Ground surface multipoint vertical displacement monitoring device and method for geotechnical engineering model test

Abstract

The invention discloses a ground surface multi-point vertical displacement monitoring device and method for geotechnical engineering model test, and the device comprises a reference water tank which is fixedly disposed at a high position; the differential pressure type static level gauges are distributed at monitoring points on the upper surface of the geotechnical material, are connected with the reference water tank to form a closed-loop network, and can monitor the hydraulic pressure difference between the liquid level of the differential pressure type static level gauges and the reference liquid level of the reference water tank in real time; the guide rods are vertically mounted at the upper ends of the differential pressure type static force level gauges, and anti-falling parts are detachably arranged at the upper ends of the guide rods; the limiting frame is horizontally mounted above the differential pressure type static leveling instrument at intervals, vertical guide holes are distributed according to the monitoring points, and the guide rods penetrate through the corresponding guide holes in a matched mode; and the data acquisition system is used for acquiring the hydraulic difference information uploaded by each differential pressure type static leveling instrument and converting the hydraulic difference information into vertical displacement information, so that the vertical displacement at each monitoring point is monitored. The device realizes wide-range measurement while ensuring high precision, and is suitable for discrete rock-soil materials.

Description

Technical Field

[0001] The present invention relates to a geotechnical engineering model test, and in particular to a surface multi-point vertical displacement monitoring device and method for a geotechnical engineering model test. Background Art

[0002] Due to the complexity of geotechnical materials and the unpredictability of the engineering environment, it is often difficult to accurately predict the deformation laws in actual engineering projects by relying solely on theoretical analysis and numerical simulation. Therefore, in the field of geotechnical engineering, physical model testing is not only an important means to study soil deformation, slope stability, foundation settlement and the mechanical behavior of surrounding rock in underground engineering, but also a key method to verify theory, optimize design and evaluate engineering safety.

[0003] The reliability of geotechnical engineering model tests depends largely on the accuracy and applicability of displacement measurement technology. At present, geotechnical engineering model tests generally use contact measurement technologies, such as mechanical displacement meters, LVDTs, and rope-type displacement sensors. Although the technology is mature, it has the following shortcomings: the range of mechanical displacement meters and LVDTs is limited, which makes it difficult to meet the needs of large deformation measurement; although the rope-type sensor has a large range, its accuracy is low and its adaptability to bulk rock and soil materials is poor, which limits its application in complex model tests. Summary of the Invention

[0004] The purpose of the present invention is to provide a surface multi-point vertical displacement monitoring device for geotechnical engineering model tests, and a surface multi-point vertical displacement monitoring method for geotechnical engineering model tests. The device can ensure high precision while achieving a large range of measurements and is applicable to bulk rock and soil materials.

[0005] The technical solution adopted in the present invention is: A surface multi-point vertical displacement monitoring device for geotechnical engineering model tests, comprising: The reference water tank is fixed at a high position on or near the model tank; Differential pressure static levels are distributed at various monitoring points on the upper surface of geotechnical materials. Each differential pressure static level is connected to the reference water tank via flexible liquid and air pipes to form a closed loop network. Each differential pressure static level is equipped with a highly sensitive pressure sensor and can monitor the hydraulic pressure difference between its own liquid level and the reference liquid level in the reference water tank in real time. The guide rod is vertically installed on the upper end of each pressure differential static level, and the upper end of the guide rod is detachable and provided with an anti-dropping part; The limit frame is installed horizontally and at intervals above the pressure differential static level. Vertical guide holes are provided according to the distribution of each monitoring point, and each guide rod is matched to pass through the corresponding guide hole; The data acquisition system is used to collect the hydraulic pressure difference information uploaded by each pressure differential static level and convert the hydraulic pressure difference information into vertical displacement information, so as to monitor the vertical displacement at each monitoring point.

[0006] Preferably, the pressure differential static level is electrically connected to a signal converter via a signal line. The signal converter is used to convert the analog signal of the hydraulic pressure difference into an electrical signal. The signal converter is electrically connected to a data acquisition system via a signal line.

[0007] Preferably, the limiting frame is connected to the model box or the independent bracket at multiple points.

[0008] Preferably, the limit frame is welded with section steel or steel pipe as components, and the position and direction of the components are consistent with the position and direction of each monitoring point.

[0009] Preferably, the guide hole is precisely machined, both ends of the guide hole are centrally positioned to ensure verticality, and the inner wall of the guide hole is polished to reduce friction resistance; the guide rod is made of high-strength material and is precisely machined to ensure straightness.

[0010] Preferably, a clearance fit is adopted between the guide rod and the guide hole.

[0011] Preferably, the lower end of the guide rod is fixed on the pressure differential type static level by welding, or is fixed on the pressure differential type static level by bonding with a high-strength adhesive.

[0012] A method for monitoring multi-point vertical displacement of the surface of a geotechnical engineering model test is based on the multi-point vertical displacement monitoring device of the surface of the geotechnical engineering model test. First, guide holes are set on a limit frame according to the distribution of monitoring points, and a guide rod is set on a pressure differential static level. After the guide rod passes through the corresponding guide hole, an anti-slip portion is installed on the upper end of the guide rod. Each pressure differential static level is connected to a reference water tank through a liquid pipe and an air pipe to form a closed-loop network; then the limit frame is installed horizontally so that each pressure differential static level is distributed at each monitoring point of the geotechnical material; then debugging is carried out to ensure normal monitoring and recording, and after passing the test, the initial displacement of each pressure differential static level is reset to zero; then the test is started, and the vertical displacement at each monitoring point is monitored during the test.

[0013] Preferably, when installing a closed-loop network, first connect the bottom liquid port of the reference water tank in series with each pressure differential static level through a liquid pipe but do not close the loop, connect the top air port of the reference water tank in series with each pressure differential static level through an air pipe and close the loop, then fill water into the reference water tank until all the bubbles in the liquid pipe are drained, and then connect the liquid pipe of the tail pressure differential static level to the bottom of the reference water tank to form a closed loop.

[0014] Preferably, during the test, a model shield machine is used to perform shield tunneling on the rock and soil materials in the model box, and the surface settlement of the soil caused by the shield tunneling process is monitored by monitoring the vertical displacement at each monitoring point.

[0015] Beneficial effects of the present invention: In this device: the reference water tank is fixed at a high position and can remain stable throughout the test cycle, thus providing a benchmark for measurement; the pressure differential static level uses a highly sensitive pressure sensor to accurately and promptly feedback the hydraulic pressure difference between its own liquid level and the reference liquid level at the reference water tank, thereby accurately and promptly capturing the slight deformation of the upper surface of the geotechnical material. The distributed pressure differential static levels, combined with the data acquisition system, can achieve precise monitoring of multi-point vertical displacement; the limit frame and the guide rod cooperate to vertically guide the pressure differential static level and prevent lateral displacement of the pressure differential static level, thereby avoiding measurement deviations caused by uneven settlement of bulk geotechnical materials and ensuring the reliability of long-term monitoring data. , and can also expand the maximum displacement range of the differential pressure static level. It only needs to ensure that the initial distance between the differential pressure static level and the limit frame is sufficient, and the guide rod is long enough. Whether the differential pressure static level rises or falls, it can have a sufficient range, avoiding monitoring interruption and data loss in extreme displacement conditions; the upper end of the guide rod is detachably provided with an anti-slip part, which can prevent the guide rod from falling out on the one hand, and on the other hand, each differential pressure static level can be suspended on the limit frame using the anti-slip part, so that all differential pressure static levels can be transferred to each monitoring point as a whole; each differential pressure static level and the reference water tank are connected by flexible liquid pipes and air pipes to avoid affecting the activity of the differential pressure static level. Therefore, the device can achieve a large range of measurements while ensuring high precision, and can be applied to bulk rock and soil materials. Compared with fiber optic monitoring, it ensures measurement accuracy while significantly reducing equipment costs, and has better cost performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 It is a cross-sectional view of the surface multi-point vertical displacement monitoring device for geotechnical engineering model test in the present invention.

[0018] Figure 2 yes Figure 1 A partial enlarged view of .

[0019] Figure 3It is a plan view of the surface multi-point vertical displacement monitoring device for geotechnical engineering model test in the present invention.

[0020] In the figure: 1-guide rod; 2-pressure differential static level; 3-liquid pipe; 4-air pipe; 5-signal line; 6-limit frame; 7-anti-slip part; 8-reference water tank; 9-signal converter; 10-data acquisition system; 11-model shield machine; 12-model box; 13-geotechnical material. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0024] In the description of this application, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on this application.

[0025] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0026] The features and performance of the present application are further described in detail below with reference to the embodiments.

[0027] Example 1 This embodiment discloses a surface multi-point vertical displacement monitoring device for geotechnical engineering model tests, such as Figures 1 to 3 As shown, it includes a reference water tank 8, a pressure differential static level 2, a guide rod 1, a limit frame 6 and a data acquisition system 10; wherein: the reference water tank 8 is fixed at a high position on the model box 12 (it can also be fixed at a high position near the model box 12), see Figure 1 and Figure 2 The differential pressure static level 2 is distributed at each monitoring point on the upper surface of the geotechnical material 13. Each differential pressure static level 2 and the reference water tank 8 are connected by a flexible liquid pipe 3 and an air pipe 4 to form a closed loop network. Each differential pressure static level 2 is equipped with a highly sensitive pressure sensor. Each differential pressure static level can monitor the hydraulic pressure difference between its own liquid level and the reference liquid level at the reference water tank 8 in real time. Figures 1 to 3 A guide rod 1 is vertically mounted on the upper end of each pressure differential static level 2, and the upper end of the guide rod 1 is detachably provided with an anti-slip portion 7, see Figures 1 to 3 The limit frame 6 is installed horizontally and spaced above the pressure differential static level 2. The limit frame 6 is provided with vertical guide holes according to the distribution of each monitoring point. Each guide rod 1 is respectively matched with a corresponding guide hole. Figures 1 to 3 The data acquisition system 10 is used to collect the hydraulic pressure difference information uploaded by each differential pressure static level 2 and convert the hydraulic pressure difference information into vertical displacement information, thereby monitoring the vertical displacement at each monitoring point, see Figures 1 to 3 .

[0028] In this device: The reference water tank 8 is fixed at a high position and can remain stable throughout the test cycle, thus providing a reference for measurement; The pressure differential static level 2 utilizes a highly sensitive pressure sensor to accurately and promptly feedback the hydraulic pressure difference between its own liquid level and the reference liquid level in the reference water tank, thereby accurately and promptly capturing the slight deformation of the upper surface of the geotechnical material. The distributed pressure differential static level 2, in conjunction with the data acquisition system 10, can achieve precise monitoring of multi-point vertical displacement. The cooperation between the limit frame 6 and the guide rod 1 can not only guide the pressure differential static level 2 vertically and prevent the pressure differential static level 2 from lateral displacement, thereby avoiding measurement deviation caused by uneven settlement of bulk rock and soil materials 13 and ensuring the reliability of long-term monitoring data, but also expand the maximum displacement range of the pressure differential static level 2. It is only necessary to ensure that the initial spacing between the pressure differential static level 2 and the limit frame 6 is sufficient and that the guide rod 1 is long enough. Whether the pressure differential static level 2 rises or falls, it can have a sufficient range, avoiding monitoring interruption and data loss in extreme displacement conditions. The upper end of the guide rod 1 is provided with a detachable anti-dropout portion 7, which can prevent the guide rod 1 from falling out, and on the other hand, each pressure differential type static level 2 can be suspended on the limit frame 6 by using the anti-dropout portion 7, so that all the pressure differential type static levels 2 can be transferred to each monitoring point as a whole; Each pressure differential type static level 2 and the reference water tank 8 are connected by a flexible liquid pipe 3 and an air pipe 4, which can avoid affecting the movement of the pressure differential type static level 2.

[0029] Therefore, the device can achieve a wide range of measurements while ensuring high precision, and can be applied to bulk rock and soil materials 13. Compared with optical fiber monitoring, it can significantly reduce equipment costs while ensuring measurement accuracy, and has better cost performance.

[0030] like Figure 1 and Figure 2 As shown, in this embodiment, preferably, the pressure differential static level 2 is electrically connected to the signal converter 9 through the signal line 5, the signal converter 9 is used to convert the analog signal of the hydraulic pressure difference into an electrical signal, and the signal converter 9 is electrically connected to the data acquisition system 10 through the signal line 5.

[0031] like Figure 1 and Figure 3 As shown, in this embodiment, preferably, the limit frame 6 is connected to the model box 8 at multiple points; of course, the limit frame 6 can also be connected to an independent bracket at multiple points. Using multiple-point connection, the installation is stable, and a level meter can be used to ensure levelness during installation.

[0032] like Figure 3 As shown, in this embodiment, preferably, the limit frame 6 is welded with steel sections or steel pipes as components, and the position and direction of the components are consistent with the position and direction of each monitoring point, which can ensure overall rigidity and avoid being too heavy.

[0033] In this embodiment, the guide hole is preferably precision-machined, its ends are aligned to ensure verticality, and its inner wall is polished to reduce frictional resistance. The guide rod 1 is made of high-strength material and precision-machined to ensure straightness. This arrangement ensures effective guidance.

[0034] In this embodiment, preferably, a clearance fit is adopted between the guide rod 1 and the guide hole to avoid jamming.

[0035] In this embodiment, preferably, the lower end of the guide rod 1 is welded and fixed to the pressure differential static level 2, or is bonded and fixed to the pressure differential static level 2 using a high-strength adhesive to ensure that the connection is strong enough and not easy to come off.

[0036] Example 2 This embodiment discloses a method for monitoring the vertical displacement of multiple points on the surface of a geotechnical engineering model test. Based on the above-mentioned device for monitoring the vertical displacement of multiple points on the surface of a geotechnical engineering model test, the following steps are adopted: S1. Set guide holes on the limit frame 6 according to the distribution of monitoring points, set guide rods 1 on the pressure differential static level 2, let the guide rods 1 pass through the corresponding guide holes, and install the anti-slip part 7 on the upper end of the guide rods 1. Connect each pressure differential static level 2 and the reference water tank 8 through the liquid pipe 3 and the air pipe 4 to form a closed loop network; When installing the closed-loop network, first connect the bottom liquid port of the reference water tank 8 in series with each pressure differential type static level 2 through the liquid pipe 3 but do not close the loop, and connect the top air port of the reference water tank 8 in series with each pressure differential type static level 2 through the air pipe 4 and close the loop, then fill water into the reference water tank 8 until all the bubbles in the liquid pipe 3 are drained, and then connect the liquid pipe 3 of the tail pressure differential type static level 2 with the bottom of the reference water tank 8 to form a closed loop.

[0037] S2, horizontal installation limit frame 6, so that each differential pressure static level 2 is distributed at each monitoring point of the geotechnical material 13. S3. Carry out debugging to ensure normal monitoring and recording. After passing the test, the initial displacement of each pressure differential static level 2 is reset to zero.

[0038] S4. Start the test and monitor the vertical displacement at each monitoring point during the test; A variety of tests can be carried out as needed, such as: Figure 1 and Figure 3 As shown, a model shield machine 11 is used to perform shield tunneling on the geotechnical material 13 in the model box 12, and the surface settlement of the soil caused by the shield tunneling process is monitored by monitoring the vertical displacement at each monitoring point.

[0039] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

Claims

1. A surface multi-point vertical displacement monitoring device for geotechnical engineering model tests, characterized in that: include: The reference water tank is fixed at a high position on or near the model tank; Differential pressure static levels are distributed at various monitoring points on the upper surface of geotechnical materials. Each differential pressure static level is connected to the reference water tank via flexible liquid and air pipes to form a closed loop network. Each differential pressure static level is equipped with a highly sensitive pressure sensor and can monitor the hydraulic pressure difference between its own liquid level and the reference liquid level in the reference water tank in real time. The guide rod is vertically installed on the upper end of each pressure differential static level, and the upper end of the guide rod is detachable and provided with an anti-dropping part; The limit frame is installed horizontally and at intervals above the pressure differential static level. Vertical guide holes are provided according to the distribution of each monitoring point, and each guide rod is matched to pass through the corresponding guide hole; The data acquisition system is used to collect the hydraulic pressure difference information uploaded by each pressure differential static level and convert the hydraulic pressure difference information into vertical displacement information, so as to monitor the vertical displacement at each monitoring point.

2. The surface multi-point vertical displacement monitoring device for geotechnical engineering model tests according to claim 1, characterized in that: The pressure differential static level is electrically connected to a signal converter via a signal line. The signal converter is used to convert the analog signal of the hydraulic pressure difference into an electrical signal. The signal converter is electrically connected to a data acquisition system via a signal line.

3. The surface multi-point vertical displacement monitoring device for geotechnical engineering model tests according to claim 1, characterized in that: The limit frame is connected to the model box or an independent bracket at multiple points.

4. The surface multi-point vertical displacement monitoring device for geotechnical engineering model testing according to claim 1, characterized in that: The limit frame is made of welded steel sections or steel pipes as components, and the position and direction of the components are consistent with the position and direction of each monitoring point.

5. The surface multi-point vertical displacement monitoring device for geotechnical engineering model testing according to claim 1, characterized in that: The guide hole is precision machined, both ends of the guide hole are centered to ensure verticality, and the inner wall of the guide hole is polished to reduce friction resistance; the guide rod is made of high-strength material and precision machined to ensure straightness.

6. The surface multi-point vertical displacement monitoring device for geotechnical engineering model tests according to claim 1, characterized in that: A clearance fit is adopted between the guide rod and the guide hole.

7. The surface multi-point vertical displacement monitoring device for geotechnical engineering model testing according to claim 1, characterized in that: The lower end of the guide rod is fixed on the pressure differential type static level by welding, or is fixed on the pressure differential type static level by bonding with a high-strength adhesive.

8. A method for monitoring vertical displacement of multiple points on the surface of a geotechnical engineering model test, characterized by: A surface multi-point vertical displacement monitoring device for geotechnical engineering model tests based on any one of claims 1 to 7 comprises the following steps: first, guide holes are set on the limit frame according to the distribution of monitoring points, and a guide rod is set on the pressure differential static level. After the guide rod passes through the corresponding guide hole, an anti-slip portion is installed on the upper end of the guide rod, and each pressure differential static level is connected to a reference water tank through a liquid pipe and an air pipe to form a closed-loop network; then, the limit frame is installed horizontally so that each pressure differential static level is distributed at each monitoring point of the geotechnical material; then, debugging is carried out to ensure normal monitoring and recording, and after passing the test, the initial displacement of each pressure differential static level is reset to zero; then, the test is started, and the vertical displacement at each monitoring point is monitored during the test.

9. The method for monitoring ground surface multi-point vertical displacements in a geotechnical engineering model test according to claim 8, wherein: When installing a closed-loop network, first connect the bottom liquid port of the reference water tank in series with each pressure differential static level through a liquid pipe but do not close the loop; connect the top air port of the reference water tank in series with each pressure differential static level through an air pipe and close the loop; then fill the reference water tank with water until all bubbles in the liquid pipe are drained; then connect the liquid pipe of the tail pressure differential static level to the bottom of the reference water tank to form a closed loop.

10. The method for monitoring ground surface multi-point vertical displacement in a geotechnical engineering model test according to claim 8, characterized in that: During the test, a model shield machine was used to perform shield tunneling on the rock and soil materials in the model box, and the surface settlement of the soil caused by the shield tunneling process was monitored by monitoring the vertical displacement at each monitoring point.

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