Virtual center point-based foundation pit horizontal displacement automatic monitoring method and system

Abstract

The application discloses a kind of based on virtual center point's foundation pit horizontal displacement automation monitoring method and system, which includes: based on the position of current foundation pit respectively confirms the arrangement point position of field monitoring, constructs the geometric characteristics of foundation pit, calculates the plane distance of each monitoring point to its corresponding foundation pit virtual center point, and the plane distance obtained by calculation is reduced to the corresponding vertical foundation pit boundary line direction;According to the type of foundation pit boundary line to which the monitoring point belongs, the corresponding horizontal displacement value of horizontal displacement monitoring point is calculated.The application greatly simplifies the calculation process of monitoring point horizontal displacement value and the determination condition of monitoring point deformation direction by setting up appropriate virtual center point, and gives the horizontal displacement calculation formula of arc boundary line foundation pit without increasing the algorithm complexity, which better solves the calculation problem of horizontal displacement value on arc boundary line.

Description

Technical Field

[0001] This invention relates to the field of foundation pit exploration technology, and in particular to an automated monitoring method and system for horizontal displacement of foundation pits based on a virtual center point. Background Technology

[0002] In traditional foundation pit monitoring, the horizontal displacement of the top of the support structure is typically monitored manually by repeatedly moving monitoring stations and using methods such as the small angle method and line of sight to monitor each edge of the foundation pit one by one. However, by using high-precision total station automated monitoring technology, it is possible to achieve automated monitoring of the foundation pit by establishing a plane control network and setting up forced centering observation piers, which greatly reduces labor costs and improves observation accuracy and real-time performance. However, in the automated monitoring of foundation pits using total stations, because the monitoring stations are fixed, it is difficult to ensure that the zero direction of the observation is orthogonal to each edge of the foundation pit (especially for irregularly shaped foundation pits). Therefore, it is particularly important to accurately convert the coordinates of the monitoring points measured by the total station into horizontal displacement values.

[0003] Patent Document 1: Chinese Invention Patent Document Authorization Announcement No. CN103526783A.

[0004] Although the aforementioned patent document 1 constructs a virtual baseline parallel to the excavation line of the foundation pit and calculates the horizontal displacement value of the monitoring point by solving the distance from the monitoring point to the virtual baseline, the calculation process for determining the deformation direction of the monitoring point is complex and has low computational efficiency. Therefore, how to quickly determine the deformation direction of the monitoring point is one of the objectives of this invention.

[0005] Secondly, the calculation method described in Patent Document 1 cannot solve for the horizontal displacement value of the monitoring point on the edge of the circular arc segment of the foundation pit. When the edge of the foundation pit is circular, the corresponding virtual baseline is also circular, and the slope of the tangent on the arc segment is unequal everywhere. At this time, it is impossible to calculate the distance between the monitoring point and the virtual baseline. Therefore, how to quickly and accurately solve for the horizontal displacement value of the monitoring point on the circular arc segment is the second objective of this invention. Summary of the Invention

[0006] In order to overcome the shortcomings of existing products, this invention proposes an automated monitoring method and system for horizontal displacement of foundation pits based on virtual center points.

[0007] This invention provides an automated monitoring method for horizontal displacement of foundation pits based on a virtual center point, comprising the following steps:

[0008] Step A: Based on the current location of the foundation pit, confirm the layout of the on-site monitoring points, including the backsight reference point, fixed frame stations, the virtual center point of the foundation pit, the horizontal displacement monitoring point at the top of the foundation pit support structure, and the outline points of the foundation pit edge. The backsight reference point is located in a stable area outside the influence range of the foundation pit construction, serving as the reference for the foundation pit's planar control network. The fixed frame stations are total stations erected on corresponding forced-centering observation piers within the foundation pit site. The virtual center point of the foundation pit is one or more center points randomly selected within the central area of ​​the foundation pit based on its shape. The outline points of the foundation pit edge are the inflection points along the outline of the foundation pit support structure, used to determine the geometry of the foundation pit. Based on the coordinates of the backsight reference point, establish the planar coordinate system of the foundation pit, and calculate the coordinates (x, y, y) of the fixed frame stations through back intersection. P ,y P );

[0009] Step B: Construct the geometric features of the foundation pit. Use a total station to observe the virtual center point, the outline points of the foundation pit, and the horizontal displacement monitoring points. Measure the azimuth angle α of each point relative to the fixed frame station in the horizontal direction, the zenith distance V in the plumb plane, and the slope distance S. The corresponding formula for calculating the coordinates of the points is:

[0010]

[0011] After measuring the coordinates of each point, the horizontal displacement monitoring points are classified according to the layout of the monitoring points and the shape of the foundation pit; Step C: Calculate the plane distance D from each monitoring point to its corresponding virtual center point of the foundation pit. i ;

[0012]

[0013] Wherein (x) i ,y i (x) represents the plane coordinates of the horizontal displacement monitoring point. O ,y O ) represents the planar coordinates of the virtual center point of the corresponding foundation pit;

[0014] Step D: Based on the classification results of Step B, calculate the planar distance D obtained in Step C. i Redirected to the corresponding vertical edge of the foundation pit;

[0015] Step E: Calculate the corresponding horizontal displacement value of the monitoring point according to the type of foundation pit edge to which the monitoring point belongs, and confirm whether the current horizontal displacement monitoring point is moving into or out of the pit.

[0016] In some embodiments of the present invention, step E specifically includes:

[0017] When the foundation pit edge line type to which the horizontal displacement monitoring point belongs is a straight line, the distance between the two endpoints of the foundation pit edge line and their corresponding virtual center point of the foundation pit is calculated according to the coordinates of the two endpoints of the foundation pit edge line. Based on the distance data, the angle formed by the lines connecting the two endpoints of the foundation pit edge line and their corresponding virtual center point of the foundation pit is obtained, and the final distance between the horizontal displacement monitoring point and the corresponding virtual center point of the foundation pit is obtained.

[0018] In some embodiments of the present invention, step E specifically further includes:

[0019] When the foundation pit edge line type to which the horizontal displacement monitoring point belongs is arc-shaped, the distance between the horizontal displacement monitoring point and the virtual center point of the foundation pit on the edge line perpendicular to the foundation pit is the horizontal distance between the two points.

[0020] The present invention also provides an automated monitoring system for horizontal displacement of foundation pits based on a virtual center point, applied to any of the above-described automated monitoring methods for horizontal displacement of foundation pits based on a virtual center point, comprising:

[0021] Point Definition Module: Used to confirm the layout of monitoring points based on the current location of the foundation pit, including backsight reference points, fixed frame stations, virtual center point of the foundation pit, horizontal displacement monitoring points at the top of the foundation pit support structure, and foundation pit edge contour points. The backsight reference points are located in stable areas outside the influence range of the foundation pit construction, serving as the reference for the foundation pit's planar control network. Fixed frame stations are total stations mounted on forced-centering observation piers corresponding to the foundation pit site. The virtual center point of the foundation pit is one or more center points randomly selected within the central area of ​​the foundation pit based on its shape. The foundation pit edge contour points are the inflection points along the edge contour of the foundation pit support structure, used to determine the geometry of the foundation pit. Based on the coordinates of the backsight reference points, a planar coordinate system for the foundation pit is established, and the coordinates (x, y, z) of the fixed frame stations are calculated through back intersection. P ,y P );

[0022] Point observation module: Used to construct the geometric features of the foundation pit. Using a total station, it observes the virtual center point, edge contour points, and horizontal displacement monitoring points of the foundation pit, respectively, measuring the azimuth angle α of each point relative to the fixed frame station in the horizontal direction, the zenith distance V within the plumb plane, and the slope distance S. The corresponding formula for calculating the point coordinates is:

[0023]

[0024] After measuring the coordinates of each point, the horizontal displacement monitoring points are classified according to the layout of the measuring points and the shape of the foundation pit;

[0025] Planar distance calculation module: Used to calculate the planar distance D from each monitoring point to its corresponding virtual center point of the foundation pit. i ;

[0026]

[0027] Wherein (x) i ,y i (x) represents the plane coordinates of the horizontal displacement monitoring point. O ,y O ) represents the planar coordinates of the virtual center point of the corresponding foundation pit;

[0028] Horizontal displacement calculation module: Used to calculate the horizontal distance D obtained by the horizontal distance calculation module based on the classification results of the point observation module. i The value is calculated based on the corresponding vertical edge of the foundation pit and the horizontal displacement value is calculated according to the type of foundation pit edge to which the monitoring point belongs, to confirm whether the current horizontal displacement monitoring point is moving into or out of the pit.

[0029] In some embodiments of the present invention, the horizontal displacement calculation module is specifically used for:

[0030] When the foundation pit edge line type to which the horizontal displacement monitoring point belongs is a straight line, the distance between the two endpoints of the foundation pit edge line and their corresponding virtual center point of the foundation pit is calculated according to the coordinates of the two endpoints of the foundation pit edge line. Based on the distance data, the angle formed by the lines connecting the two endpoints of the foundation pit edge line and their corresponding virtual center point of the foundation pit is obtained, and the final distance between the horizontal displacement monitoring point and the corresponding virtual center point of the foundation pit is obtained.

[0031] In some embodiments of the present invention, the horizontal displacement calculation module is further configured to:

[0032] When the foundation pit edge line type to which the horizontal displacement monitoring point belongs is arc-shaped, the distance between the horizontal displacement monitoring point and the virtual center point of the foundation pit on the edge line perpendicular to the foundation pit is the horizontal distance between the two points.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] 1. By using a fixed virtual center point inside the foundation pit to calculate the distance from the measuring point to the center point, the distance calculation is always calculated from the inside of the foundation pit to the outside of the foundation pit. Therefore, a larger distance value means that the deformation direction of the measuring point is towards the outside of the pit, and a smaller distance value means that the deformation direction of the measuring point is towards the inside of the pit, which greatly simplifies the process of judging the deformation direction of the monitoring point.

[0035] 2. Different calculation methods can be flexibly selected according to the type of the foundation pit's edge. In particular, when the foundation pit's edge is arc-shaped, by setting the center point of the arc segment, the change in distance from the monitoring point to the center point is the change in horizontal displacement of the monitoring point relative to the arc edge. There is no need to reduce it to the vertical direction of the foundation pit's edge, which avoids a complicated calculation process and can accurately represent the displacement of the monitoring point in the direction perpendicular to the arc segment. Compared with existing calculation and monitoring methods, it can be applied to different application scenarios and has good applicability. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments 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 drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart illustrating the automated monitoring method for horizontal displacement of foundation pits based on virtual center points as described in this invention.

[0038] Figure 2 This is a reference schematic diagram illustrating the calculation of horizontal displacement of the foundation pit in an embodiment of the present invention. Detailed Implementation

[0039] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The accompanying drawings show preferred embodiments of the present invention. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0040] Combination Figure 1-2 As shown in the figure, the automated monitoring method for horizontal displacement of foundation pit based on virtual center point according to the embodiment of the present invention includes the following steps:

[0041] Step A: Based on the current location of the foundation pit, confirm the layout of the on-site monitoring points, including backsight reference point 1, fixed frame station 2, virtual center point of the foundation pit 3, horizontal displacement monitoring point 4 at the top of the foundation pit support structure, and foundation pit edge contour point 5. Backsight reference point 1 is located in a stable area outside the influence range of the foundation pit construction and serves as the reference for the foundation pit's planar control network. Fixed frame station 2 is a total station mounted on a forced centering observation pier corresponding to the foundation pit site. Virtual center point 3 is one or more center points randomly selected within the central area of ​​the foundation pit based on its shape. Foundation pit edge contour point 5 consists of various inflection points along the edge contour of the foundation pit support structure, used to determine the geometry of the foundation pit. Based on the coordinates of backsight reference point 1, establish the planar coordinate system of the foundation pit, and calculate the coordinates (x, y, y) of fixed frame station 2 through back intersection. P ,y P );

[0042] Step B: Construct the geometric features of the foundation pit. Using a total station, observe the virtual center point 3, the outline point 5 of the foundation pit, and the horizontal displacement monitoring point 4. Measure the azimuth α of each point relative to the fixed frame station 2 in the horizontal direction, the zenith distance V within the plumb plane, and the slope distance S. The corresponding formula for calculating the coordinates of the points is:

[0043]

[0044] After obtaining the coordinates of each point, the horizontal displacement monitoring points were classified according to the layout of the monitoring points and the shape of the foundation pit; the classification of the points is shown in Table 1 below:

[0045] Table 1

[0046]

[0047] Step C: Calculate the planar distance D from each monitoring point to its corresponding virtual center point 3 of the foundation pit. i ;

[0048]

[0049] Wherein (x) i ,y i (x) represents the plane coordinates of the horizontal displacement monitoring point 4. O ,y O ) represents the planar coordinates of the virtual center point 3 of the corresponding foundation pit;

[0050] Step D: Based on the classification results of Step B, calculate the planar distance D obtained in Step C. i Redirected to the corresponding vertical edge of the foundation pit;

[0051] Step E: Calculate the corresponding horizontal displacement value of the horizontal displacement monitoring point 4 according to the type of foundation pit edge to which the monitoring point belongs, and confirm whether the current horizontal displacement monitoring point 4 is moving into or out of the pit.

[0052] Specifically, when the pit edge type to which the horizontal displacement monitoring point 4 belongs is a straight line, the distance between the two endpoints of the pit edge and the corresponding virtual center point 3 of the pit is calculated according to the coordinates of the two endpoints of the pit edge. Based on this distance data, the angle formed by the lines connecting the two endpoints of the pit edge and the corresponding virtual center point 3 of the pit is obtained, and the final distance between the horizontal displacement monitoring point 4 and the corresponding virtual center point 3 of the pit is obtained.

[0053] by Figure 2 For example, the current horizontal displacement monitoring point W10(x) 10 ,y 10 The edge of the foundation pit is formed by LK5 and LK6. The equation of the straight line of the foundation pit edge can be obtained from the plane coordinates of the two endpoints:

[0054]

[0055] The distance D between point W10 and its corresponding virtual center point O2 10 The equation of the straight line formed by it can be expressed as:

[0056]

[0057]

[0058] The angle between the two lines can be obtained. in:

[0059]

[0060]

[0061] Then point W10 and the virtual center point O2 are perpendicular to the edge line of the foundation pit l. LK5-6 Distance d in the direction 10 It can be represented as:

[0062] d 10 =D 10 ·sinα 10 .

[0063] When the foundation pit edge type to which the horizontal displacement monitoring point 4 belongs is an arc, the distance between the horizontal displacement monitoring point 4 and the virtual center point 3 of the foundation pit, perpendicular to the foundation pit edge, is the horizontal distance between the two points, which can be expressed as:

[0064]

[0065] The change in horizontal displacement at the monitoring point of the foundation pit is the difference between two adjacent horizontal displacement values, i.e., Δd = (d) n -(d) n-1 , of which (d) n This represents the horizontal displacement value measured in the nth observation.

[0066] In this embodiment of the invention, the distance value calculated in step D essentially represents the distance between the horizontal displacement monitoring point and the foundation pit. When the distance value of a certain monitoring point decreases, it indicates that the point is deformed towards the inside of the pit, and vice versa. Since the horizontal displacement point of the foundation pit mainly undergoes deformation perpendicular to the edge of the foundation pit under the action of the earth pressure outside the pit during the excavation, that is, the angle change in the angle between the two straight lines is very small and can be considered constant, therefore, taking point W10 as an example, the determination of d... 10 The size is equivalent to determining D 10 The size of the distance, i.e., the planar distance from the monitoring point to the virtual center point, can quickly determine whether the monitoring point is moving into or out of the pit.

[0067] The calculation method shown in this embodiment, based on fully considering the geometric characteristics of the foundation pit, greatly simplifies the calculation process of the horizontal displacement value of the monitoring point and the determination condition of the deformation direction of the monitoring point by setting a suitable virtual center point. At the same time, without increasing the algorithm complexity, it provides a formula for calculating the horizontal displacement of the foundation pit with arc edge, which effectively solves the problem of calculating the horizontal displacement value on the arc edge.

[0068] This invention also provides an automated monitoring system for horizontal displacement of foundation pits based on a virtual center point, applied to the automated monitoring method for horizontal displacement of foundation pits based on a virtual center point described in any of the above embodiments, comprising:

[0069] Point Definition Module: Used to confirm the layout of on-site monitoring points based on the current location of the foundation pit, including backsight reference point 1, fixed frame station 2, virtual center point of the foundation pit 3, horizontal displacement monitoring point 4 at the top of the foundation pit support structure, and foundation pit edge contour point 5. Backsight reference point 1 is located in a stable area outside the influence range of the foundation pit construction, serving as the reference for the foundation pit's planar control network; fixed frame station 2 is a total station mounted on a forced centering observation pier corresponding to the foundation pit site; virtual center point 3 is one or more center points randomly selected within the central area of ​​the foundation pit based on its shape; foundation pit edge contour point 5 consists of various inflection points along the edge contour of the foundation pit support structure, used to determine the geometry of the foundation pit; based on the coordinates of backsight reference point 1, a planar coordinate system for the foundation pit is established, and the coordinates (x, y, y) of fixed frame station 2 are calculated through back intersection. P ,y P );

[0070] Point observation module: Used to construct the geometric features of the foundation pit. Using a total station, observations are made on the virtual center point 3, the outline point 5 of the foundation pit edge, and the horizontal displacement monitoring point 4. The azimuth angle α in the horizontal direction, the zenith distance V in the plumb plane, and the slope distance S of each point relative to the fixed frame station 2 are measured. The corresponding formula for calculating the point coordinates is:

[0071]

[0072] After measuring the coordinates of each point, the horizontal displacement monitoring points are classified according to the layout of the measuring points and the shape of the foundation pit;

[0073] Planar distance calculation module: used to calculate the planar distance D from each monitoring point to its corresponding virtual center point 3 of the foundation pit. i ;

[0074]

[0075] Wherein (x) i ,y i (x) represents the plane coordinates of the horizontal displacement monitoring point 4. O ,y O ) represents the planar coordinates of the virtual center point 3 of the corresponding foundation pit;

[0076] Horizontal displacement calculation module: Used to calculate the horizontal distance D obtained by the horizontal distance calculation module based on the classification results of the point observation module. i The displacement is calculated in the direction of the corresponding vertical foundation pit edge; and the horizontal displacement value of the monitoring point 4 is calculated according to the foundation pit edge type to which the monitoring point belongs, to confirm whether the current horizontal displacement monitoring point 4 is moving into or out of the pit.

[0077] The horizontal displacement calculation module is specifically used for:

[0078] When the foundation pit edge line type to which the horizontal displacement monitoring point 4 belongs is a straight line, the distance between the two endpoints of the foundation pit edge line and the corresponding virtual center point 3 of the foundation pit is calculated according to the coordinates of the two endpoints of the foundation pit edge line. Based on the distance data, the angle formed by the lines connecting the two endpoints of the foundation pit edge line and the corresponding virtual center point 3 of the foundation pit is obtained, and the final distance between the horizontal displacement monitoring point 4 and the corresponding virtual center point 3 of the foundation pit is obtained.

[0079] When the type of the foundation pit edge line to which the horizontal displacement monitoring point 4 belongs is an arc, the distance between the horizontal displacement monitoring point 4 and the virtual center point 3 of the foundation pit on the edge line perpendicular to the foundation pit is the horizontal distance between the two points.

[0080] The automated monitoring system for horizontal displacement of foundation pits based on virtual center points described in this embodiment of the invention can execute the automated monitoring method for horizontal displacement of foundation pits based on virtual center points provided in the above embodiments. The automated monitoring system for horizontal displacement of foundation pits based on virtual center points has the corresponding functional steps and beneficial effects of the automated monitoring method for horizontal displacement of foundation pits based on virtual center points described in the above embodiments. For details, please refer to the embodiments of the automated monitoring method for horizontal displacement of foundation pits based on virtual center points described above. The embodiments of this invention will not be repeated here.

[0081] Contents not described in detail in this specification are prior art known to those skilled in the art. The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this invention.

Claims

1. A virtual center point-based method for automatic monitoring of horizontal displacement of a foundation pit, characterized in that, Comprising the following steps: Step A: based on the current location of the foundation pit, the arrangement points of the field monitoring are confirmed respectively, including the rear reference point (1), the fixed station point (2), the virtual center point of the foundation pit (3), the horizontal displacement monitoring point of the top of the foundation pit supporting structure (4) and the foundation pit boundary contour point (5), wherein the rear reference point (1) is located in a stable area outside the influence range of the foundation pit construction, serving as the reference of the foundation pit plane control network; the fixed station point (2) is a forced centering observation pier corresponding to the setting of the total station instrument in the foundation pit site; the virtual center point of the foundation pit (3) is one or more center points selected in the central area inside the foundation pit according to the shape of the foundation pit; the foundation pit boundary contour point (5) is each inflection point along the contour of the foundation pit supporting structure, used to determine the geometric shape of the foundation pit; the plane coordinate system of the foundation pit is established according to the coordinates of the rear reference point (1), and the coordinates of the fixed station point (2) are calculated by resection ; Step B: Construct the foundation pit geometry, use total station to observe the virtual center point (3) of foundation pit, the edge line contour point (5) of foundation pit, and the horizontal displacement monitoring point (4) respectively, and measure the azimuth angle of each point relative to the fixed station point (2) in the horizontal direction , the zenith distance in the plumb plane , and the slant range , then the calculation formula of the corresponding point coordinate is: ； After measuring the coordinates of each point, the horizontal displacement monitoring points (4) are classified according to the layout of the measuring points and the shape of the foundation pit; Step C: Calculate the planar distance from each horizontal displacement monitoring point (4) to its corresponding virtual center point of the foundation pit (3) ; ； wherein, in the formula is the planar coordinate of the horizontal displacement monitoring point (4), is the planar coordinate of the corresponding virtual center point (3) of the foundation pit. Step D: Based on the classification result of Step B, the planar distances calculated in Step C are reduced to the corresponding perpendicular base line directions; Step E: According to the type of the foundation pit boundary line to which the monitoring point belongs, the horizontal displacement value of the horizontal displacement monitoring point (4) is calculated, and it is determined whether the current horizontal displacement monitoring point (4) moves towards the pit or moves out of the pit; Step E specifically includes: when the type of the foundation pit boundary line to which the horizontal displacement monitoring point (4) belongs is a straight line type, the distances between the two end point coordinates of the foundation pit boundary line and the corresponding virtual center points (3) of the foundation pit are calculated respectively, and the included angle formed by the connecting line between the two end points of the foundation pit boundary line and the corresponding virtual center points (3) of the foundation pit is obtained according to the distance data, and the distance between the final horizontal displacement monitoring point (4) and the corresponding virtual center points (3) of the foundation pit is obtained. Step E specifically further includes: when the type of the foundation pit boundary line to which the horizontal displacement monitoring point (4) belongs is a circular arc type, the distance between the horizontal displacement monitoring point (4) and the virtual center point (3) of the foundation pit in the direction perpendicular to the foundation pit boundary line is the horizontal distance between the two points.

2. A virtual center point based foundation pit horizontal displacement automatic monitoring system applied to the virtual center point based foundation pit horizontal displacement automatic monitoring method of claim 1, characterized in that, Comprising: The point definition module is used to confirm the arrangement points of the field monitoring based on the position of the current foundation pit, including a rear reference point (1), a fixed frame station point (2), a virtual center point (3) of the foundation pit, a horizontal displacement monitoring point (4) at the top of the foundation pit supporting structure, and a foundation pit boundary contour point (5), wherein the rear reference point (1) is located in a stable area outside the influence range of the foundation pit construction and serves as a reference of the foundation pit plane control network; the fixed frame station point (2) is a forced centering observation pier corresponding to the setting of the total station instrument in the foundation pit site; the virtual center point (3) of the foundation pit is one or more center points selected in the central area inside the foundation pit according to the shape of the foundation pit; the foundation pit boundary contour point (5) is each inflection point along the boundary contour of the foundation pit supporting structure, which is used to determine the geometric shape of the foundation pit; the plane coordinate system of the foundation pit is established according to the coordinates of the rear reference point (1), and the coordinates of the fixed frame station point (2) are calculated by resection ​ Point observation module: for constructing the geometric characteristics of foundation pit, using total station to observe the virtual center point (3) of foundation pit, the contour point (5) of foundation pit boundary line and the horizontal displacement monitoring point (4) respectively, and measuring the azimuth angle of each point relative to the fixed station point (2) in the horizontal direction , the zenith distance in the plumb plane and the slant range , then the calculation formula of the corresponding point coordinates is: ； After measuring the coordinates of each point, the horizontal displacement monitoring points are classified according to the layout of the measuring points and the shape of the foundation pit; A plane distance calculation module is used to calculate the plane distance from each monitoring point to its corresponding virtual center point (3) of the foundation pit ; ； wherein, in the formula is the plane coordinate of the horizontal displacement monitoring point (4), is the plane coordinate of the corresponding virtual center point (3) of the foundation pit. The horizontal displacement value calculation module is configured to calculate the horizontal displacement value of the horizontal displacement monitoring point (4) according to the plane distance calculated by the plane distance calculation module and the classification result of the point position observation module. The horizontal displacement value calculation module is configured to calculate the horizontal displacement value of the horizontal displacement monitoring point (4) according to the plane distance calculated by the plane distance calculation module and the classification result of the point position observation module. The horizontal displacement value calculation module is configured to calculate the horizontal displacement value of the horizontal displacement monitoring point (4) according to the plane distance calculated by the plane distance calculation module and the classification result of the point position observation module.

3. The virtual center point based foundation pit horizontal displacement automated monitoring system according to claim 2, wherein, The horizontal displacement value calculation module is specifically used for: When the type of the foundation pit boundary line to which the horizontal displacement monitoring point (4) belongs is a straight line type, the distances between the two end point coordinates of the foundation pit boundary line and the corresponding virtual center points (3) of the foundation pit are calculated respectively, and the included angle formed by the connecting line between the two end points of the foundation pit boundary line and the corresponding virtual center points (3) of the foundation pit is obtained according to the distance data, and the distance between the final horizontal displacement monitoring point (4) and the corresponding virtual center points (3) of the foundation pit is obtained.

4. The virtual center point based foundation pit horizontal displacement automated monitoring system according to claim 3, wherein, The horizontal displacement value calculation module is further used for: When the type of the foundation pit boundary line to which the horizontal displacement monitoring point (4) belongs is a circular arc type, the distance between the horizontal displacement monitoring point (4) and the virtual center point (3) of the foundation pit in the direction perpendicular to the foundation pit boundary line is the horizontal distance between the two points.

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