

[0046] The test method of the landslide model test device based on electromagnetic principle sliding surface simulation includes the following steps:

[0047] Step 1: Making the slide bed 1: compacting clay to make the slide bed 1 and its sliding surface;

[0048] The specific operation is as follows: according to the scale of the prototype landslide being tested and the shape of the sliding surface, the size of the model is determined, and a detachable rectangular model support is made using a wooden template. Clay is compacted inside the model support to make the sliding bed 1 and the sliding surface. A plastic film is laid between the model material and the model frame. After the sliding bed is completed, the model support is removed.

[0049] Step 2: The shape of the U-shaped slide 3 is made according to the sliding surface, and the U-shaped slide 3 is placed on the sliding surface to ensure that the two are in full contact;

[0050] Step 3: weigh all reference plates 4 and sliding plates 5; fix the electromagnets at the multiple screw holes 8 at the bottom of the slide base plate 6;

[0051] Step 4: Place the reference plate 4 on the U-shaped slide 3, adjust the adjustment screw of the electromagnet to ensure that the electromagnet is in full contact with the reference plate 4, and install the latch 14 to fix the reference plate 4;

[0052] Step 5: Install other electromagnets and sliding plates 5 on the slide base plate 6 from bottom to top, and ensure that the electromagnets are in full contact with the sliding plates 5 by adjusting the adjusting screws of the electromagnets. After the multiple sliding plates 5 are installed, the installation of the entire sliding surface is completed.

[0053] Step 6: Install the retaining structure 11: Fix the retaining structure 11 to the end of the U-shaped slide 3 through the adjusting bolts 12 and the bolt holes 9. Adjust the tightness of the adjusting bolts 12 to ensure that the pressure sensor 13 is in contact with the force transmission plate 16 and produces a value slightly greater than zero, and reset the pressure sensor value.

[0054] Step 7: Unplug the plug 14, wait for the pressure sensor value to stabilize, and record the sensor value. The sliding force is calculated based on the weight of the reference plate 4 and all sliding plates 5, as well as the slope angle of the slope where the reference plate 4 and the sliding plate 5 are located, to obtain the sliding friction coefficient of the reference plate 4, the sliding plate 5, and the U-shaped slide 3;

[0055] For example, a single steel plate is 40 cm long, 20 cm wide, and 0.8 cm thick. The horizontal guide rods 17 with stainless steel wheels on the left and right sides and the rolling of the side wings 7 only serve to position the plate. Since the horizontal side pressure is very small and is rolling friction, the friction force can be ignored. The landslide model sliding body 2 above the plate is 50 cm high and has a model density of 2.0×103 kg / m3. The model inclination angle here is 300. The sliding friction coefficient between the curved steel support legs 18, the U-shaped stainless steel slide base plate 6, and the electromagnet surface is 0.15. The sliding plate weighs 60 kg. Six Xingda electromagnets XDA-80 / 80 (maximum suction force 300 kg at 24V) are installed under each plate. The main parameters and results of the sliding surface are shown in the following table:

[0056]

[0057] Table 1 Relationship between slope and dynamic friction coefficient

[0058] Step 8: Re-insert the latch 14 and remove the retaining structure 11; make the sliding body 2 on the sliding surface;

[0059] The specific method involves removing the retaining structure 11, restoring the wooden formwork frames on both sides of the slide bed 1, and then fabricating the model slide using a layered compaction method using a material similar to the slide model. A plastic sheeting is placed between the slide model material and the formwork frames. Once the model slide is fabricated, the wooden formwork and plastic sheeting are removed, creating an unconfined landslide test model. The slide 2 is secured to the sliding surface formed by the reference plate 4 and the sliding plate 5.

[0060] Step 9: n electromagnets are grouped together and connected in parallel to an adjustable DC power supply. Each electromagnet is controlled separately by its own independent adjustable power supply, and the power line is led out from the upper end of the U-shaped slide 3;

[0061] In this embodiment, n=6, and every six electromagnets form a group. A group of electromagnets is provided at the bottom of each reference plate 4 or sliding plate 5 .

[0062] Step 10: Reinstall the retaining structure 11 and adjust the tightness of the adjustment bolt 12 to ensure that the pressure sensor 13 is in contact with the force transmission plate 16 and generates a value slightly greater than zero, and clear the pressure sensor data;

[0063] Step 11: All electromagnets are powered on and adjusted to the rated voltage (24V voltage). Plug 14 is pulled out. After the pressure sensor value stabilizes, the pressure sensor value (sliding force) is recorded. By adjusting the voltage of the electromagnets of different steel plates, the pressure sensor value (sliding force) adjusted for the shear strength of the sliding surface can be obtained, or the voltage of all electromagnets is synchronously adjusted to the same value to obtain the pressure sensor value (sliding force) under different shear strengths of the sliding surface. The safety factor of the slope at different slope angles and the shear strength of the critical unstable sliding surface can be obtained. The sensitivity of the shear strength changes in different partitions of the sliding surface to the stability of the landslide can also be obtained, and the key blocks for controlling the stability of the landslide can be obtained.

[0064] In summary, the present invention can simulate the normal pressure of the sliding surface by using the electromagnetic force based on the electromagnetic principle indoors, and then simulate and adjust the change of the friction force of the sliding surface, so as to realize the overall and zoned adjustment control of the shear strength of the sliding surface of the landslide model test, and measure the sliding force of the landslide model under different voltages (electromagnetic force, normal pressure, friction coefficient). The safety factor and critical instability starting condition of the landslide at different slope angles can be obtained, and the sensitivity of the change of the shear strength of different zones of the sliding surface to the stability of the landslide can be obtained, so as to obtain the key blocks for controlling the stability of the landslide.

[0065] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. In other words, equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A landslide model test device based on electromagnetic sliding surface simulation, characterized by: It comprises a U-shaped slideway (3), a reference plate (4) and a plurality of sliding plates (5); a plurality of screw holes (8) are provided on the U-shaped slideway (3), and electromagnets are installed at the screw holes (8) through adjusting screws, and the adjusting screws are used to adjust the height of the electromagnets; The sliding plate (5) includes a panel (19), a support leg (18) is provided at the bottom of the panel (19), a horizontal guide rod (17) is provided on the support leg (18), and a roller is provided on the horizontal guide rod (17); The structure of the reference plate (4) includes the structure of the sliding plate (5), and second latch holes (15) are provided at both ends of the panel (19) of the reference plate (4), and a force transmission plate (16) is provided on the side of the panel (19); The U-shaped slide (3) includes a slide base plate (6) and a side wing (7), wherein a first latch hole (10) is provided on the side wing (7), the first latch hole (10) is matched with a second latch hole (15), and the first latch hole (10) and the second latch hole (15) are connected via a latch (14); a support structure (11) is detachably provided at the lower end of the side wing (7), and a pressure sensor (13) is provided on the support structure (11), and the position of the pressure sensor (13) is matched with the position of the force transmission plate (16); The lower end of the wing (7) is provided with a bolt hole (9), and the bolt hole (9) is connected to the support structure (11) through an adjustment bolt (12); The reference plate (4) and the sliding plate (5) are both made of ordinary low-carbon steel.

2. The landslide model test device based on electromagnetic sliding surface simulation according to claim 1 is characterized in that: The width of the panel (19) is the same as that of the U-shaped slide (3), and the height of the support leg (18) is greater than the height of the side wing (7); the bottom of the support leg (18) is arc-shaped.

3. The landslide model test device based on electromagnetic sliding surface simulation according to claim 1 is characterized in that: The U-shaped slideway (3) is made of stainless steel.

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