A groundwater floating drag model device and buoyancy measurement method

Abstract

The present invention discloses a groundwater floating and dragging effect model device and a buoyancy measurement method. The device includes an underground structure model box, an environmental model box, a stratum simulation area, a pipeline, an anti-floating anchor, a tension sensor, a friction test plate, a tension gauge, an earth pressure box, a water tank, a first water pump, a pressure gauge, and a valve. The device can simulate the anti-floating effect of the anti-floating anchor, simulate the anti-floating effect without the anti-floating anchor, and simulate the anti-floating effect of pressure relief control. The first water pump pumps water from the water tank into the environmental model box and into the stratum simulation area, and the buoyancy is calculated based on the stress conditions of the underground structure model box. The device can quickly and easily measure the buoyancy force, facilitating the observation of the floating and dragging effect of groundwater on the underground floor.

Description

Technical Field

[0001] The present invention relates to the technical field of underground engineering design research, and in particular to a groundwater floating and dragging action model device and a buoyancy measurement method. Background Art

[0002] When the bottom surface of a building foundation lies below the groundwater level, the groundwater exerts hydrostatic pressure on the foundation, creating a buoyant force. This buoyant force not only exerts on the building foundation, but also on the rock and soil beneath it. Due to the instability of groundwater head, there is no such thing as a permanently stable water surface. If the foundation elevation of a building is located above a submerged surface or stagnant water, it will experience uneven settlement over time, which can severely damage the building's integrity. With the recent development of underground engineering projects in my country, the hazards posed by groundwater to these projects remain a concern.

[0003] In recent years, when studying the effects of groundwater on underground engineering projects, the floating and dragging effects of groundwater on the base plates of underground structures have received particular attention. When studying the mechanism of groundwater floating and dragging, obtaining relevant technical parameters through indoor similarity experiments is an important research method. Field tests can only determine the process of groundwater acting on the base plates of underground structures under certain specific working conditions, and cannot simulate the dynamic process of groundwater acting on the base plates of underground structures, so they cannot meet the needs of actual projects. At the same time, large-scale outdoor tests require long time periods, are highly risky, have many uncontrollable factors, and are relatively expensive. Therefore, it is necessary to design an experimental device that is convenient for studying the floating and dragging effects of groundwater. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a groundwater floating and dragging effect model device and a buoyancy measurement method, which has a simple structure and can easily simulate the floating and dragging effect of groundwater on the underground floor.

[0005] In order to achieve the above-mentioned purpose, the present invention relates to an underground water floating and dragging model device, comprising an underground structure model box, an environmental model box, a stratum simulation area, a pipeline, an anti-floating anchor rod, a tension sensor, a friction test plate, a tension meter, an earth pressure box, a water tank, a first water pump, a pressure gauge and a valve; the anti-floating anchor rod comprises a vertebral body, a casing, an aluminum wire and a fixing bolt, a conical hole running through the casing is provided, the vertebral body cooperates with the conical hole, the narrow end of the vertebral body is inserted into the conical hole from the wide mouth of the conical hole, the aluminum wire connected to the narrow end of the vertebral body is connected with the fixing bolt, the underground structure model box and the environmental model box are both square boxes with an upper opening, soil layers and rock layers are laid in the environmental model box from top to bottom, the soil layers and rock layers constitute the stratum simulation area, and the underground structure model box is buried in the stratum simulation area The bottom plate of the underground structure model box is the underground structure bottom plate, and an earth pressure box is buried in the soil layer below the underground structure bottom plate. The earth pressure box is used to measure the soil reaction F1 below the underground structure bottom plate. A number of first threaded holes are evenly opened on the underground structure bottom plate, and a second threaded hole is correspondingly opened on the environmental model box directly below the first threaded hole. The friction test plate and the side plate of the underground structure model box are made of the same material. The friction test plate and the side plate of the underground structure model box are buried in the soil layer at the same height. An anchor bolt is fixed on the upper surface of the friction test plate, and a tensile gauge is hung on the anchor bolt to measure the tension F5 required to pull the friction test plate. A water inlet is provided at the bottom of the environmental model box, and a water outlet is provided at the top. The water inlet is connected to the water tank through a pipe, and a first water pump, a pressure gauge and a valve are sequentially provided on the pipe;

[0006] When the underground water floating drag model device simulates the anti-floating of the anti-floating anchor rod, the aluminum wire passes through the middle through hole of the tension sensor and the corresponding first threaded hole in sequence, and then is connected with the fixing bolt. The fixing bolt is fixed in the second threaded hole corresponding to the first threaded hole. The aluminum wire is tightened. The tension sensor is used to measure the downward pulling force F2 of the anti-floating anchor rod on the underground structure bottom plate. A fixed rubber gasket is set at the junction of the tension sensor and the underground structure bottom plate, and the first threaded hole is filled with sealant.

[0007] When the groundwater floating drag action model device simulates anti-floating without anti-floating anchor rods, the bolt is fixed in the first threaded hole through the rubber gasket;

[0008] When the groundwater floating and dragging action model device simulates pressure relief and anti-floating control, the first threaded hole is not blocked.

[0009] The underground structure model box and the environment model box are made of transparent materials.

[0010] Specifically, the underground water floating and dragging model device involved in this embodiment also includes a second water pump, which pumps water out of the underground structure model box through a pipeline.

[0011] The present invention relates to a method for measuring the buoyancy of a groundwater floating and dragging action model device.

[0012] When the groundwater floating drag model device simulates the anti-floating of the anti-floating anchor, the water in the water tank is pumped into the environmental model box and into the stratum simulation area through the first water pump. The stress condition of the underground structure model box is analyzed. In the vertical direction, the static equilibrium equation is calculated as follows:

[0013] F1+F3=nF2+G+F4 (1)

[0014] Buoyancy of the basement model box:

[0015] F3=nF2+G-F1+F4 (2)

[0016] F4=F5*S1 / S2 (3)

[0017] Among them, S1 is the area of the vertical surface of the side plate of the underground structure model box, and S2 is the area of the vertical surface of the friction test plate. According to formula (2), the buoyancy force on the underground structure can be obtained;

[0018] When the groundwater floating and dragging effect model device simulates anti-floating without anti-floating anchor rods, the water in the water tank is pumped into the environmental model box and into the stratum simulation area through the first water pump, and the buoyancy F3 = G-F1+F4 is applied to the underground structure model box.

[0019] Compared with the prior art, the present invention has the following beneficial effects: the buoyancy force can be measured quickly and easily, and the environmental model box adopts transparent materials to facilitate observation of the floating and dragging effect of groundwater on the underground floor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of the groundwater floating and dragging action model device involved in the present invention when simulating the anti-floating of an anti-floating anchor rod.

[0021] Figure 2 This is a schematic diagram of the structure of the groundwater floating and dragging effect model device involved in the present invention when no anti-floating anchor rods are provided to simulate anti-floating.

[0022] Figure 3 This is a structural schematic diagram of the groundwater floating and dragging action model device involved in the present invention when simulating pressure relief and anti-floating control.

[0023] Figure 4 This is a schematic diagram of the anti-floating anchor structure involved in the present invention.

[0024] Figure 5 These are the front view and top view of the tension sensor involved in the present invention.

[0025] Figure 6 Schematic diagram of the vertical force on the underground structure model box.

[0026] Figure 7Schematic diagram of the vertical force when no anti-floating anchor is installed. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] Example 1:

[0029] like Figure 1 As shown, the present embodiment involves a groundwater floating drag model device, including an underground structure model box 1, an environmental model box 2, a formation simulation area 3, a pipeline 4, an anti-floating anchor rod 5, a tension sensor 6, a friction test plate 7, a tension meter 8, an earth pressure box 9, a water tank 10, a first water pump 11, a pressure gauge 12 and a valve 13; the anti-floating anchor rod 5 includes a cone 501, a casing 502, an aluminum wire 503 and a fixing bolt 504, and a tapered hole is provided in the casing 502 to pass through the cone. The vertebral body 501 cooperates with the tapered hole, the narrow end of the vertebral body 501 is inserted into the tapered hole from the wide end of the tapered hole, and the aluminum wire 503 connected to the narrow end of the vertebral body 501 is connected with the fixing bolt 504. The underground structure model box 1 and the environmental model box 2 are both square boxes with an upper opening. The soil layer 301 and the rock layer 302 are laid from top to bottom in the environmental model box 2. The soil layer 301 and the rock layer 302 constitute the stratum simulation area 3. The underground structure model box 1 is buried in the middle of the stratum simulation area 3. The bottom plate of the underground structure model box 1 is the underground structure bottom plate 101. A soil pressure box 9 is buried in the soil layer 301 below the underground structure bottom plate 101. The soil pressure box 9 is used to measure the soil reaction force F1 below the underground structure bottom plate 101. A plurality of first threaded holes 103 are evenly opened on the underground structure bottom plate 101. Correspondingly, a second threaded hole 203 is opened on the environmental model box 2 just below the first threaded hole 103. The friction test plate 7 and the side plate 10 of the underground structure model box are connected. 2 materials, the friction test plate 7 and the side plate 102 of the underground structure model box are buried in the soil layer 301 at the same height, an anchor bolt is fixed to the upper surface of the friction test plate 7, and a tensile force meter 8 is hung on the anchor bolt to measure the tension F5 required to pull out the friction test plate 7. The environmental model box 2 is provided with a water inlet 201 at the bottom and a water outlet 202 at the top. The water inlet 201 is connected to the water tank 10 through a pipe 4. A first water pump 11, a pressure gauge 12 and a valve 13 are provided on the pipe 4 in sequence.

[0030] When the underground water floating drag model device simulates the anti-floating of the anti-floating anchor rod 5, the aluminum wire 503 passes through the middle through hole of the tension sensor 6 and the corresponding first threaded hole 103 in turn, and then is connected to the fixing bolt 504. The fixing bolt 504 is fixed in the second threaded hole 203 corresponding to the first threaded hole 103, and the aluminum wire 503 is tightened. The tension sensor 6 is used to measure the downward pulling force F2 of the anti-floating anchor rod 5 on the underground structure bottom plate 101. In order to ensure water tightness, a fixed rubber gasket is set at the junction of the tension sensor 6 and the underground structure bottom plate 101, and the first threaded hole 103 is filled with sealant (such as glass glue). The water in the water tank 10 is pumped into the environmental model box 2 and into the stratum simulation area 3 by the first water pump 11, and the stress condition of the underground structure model box 1 is analyzed, such as Figure 6 As shown, it is subject to its own gravity G, bottom soil reaction force F1, anti-floating anchor tension F2, groundwater buoyancy F3, side wall friction F4 (including side wall friction resistance and side wall cohesion). In the vertical direction, the static equilibrium equation is calculated as follows (n is the number of anti-floating anchors).

[0031] F1+F3=nF2+G+F4 (1)

[0032] Buoyancy of the basement model box:

[0033] F3=nF2+G-F1+F4 (2)

[0034] F4=F5*S1 / S2 (3)

[0035] Where S1 is the vertical surface area of the side plate of the underground structure model box, and S2 is the vertical surface area of the friction test plate. Given F1, F2, G, and F4, the buoyancy force on the underground structure can be obtained by combining formula (2).

[0036] When the groundwater floating drag model device simulates the anti-floating without anti-floating anchor rods, the bolt 14 is fixed in the first threaded hole 103 through the rubber gasket to seal the first threaded hole. The water in the water tank 10 is pumped into the environmental model box 2 and into the formation simulation area 3 by the first water pump 11, and the stress condition of the underground structure model box 1 is analyzed, such as Figure 7 As shown, the buoyancy acting on the basement model box at this time is F3=G-F1+F4.

[0037] When the groundwater floating and dragging action model device simulates pressure relief and anti-floating control, the first threaded hole 103 is not blocked.

[0038] In order to facilitate observation, the underground structure model box 1 and the environment model box 2 are made of transparent materials.

[0039] Specifically, the underground water floating and dragging model device involved in this embodiment further includes a second water pump 15 , which pumps water out of the underground structure model box 1 through a pipeline.

Claims

1. A groundwater floating drag model device, characterized in that: It includes an underground structure model box, an environmental model box, a stratum simulation area, a pipeline, an anti-floating anchor rod, a tension sensor, a friction test plate, a tension meter, an earth pressure box, a water tank, a first water pump, a pressure gauge and a valve; the anti-floating anchor rod includes a vertebral body, a casing, an aluminum wire and a fixing bolt, a conical hole running through the casing is provided, the vertebral body cooperates with the conical hole, the narrow end of the vertebral body is inserted into the conical hole from the wide mouth of the conical hole, the aluminum wire connected to the narrow end of the vertebral body is connected with the fixing bolt, the underground structure model box and the environmental model box are both square boxes with an upper opening, rock layers and soil layers are laid in sequence from bottom to top in the environmental model box, the soil layers and rock layers constitute the stratum simulation area, the underground structure model box is buried in the middle of the stratum simulation area, and the bottom plate of the underground structure model box is underground Structural base plate, an earth pressure box is buried in the soil layer below the underground structure base plate, the earth pressure box is used to measure the soil reaction force F1 below the underground structure base plate, a number of first threaded holes are evenly opened on the underground structure base plate, and a second threaded hole is correspondingly opened on the environmental model box directly below the first threaded hole, the friction test plate and the side plate of the underground structure model box are made of the same material, the friction test plate and the side plate of the underground structure model box are buried in the soil layer at the same height, an anchor bolt is fixed on the upper surface of the friction test plate, and a tensile force gauge is hung on the anchor bolt to measure the tension F5 required to pull the friction test plate, a water inlet is provided at the bottom of the environmental model box, and a water outlet is provided at the top, the water inlet is connected to the water tank through a pipe, and a first water pump, a pressure gauge and a valve are sequentially provided on the pipe; When the underground water floating drag model device simulates the anti-floating of the anti-floating anchor rod, the aluminum wire passes through the middle through hole of the tension sensor and the corresponding first threaded hole in sequence, and then is connected with the fixing bolt. The fixing bolt is fixed in the second threaded hole corresponding to the first threaded hole. The aluminum wire is tightened. The tension sensor is used to measure the downward pulling force F2 of the anti-floating anchor rod on the underground structure bottom plate. A fixed rubber gasket is set at the junction of the tension sensor and the underground structure bottom plate, and the first threaded hole is filled with sealant. When the groundwater floating drag action model device simulates anti-floating without anti-floating anchor rods, the bolt is fixed in the first threaded hole through the rubber gasket; When the groundwater floating and dragging action model device simulates pressure relief and anti-floating control, the first threaded hole is not blocked.

2. The groundwater floating drag model device according to claim 1, characterized in that: The underground structure model box and the environment model box are made of transparent materials.

3. The groundwater floating drag model device according to claim 1, characterized in that: The utility model also includes a second water pump, which pumps water out of the underground structure model box through a pipeline.

4. A buoyancy measurement method based on the groundwater floating drag model device according to claim 1, characterized in that: When the groundwater floating drag model device simulates the anti-floating of the anti-floating anchor, the water in the water tank is pumped into the environmental model box by the first water pump and enters the stratum simulation area. The stress condition of the underground structure model box is analyzed. It is subjected to its own gravity G, the bottom soil reaction force F1, the anti-floating anchor tension F2, the groundwater buoyancy F3, and the side wall friction F4, including the side wall friction resistance and the side wall cohesion. In the vertical direction, the static equilibrium equation is calculated as follows: F1+F3=nF2+G+F4 (1) Buoyancy of the basement model box: F3=nF2+G-F1+F4 (2) F4=F5*S1 / S2 (3) Where n is the number of anti-floating anchors, S1 is the area of the vertical surface of the side plate of the underground structure model box, and S2 is the area of the vertical surface of the friction test plate. The buoyancy force on the underground structure can be obtained according to formula (2); When the groundwater floating and dragging effect model device simulates anti-floating without anti-floating anchor rods, the water in the water tank is pumped into the environmental model box and into the stratum simulation area through the first water pump. The buoyancy of the underground structure model box is F3=G-F1+F4.

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