An integrated monitoring device and method for soil stress and stratified settlement

Abstract

This invention belongs to the field of geotechnical engineering monitoring technology, and particularly relates to an integrated monitoring device for soil stress and stratified settlement. The device includes a settlement receiver, a stratified settlement tube, magnetic rings, a base plate, an earth pressure gauge, and an mounting ring. The base plate is fixedly connected to the bottom of the stratified settlement tube. The earth pressure gauge is fixedly connected to the base plate via the mounting ring. Magnetic rings are spaced apart on the outer wall of the stratified settlement tube. An electromagnetic induction probe in the settlement receiver generates an induction signal with the magnetic rings to monitor the stratified settlement. The earth pressure gauge is connected to an observation cable, which is laid along the inner wall of the stratified settlement tube and extends to the ground to monitor soil stress. This invention also provides an integrated monitoring method for soil stress and stratified settlement. This invention enables integrated synchronous monitoring of both soil stress and stratified settlement parameters, with high accuracy in soil stress measurement. It also allows analysis of the causal relationship between soil stress changes and settlement deformation, making data processing more valuable for engineering applications.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of geotechnical engineering monitoring, and particularly relates to a soil stress and layered settlement integrated monitoring device and a monitoring method. BACKGROUND

[0002] It is known that soil stress and stratum settlement monitoring are both important links in geotechnical engineering monitoring, and the two monitoring works have important significance for evaluating foundation stability, predicting post-construction settlement, controlling construction risks and other links, and are one of the core technical means for guaranteeing the safety construction and long-term operation of geotechnical engineering. With the development of geotechnical engineering construction towards deepening and complication, the integration and synchronization of monitoring technology are increasingly required, but the current monitoring technology in the industry still has obvious limitations and cannot effectively realize the integrated monitoring of soil stress and layered settlement.

[0003] In the current process, soil stress and layered settlement monitoring are mostly in the mode of independent development and separate implementation. Among them, soil stress monitoring mostly uses independently buried soil pressure gauges (such as VWE type vibrating wire soil pressure gauges), and the observation cable is led to the ground reading instrument for data collection. Its core principle is to sense the soil pressure through the change of natural frequency. When the stress state of the soil changes, the measuring surface of the soil pressure gauge synchronously responds to the change of the soil stress to produce a small deformation. The deformation adjusts the internal steel string vibration frequency through the force transmission mechanism, and then reflects the soil stress size through the reading change. For example, patent 202010901298.9 discloses a soil stress testing device and a soil stress testing method, which optimizes the embedding and fixing structure of the soil pressure gauge and improves the stability of stress monitoring, but does not involve the integrated design of layered settlement monitoring, and still needs to independently arrange monitoring points.

[0004] Layered settlement monitoring typically involves drilling and embedding magnetic rings as layered settlement markers, then using a layered settlement meter for observation. The structure and soil are rigidly coupled through backfilling and the rigid anchoring claws on the magnetic ring. When the stratum heaves or settles, the magnetic ring moves synchronously with the soil. During measurement, the electromagnetic induction probe is lowered and the induction signal generated between it and the embedded magnetic ring is used to read the position parameters of the magnetic ring before and after settlement, thus obtaining the continuous stratum settlement. For example, patent 202210450882.6 discloses a comprehensive detection device for soil deformation around underground utility tunnels. It uses fiber optic grating sensing technology and deploys a fiber optic grating sensor array to achieve distributed and continuous monitoring of soil and rock layer settlement by utilizing the strain sensing characteristics of the fiber optic grating. It relies on the demodulation and analysis of fiber optic signals to obtain settlement data and belongs to the "distributed continuous monitoring" mode. It can only achieve simultaneous acquisition of two parameters: soil stress and layer settlement (both share the same fiber optic transmission channel). Patent 202320232921.5 discloses a layer settlement monitoring instrument, which simplifies the on-site installation process of the magnetic ring. However, both of the above patents only optimize layer settlement monitoring and do not involve soil stress monitoring functions, so they cannot achieve simultaneous monitoring of the two contents.

[0005] Based on existing technologies and the content disclosed in the aforementioned patents, it is clear that the core problem in the current field of geotechnical engineering monitoring is that soil stress and stratified settlement monitoring are independent of each other. The two types of monitoring require separate deployment of measuring points, drilling, and installation and burial of devices. This not only requires a large number of points and a large site, but also necessitates the separate operation of earth pressure reading instruments and stratified settlement instruments during the measurement process. The measurement steps are cumbersome and inefficient. Furthermore, independent monitoring can easily lead to poor time synchronization between the two data points, making it difficult to accurately correlate the intrinsic relationship between soil stress changes and stratified settlement, and thus failing to provide comprehensive and coordinated monitoring data support for engineering safety assessment.

[0006] Furthermore, existing monitoring technologies, whether it's the independent installation of earth pressure gauges or the layered settlement monitoring of magnetic rings, suffer from complex installation processes and poor field adaptability. For example, the earth pressure stress monitoring device in patent 202010901298.9 and the layered settlement monitoring instrument in patent 202320232921.5 are designed for a single monitoring function and cannot accommodate another monitoring requirement. To achieve simultaneous monitoring of soil stress and layered settlement, two independent devices must be deployed simultaneously, increasing engineering costs and easily leading to insufficient correlation of monitoring data due to placement deviations. Therefore, how to integrate the advantages of existing monitoring technologies to achieve integrated and synchronized monitoring of soil stress and layered settlement, simplifying on-site deployment and measurement processes, and improving data consistency, synchronization, and engineering applicability has become a major technical problem urgently needing to be solved in geotechnical engineering surveying. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is to provide an integrated monitoring device and method for soil stress and stratified settlement, which integrates the simultaneous monitoring of soil stress and stratified settlement, has high accuracy in soil stress measurement, can analyze the causal relationship between soil stress changes and settlement deformation, and makes data processing more valuable for engineering purposes.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an integrated monitoring device for soil stress and stratified settlement, comprising a settlement receiver, a stratified settlement tube, magnetic rings, a base plate, an earth pressure gauge, and an installation ring; the stratified settlement tube is a hollow tubular structure, and the base plate is fixedly connected to the bottom of the stratified settlement tube; the earth pressure gauge is fixedly connected to the base plate through the installation ring; the magnetic rings are spaced apart on the outer wall of the stratified settlement tube; the settlement receiver includes a receiver, a measuring cable, and an electromagnetic induction probe, one end of the measuring cable is electrically connected to the receiver, and the other end is connected to the electromagnetic induction probe, the electromagnetic induction probe can extend along the hollow channel of the stratified settlement tube, and when the electromagnetic induction probe corresponds to the magnetic rings, it generates an induction signal to monitor the stratified settlement; the earth pressure gauge is connected to an observation cable, the base plate has a hole with a diameter larger than the diameter of the earth pressure gauge, the observation cable passes through the hole and is laid along the inner wall of the stratified settlement tube and extends to the ground to monitor soil stress.

[0009] The aforementioned integrated monitoring device for soil stress and stratified settlement comprises a stratified settlement tube formed by connecting multiple settlement tube sections through a socket connection. In this socket connection, one end of an adjacent settlement tube section is a socket and the other end is a spigot. The outer diameter of the spigot matches the inner diameter of the socket. The spigot is inserted into the socket to splice the two settlement tube sections, and secondary tightening is performed using self-tapping screws.

[0010] The aforementioned integrated monitoring device for soil stress and stratified settlement includes positioning rings on the outer walls of the multi-section settlement tubes. These positioning rings are inserted into the insertion end of the settlement tube and fixedly connected to it via bolts. A magnetic ring is fitted between two adjacent positioning rings, allowing free movement along the axial direction of the settlement tube. The outer diameter of the positioning rings is larger than the inner diameter of the magnetic rings to limit their movement. Elastic anchoring claws are provided on the magnetic rings to achieve rigid coupling between the magnetic rings and the soil, and these claws are arranged circumferentially around the magnetic rings.

[0011] In the aforementioned integrated monitoring device for soil stress and stratified settlement, the spacing between the magnetic rings on a single section of the stratified settlement pipe ranges from 0.5m to 2m, and the shortest spacing between adjacent magnetic rings is limited to 1m; the observation cable is bonded and fixed to the inner wall of the stratified settlement pipe with epoxy resin structural adhesive; the measuring cable is provided with a measuring scale, and the accuracy of the measuring scale is not less than 1mm.

[0012] In the aforementioned integrated monitoring device for soil stress and stratified settlement, the mounting ring is a ring-shaped metal structure with 3-6 fixed feet arranged circumferentially. Each fixed foot has a bolt hole. The soil pressure gauge is placed between the mounting ring and the base plate. After the back of the soil pressure gauge is attached to the bottom surface of the base plate, the mounting ring and the soil pressure gauge are assembled. Expansion bolts pass through the bolt holes to fix the mounting ring and the base plate.

[0013] In the aforementioned integrated monitoring device for soil stress and stratified settlement, the receiver can record two scale values ​​when the electromagnetic induction probe enters and exits the magnetic ring, and automatically calculate the average value of the two scale values.

[0014] A monitoring method based on an integrated monitoring device for soil stress and stratified settlement includes the following steps:

[0015] S1. Determine the monitoring points according to the monitoring requirements, and drill holes at the monitoring points to the preset depth;

[0016] S2. Magnetic ring installation and base plate fixing: The magnetic ring is installed at the preset point of each settling pipe section by means of the positioning ring, and the last settling pipe section is fixedly connected to the base plate.

[0017] S3. Install the earth pressure gauge: Pass the earth pressure gauge through the holes in each section of the settlement pipe and the base plate, so that the back of the earth pressure gauge is in contact with the bottom surface of the base plate, and the mounting ring is attached to one side of the measuring surface of the earth pressure gauge. Lock and fix the earth pressure gauge under the base plate by the mounting ring.

[0018] S4. Laying out observation cables and connecting and fixing subsidence pipes: Lay the observation cables upward along the inner wall of each subsidence pipe section. Complete the subsidence pipe splicing and observation cable fixing operations step by step from bottom to top until the cable reaches the top outlet of the first subsidence pipe section and extends to the ground.

[0019] S5. Lower monitoring device: The assembled monitoring device is vertically lowered into the borehole to ensure that the earth pressure gauge is in close contact with the soil at the bottom of the borehole and remains vertical.

[0020] S6. Backfilling: Backfill the gap between the borehole and the monitoring device with fine sand and bentonite in layers from bottom to top, set the borehole nozzle benchmark and measure the elevation to ensure that the magnetic ring is sent to the design elevation.

[0021] S7. Monitoring: After the borehole shrinkage stabilizes, the electromagnetic induction probe of the settlement receiver is lowered into the hollow pipe of the stratified settlement pipe. The scale is read by the induction signal and the stratified settlement is calculated. At the same time, the monitoring data of the earth pressure gauge is collected to realize the synchronous monitoring of soil stress and stratified settlement.

[0022] S8. Regularly retest and track the changes in soil stress and stratified settlement.

[0023] In the aforementioned integrated monitoring method for soil stress and stratified settlement, the magnetic ring is installed in the following manner: First, the magnetic ring at the lowest measuring point on a single settlement pipe is installed. Then, a positioning ring is inserted into a preset position from one end of the settlement pipe's inlet. The positioning ring is fixed to the settlement pipe with bolts. Next, the magnetic ring is put on, and it falls freely above the positioning ring. The outer diameter of the positioning ring is larger than the inner diameter of the magnetic ring. The settlement pipe and the magnetic ring are not fixed together, and the magnetic ring can move along the axial direction of the settlement pipe. Subsequently, the remaining magnetic rings are installed at the designed distances, and the magnetic rings are isolated from each other by the positioning rings.

[0024] In the above-mentioned integrated monitoring method for soil stress and stratified settlement, in step S6, after the bentonite layer is backfilled, the monitoring device is pulled upward as a whole so that the magnetic ring can move up and down within the range of 0.5-2m.

[0025] In the above-mentioned integrated monitoring method for soil stress and stratified settlement, the soil pressure gauge is located between the mounting ring and the base plate. After the back of the soil pressure gauge is attached to the bottom surface of the base plate, the mounting ring and the soil pressure gauge are assembled. The expansion bolt passes through the bolt holes of the mounting ring fixing foot position to fix the mounting ring and the base plate. The soil pressure gauge is fixed by the clamping action of the mounting ring and the base plate.

[0026] The advantages of the integrated monitoring device and method for soil stress and stratified settlement of the present invention are as follows: The stratified settlement pipe of the present invention adopts a multi-section settlement pipe socket connection. Adjacent settlement pipes are precisely matched and spliced ​​through the socket and splice. The outer diameter of the splice and the inner diameter of the socket are strictly matched. After splicing, the connection is tight and the integrity is strong, which can effectively avoid monitoring errors caused by misalignment and loosening of settlement pipes during the monitoring process. At the same time, the multi-section design facilitates transportation and assembly. The number of settlement pipe sections can be flexibly adjusted according to the monitoring depth to adapt to the monitoring needs of different depths. The magnetic ring is positioned on the outer wall of the settlement pipe by positioning rings, which are fixed to the settlement pipe with bolts. The spacing between adjacent positioning rings can be flexibly set according to monitoring needs. The outer diameter of the positioning rings is larger than the inner diameter of the magnetic ring, effectively limiting the magnetic ring without affecting its free movement along the settlement pipe axis as the soil settles. Uniformly distributed elastic anchoring claws on the magnetic ring achieve rigid coupling between the magnetic ring and the soil, ensuring the magnetic ring accurately follows the soil's synchronous settlement and avoiding settlement monitoring deviations caused by the magnetic ring detaching from the soil, significantly improving the accuracy of stratified settlement monitoring. The settlement receiver of this invention has automatic recording and calculation functions. It can automatically record the two scale values ​​when the electromagnetic induction probe enters and exits the magnetic ring and calculate the average of the two values, reducing errors caused by manual reading and calculation, improving data processing efficiency, and further enhancing settlement monitoring accuracy.

[0027] This invention integrates soil stress monitoring and stratified settlement monitoring into a single device, enabling simultaneous acquisition and analysis of dual parameters. This completely overcomes the technical bottleneck of existing technologies that can only monitor single soil stress and cannot simultaneously acquire soil settlement and deformation data. The device accurately captures soil stress changes through an earth pressure gauge, while simultaneously monitoring stratified settlement through the combination of a magnetic ring and an electromagnetic induction probe. The data from both are correlated in real time, allowing for direct stress-settlement coupling analysis. This clearly reflects the causal relationship between soil stress and deformation, providing comprehensive and collaborative core data support for geotechnical engineering stability evaluation and hazard warning. Compared to single stress monitoring technologies, the data application value is qualitatively improved, meeting the practical needs of geotechnical engineering for comprehensive monitoring of soil mechanical behavior. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall monitoring device structure of the present invention;

[0029] Figure 2 This is a cross-sectional enlarged view of the bottom of the overall monitoring device structure of the present invention;

[0030] Figure 3 This is a bottom view of the overall monitoring device of the present invention.

[0031] Figure 4 This is a schematic diagram of the mounting ring structure in Embodiment 1;

[0032] Figure 5 This is a schematic diagram of the assembly and installation structure of the mounting ring and the earth pressure gauge in Embodiment 1.

[0033] Figure 6 This is a schematic diagram of the earth pressure gauge structure of the present invention. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] In this invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish an order. The term "multiple" means "two or more".

[0036] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0037] Example 1

[0038] likeFigures 1-6 As shown, an integrated monitoring device for soil stress and stratified settlement includes a settlement receiver 1, a stratified settlement tube 2, magnetic rings 3, a base plate 4, an earth pressure gauge 5, and an mounting ring 6. Specifically, the stratified settlement tube 2 is a hollow tubular structure, and the base plate 4 is fixedly connected to the bottom of the stratified settlement tube 2. In this embodiment, the base plate 4 and the stratified settlement tube 2 are fixed together by hot melt adhesive. Magnetic rings 3 are evenly spaced on the outer wall of the stratified settlement tube 2. Specifically, the spacing between the magnetic rings 3 on a single section of the stratified settlement tube ranges from 0.5m to 2m, and the shortest spacing between adjacent magnetic rings 3 is limited to 1m.

[0039] In this embodiment, the earth pressure gauge 5 is fixedly connected to the base plate 4 via a mounting ring 6. The mounting ring 6 is a ring-shaped metal structure with 3-6 evenly distributed fixing feet 12 around its circumference to ensure uniform clamping force and prevent the earth pressure gauge 5 from shifting or loosening. Each fixing foot 12 has a bolt hole 13. The earth pressure gauge 5 is positioned between the mounting ring 6 and the base plate 4. After the back surface 17 of the earth pressure gauge 5 is attached to the bottom surface of the base plate 4, the mounting ring 6 and the earth pressure gauge 5 are joined together. Expansion bolts 18 pass through the bolt holes 13 to fix the mounting ring 6 to the base plate 4. The clamping action between the mounting ring 6 and the base plate 4 achieves the fixation of the earth pressure gauge 5. In this embodiment, the earth pressure gauge 5 is a vibrating wire earth pressure gauge (VWE type), with its measuring surface facing the soil. The side of the measuring surface in contact with the soil has an anti-slip and wear-resistant layer. In this embodiment, the anti-slip and wear-resistant layer uses a high-hardness, wear-resistant polyurethane coating, which combines anti-slip properties with wear resistance. It can resist friction, compression, and erosion from damp underground environments, meeting the long-term monitoring needs of geotechnical engineering. The coating thickness is controlled between 0.8-1.2 mm, ensuring uniform thickness. This guarantees wear resistance without causing stress transmission lag due to excessive coating thickness, ensuring the earth pressure gauge can accurately detect changes in soil stress. The surface of the anti-slip and wear-resistant layer features uniformly distributed diamond-shaped anti-slip patterns. The anti-slip and wear-resistant layer is tightly bonded to the earth pressure gauge's measuring surface through a high-temperature curing process, ensuring no peeling or detachment between the coating and the measuring surface. It is not easily worn or aged during long-term use and can achieve long-term stable monitoring synchronously with the earth pressure gauge body.

[0040] It should be noted that the mounting ring 6 and the earth pressure gauge 5 adopt a splicing structure design. Specifically, the outer diameter of the mounting ring 6 is the same as that of the earth pressure gauge 5. After the fixing feet 12 on the mounting ring 6 are fully fitted and aligned with the side of the earth pressure gauge 5, expansion bolts 18 are passed through the bolt holes 13 of the fixing feet of the mounting ring 6 to lock the mounting ring 6 and the base plate 4. The clamping force between the mounting ring 6 and the base plate 4 ensures the reliable fixation of the earth pressure gauge 5, which not only ensures the fit and firmness of the installation, but also avoids the displacement caused by uneven force on the earth pressure gauge 5, thus ensuring the accurate perception of soil stress by the earth pressure gauge 5.

[0041] The settlement receiver 1 includes a receiver 101, a measuring cable 102, and an electromagnetic induction probe 103. One end of the measuring cable 102 is electrically connected to the receiver 101, and the other end is connected to the electromagnetic induction probe 103. The electromagnetic induction probe 103 can extend into the hollow channel of the stratified settlement pipe, and generates an induction signal when it corresponds with the magnetic ring 3 to monitor the stratified settlement. The measuring cable 102 is provided with a measuring scale with an accuracy of not less than 1 mm. The receiver 101 can record two scale values ​​when the electromagnetic induction probe 103 enters and exits the magnetic ring 3, and automatically calculate the average of the two scale values. In this embodiment, the electromagnetic induction probe 103 uses a waterproof sealing structure to resist groundwater infiltration, and its performance is not affected when used in a groundwater environment.

[0042] Specifically, the earth pressure gauge 5 is connected to an observation cable 501, which is bonded to the inner wall of the stratified settlement pipe 2 with epoxy resin structural adhesive 11. The base plate 4 has a hole 7 with a diameter larger than that of the earth pressure gauge 5, balancing the ease of installation of the earth pressure gauge 5 with the space requirements for laying the observation cable 501; the observation cable 501 passes through the hole 7 and is laid along the inner wall of the stratified settlement pipe 2 and extends to the ground surface 8 to monitor soil stress.

[0043] To ensure tight connections and high coaxiality between settlement pipes, facilitate rapid on-site assembly and docking to improve construction efficiency, and accommodate minor soil deformation to guarantee the continuity and accuracy of settlement monitoring, this embodiment uses a layered settlement pipe 2 formed by connecting multiple settlement pipe sections via a socket connection. In this connection, one end of an adjacent settlement pipe section is a socket, and the other end is a spigot. The outer diameter of the spigot is matched to the inner diameter of the socket. During assembly, the spigot is inserted into the socket to complete the splicing of the two settlement pipe sections. Self-tapping screws are used for secondary tightening to ensure reliable connection.

[0044] Specifically, positioning rings 9 are installed on the outer wall of the multi-section settlement pipe. The positioning rings 9 are inserted into the insertion end of the settlement pipe and fixedly connected to it with bolts. A magnetic ring 3 is fitted between two adjacent positioning rings 9. The magnetic ring 3 can move freely along the axial direction of the settlement pipe; the outer diameter of the positioning ring 9 is larger than the inner diameter of the magnetic ring 3, thus providing axial restraint for the magnetic ring 3. Elastic anchoring claws 10 are provided on the magnetic ring 3, evenly arranged around its circumference to ensure reliable rigid coupling with the soil, further ensuring the synchronicity of the magnetic ring 3 with soil settlement, thereby improving the accuracy of settlement monitoring.

[0045] A monitoring method based on an integrated monitoring device for soil stress and stratified settlement includes the following steps:

[0046] S1. Drilling and wall protection at monitoring points: Determine the monitoring points according to the monitoring requirements, and use a drilling rig to drill holes at the monitoring points to the preset depth. Pay attention to wall protection during drilling. The drilling depth should be 50-100cm deeper than the preset monitoring depth. The drilling diameter should be 10-20cm larger than the outer diameter of the settlement pipe to ensure the smooth lowering of the subsequent monitoring device and the commencement of backfilling operations.

[0047] S2. Installation of Magnetic Ring 3 and Fixing of Base Plate 4: According to the preset installation standards and position requirements, the magnetic ring 3 is fitted onto the preset points of each settlement pipe section through the positioning ring 9. The spacing of the magnetic ring 3 is adjusted according to the soil characteristics of the monitoring area. The spacing in soft soil areas is no more than 1m, and the spacing in hard soil areas is no more than 2m, to ensure that the magnetic ring 3 is installed accurately and securely. After all the magnetic rings 3 are installed, the last settlement pipe section is connected and fixed to the base plate 4 using the preset fixing method to ensure that the connection between the two is tight and stable, laying the foundation for the subsequent installation of the earth pressure gauge 5.

[0048] S3. Install the earth pressure gauge 5: Pass the earth pressure gauge 5 through the hollow channels of all the settlement pipes to be connected from top to bottom, and finally pass it out through the hole 7 opened in the base plate 4. Make the back of the earth pressure gauge 5 fit tightly against the bottom surface of the base plate 4, with the measuring surface facing the soil. The mounting ring 6 is attached to one side of the measuring surface of the earth pressure gauge 5. Lock and fix the earth pressure gauge 5 under the base plate 4 with the mounting ring 6 to ensure that the earth pressure gauge 5 is installed firmly and stably, and to avoid displacement during the monitoring process.

[0049] S4. Laying out the observation cable 501 and connecting and fixing the settlement pipe: Lay out the observation cable 501 of the earth pressure gauge 5 upward along the inner wall of each settlement pipe section. In order from bottom to top, gradually complete the splicing of the settlement pipe and the fixing of the observation cable 501 until it reaches the top outlet of the first settlement pipe section and extends to the ground 8. During the laying of the observation cable 501, avoid bending or damaging the cable to ensure smooth cable transmission.

[0050] S5. Lower monitoring device: Vertically lower the assembled monitoring device into the borehole, ensuring that the earth pressure gauge 5 is in close contact with the soil at the bottom of the borehole 7 and remains vertical. The entire device should be lowered slowly and at a constant speed. It is recommended to control the lowering speed to no more than 0.2 m / s to prevent the elastic anchoring claw 10 on the magnetic ring 3 from deforming due to severe friction with the borehole wall, and to prevent the earth pressure gauge 5 from being crushed.

[0051] S6. Backfilling: The gap between the borehole and the monitoring device is backfilled with fine sand and bentonite in layers from bottom to top. A reference is set at the borehole opening and the elevation is measured to ensure that the magnetic ring is delivered to the design elevation. Specifically, the fine sand layer 15 is backfilled first and compacted to cover the bottom plate 4. In this embodiment, the fine sand is backfilled first and compacted to cover the bottom plate by 60-70cm. Then, bentonite is backfilled to the height of the borehole opening to form a bentonite layer 16. Bentonite expands when it comes into contact with water and can form a dense, low-permeability sealing layer. Specifically, after the bentonite is backfilled, the entire monitoring device is pulled upward so that the magnetic ring 3 can move up and down within the pulling range without obstruction. In this embodiment, the pulling range of the magnetic ring 3 is 0.5-2m.

[0052] S7. Monitoring: After the borehole shrinkage stabilizes, the electromagnetic induction probe 103 of the settlement receiver 1 is lowered into the hollow pipe of the stratified settlement pipe 2. The scale is read by the induction signal and the stratified settlement is calculated. At the same time, the monitoring data of the earth pressure gauge 5 is collected to realize the synchronous monitoring of soil stress and stratified settlement. The criterion for judging the stability of borehole shrinkage is: the settlement at the borehole opening does not exceed 0.1 mm / d for 3 consecutive days.

[0053] S8. Regularly retest and track the changes in soil stress and stratified settlement. The height of the stratified settlement tube 2 remains constant after fixing, while the magnetic ring 3 moves freely up and down along the stratified settlement tube 2 as the soil settles. The specific frequency of regular retests is adjusted according to the construction stage: every 1-2 days during the shield tunneling or foundation pit excavation stage, and every 7-10 days after the soil stabilizes.

[0054] Finally, by regularly retesting and continuously collecting soil stress and stratified settlement data at different time periods, and comparing and analyzing the data changes in each monitoring cycle, the dynamic change law of soil stress and stratified settlement can be clearly grasped. This method is suitable for synchronous and integrated monitoring of soil internal stress and stratified settlement in scenarios such as foundation, slope, foundation pit and tunnel engineering, providing continuous and reliable monitoring support for stability evaluation, construction optimization and hazard prediction in various projects.

[0055] Furthermore, in step S3, the specific installation steps of the earth pressure gauge 5 and the base plate 4 are as follows:

[0056] Inserting the instrument: Insert the earth pressure gauge 5 through the hollow channels of all the settlement pipes to be connected from top to bottom, and finally through the hole 7 opened in the center of the base plate 4, ensuring that the back of the earth pressure gauge 5 is completely in contact with the bottom surface of the base plate 4, and that its measuring surface faces the soil to be monitored.

[0057] Fastening ring: Insert the mounting ring 6 from below the base plate 4, so that the ring body of the mounting ring 6 supports the edge and back of the earth pressure gauge 5, ensuring that each fixing foot 12 of the mounting ring 6 fits tightly with the side of the earth pressure gauge 5 and the force is evenly distributed, laying the foundation for subsequent locking and fixing.

[0058] Locking: Use expansion bolts 18 to pass through the bolt holes 13 on the mounting ring 6 fixing foot 12 and screw the expansion bolts 18 into the base plate 4 to make the mounting ring 6 and the base plate 4 tightly clamped together, thereby firmly fixing the earth pressure gauge 5 under the base plate 4, ensuring that the earth pressure gauge 5 is firmly installed and has a stable posture, avoiding displacement during the monitoring process, and ensuring the accuracy of the monitoring data.

[0059] In this embodiment, the fixing structure of the earth pressure gauge 5 is reliable, specifically as follows: the mounting ring 6 adopts a ring-shaped metal structure with 4-6 fixing feet 12 evenly distributed around its circumference, ensuring that the clamping force on the earth pressure gauge 5 is evenly distributed, which can effectively prevent the earth pressure gauge 5 from shifting or loosening, and ensure that the earth pressure gauge 5 can accurately sense changes in soil stress; at the same time, the hole 7 opened on the base plate 4 has a diameter larger than that of the earth pressure gauge 5, which not only facilitates the smooth installation of the earth pressure gauge 5, but also provides space for the laying of the observation cable, taking into account both the ease of installation and structural stability.

[0060] Furthermore, the specific operational procedures for observing the installation of cable 501 and the connection of the settling pipe in step S4 are as follows:

[0061] (1) Starting from the bottommost (already connected and fixed to the base plate 4) settlement pipe, first fix the observation cable 501 to the inner wall of the settlement pipe with epoxy resin structural adhesive 11, and then use the socket connection method to splice the bottommost settlement pipe and the second to last settlement pipe into place.

[0062] (2) After splicing, the observation cable 501 is bonded and fixed to the inner wall of the second to last settling pipe with epoxy resin structural adhesive 11;

[0063] (3) Continue to splice the second to last settling pipe with the third to last settling pipe. After splicing, fix the observation cable 501 in the corresponding settling pipe. Repeat this process until all settling pipes are spliced ​​together and all observation cables 501 in all sections are fixed in accordance with the specifications.

[0064] (4) Finally, the observation cable 501 is led to the top outlet of the first section of the settling pipe and extended to the preset observation position on the ground 8. Thus, the assembly of the entire monitoring device is completed.

[0065] The core objective of the specific operational requirements for the installation of observation cable 501 and the connection of settlement pipes is to avoid pulling or squeezing the observation cable during the settlement pipe splicing process, preventing cable damage and displacement, while ensuring the relative position stability of each settlement pipe section and the observation cable, thus guaranteeing the reliability of subsequent monitoring data transmission. To further improve the accuracy of monitoring data, after each section of the settlement pipe is connected, sealant can be used to seal the connection points to prevent groundwater from entering the interior of the stratified settlement pipes, further ensuring the reliability of subsequent monitoring data transmission.

[0066] Furthermore, the pre-installation method for the magnetic rings involves first installing the magnetic ring 3 at the lowest measuring point on a single settling pipe. The positioning ring 9 is then inserted into the pre-set position from the insertion end of the settling pipe and secured to the settling pipe with bolts. Next, the magnetic ring 3 is placed on top, allowing it to fall freely above the positioning ring 9. The outer diameter of the positioning ring 9 is larger than the inner diameter of the magnetic ring 3. The settling pipe and the magnetic ring 3 are not fixed together, allowing the magnetic ring 3 to move axially along the settling pipe. Subsequently, the remaining magnetic rings 3 are installed at the designed distances, isolated from each other by the positioning rings 9. In other words, the magnetic ring 3 is not completely fixedly connected to the settling pipe.

[0067] Specifically, the connection relationship, principle, and required pull-out length during installation between the magnetic ring 3 and the settlement pipe are as follows: After the settlement pipe, magnetic ring 3, and other structures are installed and backfilled for fixation, the absolute height of the layered settlement pipe remains constant throughout. Because its bottom contacts the bottom of the borehole, and the bottom of the borehole is typically a relatively stable bearing layer (such as bedrock or hard soil), the layered settlement pipe will not sink when the soil settles. The magnetic ring 3, however, will sink synchronously with the soil. The layered settlement pipe only provides radial fixation for the magnetic ring 3, preventing lateral and horizontal displacement. The layered settlement pipe itself does not impose any constraint on the axial movement of the magnetic ring 3. In summary, the connection relationship between the magnetic ring 3 and the layered settlement pipe is as follows: the magnetic ring 3 is fitted onto the outer wall of the layered settlement pipe 2 and can move freely along the axial direction of the layered settlement pipe 2 without obstruction, ensuring that the magnetic ring 3 accurately follows the soil settlement and guarantees the accuracy of the monitoring data.

[0068] Furthermore, the upward pulling length of the magnetic ring 3 during installation is related to the measurement point interval length. Specifically, this is explained below in conjunction with this embodiment and different measurement point interval scenarios: In this embodiment, the measurement points are arranged at 1m intervals, corresponding to a distance of 1m between two adjacent positioning rings 9. In this case, the upward pulling length of the magnetic ring 3 should be set to half the measurement point interval length, i.e., 0.5m, to ensure that the magnetic ring 3 can move freely between the upper and lower positioning rings 9, meeting the monitoring requirements. Similarly, if the measurement points are arranged at 2m intervals, the distance between two adjacent positioning rings 9 is 2m. In this case, the magnetic ring 3 should be pulled upward by 1m, i.e., half the measurement point interval length, to ensure that the magnetic ring 3 can move axially up and down without obstruction, thereby ensuring that the magnetic ring 3 can accurately follow the soil settlement and further guaranteeing the accuracy of the monitoring data. After leaving space for the magnetic ring 3 to move, the borehole is finally filled with bentonite and compacted. Once the filling is complete, the soil will envelop the magnetic ring 3. At this point, although the magnetic ring 3 can move freely, it is already tightly bonded to the soil. When the soil above settles, the magnetic ring moves downwards along with the soil, while the settlement tube remains stationary because its bottom is fixed, thus realizing the monitoring principle of "the magnetic ring moves with the soil, while the settlement tube remains stationary".

[0069] Furthermore, the magnetic ring 3 is provided with elastic anchoring claws 10, which are evenly arranged around the circumference of the magnetic ring 3. In this embodiment, the specific dimensional parameters of the elastic anchoring claws 10 are as follows: the length of the elastic anchoring claws 10 is set to 100mm, its opening angle is 30°, and the folded diameter of the elastic anchoring claws 10 is calculated to be 50mm based on the side length relationship of a triangle. This dimensional setting ensures that the elastic anchoring claws 10 can form a reliable rigid coupling with the soil, while adapting to the overall structure of the magnetic ring 3, avoiding soil disturbance or weak coupling caused by unreasonable anchoring claw dimensions, further ensuring the synchronicity of the magnetic ring 3 with soil settlement, and improving monitoring accuracy.

[0070] Furthermore, in step S7, the specific operation of the monitoring work is as follows: the electromagnetic induction probe 103 of the settlement receiver 1 is lowered into the hollow pipe of the stratified settlement pipe 2. The electromagnetic induction probe 103 senses the signal generated by the magnetic ring 3, reads the corresponding scale, and calculates the stratified settlement of the soil. At the same time, the monitoring data transmitted by the earth pressure gauge 5 is collected synchronously. By synchronously analyzing the stratified settlement and soil stress data, synchronous monitoring of soil stress and stratified settlement is achieved, ensuring that the monitoring data is comprehensive and accurate, and providing a reliable basis for the analysis of soil settlement and stress changes.

[0071] Specifically, the measurement process of the electromagnetic induction probe 103 is divided into forward measurement and return measurement to ensure the accuracy of the depth measurement of the magnetic ring 3: During the lowering process of the electromagnetic induction probe 103, when the electromagnetic induction probe 103 enters and exits the magnetic ring 3, the receiver 101 generates two induction signals respectively, and records the scale of the measuring cable 102 at the opening of the stratified settlement pipe corresponding to the two signals. This is the forward measurement. When the measuring cable 102 is retrieved, the electromagnetic induction probe 103 passes through the magnetic ring 3 again from bottom to top, and records the scale of the borehole opening corresponding to the two induction signals again. This is the return measurement. The actual depth of the magnetic ring 3 is the average of the two scale values ​​of the forward measurement and the return measurement. Based on the pre-measured borehole elevation and the calculated actual depth of the magnetic ring 3, the stratified settlement of the soil is further calculated.

[0072] In summary, to achieve synchronous correlation between soil stress and stratified settlement data and provide reliable support for engineering evaluation, this embodiment adopts the following correlation analysis method: First, the collected monitoring data is synchronously calibrated. The soil stress data collected by the earth pressure gauge 5 and the stratified settlement data measured by the electromagnetic induction probe 103 are matched according to the same monitoring time node to ensure that each set of stress data and settlement data corresponds to the same monitoring time and the same monitoring point, eliminating correlation deviations caused by time differences. Second, a synchronous monitoring data curve is established with the monitoring time as the horizontal axis and the soil stress value and stratified settlement amount as the vertical axes, respectively, to intuitively present the changes in soil stress and stratified settlement within the same time period. First, the trends are identified to clarify the changing patterns and corresponding relationships between the two factors. Second, the soil properties at the monitoring points (such as soil layer type and density) are analyzed to determine the intrinsic correlation between soil stress changes and stratified settlement. For example, it is determined whether an increase in soil stress is accompanied by an increase in settlement, and whether settlement tends to stabilize when stress is stable, thereby quantifying the correlation coefficient between the two. Finally, the synchronously correlated monitoring data is combined with engineering design parameters and construction conditions to evaluate soil stability, determine the impact of construction on soil disturbance, and predict subsequent settlement and stress change trends. This provides comprehensive and reliable data analysis support for engineering construction optimization, hidden danger investigation, and safety evaluation, ensuring engineering construction safety and project quality.

[0073] This invention enables the simultaneous acquisition of stress and settlement data, allowing for direct coupled analysis. It transforms isolated stress and settlement data into correlated information with engineering guidance significance, accurately identifying abnormal signals under hazardous conditions (such as settlement anomalies caused by stress mutations). This provides precise data support for optimizing geotechnical engineering construction, predicting post-construction settlement, and providing early warnings of safety hazards. Compared to existing technologies that can only output single stress data, the data processing of this invention has greater engineering value, effectively improving the safety of geotechnical engineering construction and operation, reducing engineering safety hazards, and generating significant technical and social benefits.

[0074] In this embodiment, the cable layout is standardized and has strong anti-interference capabilities. Specifically, the observation cable 501 of the earth pressure gauge 5 is laid along the inner wall of the layered settlement pipe and fixed by epoxy resin structural adhesive 11. This layout and fixing method effectively avoids the problem of cable wear and loosening during long-term use and reduces the interference of the external environment on the cable signal transmission. The measurement cable 102 of the settlement receiver is equipped with a measurement scale with an accuracy of not less than 1mm, which can accurately read the displacement data of the electromagnetic induction probe 103, further improving the accuracy of the monitoring data and ensuring the reliability of the monitoring results.

[0075] The following section describes the synchronous monitoring of soil stress and stratified settlement, based on the preset parameters of each core component of this device:

[0076] (a) The key parameters of the device components are as follows:

[0077] 1. Layered settling pipe:

[0078] Table 1:

[0079]

[0080] 2. Magnetic ring:

[0081] Table 2:

[0082]

[0083] 3. Earth pressure gauge (VWE type):

[0084] Table 3:

[0085]

[0086] 4. Base plate and mounting ring:

[0087] The base plate has the following dimensions: outer diameter 120mm, inner diameter 80mm, thickness 15mm, and material: PVC.

[0088] Table 4:

[0089]

[0090] 5. Settlement receiver:

[0091] Table 5:

[0092]

[0093] (II) Regarding monitoring data

[0094] 1. Soil stress monitoring

[0095] Table 6:

[0096]

[0097] 2. Cumulative settlement of soil layers at various depths

[0098] Table 7:

[0099]

[0100] 3. To achieve precise control of monitoring risks, based on the monitoring data in this embodiment and the actual needs of the project, a standard for determining the risk level of soil settlement is formulated, as shown in the table below:

[0101] Table 8: Settlement Rate Early Warning Standards

[0102]

[0103] Layered settlement data analysis: As shown in Table 6, the elevation of the borehole opening remained constant at 100m during the monitoring period, which confirms the core design of the present invention that "the absolute height remains unchanged after the layered settlement pipe is fixed"—the bottom of the settlement pipe is in contact with the stable bearing layer at the bottom of the borehole and does not shift with the soil settlement. The depth of each magnetic ring gradually increases over the monitoring period, and the settlement of magnetic rings at different depths varies. The settlement of magnetic rings at depths of 1.0m and 2.0m is the most significant (33mm and 54mm respectively after 90 days of monitoring), while the settlement of magnetic rings at depths of 3.0m and 4.0m is smaller, and the settlement of magnetic rings at depth of 5.0m is not obvious. This phenomenon is completely consistent with the working principle of the magnetic rings of this invention: the magnetic rings form a rigid coupling with the soil through elastic anchoring claws and settle synchronously with the soil. The settlement of shallow soil is greater than that of deep soil, which is consistent with the actual soil settlement law in geotechnical engineering. At the same time, the magnetic rings can move freely along the axial direction of the settlement tube, ensuring the authenticity of the settlement data. Combined with the spacing of the magnetic rings (1m interval in this embodiment), the settlement of each layer of soil can be accurately calculated, demonstrating the accuracy of the layered settlement monitoring of this device.

[0104] Soil stress data analysis: As shown in Table 7, the soil pressure was 120.0 kPa in the initial working condition (before the shield arrived). As the shield gradually approached the monitoring point (5 days, 10 days), the soil pressure gradually increased to 121.5 kPa, mainly due to the soil disturbance caused by the shield's advancement, which led to an increase in soil stress at the monitoring point. When the shield passed through the monitoring point (15 days) and after passing through (20 days, 30 days), the soil pressure gradually decreased to 117.5 kPa, until it stabilized at 117.3 kPa during the settlement stabilization period (90 days). This trend perfectly matches the disturbance law of soil stress caused by shield construction, confirming the monitoring reliability of the soil pressure gauge of this device. The soil pressure gauge is firmly fixed to the base plate through the mounting ring, and the measuring surface is in close contact with the soil, which can accurately sense the dynamic changes of soil stress. Moreover, the mounting ring adopts a ring-shaped metal structure with 4-6 fixed feet evenly distributed around the circumference to ensure that the soil pressure gauge does not deviate or loosen, further ensuring the accuracy of stress data.

[0105] Settlement distribution pattern: The settlement amount shows a significant decreasing trend with increasing soil depth. The settlement amount is large in shallow layers (1m, 2m) and very small or even non-existent in deep layers (4m, 5m), which perfectly matches the core design of this device, "magnetic ring follows soil settlement". The magnetic ring is tightly connected to the soil through elastic anchoring claws, which can accurately capture the settlement differences of soil at different depths. This fully demonstrates the core advantage of this device's layered monitoring and solves the problem that traditional monitoring cannot accurately distinguish the settlement of soil at different depths. This is consistent with the design logic of "magnetic ring settles synchronously with the soil, and settlement tube remains fixed" mentioned earlier.

[0106] Impact of tunnel boring machine (TBM) construction disturbance: The data clearly shows that the disturbance to the soil during TBM construction is mainly concentrated in the 1-3m depth range, with the 2m depth (the concentrated area of ​​shear deformation above the TBM) being the most affected, while the 5m depth is basically unaffected. This pattern is highly consistent with the actual disturbance range of TBM construction, further verifying the accuracy and reliability of the monitoring data of this device. It also shows that this device can accurately capture the soil changes caused by construction disturbance, providing accurate data support for construction optimization.

[0107] Data correlation verification: Combined with soil pressure monitoring data, it can be seen that the changes in soil stress and the changes in stratified settlement are synchronously correlated—when the shield tunneling machine approaches, the soil stress increases and the shallow settlement gradually increases; after the shield tunneling machine moves away, the soil stress tends to stabilize, the settlement rate slows down and tends to be stable. This fully reflects the design intention of the present invention, "synchronous monitoring of stress and settlement", and realizes the accurate correlation between soil stress and stratified settlement. It provides a comprehensive and reliable data basis for engineering construction optimization and hidden danger investigation, and also confirms the scientificity and practicality of this monitoring method.

[0108] As shown in Table 8, the settlement rate early warning standard used to judge soil settlement risk based on daily settlement rate and cumulative settlement amount, and to guide the safety management of engineering construction, is as follows: Based on the shield tunneling monitoring data in this embodiment, and analyzed against the above risk level judgment standard: In this embodiment, the daily settlement rate of soil at each depth is less than 1.0 mm / d, and the maximum cumulative settlement amount is 54 mm (2m depth, 90-day monitoring period), all within the green (normal) risk level range. This indicates that soil settlement development during shield tunneling is slow, consistent with project expectations, confirming that this monitoring device can accurately capture settlement changes. Furthermore, this risk level standard enables real-time judgment and control of settlement risk. If the daily settlement rate or cumulative settlement amount reaches the yellow (warning) level or above during monitoring, the cause of settlement anomalies can be quickly analyzed based on the soil stress and stratified settlement data simultaneously monitored by this device. Corresponding measures such as increased monitoring and construction adjustments can be taken in a timely manner to further ensure engineering construction safety, fully demonstrating the practicality and safety of the monitoring method of this invention.

[0109] Example 2

[0110] This embodiment provides an installation method for a soil stress and stratified settlement synchronous monitoring device. The similarities with Embodiment 1 will not be repeated here. The difference is that this embodiment provides a connection method for installing the settlement pipe after stratification and a magnetic ring embedding process.

[0111] Settlement tube installation and connection: After drilling is completed, the settlement tubes are placed into the borehole section by section. When connecting the settlement tubes, internal joints or threaded connections are used to ensure that the settlement tubes are tightly and securely connected. At the same time, the outer shell of the settlement tubes is kept smooth and free of protrusions, burrs or other obstacles to avoid affecting the free up and down movement of the magnetic ring 3 along the axial direction of the settlement tube. This provides smooth movement space for the magnetic ring 3 to follow the soil settlement and ensures the accuracy of stratified settlement monitoring.

[0112] Magnetic ring installation: Magnetic ring 3 is installed in layers, and the specific operation is as follows: Bentonite balls are filled and compacted between the settlement pipe and the borehole wall, with the filling height reaching the preset elevation of the first magnetic ring at the bottom. This ensures that the bentonite balls are filled densely, achieving initial fixation between the settlement pipe and the borehole wall, and providing a stable installation foundation for magnetic ring 3. Then, the first magnetic ring 3 is placed on the outside of the settlement pipe and slowly pushed onto the surface of the filled bentonite balls. A certain pressure is applied to the magnetic ring 3, causing the three iron claws on the magnetic ring 3 (replacing the elastic anchoring claws in embodiment 1) to insert into the surrounding soil, ensuring that the magnetic ring 3 forms a reliable coupling with the soil and can settle synchronously with the soil. After the installation of the first magnetic ring 3 is completed, bentonite balls are continued to be filled and compacted between the settlement pipe and the borehole wall until the filling height reaches the preset elevation of the second magnetic ring. The second magnetic ring 3 is installed in the same way as above, and so on, until the installation of all magnetic rings 3 in the entire borehole is completed.

[0113] In this embodiment, the settlement pipe uses an internal joint or threaded connection to ensure a smooth outer shell. The magnetic ring adopts the "layered filling of bentonite balls + iron claw anchoring" method for installation, which can also achieve reliable coupling and free movement between the magnetic ring and the soil, ensuring monitoring accuracy. Moreover, the process is simpler and adaptable to the installation requirements of different engineering scenarios, further demonstrating the practicality and adaptability of the present invention.

[0114] In summary, the monitoring device and method provided in this embodiment have the following significant beneficial effects:

[0115] First, the error control is simple and efficient, and the monitoring accuracy is high. The device effectively fills the gap between the borehole and the monitoring device through a layered backfilling process of fine sand and bentonite, ensuring that the magnetic ring, earth pressure gauge and soil are in close contact, avoiding monitoring deviations caused by poor contact. This error control method does not require complicated debugging procedures. Compared with the error correction methods of existing technologies, it is more convenient to operate and the error control effect is more stable, which can effectively ensure the accuracy of monitoring data.

[0116] Secondly, it is convenient to operate and easy to master. The monitoring method provided by this invention has clear steps and logical structure. From determining the monitoring point and drilling, to installing the magnetic ring, splicing the settlement tube, fixing the earth pressure gauge, lowering the device, backfilling in layers, and collecting data, each step conforms to the on-site construction specifications for geotechnical engineering. No special construction equipment or professional technicians are required, and those skilled in the relevant technical field can quickly master the operation. The magnetic ring installation adopts a "fixed positioning ring + free-sleeving magnetic ring" method, which is convenient to install and allows for flexible adjustment of the spacing. After the monitoring device is lowered, settlement monitoring can be achieved simply by inserting the electromagnetic induction probe into the hollow channel of the settlement tube, while simultaneously collecting earth pressure gauge data. The operation is efficient, and the periodic retesting process is simple, allowing for long-term tracking of soil stress and layered settlement changes.

[0117] Furthermore, the invention features a simple structure, low maintenance costs, and a long service life. It eliminates the complex mechanical transmission and error correction components found in existing technologies, resulting in a simple overall structure with fewer parts, convenient installation and disassembly, and low maintenance costs. All components are made of corrosion-resistant and anti-aging materials, and the observation cable is fixed with epoxy resin structural adhesive, effectively resisting adverse factors such as moisture and corrosion in the soil environment, thus extending the device's service life. Simultaneously, after deployment, the device requires no complex daily maintenance, only periodic retesting, significantly reducing the manpower and material costs of monitoring and maintenance, making it suitable for long-term continuous monitoring.

[0118] Finally, it boasts strong adaptability, high practicality, and can be applied in batches. The device can be vertically inserted into boreholes for deployment, adapting to the monitoring needs of various geotechnical engineering projects such as foundations, slopes, pits, and tunnels. Whether monitoring shallow or deep soil layers, the settlement tube section number can be adjusted, making it highly adaptable. Furthermore, the core components of the device are all existing mature parts, requiring no special processing technology, allowing for mass production, cost control, and high repeatability. It meets the practicality requirements of patent law and can be widely applied to various geotechnical engineering scenarios involving simultaneous monitoring of soil stress and stratified settlement.

[0119] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should be protected by the present invention.

Claims

1. An integrated monitoring device for soil stress and stratified settlement, characterized in that, The system includes a settlement receiver, a stratified settlement tube, magnetic rings, a base plate, an earth pressure gauge, and an mounting ring. The stratified settlement tube is a hollow tubular structure, and the base plate is fixedly connected to the bottom of the stratified settlement tube. The earth pressure gauge is fixedly connected to the base plate via the mounting ring. Magnetic rings are spaced apart on the outer wall of the stratified settlement tube. The settlement receiver includes a receiver, a measuring cable, and an electromagnetic induction probe. One end of the measuring cable is electrically connected to the receiver, and the other end is connected to the electromagnetic induction probe. The electromagnetic induction probe can extend into the hollow channel of the stratified settlement tube, and generates an induction signal when it corresponds to the magnetic rings to monitor the stratified settlement. The earth pressure gauge is connected to an observation cable. The base plate has a hole with a diameter larger than that of the earth pressure gauge. The observation cable passes through the hole and is laid along the inner wall of the stratified settlement tube, extending to the ground surface to monitor soil stress.

2. The integrated monitoring device for soil stress and stratified settlement according to claim 1, characterized in that: The layered settling pipe is formed by connecting multiple sections of settling pipe through a socket connection. In the socket connection, one end of two adjacent settling pipe sections is a socket and the other end of the settling pipe section is a spigot. The outer diameter of the spigot is adapted to the inner diameter of the socket. The spigot is inserted into the socket to splice the two sections of settling pipe.

3. The integrated monitoring device for soil stress and stratified settlement according to claim 2, characterized in that: Positioning rings are provided on the outer wall of the multi-section settlement pipe. The positioning rings are inserted into the insertion end of the settlement pipe and fixed to the settlement pipe by bolts. A magnetic ring is fitted between two adjacent positioning rings. The magnetic ring can move freely along the axial direction of the settlement pipe. The outer diameter of the positioning ring is larger than the inner diameter of the magnetic ring to limit the magnetic ring. The magnetic ring is provided with elastic anchoring claws for achieving rigid coupling between the magnetic ring and the soil. The elastic anchoring claws are arranged along the circumference of the magnetic ring.

4. The integrated monitoring device for soil stress and stratified settlement according to claim 1, characterized in that: The spacing between the magnetic rings on a single section of the layered settling pipe ranges from 0.5m to 2m, and the shortest spacing between adjacent magnetic rings is limited to 1m; the observation cable is bonded and fixed to the inner wall of the layered settling pipe with epoxy resin structural adhesive; the measuring cable is provided with a measuring scale, and the accuracy of the measuring scale is not less than 1mm.

5. The integrated monitoring device for soil stress and stratified settlement according to claim 1, characterized in that: The mounting ring is a ring-shaped metal structure with 3-6 fixed feet arranged around its circumference. Each fixed foot has a bolt hole. The earth pressure gauge is placed between the mounting ring and the base plate. After the back of the earth pressure gauge is attached to the bottom surface of the base plate, the mounting ring and the earth pressure gauge are assembled. Expansion bolts pass through the bolt holes to fix the mounting ring and the base plate.

6. The integrated monitoring device for soil stress and stratified settlement according to claim 1, characterized in that: The receiver can record two scale values ​​when the electromagnetic induction probe enters and exits the magnetic ring, and automatically calculate the average value of the two scale values.

7. A monitoring method based on the integrated soil stress and stratified settlement monitoring device according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Determine the monitoring points according to the monitoring requirements, and drill holes at the monitoring points to the preset depth; S2. Magnetic ring installation and base plate fixing: The magnetic ring is installed at the preset point of each settling pipe section by means of the positioning ring, and the last settling pipe section is fixedly connected to the base plate. S3. Install the earth pressure gauge: Pass the earth pressure gauge through the holes in each section of the settlement pipe and the base plate, so that the back of the earth pressure gauge is in contact with the bottom surface of the base plate, and the mounting ring is attached to one side of the measuring surface of the earth pressure gauge. Lock and fix the earth pressure gauge under the base plate by the mounting ring. S4. Laying out observation cables and connecting and fixing subsidence pipes: Lay the observation cables upward along the inner wall of each subsidence pipe section. Complete the subsidence pipe splicing and observation cable fixing operations step by step from bottom to top until the cable reaches the top outlet of the first subsidence pipe section and extends to the ground. S5. Lower monitoring device: The assembled monitoring device is vertically lowered into the borehole to ensure that the earth pressure gauge is in close contact with the soil at the bottom of the borehole and remains vertical. S6. Backfilling: Backfill the gap between the borehole and the monitoring device with fine sand and bentonite in layers from bottom to top, set the borehole nozzle benchmark and measure the elevation to ensure that the magnetic ring is sent to the design elevation. S7. Monitoring: After the borehole shrinkage stabilizes, the electromagnetic induction probe of the settlement receiver is lowered into the hollow pipe of the stratified settlement pipe. The scale is read by the induction signal and the stratified settlement is calculated. At the same time, the monitoring data of the earth pressure gauge is collected to realize the synchronous monitoring of soil stress and stratified settlement. S8. Regularly retest and track the changes in soil stress and stratified settlement.

8. The integrated monitoring method for soil stress and stratified settlement according to claim 7, characterized in that: The pre-installation method for the magnetic rings involves first installing the magnetic ring at the lowest measuring point on a single settling pipe. A positioning ring is then inserted into a pre-set position from one end of the settling pipe's inlet. The positioning ring is then fixed to the settling pipe with bolts. Next, the magnetic ring is placed on top, allowing it to fall freely above the positioning ring. The outer diameter of the positioning ring is larger than the inner diameter of the magnetic ring. The settling pipe and the magnetic ring are not fixed together, allowing the magnetic ring to move axially along the settling pipe. Subsequently, the remaining magnetic rings are installed at the designed distances, with the magnetic rings isolated from each other by positioning rings.

9. The integrated monitoring method for soil stress and stratified settlement according to claim 7, characterized in that: In step S6, after the bentonite layer is backfilled, the entire monitoring device is pulled upwards so that the magnetic ring can move freely up and down within the range of 0.5-2m.

10. The integrated monitoring method for soil stress and stratified settlement according to claim 7, characterized in that: The earth pressure gauge is located between the mounting ring and the base plate. After the back of the earth pressure gauge is attached to the bottom surface of the base plate, the mounting ring and the earth pressure gauge are assembled. The expansion bolts pass through the bolt holes of the mounting ring fixing feet to fix the mounting ring and the base plate. The earth pressure gauge is fixed by the clamping action of the mounting ring and the base plate.

Images