阅读说明：本技术 一种应用于浅部砂层地面塌陷隐患监测方法 (Method for monitoring hidden danger of ground collapse of shallow sand layer ) 是由 蔡剑韬 祁伏成 付栋 归浩杰 于 2020-08-01 设计创作，主要内容包括：本发明涉及一种应用于浅部砂层地面塌陷隐患监测方法,涉及地质灾害检测和监测的技术领域,其包括：在隐患巡查后,采用车载三维探地雷达对疑似隐患路段进行全面普查,确定隐患分布；采用车载三维探地雷达、管道检测、钻孔验证、三维激光扫描仪对隐患发育程度进行详查,确定地面塌陷隐患监测区；对所述地面塌陷监测区的影响区进行水准变形、水位、土体分层沉降、地表沉降监测；采用全站仪实时监测地面塌陷隐患监测区的形变趋势。本发明解决了现有监测方法准确性不高、不宜推广和实际应用的问题。本发明能对浅部砂层地面塌陷隐患多阶段、多角度的准确监测及预警,其适用性高,易于推广应用。(The invention relates to a method for monitoring hidden danger of ground collapse of a shallow sand layer, which relates to the technical field of geological disaster detection and monitoring and comprises the following steps: after the hidden danger inspection, a vehicle-mounted three-dimensional ground penetrating radar is adopted to carry out comprehensive general inspection on the suspected hidden danger road section, and the hidden danger distribution is determined; adopting a vehicle-mounted three-dimensional ground penetrating radar, pipeline detection, drilling verification and a three-dimensional laser scanner to carry out detailed investigation on the development degree of the hidden danger, and determining a ground collapse hidden danger monitoring area; carrying out level deformation, water level, soil body layered settlement and ground surface settlement monitoring on an affected area of the ground collapse monitoring area; and monitoring the deformation trend of the ground collapse hidden danger monitoring area in real time by adopting a total station. The invention solves the problems of low accuracy, and difficult popularization and practical application of the existing monitoring method. The invention can accurately monitor and early warn the hidden danger of shallow sand layer ground collapse in multiple stages and at multiple angles, has high applicability and is easy to popularize and apply.)

1. The utility model provides a be applied to shallow sand bed ground hidden danger monitoring method that collapses which characterized in that includes:

after the hidden danger inspection, a vehicle-mounted three-dimensional ground penetrating radar is adopted to carry out comprehensive general inspection on the suspected hidden danger road section, and the hidden danger distribution is determined;

adopting a vehicle-mounted three-dimensional ground penetrating radar, pipeline detection, drilling verification and a three-dimensional laser scanner to carry out detailed investigation on the development degree of the hidden danger, and determining a ground collapse hidden danger monitoring area;

carrying out level deformation, water level, soil body layered settlement and ground surface settlement monitoring on an affected area of the ground collapse monitoring area;

and monitoring the deformation trend of the ground collapse hidden danger monitoring area in real time by adopting a total station.

2. The method for monitoring the hidden danger of ground collapse of shallow sand layer according to claim 1, further comprising: and verifying the scanning precision of the three-dimensional laser scanner by adopting a total station.

3. The method for monitoring the hidden danger of ground collapse of shallow sand layer according to claim 2, wherein the verifying the scanning accuracy of the three-dimensional laser scanner by using a total station comprises:

setting at least three ground monitoring points according to a preset distance, setting at least one target between the ground monitoring point closest to the measuring station and the measuring station, and setting at least one target between two adjacent ground monitoring points;

establishing an independent total station coordinate system and an independent scanner coordinate system by taking the measuring station as a coordinate origin;

measuring three-dimensional coordinates (X, Y, Z) of the target in the total station coordinate system by using the total station;

scanning the target by using the three-dimensional laser scanner, and extracting three-dimensional coordinates (x, y, z) of the target in a scanner coordinate system;

selecting a target from the ground monitoring point closest to the measuring station and the measuring station, selecting a target from the two adjacent ground monitoring points, and calculating by using a least square method to obtain a rotation matrix R and a translation matrix T of the total station coordinate system and the scanner coordinate system;

using spatial similarity transformation formulasConverting three-dimensional coordinates of other targets in the scanner coordinate system to coordinates (x ', y ', z ') in the total station coordinate system;

and comparing the three-dimensional coordinates (X ', Y ', Z ') of the same target with the three-dimensional coordinates (X, Y, Z) to obtain the coordinate difference (delta X, delta Y, delta Z) of the target in three axial directions, and solving the point location precision of the three-dimensional laser scanner according to an error formula in the point location.

4. The method for monitoring the hidden danger of ground collapse of shallow sand layer according to claim 3, wherein the target adopts a common reference ball; the targets should be evenly distributed and arranged in a staggered manner within the scanning range.

5. The method for monitoring hidden danger of ground collapse of shallow sand layer according to any one of claims 1 to 4, wherein the detailed inspection of the development degree of the hidden danger by using a three-dimensional laser scanner comprises:

the three-dimensional laser scanner scans an operation road section to obtain point cloud data;

performing point cloud splicing, noise reduction and thinning, and cutting on the point cloud data to obtain a top view and a side view, and screening out position distribution of the hidden danger body;

measuring characteristic data of the saphenous body, wherein the characteristic data of the saphenous body comprises the coordinates, the length, the depth and the surface area of the saphenous body;

and drawing a contour map and a three-dimensional surface map according to the characteristic data of the hidden patient, and visually presenting the distribution position and the state of the hidden danger representation characteristics according to the density degree of adjacent contours.

6. The method for monitoring the hidden danger of ground collapse of the shallow sand layer according to claim 1, wherein the step of carrying out detailed investigation on the development degree of the hidden danger by adopting a vehicle-mounted three-dimensional ground penetrating radar comprises the following steps:

performing direct current drift removal and time zero correction on the three-dimensional ground penetrating radar data;

preprocessing the three-dimensional ground penetrating radar data after the direct current drift and time zero correction are removed, wherein the preprocessing comprises cutting, amplitude correction, horizontal filtering and band-pass filtering;

sequentially carrying out interpolation and offset on the preprocessed three-dimensional ground penetrating radar data;

and generating a three-dimensional slice image and a two-dimensional section image according to the interpolated and offset three-dimensional ground penetrating radar data, and creating an arbitrary line of the two-dimensional section image of the vertical cross section of the three-dimensional ground penetrating radar data in the three-dimensional slice image.

7. The method for monitoring the hidden danger of ground collapse of shallow sand layer according to claim 1, wherein the pipeline detection comprises television detection and pipeline periscope detection.

8. The method for monitoring the hidden danger of ground collapse applied to the shallow sand layer according to claim 1, wherein the monitoring of the deformation trend of the monitoring area of the hidden danger of ground collapse in real time by using a total station comprises the following steps:

the total station automatically divides grids in an area to be monitored and calculates current grid data of intersection points of the grids, wherein the grid data comprise coordinates and altitude differences;

the total station calculates the current height difference of the intersection points of all grids;

the total station subtracts the current height difference of each grid intersection point from the previous height difference of each grid intersection point to obtain original data;

the total station outputs the original data to a monitoring terminal;

the monitoring terminal carries out DEM modeling on the original data by utilizing a Diloni triangle method or a Crigin interpolation method, and a three-dimensional model is established;

and the monitoring terminal inputs a preset coordinate to the three-dimensional model and outputs a height difference corresponding to the preset coordinate, namely the deformation of the preset coordinate.

Technical Field

The invention relates to the technical field of geological disaster detection and monitoring, in particular to a method for monitoring hidden danger of ground collapse of a shallow sand layer.

Background

With the rapid development of urban construction and the large-scale development of underground spaces, underground pipelines are densely distributed, old pipelines are relatively weak in maintenance, and once the underground pipelines leak in a shallow sand distribution area, quicksand is easily generated and a ground collapse geological disaster is caused. The ground collapse refers to a geological phenomenon that an overlying rock stratum is damaged, rock-soil bodies sink or collapse in an underground cavity, and collapse pits with different shapes are formed on the ground surface. The collapse zone is often accompanied by several cracks around the collapse pit, forming annular or arc-shaped cracks of unequal sizes.

The urban ground subsidence has the characteristics of concealment, outburst and destructiveness, starts from early signs of the ground subsidence, is very necessary for early discovery, early prevention and early treatment, development of disaster hidden danger identification and investigation, monitoring analysis and evaluation prediction, can improve the ground subsidence prevention and control capability, greatly reduces personnel and economic losses brought by ground subsidence disasters, and has good economic and social benefits.

At present, the following ground collapse hidden danger monitoring methods are mainly available: the method comprises the steps of predicting potential collapse points by using a GIS space prediction method, dividing a stable area and a non-stable area by using a hierarchical fuzzy mathematical method, predicting collapse by pre-burying optical fibers and monitoring optical fiber deformation caused by soil cave development, and performing early warning on collapse by using an abnormal data analysis method.

The above prior art solutions have the following drawbacks: most of the methods are applied in a macroscopic region, but still have certain limitations, for example, collapse prediction and forecast in the macroscopic region has high subjectivity in the aspects of evaluation factor selection, weight assignment and the like, and the accuracy is not high; or the calculation method is too complex, or the optical cable needs to be pre-buried in advance, so that the generalization performance is not high, and the method is not suitable for popularization and practical application.

Disclosure of Invention

The invention aims to provide a method for monitoring hidden danger of shallow sand layer ground collapse, which can accurately monitor and early warn the hidden danger of shallow sand layer ground collapse in multiple stages and multiple angles, has high applicability and is easy to popularize and apply.

The above object of the present invention is achieved by the following technical solutions:

a method for monitoring hidden danger of ground collapse of a shallow sand layer comprises the following steps:

after the hidden danger inspection, a vehicle-mounted three-dimensional ground penetrating radar is adopted to carry out comprehensive general inspection on the suspected hidden danger road section, and the hidden danger distribution is determined;

adopting a vehicle-mounted three-dimensional ground penetrating radar, pipeline detection, drilling verification and a three-dimensional laser scanner to carry out detailed investigation on the development degree of the hidden danger, and determining a ground collapse hidden danger monitoring area;

carrying out level deformation, water level, soil body layered settlement and ground surface settlement monitoring on an affected area of the ground collapse monitoring area;

and monitoring the deformation trend of the ground collapse hidden danger monitoring area in real time by adopting a total station.

By adopting the technical scheme, four stages of hidden danger characteristic inspection, hidden danger distribution general inspection and hidden danger development degree detailed inspection to hidden danger situation deformation monitoring are provided, a vehicle-mounted three-dimensional ground penetrating radar, pipeline detection, drilling verification and a three-dimensional laser scanner are utilized to carry out geophysical prospecting, deformation measurement, pipeline detection and other comprehensive monitoring technical methods on multiple objects such as hidden objects, pipeline defects, underground water, peripheral surface subsidence, cracks, soil bodies and the like in the process of underground cavity void, the ground collapse comprehensive monitoring method is established, the early warning indexes of the multiple stages of the multiple objects are formed, the hidden danger monitoring and early warning precision of the shallow sand layer ground collapse geological disaster is improved, the effects of hidden danger investigation and hidden danger identification to hidden danger monitoring and early warning are achieved, and a solid foundation is laid for the prevention and control of the ground collapse geological disaster.

The present invention in a preferred example may be further configured to: and verifying the scanning precision of the three-dimensional laser scanner by adopting a total station.

By adopting the technical scheme, the precision of the three-dimensional laser scanner is evaluated by the total station with higher precision, so that the scanning precision of the follow-up operation of the three-dimensional laser scanner can be ensured.

The present invention in a preferred example may be further configured to: the verifying the scanning precision of the three-dimensional laser scanner by adopting the total station comprises the following steps:

setting at least three ground monitoring points according to a preset distance, setting at least one target between the ground monitoring point closest to the measuring station and the measuring station, and setting at least one target between two adjacent ground monitoring points;

establishing an independent total station coordinate system and an independent scanner coordinate system by taking the measuring station as a coordinate origin;

measuring three-dimensional coordinates (X, Y, Z) of the target in the total station coordinate system by using the total station;

scanning the target by using the three-dimensional laser scanner, and extracting three-dimensional coordinates (x, y, z) of the target in a scanner coordinate system;

selecting a target from the ground monitoring point closest to the measuring station and the measuring station, selecting a target from the two adjacent ground monitoring points, and calculating by using a least square method to obtain a rotation matrix R and a translation matrix T of the total station coordinate system and the scanner coordinate system;

using spatial similarity transformation formulasConverting three-dimensional coordinates of other targets in the scanner coordinate system to coordinates (x ', y ', z ') in the total station coordinate system;

and comparing the three-dimensional coordinates (X ', Y ', Z ') of the same target with the three-dimensional coordinates (X, Y, Z) to obtain the coordinate difference (delta X, delta Y, delta Z) of the target in three axial directions, and solving the point location precision of the three-dimensional laser scanner according to an error formula in the point location.

By adopting the technical scheme, the scanning precision test of the three-dimensional laser scanning technology is designed by using methods such as coordinate system transformation, space similarity transformation and the like, and the scanning precision can be accurately evaluated.

The present invention in a preferred example may be further configured to: the target adopts a common reference ball; the targets should be evenly distributed and arranged in a staggered manner within the scanning range.

By adopting the technical scheme, the common reference ball is used as the target, the point cloud pictures obtained by the three-dimensional laser scanner can be seamlessly spliced, and the coordinates can be corrected; the targets are uniformly distributed in the scanning range, and the heights of the targets are staggered, so that the precision requirements of all directions during coordinate conversion can be effectively guaranteed.

The present invention in a preferred example may be further configured to: the method for carrying out detailed investigation on the development degree of the hidden danger by adopting the three-dimensional laser scanner comprises the following steps:

the three-dimensional laser scanner scans an operation road section to obtain point cloud data;

performing point cloud splicing, noise reduction and thinning, and cutting on the point cloud data to obtain a top view and a side view, and screening out position distribution of the hidden danger body;

measuring characteristic data of the saphenous body, wherein the characteristic data of the saphenous body comprises the coordinates, the length, the depth and the surface area of the saphenous body;

and drawing a contour map and a three-dimensional surface map according to the characteristic data of the hidden patient, and visually presenting the distribution position and the state of the hidden danger representation characteristics according to the density degree of adjacent contours.

By adopting the technical scheme, the information such as the abnormal change position of the hidden danger of the ground collapse can be clearly and visually displayed from the surface, and the purpose of effectively monitoring the ground collapse is achieved.

The present invention in a preferred example may be further configured to: the method for carrying out detailed investigation on the development degree of the hidden danger by adopting the vehicle-mounted three-dimensional ground penetrating radar comprises the following steps:

performing direct current drift removal and time zero correction on the three-dimensional ground penetrating radar data;

preprocessing the three-dimensional ground penetrating radar data after the direct current drift and time zero correction are removed, wherein the preprocessing comprises cutting, amplitude correction, horizontal filtering and band-pass filtering;

sequentially carrying out interpolation and offset on the preprocessed three-dimensional ground penetrating radar data;

and generating a three-dimensional slice image and a two-dimensional section image according to the interpolated and offset three-dimensional ground penetrating radar data, and creating an arbitrary line of the two-dimensional section image of the vertical cross section of the three-dimensional ground penetrating radar data in the three-dimensional slice image.

By adopting the technical scheme, the underground condition can be observed and analyzed more intuitively through data processing of the three-dimensional ground penetrating radar.

The present invention in a preferred example may be further configured to: the pipeline detection comprises television detection and pipeline periscope detection.

By adopting the technical scheme, the accuracy of judging the flaw detection position of the inner wall of the pipeline can be greatly improved by adopting a television detection technology; by adopting the pipeline periscope detection technology, the internal conditions of pipeline cracks, blockage and the like can be clearly displayed.

The present invention in a preferred example may be further configured to: adopt the deformation trend in total powerstation real-time supervision ground hidden danger monitoring area of collapsing, include:

the total station automatically divides grids in an area to be monitored and calculates current grid data of intersection points of the grids, wherein the grid data comprise coordinates and altitude differences;

the total station calculates the current height difference of the intersection points of all grids;

the total station subtracts the current height difference of each grid intersection point from the previous height difference of each grid intersection point to obtain original data;

the total station outputs the original data to a monitoring terminal;

the monitoring terminal carries out DEM modeling on the original data by utilizing a Diloni triangle method or a Crigin interpolation method, and a three-dimensional model is established;

and the monitoring terminal inputs a preset coordinate to the three-dimensional model and outputs a height difference corresponding to the preset coordinate, namely the deformation of the preset coordinate.

By adopting the technical scheme, the system can replace a person to automatically search, track, identify and accurately find the target and acquire information such as angles, distances, three-dimensional coordinates and images, and can realize full-automatic and intelligent deformation monitoring.

In summary, the invention includes at least one of the following beneficial technical effects:

1. the method comprises the following steps of providing four stages of potential hazard characteristic inspection, potential hazard distribution general inspection and potential hazard development degree detailed inspection to potential hazard situation deformation monitoring, utilizing a vehicle-mounted three-dimensional ground penetrating radar, pipeline detection, drilling verification and a three-dimensional laser scanner to empty underground cavities and hide sick bodies, pipeline defects, underground water, peripheral surface subsidence, cracks, soil bodies and other multiple objects, and adopting comprehensive monitoring technical methods such as geophysical prospecting, deformation measurement, pipeline detection and the like to establish a ground subsidence comprehensive monitoring method, forming early warning indexes of the multiple stages of the multiple objects, improving the monitoring and early warning precision of the shallow sand layer ground subsidence geological hazard, achieving the effects of potential hazard investigation and potential hazard identification to potential hazard monitoring and early warning, and laying a solid foundation for prevention and control of ground geological subsidence disasters;

2. the system can replace a person to automatically search, track, identify and accurately find a target and acquire information such as angles, distances, three-dimensional coordinates and images, and can realize full-automatic and intelligent deformation monitoring.

Drawings

FIG. 1 is a schematic flow chart of a method according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The embodiment of the invention provides a method for monitoring hidden danger of ground collapse of a shallow sand layer, which is applied to the method with reference to FIG. 1 and mainly comprises the following steps:

step S101: after the hidden danger inspection, a vehicle-mounted three-dimensional ground penetrating radar is adopted to carry out comprehensive general inspection on the suspected hidden danger road section, and the hidden danger distribution is determined;

the method comprises the steps of collecting address information of a required detection operation road section, road completion map and pipeline distribution map and basic topographic map data, detecting underground engineering construction information such as regional subways and pipe jacking, related information such as recent road surface collapse, settlement and cracks, related information such as road structure and road reconstruction and intermediate repair, and other related detection information.

When the site survey is carried out on the collapse hidden trouble area, the peripheral terrain, the engineering geological condition, the traffic condition, the noise interference source and the road surface basic condition are mainly recorded. For the road sections with heavy traffic and noisy traffic, the vehicle is required to avoid the peak time of the vehicle coming and going, and the field operation is preferably carried out at night. The method comprises the steps of determining the length, the width and the specified driving direction of each detection road section, recording detection influence conditions such as a central separation zone, a road construction area and parking, and observing traffic flow information and road surface subsidence conditions of the operation road section.

And (3) according to data collected in the earlier stage, determining key points, difficult points and countermeasures of detection work, drawing a side-line graph, determining a route of a detected vehicle travel, implementing time planning, and preparing equipment, vehicles, engineering materials, safety protection equipment and personnel labor division, safety guarantee measures and emergency plans.

The vehicle-mounted three-dimensional ground penetrating radar adopts a frequency stepping technology, can realize multi-antenna multi-point synchronous combined scanning and measurement on underground hidden dangers, captures target space information and special information to the maximum extent, and improves the quality of radar detection and identification. Meanwhile, the vehicle-mounted detection requirement can be met, the maximum vehicle speed can reach 30km/h, field collection is rapid and efficient, three-dimensional imaging of horizontal sections and vertical sections in any direction is presented in image processing, space visualization and quantification of collapse hidden patients such as cavities can be realized, the position reflection of collapse hidden dangers is more visual, interpretation is more accurate, true three-dimensional collection and rapid detection are achieved, and the vehicle-mounted detection system has the advantages of being capable of providing all-dimensional information and being gradually widely used.

The vehicle-mounted three-dimensional ground penetrating radar can be used for setting multiple channels for simultaneous acquisition, a three-dimensional data set is obtained by acquiring two-dimensional data of multiple parallel and crossed antennas, and vehicles can be carried to perform high-density and rapid seamless scanning, so that area detection is realized. Compared with a two-dimensional ground penetrating radar, the method has the advantages of massive data, true three-dimensional homing, true restoration of underground hidden dangers and the like.

Because the radar detection mainly realizes the qualitative analysis and the semi-quantitative analysis of the hidden danger, the radar data is used for explaining the type and the position of the hidden danger and then corresponding to the verification of the underground hidden danger. On one hand, a relevant geophysical prospecting conclusion can be corrected according to a verification result, a geophysical prospecting interpretation mark is perfected, on the other hand, characteristic data such as hidden danger types, scales, burial depths and the like can be visually obtained, the method is favorable for mastering and analyzing the cause of the cavity, and a reference basis is provided for underground hidden danger disposal such as the cavity.

For data collection, MALAImaging Radar Array (MIRA) Mara Array imaging Radar of the Sweden MALA instrument company is adopted, the Array antenna frequency is 200MHz and 400MHz, and the application effect in hidden danger detection is mutually verified. The array antenna with the central frequency of 400MHz has data of 16 channels, 9 transmitting antennas and 8 receiving antennas, and the effective detection width is 1.2 m; the array antenna with the center frequency of 200MHz has data of 8 channels, 5 transmitting antennas and 4 receiving antennas, the effective detection width is 0.91m, the antenna arrangement distance meets the requirement of seamless coverage, and the array antenna can be effectively coupled to reduce interference.

The acquired MIRA three-dimensional ground penetrating radar data needs to be subjected to a series of processing operations, and the data processing work flow is as follows:

(1) opening rSlicer software, building a new work area, and loading collected three-dimensional ground penetrating radar data;

(2) adjustments (typically with default values) to remove dc drift and time zero correction are made after the data is loaded;

(3) pretreatment: cutting, amplitude correction, horizontal filtering and band-pass filtering; the amplitude correction processing selects Automatic Gain Control (AGC), the application of divergence rate selection Lead (LEADING) is to apply a coefficient to the first sampling point of each sliding window, 20-30ns is selected for the length of 200MHz antenna operator, and about 20ns is selected for the length of 400MHz antenna operator; removing the ringing signal of the antenna (horizontal filtering), and selecting 400 channels and 500 channels in the operator design window at the moment; the band-pass filtering is used for increasing the signal-to-noise ratio, for a 400MHz antenna, the low cut, the low pass, the high pass and the high cut are respectively selected to be about 60MHz, about 250MHz, about 750MHz and about 1000MHz, for a 200MHz antenna, the low cut, the low pass, the high pass and the high cut are respectively selected to be about 40MHz, about 100MHz, about 400 plus 500MHz and about 800 MHz;

(4) interpolation: for a subsequent offset algorithm, data needs to be interpolated into a rectangular grid, meanwhile, various processing can be faster through interpolation, the boundary of a block needs to be defined before interpolation, and the step length (dx) of a specification grid is generally set to be the size of a sampling interval;

(5) offsetting: the method is used for recovering the real position and the shape of a reflector, is particularly effective when being applied to a parabolic object, and sets the offset speed to be about 10 cm/ns;

(6) an interactive tool: and generating a three-dimensional slice image and a two-dimensional section image according to the interpolated and offset three-dimensional ground penetrating radar data, and creating an arbitrary line of the two-dimensional section image of the vertical cross section of the three-dimensional ground penetrating radar data in the three-dimensional slice image.

Step S102: adopting a vehicle-mounted three-dimensional ground penetrating radar, pipeline detection, drilling verification and a three-dimensional laser scanner to carry out detailed investigation on the development degree of the hidden danger, and determining a ground collapse hidden danger monitoring area

Specifically, the detection method of the vehicle-mounted three-dimensional ground penetrating radar is described in detail in the step S101, and is not described herein again.

The pipeline detection can adopt television detection (CCTV detection for short) and pipeline periscope detection. The closed circuit television system is an image communication detection system which carries out visual image display and image record storage on a terminal television screen after shooting image data are transmitted to a computer by arranging a camera in a drainage pipeline in a closed circuit television recording mode. The detection system generally includes camera system, lighting system, crawl device, cable reel, controller, computer and related software, it is the tool specially used for underground pipeline detection, it collects light, electromechanics, image processing software in an organic whole, the industrial endoscope inspection tester is equipped with the colored monitor of high resolution or notebook computer of USB mouth and thanks to wear more conveniently, it is clearer to observe the image, make the operator utilize high-resolution colored CCD, will observe a point and flaw detection position with the help of the exclusive professional software processing system, freeze, enlarge, analyze, measure, print the report, greatly improve the accuracy of judging the inner wall flaw detection position of the pipeline.

The pipeline periscope detection is also called as an electronic periscope, and the pipeline periscope can clearly display pipeline cracks by placing a camera with high magnification into an inspection well or a hidden space through a control lever. Blockage, etc. The equipment consists of a searchlight, a camera, a controller, a telescopic rod and a video imaging and storing unit.

In the ground collapse inspection work, the investigation of geological disasters is not enough only by means of visual inspection by naked eyes, measurement by steel rulers and image photographing. In the early stage of ground collapse, a ground type three-dimensional laser scanning technology is adopted for the ground surface of the whole road section, and quantitative information such as hidden danger characteristics of the ground surface and space accurate three-dimensional coordinates of the surrounding environment can be rapidly obtained through scanning.

The three-dimensional laser scanner adopts panoramic scanning operation to scan the hidden danger body characteristics of ground collapse and the surrounding complex environment, a single station can generate very detailed three-dimensional data in a few minutes to form photo-like vivid three-dimensional color point cloud image data, the hidden danger characteristics of ground collapse can be digitized, and the identification of all the hidden dangers of ground collapse and the vectorization of the hidden danger characteristics in an operation section are realized.

The scanner position is scientifically and reasonably erected, and the method has very important significance for acquiring high-quality three-dimensional data, improving the measurement precision and comprehensively reflecting scene details. In order to effectively meet the requirement of surface damage scanning, the following setting requirement of a scanner measuring station is met during general survey three-dimensional scanning operation, the influence of road interference is effectively solved, redundant data processing is reduced, and the scanning precision is improved.

The three-dimensional laser scanner erecting station is arranged in a safe area with a wide visual field and stable ground, and a sufficient safe distance is kept between the three-dimensional laser scanner erecting station and a collapse hidden danger day, and the specific distance is determined according to the actual situation on site; the scanning range of the three-dimensional laser scanner is required to cover the whole geological disaster body and is uniformly distributed, the number of stations is required to be reduced as much as possible, and the scanning data splicing error is reduced; the lens of the scanner and the target have an included angle of 45-85 degrees so as to obtain a high-precision fitting coordinate of the control point of the target; by adopting road traffic control measures, night operation with low urban road traffic flow can be selected, the survey stations adopt a Z-shaped opposite staggered arrangement principle, the scanning targets are collected by the few survey stations as far as possible, the distance between the survey stations is controlled within 50m, the error accumulation of scanning data can be controlled, and the scanning operation effect is improved.

And (3) splicing, denoising, rarefying and cutting the scanning data by adopting Cyclone software in the interior industry to obtain an integral point cloud data model of the surrounding environment of the scanning place, and further denoising and cutting redundant data to obtain a road surface point cloud picture and a side-looking point cloud data model of the scanning place.

The method comprises the steps of obtaining real-color point cloud data of a whole road section through three-dimensional scanning, screening position distribution of a hidden danger body by means of overhead view and side view obtained through processing by means of interior processing software, zooming the hidden danger, rotating the hidden danger to a proper visual angle in a three-dimensional mode, and measuring characteristic information data such as the length, the depth and the surface area of the hidden danger.

By extracting dynamic three-dimensional data of the hidden danger body, the contour map and the three-dimensional surface map are quickly drawn, and further position distribution attribute information of hidden danger representation features such as deformation and subsidence is visually presented according to the density degree of adjacent contour lines.

Step S103: carrying out level deformation, water level, soil body layered settlement and ground surface settlement monitoring on an affected area of a ground collapse monitoring area;

specifically, the static leveling method is a method based on the principle of a communicating pipe, wherein each measuring point is provided with a container, the containers are communicated through a liquid communicating pipe, the initial elevations of the measuring points are arranged at the same elevation, a non-gas liquid is injected into the liquid communicating pipe and the containers, when the measuring points are relatively sunk, the relative change of the liquid level in the container of each measuring point is measured through a capacitance sensor, and then the relative sinking amount of each point relative to a base point is calculated.

In an area with dense ground collapse hidden danger points and relatively large damage degree, a physical exploration abnormal reaction strongest part or a central part in a physical exploration detailed inspection result is selected, static level monitoring points are distributed by utilizing ground drilling of a small-sized water mill drilling machine, the number of the monitoring points is preferably not less than three, each observation point is provided with a set of LY211A type wide-range static level, each static level needs to be additionally connected with a three-way joint, each measuring point sensor is connected with a bus, and a reference point needs to be stable.

An automatic acquisition instrument and a power supply control box are arranged at a safe and stable position outside a potential hazard monitoring area, the effective range of the static force level instrument is comprehensively determined by combining the size and the development degree of an underground hidden patient body and geological conditions, generally not less than 1000mm, the display precision is preferably 0.01mm, and the actual precision is not less than 0.1 mm. The power supply can adopt a solar panel to supply power in a centralized way, the working voltage is controlled to be 12 v-36 v, and the cable and the liquid pipe are suitable for being buried in a position which is not suitable for being damaged below a road after being cut and grooved on the road surface.

Liquid storage containers of the static level gauge are mutually and completely communicated through liquid through pipes, liquid is injected into the liquid storage containers, after the liquid level of the liquid is completely static, the liquid levels in all the communicated containers in the system are equal to O on a ground level surface, at the moment, the liquid level of each container is measured by a sensor, namely the initial liquid level values are respectively as follows: a0, B0, C0, D0 and E0, taking a base point A0 as a reference point, the foundation of the measuring point 1 sinks, the foundation of the measuring point 2 rises, the foundation of the measuring point 3 sinks, the foundation of the measuring point 4 does not change and the like, and then the new liquid level value of each measuring point communicated with the container is respectively as follows: a1, B1, C1, D1 and E1, calculating delta hi to calculate the settlement change amount of the monitoring point.

Step S104: and monitoring the deformation trend of the ground collapse hidden danger monitoring area in real time by adopting a total station.

Optionally, step S104 may include the following sub-steps:

(1) the total station automatically divides grids in an area to be monitored and calculates current grid data of intersection points of the grids, wherein the grid data comprise coordinates and altitude differences;

determining a region to be monitored by measuring three-dimensional coordinates of a plurality of region control points; dividing an area to be monitored into grids according to a set value; calculating the three-dimensional coordinates of the intersection points of the grids by forward and backward calculation according to the region control points; and calculating the horizontal angle and the vertical angle of the station and each grid intersection point, automatically rotating to the angle according to the horizontal angle and the vertical angle of each grid intersection point, measuring the distance from the station to each grid intersection point by using a prism-free measuring method, and calculating the current elevation of each grid intersection point according to the measured distance.

(2) The total station calculates the current height difference of the intersection points of all grids;

(3) the total station subtracts the difference of the current height difference of each grid intersection point from the difference of the height difference of each grid intersection point at the last time to obtain original data;

(4) the total station outputs original data to the monitoring terminal;

(5) the monitoring terminal carries out DEM modeling on the original data by using a Diloni triangle method or a Crigin interpolation method, and a three-dimensional model is established;

(6) and the monitoring terminal inputs a preset coordinate to the three-dimensional model and outputs a height difference corresponding to the preset coordinate, namely the deformation of the preset coordinate.

The total station also corrects the grid data of each grid intersection point by atmosphere correction, horizontal displacement correction of the measuring station and vertical displacement correction of the measuring station.

Wherein, the formula of atmosphere correction is as follows:

in the formula, Δ G is corrected by atmosphere, p is air pressure, t is air temperature, h is relative humidity, a is 1/273.15, and x is (7.5 × t/(237.3+ t)) + 0.7857.

The horizontal displacement correction mode of the measuring station is as follows:

and setting coordinates of the station points by adopting a back intersection method, and calculating the horizontal angle and the vertical angle of each grid intersection point by adopting new coordinates of the station points when the difference between the coordinates of the observation pier and the coordinates of the last time exceeds a threshold value.

In this embodiment, the total station may be TS 30. And automatically scanning the area to be measured without a prism by adopting a TS30 total station through control integrated software to obtain a three-dimensional coordinate of the area to be measured, comparing the three-dimensional coordinate with the original data to obtain the unique surface variation, and measuring the elevation by adopting a triangular elevation. The total station control part (field data acquisition) of the system controls the total station to calculate grid coordinates in an area after determining the area to be measured by compiling a program capable of running on the total station, finds corresponding point positions by calculating the coordinates, and measures the height difference. TS30 is one of the highest precision total stations, with an angular precision of 0.5 "; the distance accuracy was (0.6mm +1 ppm).

The total station automatic monitoring system comprises outdoor measuring equipment, transmission equipment, power supply equipment and indoor control equipment. The outdoor measuring equipment is a come card total station TS30 and come card 360-degree small prism or reflector plate, and if the small prism is adopted, the burial depth is lower than the road surface and is fixed on the hidden trouble of ground collapse. When the hidden trouble body takes place the displacement, little prism can be along with the instrument displacement. And measuring the small prism through the total station to obtain the displacement change condition of the detection object. The transmission equipment is connected with outdoor measuring equipment and indoor control equipment, conditionally adopts wired equipment, considers urban road influence factors, mainly selects wireless transmission equipment and adopts a 3G/4G network. The power supply equipment is equipment for providing power supply for the total station and the transmission equipment. This time power supply unit adopts special adapter to become total powerstation practical voltage (9V) and wireless transmission equipment service voltage (6V) with 12V storage battery. The indoor control equipment mainly controls the total station to carry out measurement work on the laika small prism through the transmission equipment, and simultaneously carries out data processing and data analysis on the acquired data.

Preferably, the scanning accuracy of the three-dimensional laser scanner is verified by using a total station.

And (3) evaluating the quality of the Lerca P40 laser scanning data by comparing the Leica P40 laser scanning measurement data with a high-precision total station Ts30 measurement structure. The electronic total station has absolute facts in the aspect of coordinate measurement, and the precision reaches mm level or even higher, so the total station Ts30 is adopted to measure the coordinates of the ground control point three times, the calculated three-time average value is used as a quasi-true value of a coordinate observation value, and the laser scanning data is compared with the coordinate observation value, so that the precision of the laser scanning data is measured.

Establishing an independent total station coordinate system and an independent scanner coordinate system by taking the measuring station as a coordinate origin; at least three ground monitoring points are arranged according to a preset distance, at least one target is arranged between the ground monitoring point closest to the measuring station and the measuring station, and at least one target is arranged between two adjacent ground monitoring points.

For example, three ground monitoring points A, B, C are provided, the distance between a and the survey station is 20m, the distance between a and B, B and C is 30m and 50m, 10 targets are provided between a and the survey station, and are marked as a1 to a10, and 10 targets are provided between a and B, B and C, and are marked as B1 to B10, and C1 to C10. The target was a Leica6 inch proprietary target. Preferably, the target uses a common reference ball; the targets should be evenly distributed and arranged in a staggered manner within the scanning range.

Measuring three-dimensional coordinates (X, Y and Z) of the target under a coordinate system of the total station by using a high-precision Leica Ts30 total station; the target was scanned using a Leica P40 three-dimensional laser scanner, and the three-dimensional coordinates (x, y, z) of the target in the scanner coordinate system were extracted.

Selecting a target from the ground monitoring points closest to the test station and the test station, and selecting a target from the two adjacent ground monitoring points, for example: selecting targets A1, B6 and C8, and calculating by using a least square method to obtain a rotation matrix R and a translation matrix T of a total station coordinate system and a scanner coordinate system; using spatial similarity transformation formulasThe three-dimensional coordinates of the other targets in the scanner coordinate system are converted to coordinates (x ', y ', z ') in the total station coordinate system.

Comparing the three-dimensional coordinates (X ', Y ', Z ') of the same target with the three-dimensional coordinates (X, Y, Z) to obtain the coordinate difference Ai (delta X, delta Y, delta Z) (i ═ 2,3, ·, 9) of the target in three axial directions, and then according to the error formula in the point location

And solving the point position precision of the three-dimensional laser scanner.

Under the actual measurement environment, the measurement accuracy of the scanner is positively correlated with the observation times and the scanning distance, and the error in the point location is larger as the distance is longer. The point location accuracy of the Leica P40 type scanner is +/-1.0 mm at a distance of 20m and +/-1.5 mm at a distance of 30m, the positioning accuracy in the X and Y directions is better than 1mm and obviously higher than that in the Z direction, the Z direction is mainly influenced by the vertical angle observation accuracy and the reflectivity, and the single-point positioning accuracy is better than 2 mm; at the distance of 50m, the point position precision reaches +/-4.2 mm.

The present invention is not limited to the specific embodiments, but can be modified as required by those skilled in the art after reading the present specification without any inventive contribution to the present invention, and all of the modifications are protected by patent laws within the scope of the claims.