Ground surface settlement monitoring method based on serially connected hydrostatic level gauges

Abstract

The invention relates to a ground surface settlement monitoring method based on tandem hydrostatic level gauges. The method comprises the following steps: determining a datum point and a monitoring point; fixing the hydrostatic level gauge on the auxiliary stand column by using a hoop connecting piece, and deploying the auxiliary stand column to the reference point and the monitoring point; all the hydrostatic level gauges are connected in series through liquid communicating pipes, anti-freezing liquid is poured into the liquid communicating pipes, and airtight openings of all the hydrostatic level gauges are communicated through airtight pipes; all the hydrostatic level gauges are connected to a data acquisition instrument through shielding cables; the liquid level reading of the hydrostatic level gauge at each measuring point is sent to a data acquisition instrument, the liquid level variation is calculated, and the settling volume of each measuring point is further calculated. According to the invention, the auxiliary stand column and the hoop connecting piece are adopted to mount the hydrostatic level on the ground surface, so that the vertical adjustment amplitude of the hydrostatic level during mounting is improved, and the monitoring method of the hydrostatic level can be applied to more complex ground surface settlement monitoring.

Description

Technical Field

[0001] This invention relates to the field of land subsidence monitoring technology, and specifically to a land subsidence monitoring method based on a cascaded hydrostatic level. Background Technology

[0002] A hydrostatic level is an instrument that utilizes the principle of communicating vessels, connecting various hydrostatic levels through a liquid connecting pipe to measure changes in the liquid level within each level, thereby calculating the settlement changes at each measuring point. A hydrostatic level typically consists of two or more interconnected observation devices; the number depends on the application requirements. For settlement observation of large structures and surface settlement monitoring, a dozen or even dozens of interconnected hydrostatic levels are often required. When used for settlement monitoring of dams, high-rise buildings, mines, landslides, bridges, etc., the hydrostatic leveling system is generally installed on a measuring pier at the same height as the object being measured or on the contour line of the wall of the object. It uses an integrated modular automatic measurement unit to collect data and connects to a computer via wired or wireless communication to achieve automated monitoring.

[0003] However, current settlement monitoring using hydrostatic levels typically involves directly mounting the level on the surface of the object being monitored using a support frame. For settlement monitoring on uneven surfaces, it's impossible to guarantee that the hydrostatic level is installed on a perfectly horizontal plane. This is particularly true for settlement monitoring near construction sites adjacent to operational railway lines, such as settlement between two existing railways or outside protective fences. These areas often have dense vegetation and undulating surfaces, making traditional hydrostatic level installation methods difficult to implement.

[0004] Therefore, it is necessary to propose new measures to overcome the above-mentioned shortcomings. Summary of the Invention

[0005] The purpose of this invention is to provide a method for monitoring land subsidence based on a tandem hydrostatic level, so as to solve the problem of proper installation of hydrostatic levels in special areas such as areas with lush vegetation and undulating terrain.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for monitoring land subsidence based on a cascaded hydrostatic level is provided, the method comprising: Determine the location of the measuring points, including the benchmark point and the monitoring point; The hydrostatic level is fixed to the auxiliary column using clamp connectors, and the auxiliary column is deployed at the benchmark point and monitoring point; Connect all the hydrostatic level instruments in series through the liquid connecting pipe and pour in antifreeze. Connect the airtight ports of all the hydrostatic level instruments through the airtight pipe. Connect all hydrostatic level instruments to the data acquisition unit using shielded cables; The liquid level readings of the hydrostatic level at each measuring point are sent to the data acquisition instrument to calculate the liquid level change, and then the settlement at each measuring point is calculated.

[0007] Furthermore, the auxiliary column includes an auxiliary column base and an auxiliary column body on top of it. The auxiliary column base is fixed to the ground at the measuring point or to a concrete foundation or concrete base embedded at the measuring point location by expansion bolts.

[0008] Furthermore, the clamp connector includes a clamp connector mounting platform, a clamp connector support rod, a lower clamp component, and an upper clamp component; The upper and lower clamps are arranged vertically to tighten the main body of the auxiliary column; The clamp connector mounting platform is connected to the side of the upper clamp, and the clamp connector support rod is obliquely connected between the end of the clamp connector mounting platform and the lower clamp.

[0009] Furthermore, the upper clamp is semi-circular in shape with connecting plates at both ends, and is fixed to the end of the clamp connector mounting platform by clamp connector fixing screws.

[0010] Furthermore, the lower clamping component includes two semi-circular tubes, one side of which is connected by bolts, and the other side is connected to the clamping connector support rod by bolts.

[0011] Furthermore, the height of the hydrostatic level is adjusted using the clamp connector to ensure that all hydrostatic levels are on the same horizontal plane.

[0012] Furthermore, the liquid connecting pipe, airtight pipe, and shielded cable are wrapped inside the insulation cotton.

[0013] Furthermore, the calculation of the hydrostatic level change Δhj at the reference point includes: △hj=Kj(Fj-Foj); In the formula: Kj is the sensor coefficient of the reference point of the hydrostatic level; Fj is the current reading of the reference point of the hydrostatic level; Foj is the initial reading of the reference point of the hydrostatic level.

[0014] Furthermore, the change in liquid level Δhj at the monitoring point using the hydrostatic level is calculated, including: △hi = Ki(Fi - Foi); In the formula: Ki is the sensor coefficient at the monitoring point of the hydrostatic level; Fi represents the current reading at the monitoring point of the hydrostatic level; Foi represents the initial reading of the monitoring point of the hydrostatic level.

[0015] Furthermore, the settlement ΔHi at each measuring point is calculated, including: △Hi=△hj-△hi=Kj(Fj-Foj)-Ki(Fi-Foi).

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for monitoring land settlement based on a tandem hydrostatic level. The hydrostatic level is installed on the ground using auxiliary columns and clamp connectors, increasing the vertical adjustment range during installation and enabling the method to be applied to more complex land settlement monitoring scenarios. Furthermore, the hydrostatic level installed on the ground using auxiliary facilities is essentially on the same horizontal plane, eliminating high and low points in the liquid pipeline, thus preventing issues such as foaming and impurities, and improving settlement monitoring accuracy. Simultaneously, this method eliminates the need for a storage tank; the liquid inside the hydrostatic level can be used for long-term monitoring, reducing consumable materials and saving monitoring costs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a method provided in an embodiment of the present invention.

[0019] Figure 2 A side view of an auxiliary column provided for an embodiment of the present invention.

[0020] Figure 3 This is a side view of the clamp connector provided in an embodiment of the present invention.

[0021] Figure 4 This is a top view of the clamp connector provided in an embodiment of the present invention.

[0022] Figure 5 This is a schematic diagram of the installation of a single hydrostatic level provided in an embodiment of the present invention.

[0023] Figure 6 A diagram showing the installation route of multiple static levels for surface subsidence monitoring, provided in an embodiment of the present invention.

[0024] The diagram is labeled as follows: 1-Auxiliary column main body, 2-Auxiliary column base, 3-Auxiliary column base screw hole, 4-Clamp connector mounting platform, 5-Clamp connector support rod, 6-Lower clamp, 7-Upper clamp, 8-Clamp connector fixing screw, 9-Liquid straight pipe reserved opening, 10-Mounting platform reserved screw hole, 11-Liquid hydrostatic level, 12-Hydrostatic level with built-in bracket, 13-Shielded cable, 14-Airtight pipe, 15-Liquid connecting pipe, 16-Insulation cotton, 17-Solar panel, 18-Wire, 19-Data acquisition instrument protection box. Detailed Implementation

[0025] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0026] In the description of this invention, it should be understood that the terms "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "setting," etc., should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] It should also be noted that although the order of steps is mentioned in the method description, in some cases, steps may be performed in a different order than that described here, and this should not be interpreted as a restriction on the order of steps.

[0029] Detailed implementation method: (1) A liquid hydrostatic level is a precision instrument that measures the relative elevation changes between two or more points by measuring changes in the liquid level.

[0030] (2) The benchmark point is the benchmark for settlement monitoring and the reference for the change of the monitoring point. The point should have higher stability and must be established in a stable area outside the deformation zone.

[0031] (3) Monitoring point refers to the point directly buried in the part that can reflect the deformation characteristics of the monitored body.

[0032] (4) Data acquisition instrument is an instrument that automatically collects sensor data from each monitoring point and transmits it wirelessly to the automated monitoring cloud platform.

[0033] To address the difficulty in installing hydrostatic levels for settlement monitoring on complex surfaces in existing technologies, this invention provides a method for monitoring surface settlement based on a cascaded hydrostatic level. This method utilizes specially designed auxiliary columns and clamp connectors to securely install the hydrostatic level, making it suitable for monitoring surface settlement in special areas with lush vegetation and undulating terrain.

[0034] Specifically, such as Figure 1 The method includes the following steps: S1: Determine the location of the measuring points, including the benchmark point and the monitoring point.

[0035] The first and most crucial step is to conduct on-site reconnaissance of the monitoring target to understand the topographic features of the surface settlement monitoring area. This involves determining the location of benchmark points, identifying and confirming one or more absolutely stable locations (if on-site conditions are unavailable, a concrete benchmark pile may need to be installed), and then dividing the monitoring area into different zones based on the surface topography. Monitoring point layout methods include: ① Line layout (most common), suitable for settlement monitoring of linear projects, typically used along railway lines, with points spaced at regular intervals along the axis; ② Grid layout, suitable for large-area surface settlement monitoring (such as industrial squares, reservoir areas, large sites), forming a regular grid that comprehensively reflects the morphology of the settlement area. The shortest and most direct paths should be chosen to connect the monitoring points, minimizing pipeline length and the number of bends to reduce fluid resistance, temperature effects, and hysteresis.

[0036] Reasonable placement of monitoring points is a prerequisite for ensuring accurate, reliable, and representative monitoring data. The core objective of the placement is to comprehensively and accurately capture the settlement and deformation characteristics of the monitored body using the most reasonable monitoring point route. Specifically, based on the settlement monitoring point location map, the locations of each settlement monitoring point on the ground are determined on-site and marked. If the surface monitoring location is hardened, the monitoring equipment can be directly installed. If the monitoring area is soft soil, concrete foundations or concrete bases need to be embedded at the monitoring point locations.

[0037] The benchmark point (reference point) must be located in an absolutely stable area unaffected by settlement. This is the "zero point" of the entire monitoring system, and the settlement values ​​of all measuring points are calculated relative to it. It can be separated from unstable layers by deeply buried marker points. Selecting an absolutely stable point as the benchmark point is crucial, as it serves as the reference for the entire settlement system. It is typically chosen on stable bedrock or deeply buried piles outside the settlement influence area, far from load and vibration sources.

[0038] Once all monitoring points and benchmark points are set up, they need to be connected. Choose gentle paths with minimal interference to avoid high points and low points in the liquid pipeline. High points are prone to foaming and low points are prone to sedimentation of impurities. Ultimately, construct a spatial network that covers the land subsidence area, with absolutely stable benchmark points as the control and monitoring lines as the framework.

[0039] S2: As Figure 5 The hydrostatic level 11 is fixed to the auxiliary column using clamp connectors, and the auxiliary column is deployed at the benchmark point and monitoring point. After the clamp connectors are fixed to the auxiliary column, a stable and level mounting platform is provided for the hydrostatic level, and the instrument is mounted using the built-in bracket 12 of the hydrostatic level.

[0040] like Figure 2 The auxiliary column includes an auxiliary column base 2 and an auxiliary column body 1 at its top. The auxiliary column base 2 is fixed to the ground at the measuring point or a concrete foundation or base embedded at the measuring point location using expansion bolts to ensure the auxiliary column is stable and does not wobble. A suitable column type can be selected based on the site environment (such as temperature difference, wind force, and risk of human interference). Common types include: concrete columns, which are relatively stable and suitable for long-term, high-precision monitoring; and stainless steel columns, which are relatively quick to install and can be connected to the concrete ground using expansion bolts to ensure stability. The center position of the column is marked on site according to the coordinates of the design drawings, and wooden stakes or paint markings are used. If the ground is concrete, expansion bolts can be used to directly fix the auxiliary column base 2 to the ground using the bolt holes. If the monitoring area is soil, a concrete foundation must first be embedded. The depth of the concrete foundation must exceed the local frost line depth to prevent the concrete foundation from rising due to frost heave. The auxiliary column is then fixed on the concrete foundation.

[0041] Using a precision spirit level, level the top or side of the column. This can be achieved by shimming the bottom of the column with a thin steel plate or using adjustable bolts. Ensure the top of the column is strictly level; this is a prerequisite for the subsequent installation of the static level. After successful leveling, use a wrench to tighten the nuts of the anchor bolts symmetrically, in batches, and gradually. During tightening, continuously monitor the precision spirit level to prevent the auxiliary column from tilting. A gap exists between the auxiliary column base and the concrete foundation. High-strength, non-shrink grout (such as anchoring adhesive) can be injected from one side until it overflows from the other. The grout has good fluidity and high strength, ensuring 100% contact between the column base and the foundation, creating a dense, seamless seal, and evenly distributing the load, preventing tilting or deformation of the auxiliary column. Install a sign in a prominent location next to the auxiliary column.

[0042] like Figure 3The clamp connector includes a clamp connector mounting platform 4, a clamp connector support rod 5, a lower clamp 6, and an upper clamp 7, all made of high-strength aluminum alloy. The upper clamp 7 and lower clamp 6 are arranged vertically to clamp the auxiliary column body 1. The clamp connector mounting platform 4 is connected to the side of the upper clamp 7, and the clamp connector support rod 5 is obliquely connected between the end of the clamp connector mounting platform 4 and the lower clamp 6. The upper clamp 7 is semi-circular tubular with connecting plates at both ends, and is fixed to the end of the clamp connector mounting platform 4 by clamp connector fixing screws 8. The lower clamp 6 includes two semi-circular tubes, one side connected by bolts, and the other side connected to the clamp connector support rod 5 by bolts. The height of the hydrostatic level is adjusted using the clamp connector to ensure that all hydrostatic levels are on the same horizontal plane. Figure 4 The mounting platform 4 of the clamp connector has a reserved opening 9 for a liquid straight pipe to pass through the liquid connecting pipe 15, and a reserved screw hole 10 for the mounting platform. It should match the support 12 of the static level instrument and be used to install the support 12 of the static level instrument.

[0043] First, determine the monitoring target. Based on the surface settlement monitoring accuracy requirements provided in the design data, select a suitable hydrostatic level, such as the HD-JL80 series inductive hydrostatic level. Place a precision spirit level on the clamp connector mounting platform 4. Adjust the clamp connector to ensure the mounting platform 4 is perfectly level; this is a crucial step in ensuring the initial accuracy of the instrument. Tighten the side nuts of the clamp connector mounting platform 4 to prevent changes in level during subsequent operations. Then, place the hydrostatic level sensor body onto the leveled clamp connector mounting platform 4 and secure it to the platform using the matching screws. Ensure even tightening to avoid sensor deformation. Double-check that the hydrostatic level body is level, ensuring no leveling changes during tightening. After the hydrostatic level body is installed, use a laser level to confirm that the body is installed on the same horizontal plane. If not, adjust the screws on the hydrostatic level bracket to ensure that all equipment is at the same height, with a height deviation ≤1cm.

[0044] S3: Connect all the hydrostatic level instruments 11 in series through the liquid connecting pipe 15 and pour in antifreeze. Connect the airtight ports of all the hydrostatic level instruments 11 through the airtight pipe 14.

[0045] Necessary connecting pipe tees and straight connectors are installed on the liquid connecting pipe 15. Antifreeze is poured in, ensuring the antifreeze is connected. During installation, avoid creating high or low points in the liquid pipeline. Therefore, the height of the selected auxiliary column should be adaptable to the terrain of the monitoring area, ensuring sufficient adjustment space for the hydrostatic level and clamp connectors. The hydrostatic level can be installed under the guidance of a laser level. After the auxiliary column is fixed, turn on the laser level on site. A horizontal laser line will appear on the column. Mark this position on the column as the installation location for the connectors, ensuring the connectors are on the same horizontal plane.

[0046] When connecting liquid pipelines, use a dedicated pipe cutter to cut the pipe joints, ensuring a clean, vertical, and burr-free cut. Before connection, clean the inside and outside of the pipe joints with anhydrous ethanol or a lint-free cloth to prevent impurities from entering the system. Connect the liquid pipeline to the straight-through or tee connectors and tighten them using professional tools to prevent leakage. Lay the liquid pipeline along the measuring points, connecting all hydrostatic levels in series using tee connectors to avoid blockages caused by bends. Liquid and gas pipelines should be laid in parallel, keeping as far away as possible from high-voltage power cables.

[0047] Select intermediate measuring points as filling points for antifreeze to speed up the filling process and shorten the filling time. Unscrew the top cap of the filling point's reservoir and fill the reservoirs at each measuring point of the hydrostatic leveling system with the purchased antifreeze. After filling, add a small amount of glycerin to each reservoir to prevent evaporation. Filling should only be done from the selected filling points, and the filling should be done evenly, slowly, and continuously. Air in the fluid inlet pipe should be completely removed, and air bubbles should be eliminated. During the filling process, continuously observe the liquid level in each reservoir at each measuring point. Stop filling when the liquid level reaches the mark on the reservoir cylinder after equilibrium has been reached. After filling, promptly check the system's sealing performance, observing for any leakage at the joints. Only proceed to the next step if there is no leakage. When filling the hydrostatic level with antifreeze, pay attention to venting. Repeatedly vent air from the top of the reservoir at each measuring point and at the highest point's vent valve until no more visible air bubbles emerge from the liquid. Air bubbles are the most significant factor affecting measurement accuracy. Air bubbles can compress, causing pressure measurements to become inaccurate. Air bubbles must be completely removed during installation, and the venting process should be checked regularly during subsequent maintenance.

[0048] Connect the hydrostatic levels using airtight pipe 14 and the airtight ports on the hydrostatic levels themselves to prevent air from entering and affecting their measurement accuracy. Connect the spaces above the liquid surface at all measuring points to form a unified "pressure compensation chamber." Its function is to ensure that the liquid surface at all measuring points is subjected to the same atmospheric pressure, thereby eliminating measurement errors caused by local pressure variations. Cut the airtight pipe according to the spacing of the hydrostatic levels on site, clean the inlet, and then connect the vent pipe opening to the pipe fitting to connect all measuring points in series. Secure the airtight pipe. After completing the airtight pipe connection of the entire system, an airtightness test must be performed. Inject a small amount of low-pressure air into the pipeline using a barometer, maintain this pressure for a period of time, and observe whether the pressure drops.

[0049] S4: Connect all hydrostatic level instruments 11 to the data acquisition instrument via shielded cable 13.

[0050] The 4-core shielded cable from Shanghai Huahuan was selected. The cable that comes with the top of the hydrostatic level was inserted into the cable tee. The shielded cables were connected in series between the cable tees and fixed with cable ties of about 0.5 meters each to prevent shaking and ensure smooth power and communication.

[0051] The process of debugging the data acquisition instrument is as follows: After the system is powered on, check whether all measuring points are online and whether the data is stable on the automated monitoring cloud platform; after the system has been running stably for 48 hours, record the initial readings of each measuring point. At this point, it can be considered that all measuring points are at "relative zero", that is, the initial value acquisition is complete.

[0052] Finally, the liquid connecting pipe 15, airtight pipe 14, and shielded cable 13 need to be wrapped inside the insulation cotton 16 to prevent the liquid from freezing. After installation, all hydrostatic levels should be covered with protective covers. The filling of all pipes and cables must serve the stability and consistency of the system, avoiding reading drift caused by factors such as temperature changes, mechanical vibration, and electromagnetic interference; ensure that all measuring points are in the same physical environment and that the liquid properties in the connecting pipes are consistent. Insulation must be continuous, from the first measuring point to the last, without any omissions; the insulation cotton should be securely fixed with cable ties to prevent it from falling off; after the system is running, regularly check the insulation cotton for damage, falling off, water immersion, etc., and repair it in a timely manner.

[0053] The outdoor environment is complex, affected by sunlight, wind, and significant temperature variations. Therefore, hydrostatic levels used for surface settlement monitoring must possess the following characteristics: good stability and strong anti-interference capabilities; minimal susceptibility to external environmental influences, suitable for outdoor monitoring; built-in temperature coefficient correction function, with sensors undergoing high and low temperature testing, each sensor having a different temperature compensation coefficient; good airtightness, suitable for surface settlement monitoring near high-speed railways, subways, and other operational lines, reducing air pressure fluctuations caused by passing trains; and a unique serial number, bus connection, and the ability to query the operating status of each hydrostatic level on the platform.

[0054] S5: The liquid level readings of the hydrostatic level 11 at each measuring point are sent to the data acquisition instrument to calculate the liquid level change and further calculate the settlement at each measuring point.

[0055] like Figure 6 The data acquisition instrument is placed inside the instrument protection box 19 and mounted on a fixed column. In this embodiment, the data acquisition instrument can be powered by solar energy. Specifically, a solar panel 17 is installed on the top of the fixed column and connected to the data acquisition instrument to ensure normal power supply, data acquisition, and data transmission. The monitoring data can be viewed in real time, the monitoring frequency can be set, and monitoring reports can be exported.

[0056] After powering on, observe whether the power indicator light on the data acquisition instrument is on and whether the operation indicator light is flashing, indicating that the equipment has started normally. Using the configuration software provided by the manufacturer, read the hydrostatic levels at each monitoring point connected in series. The software should be able to identify all connected level gauges and display their device addresses, indicating that the physical connection and communication protocol settings are correct. Set the interval for the data acquisition instrument to read all hydrostatic levels (e.g., 5 minutes / time, 10 minutes / time); set the frequency of data upload to the automated monitoring cloud platform (e.g., 1 hour / time). After the system is stable and the data is verified to be correct, set all sensor readings at the current moment to the initial reference value (zero). All subsequent changes are relative to this initial state. Run the system continuously for at least 48 hours, observing the stability of the data curves. Under conditions of no external interference, the data at each measuring point should fluctuate within a very small range (the fluctuation value should be less than the nominal accuracy of the whole). Check whether the data upload is stable and complete. After the trial run is normal, begin surface settlement monitoring.

[0057] Hydrostatic levels operate based on the principle of communicating vessels, meaning that the liquid surfaces in all connected containers always remain at the same horizontal level. Based on this principle, the following calculations are performed: The calculation of the hydrostatic level change Δhj at the reference point includes: △hj=Kj(Fj-Foj); In the formula: Kj is the sensor coefficient of the reference point of the hydrostatic level; Fj is the current reading of the reference point of the hydrostatic level; Foj is the initial reading of the reference point of the hydrostatic level.

[0058] Calculate the change in liquid level Δhj at the monitoring point using a hydrostatic level, including: △hi = Ki(Fi - Foi); In the formula: Ki is the sensor coefficient at the monitoring point of the hydrostatic level; Fi represents the current reading at the monitoring point of the hydrostatic level; Foi represents the initial reading of the monitoring point of the hydrostatic level.

[0059] Calculate the settlement ΔHi at each measuring point, including: △Hi=△hj-△hi=Kj(Fj-Foj)-Ki(Fi-Foi).

[0060] The installation of a hydrostatic level is a meticulous systems engineering project. "A stable reference point, smooth, airless piping, and a strictly level base" are the three key factors for success. Thorough design before installation, strict quality control at every stage during installation, and meticulous maintenance afterward are essential to ensure the system provides reliable, stable, and accurate surface settlement data over the long term.

[0061] Example: This paper uses the monitoring of ground settlement between two existing railways as an example. The ground settlement area between the two lines is a long and narrow linear terrain with dense vegetation, making automated monitoring using traditional intelligent total stations difficult. Therefore, a hydrostatic level method is adopted. The ground settlement monitoring area between the two lines is located within the railway fence, and all equipment installation, commissioning, and maintenance work must be carried out during the maintenance window. Therefore, the hydrostatic level equipment must be easy to install, fast, and efficient.

[0062] The existing surface settlement monitoring area between railway lines is a concrete irrigation canal. Monitoring points were set up along the canal, and the installation locations of the support columns were marked. The following methods were used: Figure 2 The stainless steel auxiliary columns shown are fixed to the side of the canal, allowing for efficient and quick installation and making good use of skylight opening times. (The text repeats itself here.) Figure 3 , Figure 4 The clamp connector shown is fixed to the auxiliary column to keep the installation platform level and stable. Figure 5 As shown, a hydrostatic level is installed on a platform with specially designed connectors to ensure that the hydrostatic level at each measuring point is at the same horizontal height, with an installation error of ≤1cm. The hydrostatic level uses an HD-JL80 series inductive displacement sensor, and the equipment parameters are shown in the table below.

[0063] After the hydrostatic level is installed, connect the liquid connecting pipe (polyethylene material), shielded cable (4-core shield), and airtight pipe (polyurethane material) in series with the sensors at each monitoring point, and wrap and secure them with insulation cotton to prevent shaking and falling off. Install the solar panel and data acquisition instrument, such as... Figure 6 As shown. The data acquisition instrument is model HD-JCX2107, and the acquisition module is model HD-MK1201. After debugging the data acquisition instrument and setting the initial values, the monitoring data is uploaded to the automated monitoring cloud platform in real time. On the platform, the surface subsidence situation can be viewed in real time, and monitoring reports can be exported, realizing automated monitoring of surface subsidence between existing railways.

[0064] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A method for monitoring surface settlement based on a cascaded hydrostatic level, characterized in that: The method includes: Determine the location of the measuring points, including the benchmark point and the monitoring point; The hydrostatic level (11) is fixed to the auxiliary column using clamp connectors, and the auxiliary column is deployed at the reference point and monitoring point; All the hydrostatic level instruments (11) are connected in series through the liquid connecting pipe (15) and antifreeze is poured in. The airtight ports of all the hydrostatic level instruments (11) are connected through the airtight pipe (14). All hydrostatic levels (11) are connected to the data acquisition unit via shielded cables (13); The liquid level readings of the hydrostatic level (11) at each measuring point are sent to the data acquisition instrument to calculate the liquid level change and further calculate the settlement at each measuring point.

2. The method for monitoring surface subsidence based on a cascaded hydrostatic level as described in claim 1, characterized in that: The auxiliary column includes an auxiliary column base (2) and an auxiliary column body (1) on top of it. The auxiliary column base (2) is fixed to the ground of the measuring point or the concrete foundation or concrete base buried at the measuring point location by expansion bolts.

3. The method for monitoring surface subsidence based on a cascaded hydrostatic level as described in claim 2, characterized in that: The clamp connector includes a clamp connector mounting platform (4), a clamp connector support rod (5), a lower clamp (6), and an upper clamp (7). The upper clamp (7) and the lower clamp (6) are arranged vertically to clamp the auxiliary column body (1). The clamp connector mounting platform (4) is connected to the side of the upper clamp (7), and the clamp connector support rod (5) is obliquely connected between the end of the clamp connector mounting platform (4) and the lower clamp (6).

4. The method for monitoring surface subsidence based on a cascaded hydrostatic level as described in claim 3, characterized in that: The upper clamp (7) is semi-circular tube with connecting plates at both ends. It is fixed to the end of the clamp connector mounting platform (4) by clamp connector fixing screws (8).

5. The method for monitoring surface subsidence based on a cascaded hydrostatic level as described in claim 4, characterized in that: The lower clamp (6) includes two semi-circular tubes, one side of which is connected by bolts, and the other side is connected to the clamp connector support rod (5) by bolts.

6. The method for monitoring surface subsidence based on a cascaded hydrostatic level according to claim 5, characterized in that: Adjust the height of the hydrostatic level using the clamp connectors to ensure that all hydrostatic level instruments are on the same horizontal plane.

7. The method for monitoring surface subsidence based on a cascaded hydrostatic level as described in claim 6, characterized in that: The liquid connecting pipe (15), the airtight pipe (14), and the shielded cable (13) are wrapped in the insulation cotton (16).

8. The method for monitoring surface subsidence based on a cascaded hydrostatic level according to claim 7, characterized in that: The calculation of the hydrostatic level change Δhj at the reference point includes: △hj=Kj(Fj-Foj); In the formula: Kj is the sensor coefficient of the reference point of the hydrostatic level; Fj is the current reading of the reference point of the hydrostatic level; Foj is the initial reading of the reference point of the hydrostatic level.

9. The method for monitoring surface subsidence based on a cascaded hydrostatic level as described in claim 8, characterized in that: Calculate the change in liquid level Δhj at the monitoring point using a hydrostatic level, including: △hi = Ki(Fi - Foi); In the formula: Ki is the sensor coefficient at the monitoring point of the hydrostatic level; Fi represents the current reading at the monitoring point of the hydrostatic level; Foi represents the initial reading of the monitoring point of the hydrostatic level.

10. The method for monitoring surface subsidence based on a cascaded hydrostatic level according to claim 9, characterized in that: Calculate the settlement ΔHi at each measuring point, including: △Hi=△hj-△hi=Kj(Fj-Foj)-Ki(Fi-Foi).

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