CN116805441A

CN116805441A - Early warning method and device for foundation pit monitoring, electronic equipment and storage medium

Info

Publication number: CN116805441A
Application number: CN202310896603.3A
Authority: CN
Inventors: 李欢; 杨博; 李明辉; 吕尧; 何坤; 武进丽
Original assignee: Aerial Photogrammetry and Remote Sensing Co Ltd
Current assignee: Aerial Photogrammetry and Remote Sensing Co Ltd
Priority date: 2023-07-20
Filing date: 2023-07-20
Publication date: 2023-09-26

Abstract

The application provides a pre-warning method and device for foundation pit monitoring, electronic equipment and a storage medium, wherein the pre-warning method comprises the following steps: acquiring a multi-angle image shot by the unmanned aerial vehicle aiming at a monitoring area where a target foundation pit is located and recording the current shooting date; constructing a three-dimensional model of the current shooting date of the monitoring area where the target foundation pit is located under a preset coordinate system based on the multi-angle images; acquiring three-dimensional coordinates of each monitoring point of a plurality of monitoring points which are pre-arranged in a monitoring area in a three-dimensional model; comparing the three-dimensional coordinate of each monitoring point under the current shooting date with the pre-stored three-dimensional coordinate of the monitoring point under the last shooting date, and determining the change rate of the monitoring point; and if the change rate of the monitoring point reaches the corresponding preset condition, generating alarm information of abnormality of the monitoring point. By adopting the technical scheme provided by the application, the efficiency and convenience of foundation pit monitoring and early warning can be improved.

Description

Early warning method and device for foundation pit monitoring, electronic equipment and storage medium

Technical Field

The application relates to the technical field of building construction, in particular to a method and a device for early warning of foundation pit monitoring, electronic equipment and a storage medium.

Background

The foundation pit monitoring is an important link in foundation pit engineering construction, and is to conduct various observation and analysis work on the characteristics of foundation pit rock and soil, the deflection of supporting structures and the change of surrounding environment conditions in the foundation pit excavation and underground engineering construction process, timely feed back monitoring results, predict the deformation and the development of stable states which are caused after further construction, and guide design and construction according to the prediction and judge the influence degree of the construction on the surrounding environment so as to realize informationized construction.

At present, the foundation pit monitoring adopts a manual monitoring mode, and the manual monitoring is still the mainstream of the deep foundation pit monitoring of most construction projects, and because the deep foundation pit monitoring has a certain danger, the monitoring work is easily restricted by factors such as measuring equipment precision, on-site meteorological environment (for example, the manual monitoring cannot be performed when the device encounters shutdown in a freezing period or the road surface is muddy in a rainstorm), and the like, and cannot be performed. In addition, the traditional manual monitoring method has the defects of overlong data acquisition interval time, excessive consumption of human resources, slow information data feedback speed and possible retesting during one-time monitoring. Therefore, how to improve the efficiency and convenience of foundation pit monitoring and early warning becomes a problem to be solved urgently.

Disclosure of Invention

Accordingly, the application aims to provide a method, a device, electronic equipment and a storage medium for early warning of foundation pit monitoring, wherein a three-dimensional model can be constructed through multi-angle images shot by unmanned aerial vehicle inclined aviation, the change rate of each monitoring point is determined based on the three-dimensional model, and when the change rate reaches a corresponding preset condition, an alarm is given, so that the efficiency and convenience of foundation pit monitoring and early warning are improved.

The application mainly comprises the following aspects:

in a first aspect, an embodiment of the present application provides an early warning method for pit monitoring, where the early warning method includes:

acquiring a multi-angle image shot by the unmanned aerial vehicle aiming at a monitoring area where a target foundation pit is located during inclined aviation and recording the current shooting date;

constructing a three-dimensional model of a monitoring area where a target foundation pit is located under the current shooting date under a preset coordinate system based on the multi-angle image;

acquiring three-dimensional coordinates of each monitoring point of a plurality of monitoring points which are pre-arranged in the monitoring area in the three-dimensional model, and storing the three-dimensional coordinates of each monitoring point under the current shooting date;

comparing the three-dimensional coordinates of each monitoring point under the current shooting date and a preset coordinate system with the pre-stored three-dimensional coordinates of the last shooting date of the monitoring point and the preset coordinate system, and determining the change rate of the monitoring point;

And if the change rate of the monitoring point reaches the corresponding preset condition, generating alarm information of abnormality of the monitoring point.

Further, a three-dimensional model of the current shooting date of the monitoring area where the target foundation pit is located under a preset coordinate system is constructed through the following steps:

performing field image control measurement processing on a monitoring area where the target foundation pit is located, and acquiring actual three-dimensional coordinates of preset image control points in the monitoring area under the preset coordinate system;

acquiring camera parameters of the unmanned aerial vehicle for performing inclined flight aiming at a monitoring area where a target foundation pit is located;

under the camera parameters, rotating the actual three-dimensional coordinates of the image control points in the preset coordinate system into the multi-angle image to obtain a multi-angle image after rotating;

and performing space three operation processing on the multi-angle image after the rotating and puncturing, and constructing a three-dimensional model of the current shooting date of the monitoring area where the target foundation pit is located under a preset coordinate system.

Further, the monitoring points comprise displacement monitoring points, first-class settlement monitoring points and second-class settlement monitoring points; the displacement monitoring points are arranged on the side slope of the target foundation pit; the first type settlement monitoring points are distributed on the road surface within the monitoring area and away from the preset range of the target foundation pit; and the second type settlement monitoring points are arranged at four corners and on side lines of the building in the target foundation pit.

Further, the step of comparing, for each monitoring point, the three-dimensional coordinates of the monitoring point under the current shooting date and the preset coordinate system with the pre-stored three-dimensional coordinates of the monitoring point under the last shooting date and the preset coordinate system, and determining the change rate of the monitoring point includes:

for each monitoring point, if the monitoring point is a displacement monitoring point, determining a difference value between a horizontal axis coordinate in a three-dimensional coordinate of the displacement monitoring point and a horizontal axis coordinate in a three-dimensional coordinate of a last shooting date and a preset coordinate system of the displacement monitoring point stored in advance as an accumulated transverse displacement of the displacement monitoring point, and determining a difference value between a vertical axis coordinate in the three-dimensional coordinate of the displacement monitoring point and a vertical axis coordinate in the three-dimensional coordinate of the last shooting date and the preset coordinate system of the displacement monitoring point stored in advance as an accumulated longitudinal displacement of the displacement monitoring point;

if the monitoring point is a first type settlement monitoring point or a second type settlement monitoring point, determining a difference value between a vertical axis coordinate in the three-dimensional coordinate of the monitoring point and a pre-stored vertical axis coordinate in the three-dimensional coordinate of the last shooting date of the monitoring point and a preset coordinate system as an accumulated settlement height of the monitoring point;

Determining the interval days between the current shooting date and the last shooting date of the monitoring point as the monitoring days of the monitoring point;

determining the quotient of the accumulated lateral displacement of the monitoring point and the monitoring days of the monitoring point as the change rate of the monitoring point for the lateral displacement;

determining the quotient of the accumulated longitudinal displacement of the monitoring point and the monitoring days of the monitoring point as the change rate of the monitoring point for the longitudinal displacement;

and determining the quotient of the accumulated sedimentation height of the monitoring point and the monitoring days of the monitoring point as the elevation change rate of the monitoring point.

Further, the step of generating the alarm information of the abnormality of the monitoring point if the change rate of the monitoring point reaches the corresponding preset condition includes:

if any one of the change rate of the monitoring point for transverse displacement, the change rate of the monitoring point for longitudinal displacement and the change rate of the elevation reaches a corresponding change rate threshold value or a preset multiple of the corresponding change rate threshold value is met for N consecutive days, abnormal alarm information of the monitoring point is generated.

Further, the early warning method further includes:

acquiring a three-dimensional model of the last shooting date of a monitoring area where a target foundation pit is located under a preset coordinate system;

And superposing the three-dimensional model of the current shooting date and the three-dimensional model of the last shooting date in a preset coordinate system aiming at the monitoring area where the target foundation pit is located, so as to obtain a superposed three-dimensional model, and analyzing the change area of the three-dimensional model of the current shooting date compared with the three-dimensional model of the last shooting date.

Further, the early warning method further includes:

acquiring a three-dimensional model of each shooting date of a monitoring area where a target foundation pit is located under a preset coordinate system;

and sequencing each three-dimensional model according to the corresponding shooting date to obtain a sequenced three-dimensional model sequence, and displaying the three-dimensional model sequence according to the sequencing of the shooting dates so as to dynamically demonstrate the change process of the monitoring area where the target foundation pit is located.

In a second aspect, an embodiment of the present application further provides an early warning device for pit monitoring, where the early warning device includes:

the acquisition module is used for acquiring multi-angle images shot by the unmanned aerial vehicle when the unmanned aerial vehicle is inclined to the monitoring area where the target foundation pit is located and recording the current shooting date;

the construction module is used for constructing a three-dimensional model of the current shooting date of the monitoring area where the target foundation pit is located under a preset coordinate based on the multi-angle image;

The processing module is used for acquiring the three-dimensional coordinates of each monitoring point of the plurality of monitoring points which are pre-arranged in the monitoring area in the three-dimensional model, and storing the three-dimensional coordinates of each monitoring point under the current shooting date;

the determining module is used for comparing the three-dimensional coordinates of each monitoring point under the current shooting date and the preset coordinate system with the pre-stored three-dimensional coordinates of the last shooting date of the monitoring point and the preset coordinate system for each monitoring point, and determining the change rate of the monitoring point;

and the early warning module is used for generating abnormal warning information of the monitoring point if the change rate of the monitoring point reaches a corresponding preset condition.

In a third aspect, an embodiment of the present application further provides an electronic device, including: the system comprises a processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, the processor and the memory are communicated through the bus when the electronic device is running, and the machine-readable instructions are executed by the processor to perform the steps of the pit monitoring early warning method.

In a fourth aspect, embodiments of the present application further provide a computer readable storage medium, where a computer program is stored, where the computer program when executed by a processor performs the steps of the pit monitoring pre-warning method as described above.

The embodiment of the application provides a pre-warning method, a device, electronic equipment and a storage medium for foundation pit monitoring, wherein the pre-warning method comprises the following steps: acquiring a multi-angle image shot by the unmanned aerial vehicle aiming at a monitoring area where a target foundation pit is located during inclined aviation and recording the current shooting date; constructing a three-dimensional model of the current shooting date of the monitoring area where the target foundation pit is located under a preset coordinate system based on the multi-angle image; acquiring three-dimensional coordinates of each monitoring point of a plurality of monitoring points which are pre-arranged in the monitoring area in the three-dimensional model, and storing the three-dimensional coordinates of each monitoring point under the current shooting date; comparing the three-dimensional coordinates of each monitoring point under the current shooting date and a preset coordinate system with the pre-stored three-dimensional coordinates of the last shooting date of the monitoring point and the preset coordinate system, and determining the change rate of the monitoring point; and if the change rate of the monitoring point reaches the corresponding preset condition, generating alarm information of abnormality of the monitoring point.

Therefore, the technical scheme provided by the application can construct a three-dimensional model through the multi-angle images photographed by the unmanned aerial vehicle inclined aerial vehicle, the change rate of each monitoring point is determined based on the three-dimensional model, and when the change rate reaches the corresponding preset condition, an alarm is given, so that the efficiency and convenience of foundation pit monitoring and early warning are improved.

In order to make the above objects, features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 shows a flowchart of an early warning method for foundation pit monitoring according to an embodiment of the present application;

FIG. 2 is a flowchart of another method for pre-warning of foundation pit monitoring according to an embodiment of the present application;

fig. 3 is a schematic diagram of a foundation pit monitoring flow provided by an embodiment of the present application;

fig. 4 shows one of the structural diagrams of a pit monitoring early warning device according to an embodiment of the present application;

FIG. 5 shows a second block diagram of a pit monitoring and early warning device according to an embodiment of the present application;

fig. 6 shows a schematic structural diagram of an electronic device according to an embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application, and it should be understood that the drawings in the present application are for the purpose of illustration and description only and are not intended to limit the scope of the present application. In addition, it should be understood that the schematic drawings are not drawn to scale. A flowchart, as used in this disclosure, illustrates operations implemented according to some embodiments of the present application. It should be appreciated that the operations of the flow diagrams may be implemented out of order and that steps without logical context may be performed in reverse order or concurrently. Moreover, one or more other operations may be added to or removed from the flow diagrams by those skilled in the art under the direction of the present disclosure.

In addition, the described embodiments are only some, but not all, embodiments of the application. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by a person skilled in the art based on embodiments of the application without making any inventive effort, fall within the scope of the application.

In order to enable those skilled in the art to make use of the present disclosure, the following embodiments are provided in connection with a specific application scenario "pre-warning of pit monitoring", and the general principles defined herein may be applied to other embodiments and application scenarios for a person skilled in the art without departing from the spirit and scope of the present disclosure.

The method, the device, the electronic equipment or the computer readable storage medium can be applied to any scene needing to be monitored by the foundation pit early warning, the embodiment of the application does not limit specific application scenes, and any scheme using the method, the device, the electronic equipment and the storage medium for the foundation pit monitoring provided by the embodiment of the application is within the protection scope of the application.

It is noted that foundation pit monitoring is an important link in foundation pit engineering construction, and is to perform various observation and analysis operations on the characteristics of the rock and soil of the foundation pit, the deflection of a supporting structure and the change of surrounding environment conditions in the foundation pit excavation and underground engineering construction process, timely feed back monitoring results, predict the deformation and the development of a stable state which are caused after further construction, and instruct design and construction according to the prediction and judge the influence degree of the construction on the surrounding environment, so-called informationized construction is realized.

Based on the above, the application provides a method, a device, electronic equipment and a storage medium for early warning of foundation pit monitoring, wherein the early warning method comprises the following steps: acquiring a multi-angle image shot by the unmanned aerial vehicle aiming at a monitoring area where a target foundation pit is located during inclined aviation and recording the current shooting date; constructing a three-dimensional model of the current shooting date of the monitoring area where the target foundation pit is located under a preset coordinate system based on the multi-angle image; acquiring three-dimensional coordinates of each monitoring point of a plurality of monitoring points which are pre-arranged in the monitoring area in the three-dimensional model, and storing the three-dimensional coordinates of each monitoring point under the current shooting date; comparing the three-dimensional coordinates of each monitoring point under the current shooting date and a preset coordinate system with the pre-stored three-dimensional coordinates of the last shooting date of the monitoring point and the preset coordinate system, and determining the change rate of the monitoring point; and if the change rate of the monitoring point reaches the corresponding preset condition, generating alarm information of abnormality of the monitoring point.

To facilitate an understanding of the present application, a brief description of the prior art will be first provided; in order to scientifically predict the stability of the foundation pit support and the change of the surrounding environment, timely forecast and provide accurate and reliable deformation data, a foundation pit support construction deformation and settlement observation network needs to be established, and deformation settlement observation is carried out regularly. For the observation of the horizontal displacement of the foundation pit support, a base line (one base line is arranged on each foundation pit side) needs to be arranged on the top of the foundation pit side slope, and 1-3 deformation observation points are arranged on each base line and serve as sedimentation observation points. For foundation pit support settlement observation, a leveling control point or an independent leveling point far away from the foundation pit position in a measuring area is used as a starting point of settlement observation, and the leveling control point or the independent leveling point is combined with the starting point to form the foundation pit support settlement observation net. In addition, four settlement observation points are respectively arranged near the periphery of the four-side enclosing wall, and the settlement observation points and the foundation (building) and important pipeline monitoring points are shallow buried at the periphery of the foundation pit together form a settlement observation network for monitoring the surrounding environment. When horizontal displacement observation is carried out, stations are respectively arranged at four corners of a base line point, a J2 type theodolite is used for observing the horizontal angle (quadrilateral inner angle) of a four-side network, the horizontal angle is measured together with the triangular point of the urban geodetic control network, and whether the base line point is displaced is checked. When sedimentation observation is carried out, a sedimentation observation network is established for each point and peripheral points on the foundation pit side, and the measurement method comprises the following steps: firstly, starting to observe from a city level control point far away from a foundation pit, guiding to the periphery of the foundation pit, sequentially observing according to the observing sequence of each programmed point, and finally measuring to another level control point, wherein an S3 type precise level gauge is adopted as an observation instrument. In addition, the engineering monitors all building (construction) structures in the range of 50 meters around the foundation pit, and particularly monitors the building (construction) structures in the range of 1.5H-2.0H, including the reinforcing monitoring forces of roads, municipal pipelines, power cables, telecommunication pipe networks and the like, wherein the specific monitoring measures are as follows: carrying out settlement deformation observation on a building (structure) at regular intervals, knowing the distribution condition of underground pipelines before construction, bottoming the underground pipelines of the whole field, and arranging deformation observation points for monitoring; and (3) carrying out reinforcement treatment on important pipelines with high deformation requirements and close to the excavation edge of the foundation pit.

Specifically, the technical scheme provided by the application will be described in detail below with reference to specific embodiments.

Referring to fig. 1, fig. 1 is a flowchart of an early warning method for pit monitoring according to an embodiment of the present application, as shown in fig. 1, the early warning method includes:

s101, acquiring a multi-angle image shot by an unmanned aerial vehicle aiming at a monitoring area where a target foundation pit is located during inclined aviation and recording the current shooting date;

in the step, the unmanned aerial vehicle is inclined to fly by installing high-resolution cameras with different angles at the bottom of the unmanned aerial vehicle, the same ground object is photographed at multiple angles at the same place, a large number of ground object textures and position information thereof are collected, then three-dimensional imaging is carried out on each ground object point, a three-dimensional stereogram is finally formed, and meanwhile digital elevation model data DEM is obtained. Compared with traditional photogrammetry, unmanned aerial vehicle oblique photogrammetry can acquire images of 5 directions (vertical, left-view, right-view, front-view and rear-view) of a target point, and can generate a three-dimensional live-action model. For unmanned aerial vehicle oblique photogrammetry technology, not only can three-dimensional coordinates and image information of a target point be obtained, but also a three-dimensional live-action model can be generated, and the surrounding environment of the target point can be truly displayed.

S102, constructing a three-dimensional model of the current shooting date of a monitoring area where a target foundation pit is located under a preset coordinate system based on the multi-angle image;

in the step, a unified coordinate system is needed, and the preset coordinate system can be a 2000-national geodetic coordinate system or other independent coordinate systems preset by people; here, the advantages of the unmanned aerial vehicle oblique photogrammetry three-dimensional modeling technique are mainly represented in the following aspects: (1) the obtained image has high precision and high resolution, and can quickly build the two-dimensional and three-dimensional geographic information of the target area; (2) the generated three-dimensional model has scalability; (3) compared with an orthophoto three-dimensional GIS, the model data volume generated by the unmanned aerial vehicle photographic tilting technology is smaller, and convenience is provided for sharing and release of the model data volume.

It should be noted that, referring to fig. 2, fig. 2 is a flowchart of another method for pre-warning pit monitoring according to an embodiment of the present application, as shown in fig. 2, the three-dimensional model of the current shooting date of the monitoring area of the target pit in the preset coordinate system is constructed by the following steps:

S201, performing field image control measurement processing on a monitoring area where the target foundation pit is located, and acquiring actual three-dimensional coordinates of a preset image control point in the monitoring area under the preset coordinate system;

in this step, before the field image control measurement is performed on the monitored area where the target foundation pit is located, a reference network is first required to be laid, for example, 4 permanent reference points (MH 01-MH 03) may be set on the reference network to form a first-stage reference network, and the reference points are laid according to the requirements of the monitored object and the field conditions, so that in order to facilitate the daily monitoring work on the field, for example, 5 working base points are planned to be set at stable positions near the excavation boundary of the foundation pit, and the working base points are periodically measured in combination with the reference points to test the stability of the working base points. However, if the field of view around the foundation pit is wide, for example, 4 working foundation points are coincident with the permanent reference points, and the remaining 1 working foundation point is laid on the west side of the target building. The layout and measurement work of the working foundation points are laid and tested in stages according to the construction excavation progress, and the layout positions and the number of the foundation points can be adjusted according to the on-site condition change. Then, the determined permanent datum point and the working datum point are buried, then, plane measurement of the datum network is carried out, GPS measurement is adopted for joint measurement between the permanent datum point and the working datum point, and encryption measurement is carried out on part of the working datum point according to site vision conditions by adopting methods such as total station coordinate measurement, precision theodolite angle intersection and distance intersection. The initial data of the first-level reference network of this embodiment adopts a 2000-country geodetic coordinate system according to the requirements (a hypothetical independent coordinate system may be used if not required). The GPS measurement of the plane coordinates of the reference network is performed according to the technical requirements of the D-level GPS network measurement in the specification, and various technical indexes are shown in the following table.

D-level GPS network measurement technical requirement table

Secondly, the elevation measurement and the periodic detection of the reference network are required, the elevation reference is preferentially adopted for construction, and the assumed elevation reference can be adopted if the conditions are limited. The elevation measurement of the reference net is performed by adopting a second-level geometric method. For example, two leveling measurements are independently performed after the datum point is buried stably, and an average value of the two leveling measurements is taken as an elevation calculation value of the datum point under the condition that the observation result meets the standard requirement and is worse than the standard. The elevation working base point is established by adopting a geometric level round trip measurement method, and at least two permanent level points are used for checking each time. And re-measuring and checking the elevation of the reference net once every six months, and detecting the working base point once every month during the freezing and thawing period. The elevation measurement is performed according to the requirement of the second level measurement, and the technical indexes are shown in the following table.

Main technical requirement table for measuring reference net elevation

Secondly, the monitoring points are required to be arranged, and the method mainly comprises the arrangement of foundation pit slope protection and monitoring points close to the ground and the arrangement of monitoring points of a main structure of a building; the foundation pit slope protection and the adjacent ground monitoring point layout are that displacement monitoring points are laid on the edge of a newly built building body enclosure (side slope) according to the foundation pit construction site condition so as to measure the horizontal displacement and the vertical displacement of the enclosure (side slope), and meanwhile, first class settlement monitoring points are laid on the road near the foundation pit so as to measure the subsidence of the area. According to the reference specification, for example, the monitoring points are distributed at intervals of 20m, and under special conditions, the intervals of the monitoring points can be increased or decreased on the premise of ensuring that the displacement deformation condition can be well reflected. According to the foundation pit design drawing, arranging displacement monitoring points such as 13 (J01-J13); the building main body structure monitoring points are arranged according to the construction condition of a building main body, the second type of settlement monitoring points are mainly arranged on four corners of a building and the midline of a building side line according to the standard requirements, and for example, 10 (CJ 01-CJ 10) building settlement monitoring points are arranged in sequence according to the construction progress and the construction part.

S202, acquiring camera parameters of the unmanned aerial vehicle for inclined flight aiming at a monitoring area where a target foundation pit is located;

in the step, unmanned aerial vehicle oblique photography is performed based on an observation object (a monitoring area where a target foundation pit is located), and a route and camera parameters are planned. Five-angle-direction shooting is carried out on a monitoring area where a target foundation pit is located by using an unmanned aerial vehicle-mounted high-resolution lens in stages (according to a required observation period), multi-angle aerial image data and image POS (space attitude) data are obtained, and POS information is written into an image. Because the foundation pit monitoring measurement accuracy index is required to be within the mm-level accuracy range, the unmanned aerial vehicle and the aerial camera are selected and controlled strictly, and the following technical parameter setting is carried out empirically: for example, a tilt photographing system can be formed by using a multi-rotor unmanned aerial vehicle, a large-scale longitude and latitude M300RTK unmanned aerial vehicle and a Buddhist P1 camera to perform tilt photographing; course parameter design may set the heading overlap ratio to 80% and the side overlap ratio to 75%; resolution (GSD) was set to 0.008m; the flying height is set to 90m (h=gsd. F/a, where H is the flying height, GSD is the resolution, f is the focal length, a is the pixel size) (no super high building, i.e. no building higher than 80 meters, is required to be within 50m of the vicinity of the target pit, and unmanned aerial vehicle flying can be performed); the flying speed was set to 8m/s. Adding camera file parameters, setting a photographing mode (using equidistant photographing), and automatically returning after the task is completed; setting a main course angle, which is parallel to the long side of the monitoring area, reducing the flying turning course and increasing the effective course (adjusting the course direction to be perpendicular to the complex plane flying is more beneficial to improving the modeling effect); edge distance setting: the margin of the monitoring area which is expanded is set to 0, and the margin which is not expanded is set to 1 voyage height.

S203, under the camera parameters, rotating the actual three-dimensional coordinates of the image control points in the preset coordinate system into the multi-angle image to obtain the multi-angle image after rotating;

s204, performing space three operation processing on the multi-angle image after the rotating thorns, and constructing a three-dimensional model of the current shooting date of the monitoring area where the target foundation pit is located under a preset coordinate system.

In the step, after the aerial uploading is finished, aerial image data under the camera parameters are obtained, field image control measurement is completed on a monitoring area, actual three-dimensional coordinates of preset image control points in the monitoring area are obtained, the actual three-dimensional coordinates of the image control points are spinned in the multi-angle images, the multi-angle images after spinned are obtained, and the image control points are preset objects with the markedness, such as a manhole cover and the like. The three-dimensional model can be produced by performing three-dimensional processing and generating a three-dimensional model by using ' Context Capture ' software, wherein three-dimensional processes are required to be performed through ' construction project (for example, POS files are imported for parameter setting, camera focal length and sensor size are input, camera focal length is generally different from other cameras), three-dimensional measurement (for example, relative orientation, control points are imported, stab high points, check points, adjustment and the like), selection of ' rigid registration by using image metadata ' during free network adjustment, selection of adjustment by using control points during constrained network adjustment ', and check whether three-dimensional fruits meet precision indexes (for example, precision evaluation of three-dimensional model data of a monitoring area refers to a foundation pit monitoring precision requirement, errors in a plane are smaller than +/-1 cm, gao Chengzhong errors are smaller than +/-1 cm, and if all image control points and check points are within the precision requirements, three-dimensional results meet the precision indexes) ' and the like processes are determined, three-dimensional reconstruction is performed to output a three-dimensional real-dimensional model, and an aviation model (Mesh model) of corresponding time period is manufactured respectively; after encryption is completed, the camera is stable in posture, five-lens photos at the same position are aggregated at the same position, obvious scattering does not occur, and a three-dimensional model can be output under the condition that connecting points are not layered. And after the model is rebuilt, outputting the three-dimensional model in a specified format according to the information such as a reference coordinate system, an elevation benchmark and the like required by the production project, and completing the production task of the live-action three-dimensional model of the oblique photography.

S103, acquiring three-dimensional coordinates of each monitoring point of a plurality of monitoring points which are pre-arranged in the monitoring area in the three-dimensional model, and storing the three-dimensional coordinates of each monitoring point under the current shooting date;

in the step, the monitoring points comprise displacement monitoring points, first class settlement monitoring points and second class settlement monitoring points; the displacement monitoring points are arranged on the side slope of the target foundation pit; the first type settlement monitoring points are distributed on the road surface within a monitoring area and away from a preset range of the target foundation pit; the second type settlement monitoring points are arranged at four corners and edges of the building in the target foundation pit; here, when the preset range is small, the road surface laid in the monitoring area at a distance from the preset range of the target foundation pit may be on the side slope of the target foundation pit, so that the first type settlement monitoring points may be displacement monitoring points, so that the settlement height of the first type settlement monitoring points may be the variation amount in the vertical axis (Z direction) of the displacement monitoring points. And determining the three-dimensional coordinates of each monitoring point in the three-dimensional model through the constructed three-dimensional model.

S104, comparing the three-dimensional coordinates of each monitoring point under the current shooting date and the preset coordinate system with the pre-stored three-dimensional coordinates of the last shooting date of the monitoring point and the preset coordinate system, and determining the change rate of the monitoring point;

It should be noted that, for each monitoring point, comparing the three-dimensional coordinates of the monitoring point under the current shooting date and the preset coordinate system with the pre-stored three-dimensional coordinates of the monitoring point under the last shooting date and the preset coordinate system, and determining the change rate of the monitoring point, including:

s1041, determining a difference value between a horizontal axis coordinate in a three-dimensional coordinate of the displacement monitoring point and a horizontal axis coordinate in a three-dimensional coordinate of a pre-stored last shooting date of the displacement monitoring point and a preset coordinate system as an accumulated horizontal displacement of the displacement monitoring point, and determining a difference value between a vertical axis coordinate in the three-dimensional coordinate of the displacement monitoring point and a vertical axis coordinate in a three-dimensional coordinate of the pre-stored last shooting date of the displacement monitoring point and a preset coordinate system as an accumulated longitudinal displacement of the displacement monitoring point if the monitoring point is a displacement monitoring point;

in the step, the accumulated lateral displacement is displacement in the X direction, the accumulated longitudinal displacement is displacement in the Y direction, and here, the difference between the vertical axis coordinate in the three-dimensional coordinates of the displacement monitoring point and the pre-stored vertical axis coordinate in the three-dimensional coordinates of the last shooting date and the preset coordinate system of the displacement monitoring point can be determined as the accumulated height displacement of the displacement monitoring point, and if the change rate of the monitoring point for the accumulated height displacement reaches the corresponding change rate threshold or meets the preset multiple of the corresponding change rate threshold for all N days, the abnormal alarm information of the monitoring point is generated.

S1042, if the monitoring point is a first type settlement monitoring point or a second type settlement monitoring point, determining the difference value between the vertical axis coordinate in the three-dimensional coordinate of the monitoring point and the vertical axis coordinate in the three-dimensional coordinate of the last shooting date of the monitoring point and the preset coordinate system stored in advance as the accumulated settlement height of the monitoring point;

in this step, the integrated sedimentation height is the displacement in the Z direction.

S1043, determining the interval days between the current shooting date and the last shooting date of the monitoring point as the monitoring days of the monitoring point;

s1044, determining the quotient of the accumulated lateral displacement of the monitoring point and the monitoring days of the monitoring point as the change rate of the monitoring point for the lateral displacement;

s1045, determining the quotient of the accumulated longitudinal displacement of the monitoring point and the monitoring days of the monitoring point as the change rate of the monitoring point for the longitudinal displacement;

s1046, determining the quotient of the accumulated sedimentation height of the monitoring point and the monitoring days of the monitoring point as the elevation change rate of the monitoring point.

For example, the monitoring content and the frequency of each monitoring item in the monitoring area are determined according to the specification requirements and in combination with the specific conditions of the construction site as shown in the following table.

Monitoring content and monitoring frequency table

S105, if the change rate of the monitoring point reaches the corresponding preset condition, generating alarm information of abnormality of the monitoring point.

It should be noted that, if the change rate of the monitoring point reaches the corresponding preset condition, the step of generating the alarm information of the abnormality of the monitoring point includes:

s1051, if any one of the change rate of the monitoring point for transverse displacement, the change rate of the monitoring point for longitudinal displacement and the change rate of the elevation change rate reaches a corresponding change rate threshold value or a preset multiple of the corresponding change rate threshold value is met for N consecutive days, generating abnormal alarm information of the monitoring point.

In this step, the monitoring alarm index is generally controlled by two amounts of total variation and variation rate, and the alarm index of accumulated variation is generally not suitable to exceed the design limit. The alarm index of this embodiment is initially formulated as shown in the following table (with confirmation of the relevant unit being required).

Monitoring alarm index table

The alarm should be given when the change rate of the monitored object reaches a prescribed value (change rate threshold value) in the above table or exceeds a preset multiple of the value (e.g., 0.7 times the change rate threshold value, i.e., 70%) for N consecutive days (e.g., 3 d). In order to quickly and accurately grasp the development state of foundation pit deformation, for monitoring points with larger deformation (for example, reaching an allowable value of 50%), faster deformation rate or abnormal deformation, the obtained monitoring data are utilized to predict the change trend of displacement through a theoretical model, and the prediction model is timely adjusted by tracking actual measurement data. Meanwhile, for monitoring points close to the early warning value, displacement deformation must be calculated on site, and the measurement result is immediately reported.

Here, at the project initial stage, manual instrument monitoring is performed once every other week and unmanned aerial vehicle inclined flying is adopted, and instrument monitoring results are tidied. And (3) constructing a three-dimensional model, measuring coordinates of the monitoring points, respectively importing the three-dimensional model at different periods under the 'three-dimensional space-time big data dynamic monitoring system' which is independently researched and developed, and acquiring observation data of the monitoring points through a measuring plug-in unit so as to calculate the variation of the monitoring points of the foundation pit. The method comprises the steps of calculating a pit top plane/vertical displacement monitoring point and a building settlement value, comparing a monitoring point coordinate value measured by an instrument with a monitoring point coordinate value read by a model, and performing several periods of comparison analysis, wherein the difference between the instrument measurement difference and the model measurement difference is smaller than 1cm, and performing empirical analysis. The visual measurement of the monitoring points on the live-action three-dimensional model can ensure the timeliness and consistency of the data, improve the authenticity and reliability of the data, and display the change situation of a period and the change quantity of the source data in an inclined model mode.

It should be noted that, the early warning method further includes:

1) Acquiring a three-dimensional model of the last shooting date of a monitoring area where a target foundation pit is located under a preset coordinate system;

2) And superposing the three-dimensional model of the current shooting date and the three-dimensional model of the last shooting date in a preset coordinate system aiming at the monitoring area of the target foundation pit to obtain a superposed three-dimensional model so as to analyze the change area of the three-dimensional model of the current shooting date compared with the three-dimensional model of the last shooting date.

It should be noted that, the early warning method further includes:

1) Acquiring a three-dimensional model of each shooting date of a monitoring area where a target foundation pit is located under a preset coordinate system;

2) And sequencing each three-dimensional model according to the corresponding shooting date to obtain a sequenced three-dimensional model sequence, and displaying the three-dimensional model sequence according to the sequencing of the shooting dates so as to dynamically demonstrate the change process of the monitoring area where the target foundation pit is located.

By way of example, the periodic high-precision inclined three-dimensional model manufactured by unmanned aerial vehicle aviation is led into an independently-developed three-dimensional space-time big data dynamic monitoring system, and dynamic display of an engineering foundation pit construction model interested by a user can be obtained through two inlets of superposition monitoring and a time axis. The system for dynamically monitoring the multi-time space aviation inclination model data and the three-dimensional space-time big data comprehensively grasps the planning implementation conditions of the foundation pit excavation and the building, assists the management department in grasping the building change condition in time, and provides visual space information support for treating emergency. The monitoring result has scalability, can measure the height and the building area of the building, grasp the change condition of the height and the area, and is used for a management department to know whether the building is built according to the requirement. The monitoring system has the functions of superposition monitoring and a time axis. The superposition monitoring can superpose the multi-time space inclination model data, visually reflect the change areas of the buildings in the current time period and the previous time period, and is used for monitoring the periodic change of the buildings known by the authorities, analyzing the change rate and dynamically managing the project progress. The time axis is dragged by using the time axis function, so that an animation effect can be realized, the space-time change process of the building can be dynamically demonstrated, and the method can be used for dynamically exhibiting the space-time change. The technology for constructing the live-action three-dimensional model by unmanned aerial vehicle oblique photogrammetry can be applied to dynamic monitoring of foundation pit monitoring in an auxiliary mode through empirical analysis.

Here, by the dynamically changing region of the plurality of flying flies, an inclined three-dimensional model of the building change at each time point is obtained. The inclination models which are photographed and manufactured in a plurality of different periods are measured, the observed object is dynamically monitored, monitoring and early warning can still be realized under the condition that manual monitoring cannot be carried out for a long time due to external factors in a special period, and visual, accurate, timely and effective data support is provided for management of the observed object. The inclined model dynamic transformation of the building at a plurality of time points is connected in series and displayed to a user through the three-dimensional space-time big data dynamic monitoring system, so that the monitoring result and the construction progress are more stereoscopic and visual, the management department is assisted to grasp the construction change condition in time, and visual space information support is provided for processing emergency.

Referring to fig. 3, fig. 3 is a schematic diagram of a foundation pit monitoring flow provided by an embodiment of the present application, as shown in fig. 3, firstly, determining a monitoring target and monitoring content of a foundation pit according to a foundation pit design diagram, laying a reference network according to the monitoring target and the monitoring content of the foundation pit, performing plane and elevation measurement on a reference point in the reference network, also laying each monitoring point in the monitoring target, performing plane and elevation measurement, establishing a coordinate system with the reference point as a reference, and measuring each monitoring point according to a monitoring frequency to obtain a monitoring result table; the unmanned aerial vehicle aerial photography obtains photos, field control measurement is firstly carried out, then aerial triangulation is carried out on the photos, a three-dimensional inclined model is generated, a corresponding live-action three-dimensional model is created according to the aerial frequency, the model is led into a three-dimensional space-time big data dynamic monitoring system, observation data of monitoring points are obtained from the model, whether the monitoring points are out of limit or reach corresponding early warning values is determined based on the observation data or a monitoring result table, if yes, measurement is carried out again manually, the manual monitoring frequency is quickened, the monitoring data are continuously obtained, whether the monitoring early warning value is exceeded is continuously determined, if the monitoring early warning value is exceeded, manual measurement is continuously carried out, the monitoring result table is output, and a constructor is informed by letter; if the monitoring result is normal, the monitoring time can be prolonged, and the manual monitoring can be assisted by continuously establishing a three-dimensional model through the unmanned aerial vehicle flight. The method for assisting the manual monitoring by the measurement mode of creating the three-dimensional model through unmanned aerial vehicle aviation flight can save labor cost, improve monitoring efficiency, avoid the condition that manual monitoring cannot be performed due to environmental problems, and the method for assisting the foundation pit monitoring by monitoring can reduce the number of times of manual on-site measurement monitoring, but cannot completely replace instrument monitoring, and when the model measured value reaches an early warning value, the manual monitoring frequency is increased according to the specification for verification, so that the method is a project problem, and timely feeds back to a constructor to ensure that project quality and quantity are ensured and the project is performed safely. The application of constructing the three-dimensional model based on unmanned aerial vehicle oblique photography is an important part of geographic space information, and the main purpose of the embodiment is to construct the monitoring and early warning of the high-precision live-action three-dimensional model based on unmanned aerial vehicle oblique photography on monitoring points of each observation stage of the space change from a pit to completion of a foundation pit and visual and dynamic display of the morphological change of a building. The high-precision inclined live-action three-dimensional model data can intuitively express the space integral information of the target, and combines deformation monitoring and three-dimensional space data of foundation pit monitoring engineering, so that not only can the deformation of a target object be intuitively and comprehensively recognized, but also the deformation result, the deformation trend and the monitoring point can be matched and corresponding, the relevance and the integrity of monitoring are improved, and the monitoring result and the construction progress are more stereoscopic and intuitive. The three-dimensional data are used for extracting discrete points and building component information, and the multi-period measurement data are compared, so that the coordinate difference value and the integral deformation of each stage can be obtained, and the integral deformation monitoring of the building is realized. The method can effectively avoid the dispersibility and the one-sided property of the traditional monitoring. The unmanned aerial vehicle oblique photogrammetry technology for constructing a live-action three-dimensional model has the following advantages of the auxiliary foundation pit monitoring technology by the monitoring result obtained in multiple time: (1) the monitoring mode has more flexibility, is less limited by factors of weather and instruments, can still realize monitoring and early warning even if manual monitoring cannot be carried out for a long time, and provides precision guarantee for monitoring the whole project; (2) the model has high precision, high resolution and scalability, the acquisition of monitoring data is more real-time and convenient, the plane and settlement displacement change of foundation pit support can be measured by the three-dimensional model manufactured by aviation flight in different periods (monitoring period) or not, and measures are taken in time through monitoring and early warning. The condition that manual monitoring cannot be performed due to interference of redundant manpower and other factors is avoided; (3) the unmanned aerial vehicle oblique photography three-dimensional modeling technology assists foundation pit monitoring to realize dynamic and visual monitoring, reduces the repeated measurement period of manual monitoring, saves cost, improves quality and improves efficiency.

The embodiment of the application provides a pre-warning method for foundation pit monitoring, which comprises the following steps: acquiring a multi-angle image shot by the unmanned aerial vehicle aiming at a monitoring area where a target foundation pit is located during inclined aviation and recording the current shooting date; constructing a three-dimensional model of the current shooting date of the monitoring area where the target foundation pit is located under a preset coordinate system based on the multi-angle image; acquiring three-dimensional coordinates of each monitoring point of a plurality of monitoring points which are pre-arranged in the monitoring area in the three-dimensional model, and storing the three-dimensional coordinates of each monitoring point under the current shooting date; comparing the three-dimensional coordinates of each monitoring point under the current shooting date and a preset coordinate system with the pre-stored three-dimensional coordinates of the last shooting date of the monitoring point and the preset coordinate system, and determining the change rate of the monitoring point; and if the change rate of the monitoring point reaches the corresponding preset condition, generating alarm information of abnormality of the monitoring point.

Based on the same application conception, the embodiment of the application also provides a pre-warning device for foundation pit monitoring corresponding to the pre-warning method for foundation pit monitoring provided by the embodiment, and because the principle of solving the problem by the device in the embodiment of the application is similar to that of the pre-warning method for foundation pit monitoring in the embodiment of the application, the implementation of the device can refer to the implementation of the method, and the repetition is omitted.

Referring to fig. 4 and 5, fig. 4 is a block diagram of a pre-warning device for foundation pit monitoring according to an embodiment of the present application, and fig. 5 is a second block diagram of a pre-warning device for foundation pit monitoring according to an embodiment of the present application. As shown in fig. 4, the early warning device 410 includes:

the acquiring module 411 is configured to acquire a multi-angle image captured by the unmanned aerial vehicle when the unmanned aerial vehicle performs oblique aviation flight aiming at a monitoring area where the target foundation pit is located, and record a current shooting date;

a construction module 412, configured to construct a three-dimensional model for the current shooting date of the monitoring area where the target foundation pit is located in a preset coordinate system based on the multi-angle image;

the processing module 413 is configured to obtain, in the three-dimensional model, a three-dimensional coordinate of each monitoring point of the plurality of monitoring points pre-arranged in the monitoring area, and store the three-dimensional coordinate of each monitoring point under a current shooting date;

The determining module 414 is configured to compare, for each monitoring point, a three-dimensional coordinate of the monitoring point under a current shooting date and a preset coordinate system with a pre-stored three-dimensional coordinate of the monitoring point under a last shooting date and a preset coordinate system, and determine a change rate of the monitoring point;

and the early warning module 415 is configured to generate alarm information of abnormality of the monitoring point if the change rate of the monitoring point reaches a corresponding preset condition.

Optionally, the construction module 412 is specifically configured to:

Optionally, the monitoring points comprise displacement monitoring points, first class settlement monitoring points and second class settlement monitoring points; the displacement monitoring points are arranged on the side slope of the target foundation pit; the first type settlement monitoring points are distributed on the road surface within the monitoring area and away from the preset range of the target foundation pit; and the second type settlement monitoring points are arranged at four corners and on side lines of the building in the target foundation pit.

Optionally, when the determining module 414 is configured to compare, for each monitoring point, a three-dimensional coordinate of the monitoring point under the current shooting date and the preset coordinate system with a pre-stored three-dimensional coordinate of the monitoring point under the last shooting date and the preset coordinate system, and determine a change rate of the monitoring point, the determining module 414 is specifically configured to:

Optionally, when the early warning module 415 is configured to generate the alarm information of the abnormality of the monitoring point if the change rate of the monitoring point reaches the corresponding preset condition, the early warning module 415 is specifically configured to:

Optionally, as shown in fig. 5, the early warning device 410 further includes a first application module 416, where the first application module 416 is configured to:

Optionally, as shown in fig. 5, the early warning device 410 further includes a second application module 417, where the second application module 417 is configured to:

The embodiment of the application provides an early warning device for foundation pit monitoring, which comprises: the acquisition module is used for acquiring multi-angle images shot by the unmanned aerial vehicle when the unmanned aerial vehicle is inclined to the monitoring area where the target foundation pit is located and recording the current shooting date; the construction module is used for constructing a three-dimensional model of the current shooting date of the monitoring area where the target foundation pit is located under a preset coordinate system based on the multi-angle image; the processing module is used for acquiring the three-dimensional coordinates of each monitoring point of the plurality of monitoring points which are pre-arranged in the monitoring area in the three-dimensional model, and storing the three-dimensional coordinates of each monitoring point under the current shooting date; the determining module is used for comparing the three-dimensional coordinates of each monitoring point under the current shooting date and the preset coordinate system with the pre-stored three-dimensional coordinates of the last shooting date of the monitoring point and the preset coordinate system for each monitoring point, and determining the change rate of the monitoring point; and the early warning module is used for generating abnormal warning information of the monitoring point if the change rate of the monitoring point reaches a corresponding preset condition.

Referring to fig. 6, fig. 6 is a schematic structural diagram of an electronic device according to an embodiment of the application. As shown in fig. 6, the electronic device 600 includes a processor 610, a memory 620, and a bus 630.

The memory 620 stores machine-readable instructions executable by the processor 610, when the electronic device 600 is running, the processor 610 communicates with the memory 620 through the bus 630, and when the machine-readable instructions are executed by the processor 610, the steps of the pit monitoring early warning method in the method embodiments shown in fig. 1 and fig. 2 can be executed, and detailed implementation is referred to method embodiments and is not repeated herein.

The embodiment of the present application further provides a computer readable storage medium, where a computer program is stored on the computer readable storage medium, and the computer program can execute the steps of the method for early warning of foundation pit monitoring in the method embodiments shown in fig. 1 and fig. 2 when the computer program is run by a processor, and the specific implementation manner can refer to the method embodiments and is not repeated herein.

It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, and are not repeated herein.

In the several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. The above-described apparatus embodiments are merely illustrative, for example, the division of the units is merely a logical function division, and there may be other manners of division in actual implementation, and for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be through some communication interface, device or unit indirect coupling or communication connection, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a non-volatile computer readable storage medium executable by a processor. Based on this understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

Finally, it should be noted that: the above examples are only specific embodiments of the present application, and are not intended to limit the scope of the present application, but it should be understood by those skilled in the art that the present application is not limited thereto, and that the present application is described in detail with reference to the foregoing examples: any person skilled in the art may modify or easily conceive of the technical solution described in the foregoing embodiments, or perform equivalent substitution of some of the technical features, while remaining within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims

1. The early warning method for foundation pit monitoring is characterized by comprising the following steps:

constructing a three-dimensional model of the current shooting date of the monitoring area where the target foundation pit is located under a preset coordinate system based on the multi-angle image;

2. The pre-warning method according to claim 1, characterized in that the three-dimensional model of the current shooting date under a preset coordinate system for the monitoring area where the target foundation pit is located is constructed by the following steps:

3. The method of claim 1, wherein the monitoring points comprise displacement monitoring points, first class sedimentation monitoring points, and second class sedimentation monitoring points; the displacement monitoring points are arranged on the side slope of the target foundation pit; the first type settlement monitoring points are distributed on the road surface within the monitoring area and away from the preset range of the target foundation pit; and the second type settlement monitoring points are arranged at four corners and on side lines of the building in the target foundation pit.

4. The method of claim 3, wherein the step of comparing, for each monitoring point, the three-dimensional coordinates of the monitoring point on the current shooting date and the preset coordinate system with the pre-stored three-dimensional coordinates of the monitoring point on the last shooting date and the preset coordinate system, and determining the change rate of the monitoring point includes:

5. The method of claim 1, wherein the step of generating the alarm information of the abnormality of the monitoring point if the rate of change of the monitoring point reaches a corresponding preset condition comprises:

6. The method of claim 1, further comprising:

7. The method of claim 1, further comprising:

8. An early warning device of foundation ditch monitoring, its characterized in that, early warning device includes:

The construction module is used for constructing a three-dimensional model of the current shooting date of the monitoring area where the target foundation pit is located under a preset coordinate system based on the multi-angle image;

9. An electronic device, comprising: a processor, a memory and a bus, said memory storing machine readable instructions executable by said processor, said processor and said memory communicating via said bus when the electronic device is operating, said machine readable instructions when executed by said processor performing the steps of the pit monitoring pre-warning method according to any one of claims 1 to 7.

10. A computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, which when executed by a processor performs the steps of the pit monitoring pre-warning method according to any one of claims 1 to 7.