Model test device for simulating structural-soil interaction under groundwater level fluctuation and underground structure movement and test method thereof

Abstract

The application discloses a model test device and a test method for simulating structure-soil interaction under the conditions of groundwater level change and underground structure movement, and the method comprises the following steps: 1) filling sand cushion and self-weight consolidation; 2) arranging geotextile and water-permeable curtain; 3) filling model soil, burying an underground structure model, and recording initial data by a displacement sensor; 4) water injection, self-weight consolidation of the model soil; 5) recording initial data by each sensor, and recording settlement data by the displacement sensor; 6) pulling the underground structure model by a screw elevator, and recording data by each sensor; and 7) analyzing data and obtaining test results. The application can simulate the process of the interface characteristics change of the underground structure-soil caused by the groundwater level change and the deformation of the underground structure-soil, and can accurately measure the stress field change of the underground structure and the surrounding soil, and the data of tensile load, displacement and the like during the groundwater level change and the loading process.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, specifically to a model test device and test method for simulating structure-soil interaction under groundwater level fluctuations and underground structure movement. Background Technology

[0002] With the advancement of urbanization in my country, the demand for urban space and transportation capacity is constantly increasing, leading to the rapid development and utilization of urban underground space. For underground structures, floods such as torrential rains and flash floods have a significant impact on the underground structure and surrounding soil. Therefore, studying the influence of water level fluctuations on the characteristics of the underground structure-soil interface and the deformation of the underground structure-soil system is of great practical significance.

[0003] Currently, research on underground structure-soil interaction models mainly includes foundation beam models, spatial shell models, soil spring models, spatial theory models, multi-field coupling models, and nonlinear contact models of underground structures and soil. Existing studies on the interface properties of underground structures and soil have largely focused on experiments in frozen soil and soft soil conditions, without considering the interface properties of underground structures and soil under varying water levels or the changing stress fields of the underground structure-soil interface.

[0004] Therefore, there is an urgent need to develop an experimental device and method that can solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a model test device and test method for simulating structure-soil interaction under groundwater level fluctuations and underground structure movement, so as to solve the problems existing in the prior art.

[0006] The technical solution adopted to achieve the purpose of this invention is as follows: a model test device for simulating the interaction between structure and soil under groundwater level changes and underground structure movement, including a model box, an underground structure model, an underground structure fixing device, a monitoring system, a loading system and a water injection and pumping system.

[0007] The model box includes a main body and an L-shaped box. The main body is a rectangular box with an open top. The four side plates of the main body are labeled as side plate A, side plate B, side plate C and side plate D. Side plate A has a hole for the underground structure model to pass through.

[0008] The model box body is equipped with a sand cushion layer and a permeable curtain, with the sand cushion layer laid at the bottom of the model box body.

[0009] The water permeable curtain is installed on the sand cushion, and the water permeable curtain comprises side plates E, F and G, the side plates E are parallel to the side plates B and spaced from each other, the side plates F are parallel to the side plates C and spaced from each other, and the side plates G are parallel to the side plates D and spaced from each other, the side plates E, F and G are sequentially connected to form a U-shaped groove structure, the opening of the U-shaped groove structure faces the side plate A, and the side plates E and G are in contact with the side plate A. The space S surrounded by the water permeable curtain, the side plate A and the sand cushion is filled with model soil, and geotextile is arranged between the sand cushion and the model soil.

[0010] The L-shaped box comprises a rectangular box I and a rectangular box II, the length direction of the rectangular box I is parallel to the horizontal direction, the length direction of the rectangular box II is parallel to the vertical direction, one end of the rectangular box I is connected perpendicularly to the side plate A and communicates with the hole, the other end of the rectangular box I is connected to the lower end of the rectangular box II and communicates with each other, and the upper end of the rectangular box II is in an open state.

[0011] One side plate of the rectangular box II which is parallel to and away from the side plate A is referred to as a side plate H, a vertical strip-shaped through hole is formed in the side plate H, a sliding plate is arranged on the outer side of the side plate H, and a fixed pulley located on the inner side of the side plate H penetrates through the strip-shaped through hole and is connected with the sliding plate.

[0012] The underground structure model is a hollow cylindrical structure, and the axis of the underground structure model is perpendicular to the side plate A.

[0013] The underground structure fixing device comprises a support, two steel wires and a plastic plate, the plastic plate is provided with a through hole with a diameter consistent with the diameter of the underground structure model, the plastic plate is fixed to the inner wall of the side plate A, and the through hole of the plastic plate communicates with the hole.

[0014] One end of the underground structure model is embedded in the model soil, and the other end penetrates through the plastic plate and the hole and extends into the L-shaped box.

[0015] The monitoring system comprises a force sensor, two displacement sensors, a plurality of soil pressure sensors, a plurality of pore water pressure sensors and a plurality of strain sensors, the plurality of soil pressure sensors are arranged on the outer wall of the underground structure model and in the soil around the underground structure model, the plurality of pore water pressure sensors are arranged on the outer wall of the underground structure model, and the plurality of strain sensors are arranged on the inner wall and the outer wall of the underground structure model.

[0016] The support comprises two telescopic columns and a support plate, the two telescopic columns are respectively arranged on the upper edges of the side plate A and the side plate C, and the support plate is connected to the two telescopic columns.

[0017] The upper ends of the two steel wires penetrate through the support plate and are respectively connected to the two displacement sensors, and the lower ends of the two steel wires are connected to the underground structure model.

[0018] The loading system includes a screw jack, a steel support frame, and steel strands. The screw jack is mounted on the steel support frame, and the lower end of the screw jack's lifting rod extends into the rectangular box II from the upper port of the box II.

[0019] The lower end of the lifting rod of the spiral jack is connected to a force sensor, which is connected to a steel strand. The steel strand passes around a fixed pulley and is connected to the end face of the underground structure model.

[0020] During operation, the water injection and pumping system injects or pumps water into the gap between the permeable curtain and the main body of the model box. After the water level stabilizes and the model soil is consolidated, the screw lift is activated to move the underground structure model by pulling it with steel strands. The monitoring system acquires the stress field, strain, and tensile load data of the underground structure model and the surrounding soil. By analyzing the data, the changes in the characteristics of the underground structure-soil interface and the deformation of the underground structure-soil caused by groundwater level fluctuations are obtained.

[0021] Furthermore, the slide plate is a vertical rectangular plate, and several threaded holes are provided on both vertical edges of the slide plate. The two steel plates with threaded holes are vertically connected to the two vertical edges of the slide plate by several bolts.

[0022] Furthermore, the plastic sheet comprises two rectangular plates, each with a semi-circular notch, and the notches of the two rectangular plates face each other and are joined together.

[0023] Furthermore, a hook I is connected to the end face of the underground structure model that extends into the L-shaped box, and two hooks II that are spaced apart are connected to the outer wall of the underground structure model. The lower end of the steel wire is connected to the underground structure model through hook II, and the steel strand is connected to the underground structure model through hook I.

[0024] Furthermore, the force sensor is connected to the steel strand via a steel hook.

[0025] Furthermore, the water injection and pumping system includes several water pipes and a water pump. One end of the water pipe is connected to the water pump, and the other end extends into the gap between the permeable curtain and the main body of the model box.

[0026] Furthermore, one side panel of the L-shaped box is made of plexiglass, while the main body of the model box and the underground structure model are made of steel.

[0027] A test method for a model test device based on the above-mentioned simulation of structure-soil interaction under groundwater level fluctuations and underground structure movement includes the following steps:

[0028] 1) Fill the bottom of the model box with a sand cushion layer and let it solidify under its own weight for a set time.

[0029] 2) Arrange geotextile and permeable curtain on the sand cushion layer.

[0030] 3) Fill the model soil in the space S to the design height, and install a plurality of soil pressure sensors, a plurality of pore water pressure sensors and a plurality of strain sensors to the corresponding positions of the underground structure model as required, bury the underground structure model and fix it to the underground structure fixing device, and continue to fill the model soil to the design height of the soil layer. During the filling process, a plurality of soil pressure sensors are arranged in the soil around the underground structure fixing device as required, and the data of the displacement sensor are recorded as initial data.

[0031] 4) Use the water injection and pumping system to inject water to the design water level in the gap between the water permeable curtain and the main body of the model box, and consolidate the model soil by self weight for a set time.

[0032] 5) Record the data of the soil pressure sensors, pore water pressure sensors and strain sensors as initial data, and record the data of the displacement sensor as post-settlement data.

[0033] 6) Adjust the height of the sliding plate up and down so that the part of the steel strand located in the rectangular box I coincides with the axis of the underground structure model. Turn on the screw elevator, and pull the underground structure model to the designated position through the steel strand, during which the data of the force sensor, soil pressure sensor, pore water pressure sensor and strain sensor are recorded.

[0034] 7) Save the data and arrange the test equipment.

[0035] 8) Analyze the obtained data to obtain the rules of the changes of the underground structure-soil interface characteristics and the deformation of the underground structure-soil caused by the change of the underground water level.

[0036] Further, in step 1), the filling thickness of the sand cushion is 10 cm, and the self-weight consolidation is 24 h.

[0037] Further, in step 4), the model soil after water injection is consolidated by self weight for 1 month.

[0038] The beneficial effects of the present application are:

[0039] A. The present application can truly simulate the changes of the underground structure-soil interface characteristics and the deformation process of the underground structure-soil caused by the change of the underground water level;

[0040] B. The present application can accurately measure the vertical displacement of the underground structure model, the tensile load and the corresponding displacement value generated by the underground structure model during the horizontal loading process, the strain of the underground structure model, the change rule of the soil pressure around the underground structure model and the pore water pressure around the underground structure model when the underground water level changes;

[0041] C. The device of the present application is reasonably arranged, the test operation is convenient, the cost is low, and the reliability is high. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the device of the present invention;

[0043] Figure 2 This is a schematic diagram of the main body of the model box;

[0044] Figure 3 This is a sectional view of the L-shaped box.

[0045] Figure 4 This is a schematic diagram showing the connection between the underground structure fixing device and the underground structure model.

[0046] Figure 5 This is a layout diagram of the earth pressure sensors;

[0047] Figure 6 This is a diagram showing the arrangement of the pore water pressure sensor.

[0048] Figure 7 This is a diagram showing the arrangement of strain sensors.

[0049] In the diagram: Model box 1, Model box body 101, Hole 1011, L-shaped box 102, Fixed pulley 1021, Slide plate 1022, Steel plate 1023, Sand cushion layer 103, Permeable curtain 104, Geotextile 105, Underground structure model 2, Hook I 201, Hook II 202, Underground structure fixing device 3, Support 301, Telescopic column 3011, Steel wire 302, Plastic plate 303, Force sensor 4, Displacement sensor 501, Soil pressure sensor 6, Pore water pressure sensor 7, Strain sensor 8, Screw jack 9, Steel support 10, Steel strand 11, Steel hook 12, Water pipe 13 and Water pump 14. Detailed Implementation

[0050] The present invention will be further described below with reference to embodiments, but it should not be construed that the scope of the present invention is limited to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention should be included within the scope of protection of the present invention.

[0051] Example 1:

[0052] See Figure 1 This embodiment discloses a model test device for simulating the interaction between structure and soil under groundwater level changes and underground structure movement, including a model box 1, an underground structure model 2, an underground structure fixing device 3, a monitoring system, a loading system and a water injection and pumping system.

[0053] The model box 1 includes a model box body 101 and an L-shaped box body 102. See below. Figure 2The model box body 101 is a rectangular box with an open upper end, and four side plates of the model box body 101 are sequentially labeled as side plate A, side plate B, side plate C and side plate D. The side plate A is provided with a hole 1011 for the underground structure model 2 to pass through.

[0054] The sand cushion 103 is arranged in the model box body 101.

[0055] The water permeable curtain 104 is installed on the sand cushion 103, and the water permeable curtain 104 includes side plate E, side plate F and side plate G. The side plate E is parallel to the side plate B and spaced apart from the side plate B. The side plate F is parallel to the side plate C and spaced apart from the side plate C. The side plate G is parallel to the side plate D and spaced apart from the side plate D. The side plate E, the side plate F and the side plate G are sequentially connected to form a U-shaped groove structure. The U-shaped groove structure has a groove opening facing the side plate A, and the side plate E and the side plate G are in contact with the side plate A. The space S surrounded by the water permeable curtain 104, the side plate A and the sand cushion 103 is filled with model soil, and the sand cushion 103 and the model soil are provided with geotextile 105.

[0056] The water injection and pumping system includes a plurality of water pipes 13 and a water pump 14. One end of the water pipe 13 is connected to the water pump 14, and the other end of the water pipe 13 extends into the gap between the water permeable curtain 104 and the model box body 101.

[0057] Referring to Figure 3 The L-shaped box 102 includes a rectangular box I and a rectangular box II. The length direction of the rectangular box I is parallel to the horizontal direction, and the length direction of the rectangular box II is parallel to the vertical direction. One end of the rectangular box I is connected to the side plate A perpendicularly and communicates with the hole 1011. The other end of the rectangular box I is connected to the lower end of the rectangular box II and communicates with each other. The upper end of the rectangular box II is open.

[0058] One side plate of the rectangular box II, which is parallel to and away from the side plate A, is labeled as side plate H. The side plate H is provided with a vertical strip-shaped through hole. The outer side of the side plate H is provided with a sliding plate 1022. A fixed pulley 1021 located on the inner side of the side plate H passes through the strip-shaped through hole and is connected to the sliding plate 1022.

[0059] The sliding plate 1022 is a vertical rectangular plate. A plurality of threaded holes are formed in the two vertical edges of the sliding plate 1022. Two steel plates 1023 with screw holes are connected to the two vertical edges of the sliding plate 1022 perpendicularly through a plurality of bolts.

[0060] The underground structure model 2 is a hollow cylindrical structure, and the axis of the underground structure model 2 is perpendicular to the side plate A. One side plate of the L-shaped box 102 is made of organic glass. The model box body 101 and the underground structure model 2 are made of steel.

[0061] The underground structure fixing device 3 comprises a support 301, two steel wires 302 and a plastic plate 303, the plastic plate 303 is provided with a through hole with the same diameter as the underground structure model 2, the plastic plate 303 is fixed on the inner wall of the side plate A, and the through hole of the plastic plate 303 is in communication with the hole 1011.

[0062] The plastic plate 303 comprises two rectangular plates, and semicircular notches are formed on the rectangular plates, the notches of the two rectangular plates are opposite to each other and are spliced with each other.

[0063] One end of the underground structure model 2 is embedded in the model soil, and the other end penetrates the plastic plate 303 and the hole 1011 and extends into the L-shaped box 102.

[0064] The monitoring system comprises a force sensor 4, two displacement sensors 501, a plurality of soil pressure sensors 6, a plurality of pore water pressure sensors 7 and a plurality of strain sensors 8, as shown in Figure 5 The plurality of soil pressure sensors 6 are installed on the outer wall of the underground structure model 2 and in the soil around the underground structure model 2, as shown in Figure 6 The plurality of pore water pressure sensors 7 are installed on the outer wall of the underground structure model 2, as shown in Figure 7 The plurality of strain sensors 8 are arranged on the inner wall and the outer wall of the underground structure model 2.

[0065] The support 301 comprises two telescopic columns 3011 and a support plate, the two telescopic columns 3011 are respectively installed on the upper edges of the side plate A and the side plate C, and the support plate is connected to the two telescopic columns 3011.

[0066] As shown in Figure 4 The upper ends of the two steel wires 302 penetrate the support plate and are respectively connected to the two displacement sensors 501, and the lower ends are connected to the underground structure model 2.

[0067] The loading system comprises a screw elevator 9, a steel support 10 and a steel wire 11, the screw elevator 9 is installed on the steel support 10, and the lower end of the lifting rod of the screw elevator 9 extends into the rectangular box II from the upper end of the rectangular box II.

[0068] The lower end of the lifting rod of the screw elevator 9 is connected to the force sensor 4, the force sensor 4 is connected to the steel wire 11 through a steel hook 12, the steel wire 11 passes through the fixed pulley 1021 and is connected to the end face of the underground structure model 2.

[0069] The end face of the end of the underground structure model 2 extending into the L-shaped box 102 is connected with a hook I 201, the outer wall of the underground structure model 2 is connected with two hooks II 202 which are spaced apart from each other, the lower end of the steel wire 302 is connected to the underground structure model 2 through the hook II 202, and the steel wire 11 is connected to the underground structure model 2 through the hook I 201.

[0070] Before work, adjust two telescopic columns 3011 to the appropriate height, ensure that the displacement sensor 501 can accurately measure the settlement value of the underground structure model 2 in the subsequent test.

[0071] In work, the water injection and pumping system injects or pumps water into the gap between the water permeable curtain 104 and the model box body 101. After the water level stabilizes and the model soil is consolidated, the underground structure model 2 will produce vertical displacement with the model soil, causing the two hooks Ⅱ 202 above the underground structure model 2 and the steel wire 302 connected thereto to move, and the displacement sensor 501 to monitor the displacement change of the steel wire 302, thereby reflecting the vertical displacement change of the underground structure model 2. By recording the data changes of the soil pressure sensor 6, the pore water pressure sensor 7 and the strain sensor 8, the data of the soil pressure, pore water pressure and self-strain of the underground structure model 2 around the water level change are obtained. Then open the spiral elevator 9 to pull the underground structure model 2 outwards by the loading system. The monitoring system obtains the data of the stress field of the underground structure model 2 and the surrounding soil, the pipeline strain, the tensile load and the like. By analyzing the data, the change of the underground structure-soil interface characteristics and the deformation of the underground structure-soil caused by the change of the underground water level are obtained.

[0072] It is worth noting that the device described in the embodiment can simulate the process of the change of the underground structure-soil interface characteristics and the deformation of the underground structure-soil caused by the change of the underground water level, and can accurately measure the change of the underground water level and the stress field of the underground structure and the surrounding soil, as well as the tensile load, displacement and the like during the loading process. The embodiment has low cost and broad application prospect.

[0073] Embodiment 2:

[0074] The embodiment discloses a test method of a model test device for simulating the structure-soil interaction under the change of underground water level and the movement of underground structure based on the model test device for simulating the structure-soil interaction under the change of underground water level and the movement of underground structure.

[0075] 1) Fill the sand cushion layer 103 at the bottom of the model box body 101 and consolidate it to the set time by self weight. The filling thickness of the sand cushion layer 103 is 10 cm, and the self-weight consolidation time is 24 h.

[0076] 2) Arrange the geotextile 105 and the water permeable curtain 104 on the sand cushion layer 103.

[0077] 3) Fill the model soil in the space S to the design height, and install the plurality of soil pressure sensors 6, the plurality of pore water pressure sensors 7 and the plurality of strain sensors 8 to the corresponding positions of the underground structure model 2 according to the requirements, bury the underground structure model 2 and fix it with the underground structure fixing device 3, and continue to fill the model soil to the design height of the soil layer. During the filling process, the plurality of soil pressure sensors 6 are arranged in the soil body around the underground structure fixing device 3 according to the requirements, and the data of the displacement sensor 501 is recorded as the initial data.

[0078] 4) Use the water injection and pumping system to inject water to the design water level in the gap between the water permeable curtain 104 and the model box main body 101, and consolidate the model soil by self weight for a set time. Among them, the model soil by self weight is consolidated for 1 month.

[0079] 5) Record the data of the soil pressure sensor 6, the pore water pressure sensor 7 and the strain sensor 8 as the initial data, and record the data of the displacement sensor 501 as the post-settlement data.

[0080] 6) Adjust the height of the sliding plate 1022 up and down so that the part of the steel strand 11 in the rectangular box I coincides with the axis of the underground structure model 2. Turn on the screw elevator 9, pull the underground structure model 2 to the designated position through the steel strand 11, and record the data of the force sensor 4, the soil pressure sensor 6, the pore water pressure sensor 7 and the strain sensor 8 during the process.

[0081] 7) Save the data and arrange the test equipment.

[0082] 8) Analyze the obtained data to obtain the rules of the change of the underground structure-soil interface characteristics and the deformation of the underground structure-soil caused by the change of the underground water level.

[0083] Example 3:

[0084] Referring to Figure 1 , the embodiment discloses a model test device for simulating the structure-soil interaction under the change of underground water level and the movement of underground structure, which comprises a model box 1, an underground structure model 2, an underground structure fixing device 3, a monitoring system, a loading system and a water injection and pumping system.

[0085] The model box 1 comprises a model box main body 101 and an L-shaped box 102, referring to Figure 2 , the model box main body 101 is a rectangular box with an open upper end, and the four side plates of the model box main body 101 are sequentially referred to as side plate A, side plate B, side plate C and side plate D, and the side plate A is provided with a hole 1011 for the underground structure model 2 to pass through.

[0086] The sand cushion 103 is laid on the bottom of the model box body 101.

[0087] The water permeable curtain 104 is installed on the sand cushion 103, and the water permeable curtain 104 comprises side plates E, F and G, the side plates E are parallel to the side plate B and spaced from each other, the side plates F are parallel to the side plate C and spaced from each other, and the side plates G are parallel to the side plate D and spaced from each other, the side plates E, F and G are sequentially connected to form a U-shaped groove structure, the groove opening of the U-shaped groove structure faces the side plate A, and the side plates E and G are in contact with the side plate A. The space S surrounded by the water permeable curtain 104, the side plate A and the sand cushion 103 is filled with model soil, and the geotextile 105 is arranged between the sand cushion 103 and the model soil.

[0088] Referring to Figure 3 , the L-shaped box 102 comprises a rectangular box I and a rectangular box II, the length direction of the rectangular box I is parallel to the horizontal direction, the length direction of the rectangular box II is parallel to the vertical direction, one end of the rectangular box I is connected perpendicularly to the side plate A and communicates with the hole 1011, the other end of the rectangular box I is connected to the lower end of the rectangular box II and communicates with each other, and the upper end of the rectangular box II is in an open state.

[0089] One side plate of the rectangular box II which is parallel to and away from the side plate A is referred to as the side plate H, a vertical strip-shaped through hole is formed in the side plate H, and the slide plate 1022 is arranged on the outer side of the side plate H, and the fixed pulley 1021 located on the inner side of the side plate H penetrates through the strip-shaped through hole and is connected with the slide plate 1022.

[0090] The underground structure model 2 is a hollow cylindrical structure, and the axis of the underground structure model 2 is perpendicular to the side plate A.

[0091] The underground structure fixing device 3 comprises a support 301, two steel wires 302 and a plastic plate 303, the plastic plate 303 is provided with a through hole with a diameter consistent with the diameter of the underground structure model 2, the plastic plate 303 is fixed on the inner wall of the side plate A, and the through hole of the plastic plate 303 communicates with the hole 1011.

[0092] One end of the underground structure model 2 is embedded in the model soil, and the other end penetrates through the plastic plate 303 and the hole 1011 and extends into the L-shaped box 102.

[0093] The monitoring system comprises a force sensor 4, two displacement sensors 501, a plurality of soil pressure sensors 6, a plurality of pore water pressure sensors 7 and a plurality of strain sensors 8, referring to Figure 5 The plurality of soil pressure sensors 6 are installed on the outer wall of the underground structure model 2 and in the soil body around the underground structure model 2, referring to Figure 6 The plurality of pore water pressure sensors 7 are installed on the outer wall of the underground structure model 2, referring toFigure 7 A plurality of strain sensors 8 are arranged on the inner wall and the outer wall of the underground structure model 2.

[0094] The support 301 comprises two telescopic columns 3011 and a support plate, the two telescopic columns 3011 are respectively arranged on the upper edges of the side plates A and C, and the support plate is connected to the two telescopic columns 3011.

[0095] Referring to Figure 4 The upper ends of the two steel wires 302 pass through the support plate and are respectively connected to the two displacement sensors 501, and the lower ends are connected to the underground structure model 2.

[0096] The loading system comprises a screw elevator 9, a steel support 10 and a steel wire 11, the screw elevator 9 is arranged on the steel support 10, and the lower end of the lifting rod of the screw elevator 9 extends into the rectangular box body II from the upper end of the rectangular box body II.

[0097] The lower end of the lifting rod of the screw elevator 9 is connected to a force sensor 4, the force sensor 4 is connected to the steel wire 11, and the steel wire 11 passes through the fixed pulley 1021 and is connected to the end face of the underground structure model 2.

[0098] In operation, the water injection and pumping system injects or pumps water into the gap between the water permeable curtain 104 and the model box body 101, after the water level is stable and the model soil is consolidated, the screw elevator 9 is started, the underground structure model 2 is pulled through the steel wire 11, the monitoring system obtains the stress field, strain and tensile load data of the underground structure model 2 and the surrounding soil, and the change of the underground water level leads to the change of the underground structure-soil interface characteristics and the deformation of the underground structure-soil.

[0099] Embodiment 4:

[0100] The main structure of this embodiment is the same as that of embodiment 3, further, the sliding plate 1022 is a vertical rectangular plate, a plurality of threaded holes are formed on the two vertical edges of the sliding plate 1022, and two steel plates 1023 with screw holes are vertically connected to the two vertical edges of the sliding plate 1022 through a plurality of bolts.

[0101] Embodiment 5:

[0102] The main structure of this embodiment is the same as that of embodiment 3, further, the plastic plate 303 comprises two rectangular plates, semicircular notches are formed on the rectangular plates, and the notches of the two rectangular plates are opposite and spliced with each other.

[0103] Embodiment 6:

[0104] The embodiment mainly has the same structure as that of the embodiment 3, further, the underground structure model 2 is connected with a hook 201 on the end surface of one end of the L-shaped box 102, two hooks 202 are connected with the outer wall of the underground structure model 2, the lower end of the steel wire 302 is connected with the underground structure model 2 through the hook 202, and the steel strand 11 is connected with the underground structure model 2 through the hook 201.

[0105] Embodiment 7

[0106] The embodiment mainly has the same structure as that of the embodiment 3, further, the force sensor 4 is connected with the steel strand 11 through the steel hook 12.

[0107] Embodiment 8

[0108] The embodiment mainly has the same structure as that of the embodiment 3, further, the water injection and pumping system comprises a plurality of water pipes 13 and a water pump 14, one end of the water pipe 13 is connected with the water pump 14, and the other end is inserted into the gap between the water curtain 104 and the model box main body 101.

[0109] Embodiment 9

[0110] The embodiment mainly has the same structure as that of the embodiment 3, further, one side plate of the L-shaped box 102 is made of organic glass, and the model box main body 101 and the underground structure model 2 are made of steel.

Claims

1. A model test device for simulating structure-soil interaction under groundwater level fluctuations and underground structure movement, characterized in that: The model box (1), the underground structure model (2), the underground structure fixing device (3), a monitoring system, a loading system and a water injection and pumping system are included. The model box (1) includes a model box body (101) and an L-shaped box (102). The model box body (101) is a rectangular box with an open upper end. Four side plates of the model box body (101) are sequentially labeled as side plate A, side plate B, side plate C and side plate D. The side plate A is provided with a hole (1011) for the underground structure model (2) to pass through. The model box body (101) is provided with a sand cushion (103) and a water permeable curtain (104) inside. The sand cushion (103) is laid on the bottom of the model box body (101). The water permeable curtain (104) is installed on the sand cushion (103). The water permeable curtain (104) includes side plate E, side plate F and side plate G. The side plate E is parallel to the side plate B and spaced apart from each other. The side plate F is parallel to the side plate C and spaced apart from each other. The side plate G is parallel to the side plate D and spaced apart from each other. The side plate E, the side plate F and the side plate G are sequentially connected to form a U-shaped groove structure. The opening of the U-shaped groove structure faces the side plate A. The side plate E and the side plate G are in contact with the side plate A. The space S surrounded by the water permeable curtain (104), the side plate A and the sand cushion (103) is filled with model soil. The sand cushion (103) and the model soil are provided with a geotextile (105) therebetween. The L-shaped box (102) includes a rectangular box I and a rectangular box II. The length direction of the rectangular box I is parallel to the horizontal direction. The length direction of the rectangular box II is parallel to the vertical direction. One end of the rectangular box I is connected perpendicularly to the side plate A and communicates with the hole (1011). The other end of the rectangular box I is connected to the lower end of the rectangular box II and communicates with each other. The upper end of the rectangular box II is open. One side plate of the rectangular box II, which is parallel to and away from the side plate A, is labeled as side plate H. A vertical strip-shaped through hole is formed in the side plate H. A sliding plate (1022) is arranged on the outer side of the side plate H. A fixed pulley (1021) located on the inner side of the side plate H passes through the strip-shaped through hole and is connected with the sliding plate (1022). The underground structure model (2) is a hollow cylindrical structure. The axis of the underground structure model (2) is perpendicular to the side plate A. The underground structure fixing device (3) includes a support (301), two steel wires (302) and a plastic plate (303). The plastic plate (303) is provided with a through hole with a diameter consistent with the diameter of the underground structure model (2). The plastic plate (303) is fixed on the inner wall of the side plate A. The through hole of the plastic plate (303) communicates with the hole (1011). One end of the underground structure model (2) is embedded in the model soil. The other end passes through the plastic plate (303) and the hole (1011) and extends into the L-shaped box (102). The monitoring system comprises a force sensor (4), two displacement sensors (501), a plurality of soil pressure sensors (6), a plurality of pore water pressure sensors (7) and a plurality of strain sensors (8), the plurality of soil pressure sensors (6) are installed on the outer wall of the underground structure model (2) and in the soil around the underground structure model (2), the plurality of pore water pressure sensors (7) are installed on the outer wall of the underground structure model (2), and the plurality of strain sensors (8) are arranged on the inner wall and the outer wall of the underground structure model (2); The support (301) comprises two telescopic columns (3011) and a support plate, the two telescopic columns (3011) are respectively installed on the upper edges of the side plate A and the side plate C, and the support plate is connected to the two telescopic columns (3011). The upper ends of the two steel wires (302) pass through the support plate and are respectively connected to the two displacement sensors (501), and the lower ends are connected to the underground structure model (2). The underground structure model (2) is connected with a hook I (201) on the end face of one end of the L-shaped box (102), the outer wall of the underground structure model (2) is connected with two hooks II (202) which are spaced apart from each other, the lower ends of the steel wires (302) are connected to the underground structure model (2) through the hooks II (202), and the steel strand (11) is connected to the underground structure model (2) through the hook I (201). The loading system comprises a screw elevator (9), a steel support (10) and a steel strand (11), the screw elevator (9) is installed on the steel support (10), and the lower end of the lifting rod of the screw elevator (9) extends into the rectangular box II from the upper end of the rectangular box II. The lower end of the lifting rod of the screw elevator (9) is connected with the force sensor (4), the force sensor (4) is connected with the steel strand (11), the steel strand (11) passes through the fixed pulley (1021) and is connected to the end face of the underground structure model (2). In operation, the water injection and pumping system injects or pumps water into the gap between the water permeable curtain (104) and the model box main body (101), after the water level is stable and the model soil is consolidated, the screw elevator (9) is started, the underground structure model (2) is pulled through the steel strand (11), the stress field, the strain and the tension load data of the underground structure model (2) and the surrounding soil are obtained by the monitoring system, and the change of the underground water level leads to the change of the underground structure-soil interface characteristics and the deformation law of the underground structure-soil is obtained by analyzing the data.

2. The model test apparatus for simulating the structural-soil interaction under the groundwater level fluctuation and the underground structure movement according to claim 1, characterized in that: The slide plate (1022) is a vertical rectangular plate, a plurality of threaded holes are formed in the two vertical edges of the slide plate (1022), and two steel plates (1023) with screw holes are vertically connected to the two vertical edges of the slide plate (1022) through a plurality of bolts.

3. The model testing apparatus for simulating the structural-soil interaction under the groundwater level fluctuation and the underground structure movement according to claim 1 or 2, characterized in that: The plastic plate (303) comprises two rectangular plates, a semicircular notch is formed in each of the rectangular plates, and the notches of the two rectangular plates are opposite and spliced with each other.

4. The model testing apparatus of claim 1, wherein: The force sensor (4) is connected with the steel strand (11) through a steel hook (12).

5. The model testing apparatus of claim 1, wherein: The water injection and pumping system comprises a plurality of water pipes (13) and a water pump (14), one end of the water pipes (13) being connected to the water pump (14) and the other end extending into the gap between the water permeable curtain (104) and the model box body (101).

6. The model testing apparatus of claim 1, wherein: One side plate of the L-shaped box body (102) is made of organic glass, and the model box body (101) and the underground structure model (2) are made of steel.

7. A test method based on the model test apparatus for simulating the structural-soil interaction under the change of underground water level and the movement of underground structure according to any one of claims 1 to 6, characterized by, The method comprises the following steps: 1) filling the sand cushion (103) at the bottom of the model box body (101) and self-consolidating to a set time; 2) arranging the geotextile (105) and the water permeable curtain (104) on the sand cushion (103); 3) filling the model soil in layers in the space S to a design height, installing a plurality of soil pressure sensors (6), a plurality of pore water pressure sensors (7) and a plurality of strain sensors (8) to corresponding positions of the underground structure model (2) as required, burying the underground structure model (2) and fixedly connecting the underground structure model (2) with the underground structure fixing device (3), and continuing to fill the model soil to the design height of the soil layer; during the filling process, arranging the plurality of soil pressure sensors (6) in the soil body around the underground structure fixing device (3) as required, recording the data of the displacement sensor (501) as initial data; 4) using the water injection and pumping system to inject water into the gap between the water permeable curtain (104) and the model box body (101) to a design water level, and self-consolidating the model soil to a set time; 5) recording the data of the soil pressure sensor (6), the pore water pressure sensor (7) and the strain sensor (8) as initial data, and recording the data of the displacement sensor (501) as post-settlement data; 6) adjusting the height of the sliding plate (1022) up and down so that the part of the steel strand (11) located in the rectangular box I coincides with the axis of the underground structure model (2); opening the screw elevator (9) to pull the underground structure model (2) to a designated position through the steel strand (11), and recording the data of the force sensor (4), the soil pressure sensor (6), the pore water pressure sensor (7) and the strain sensor (8) during the process; 7) saving the data and arranging the test equipment; 8) analyzing and arranging the obtained data to obtain the rules of the changes of the underground water level, the changes of the underground structure-soil body interface characteristics and the deformation of the underground structure-soil body caused by the changes of the underground water level.

8. A test method for a model test apparatus for simulating the structural-soil interaction under the change in groundwater level and the movement of underground structures according to claim 7, characterized in that: In step 1), the filling thickness of the sand cushion (103) is 10 cm, and the self-consolidation time is 24 h.

9. The test method of the model test apparatus for simulating the structure-soil interaction under the groundwater level fluctuation and the underground structure movement according to claim 7, characterized in that: In step 4), the model soil is self-consolidated for 1 month.

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