CN115388798A

CN115388798A - Method and device for rapidly measuring deformation of tunnel excavation surface

Info

Publication number: CN115388798A
Application number: CN202210974779.1A
Authority: CN
Inventors: 刘学增; 杨晓秋; 桑运龙; 师刚; 陈许蓬
Original assignee: SHANGHAI TONGYAN CIVIL ENGINEERING TECHNOLOGY CO LTD
Current assignee: SHANGHAI TONGYAN CIVIL ENGINEERING TECHNOLOGY CO LTD
Priority date: 2022-08-15
Filing date: 2022-08-15
Publication date: 2022-11-25

Abstract

The invention relates to a method and a device for rapidly measuring deformation of a tunnel excavation surface, wherein the method comprises the following steps: acquiring a complete palm surface image through binocular shooting, and preprocessing the image; performing face contour fitting on the preprocessed face image based on blast hole traces after blasting, and extracting a face contour to obtain a face area; extracting tunnel section contour key points based on curvature change characteristics of the tunnel face contour, wherein the tunnel section contour key points comprise a vault and two arch feet; obtaining a plurality of reference points based on the key points of the profile of the tunnel section, and calculating the three-dimensional space deformation of each reference point, wherein the deformation types of the three-dimensional space deformation comprise in-plane deformation and bulging deformation, and the reference points are selected based on the deformation types; and calculating the three-dimensional space deformation of any point in the palm surface area based on the deformation of the three reference points. Compared with the prior art, the method has the advantages of construction safety guarantee, small calculation amount and the like.

Description

Method and device for rapidly measuring deformation of tunnel excavation surface

Technical Field

The invention relates to the technical field of deformation identification after tunnel excavation, in particular to a method and a device for quickly measuring deformation of an excavation surface of a tunnel.

Background

In actual tunnel engineering, constantly mastering the stability state of a tunnel is key work for ensuring tunnel propulsion safety construction. The traditional tunnel face deformation monitoring technology mainly takes an embedded measuring instrument as a main technology, and a method of using a level gauge, a total station or a method of arranging a sliding micrometer in the surrounding rock is mainly adopted for measuring the surrounding rock deformation. However, the above methods have disadvantages: firstly, the arrangement of measuring instruments has large workload, long time consumption and low efficiency; secondly, the measurement work and the site construction interfere with each other, the influence of human factors on the measurement precision is large, and the measurement result is unstable; finally, the field operation time is long, many field conditions are severe, and the personal safety of measuring personnel is threatened.

In order to avoid the above drawbacks, in recent years workers have introduced contactless measurement methods, mainly photogrammetry techniques based on digital photography. The digital photographic technology is applied to geotechnical engineering, so that the automation degree of monitoring can be improved, the result can be visually and detailedly displayed, the working efficiency of measurement is improved, and the interference to construction work is reduced. However, the close-range photogrammetry technique also faces the following outstanding problems:

(1) At present, all the close-range photogrammetry methods for the face need to be laid with artificial mark points. For example, chinese patent CN110849324B discloses a holographic measurement method for a long exposure oblique photography tunnel, which includes the implementation steps of marking image control points and measuring coordinates during tunnel face drilling and lofting; acquiring hole body images with different angles, high resolution and carrying rock stratum textures in a low-illumination environment by long-exposure photography; the method comprises the steps of identifying characteristic points on a plurality of hole body images aiming at the hole body images, calculating space coordinates of the characteristic points on the basis of a multi-image space forward intersection method, and expanding the points to form a grid surface model, so that a digital surface model carrying stratum information and the surface relief of the hole body outline is obtained. However, most of the artificial mark points are made of reflective materials, the installation mode is mainly sticking or drilling installation, in the actual engineering, the arrangement of the mark points on the tunnel face consumes time, and workers need to frequently contact and be exposed under the tunnel face for a long time, so that the tunnel face is exposed to a greater safety risk; for the area above the tunnel face, the installation work is difficult, a large amount of time is needed, and the normal tunnel construction operation is interfered, and the measurement mode of installing the artificial mark point obviously violates the guiding principle of 'timely closing' in the tunnel construction.

(2) The results of a few researchers in landmark-free photogrammetry. For example, the document "palm surface deformation monitoring technology based on a sub-pixel non-punctuation method" proposes a non-punctuation sub-pixel monitoring method, designs an indoor test based on a gray image correlation algorithm, sets a corner point as a feature point, and analyzes a photo which has no light change and is not disturbed accidentally. However, the existing detection technology for deformation of the tunnel face without the mark points adopts a single-camera fixed monitoring scheme, and the technical means has no practicability in the actual tunnel construction process and can seriously interfere with the subsequent construction of the tunnel face; on the other hand, by adopting the technical scheme of a single camera, the obtained deformation of the palm surface is planar two-dimensional deformation, and the deformation data of the palm surface is lacked.

(3) The conventional three-dimensional space deformation calculation of the tunnel face is based on the traditional binocular photography technology, the three-dimensional coordinates of all pixel points of the tunnel face need to be solved, images are successively compared, and the space deformation of the pixel points is solved, but the calculation method is large in calculation amount, long in time consumption and poor in timeliness.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a method and a device for rapidly measuring the deformation of the tunnel excavation surface, which guarantee the construction safety and have small calculated amount.

The purpose of the invention can be realized by the following technical scheme:

a method for rapidly measuring deformation of a tunnel excavation surface comprises the following steps:

acquiring a complete palm surface image through binocular shooting, and preprocessing the image;

performing face contour fitting on the preprocessed face image based on blast hole traces after blasting, and extracting a face contour to obtain a face area;

extracting tunnel section contour key points based on curvature change characteristics of the tunnel face contour, wherein the tunnel section contour key points comprise a vault and two arch feet;

obtaining a plurality of reference points based on the key points of the profile of the tunnel section, and calculating the three-dimensional space deformation of each reference point, wherein the deformation types of the three-dimensional space deformation comprise in-plane deformation and bulging deformation, and the reference points are selected based on the deformation types;

and calculating the three-dimensional space deformation of any point in the palm surface area based on the deformation of the three reference points.

Further, the preprocessing comprises image denoising processing and image size unification.

Further, the performing of the face contour fitting on the preprocessed face image based on the shot hole trace after blasting specifically includes:

performing corrosion operation from the periphery of the target image to the center of the target step by adopting a K3M sequential iterative processing algorithm until the target image is corroded to the width of a single-layer pixel, and extracting a blast hole skeleton;

extracting the end points of each blast hole skeleton one by one, and screening to obtain skeleton end points;

based on the curvature change characteristic of the fitting curve, deleting abnormal points from the framework end points obtained by screening to obtain contour points;

and fitting the palm surface contour based on a least square method by taking the contour points as fitting data.

Further, the screening to obtain the framework end point specifically comprises:

and carrying out binarization processing on the blast hole skeleton to obtain end points at two ends of the blast hole skeleton, respectively calculating Euclidean distances from the end points at the two ends to a reference pixel by taking a central pixel of a shot picture as the reference pixel, and screening the end points with smaller distances as the skeleton end points.

Further, the abnormal point is obtained based on the judgment of the vector included angle, specifically:

establishing a rectangular coordinate system based on a point B to be determined and two points A, C adjacent to the point B to be determined, wherein the AC direction is an x axis, and the Y axis is established by taking the AC midpoint as a coordinate origin O;

and judging whether the included angle between the vector AB and the positive direction of the y axis is greater than 90 degrees, if so, judging that the point B to be judged is an abnormal point.

Further, the vault extraction method comprises the following steps:

judging the vertical coordinate value of each contour pixel point, and taking the pixel point with the largest vertical coordinate value as a vault;

the extraction method of the arch springing comprises the following steps:

for the step method excavation, taking pixel points with the curvature mutation of outline pixel points to be 0 as arch springing;

for the full-section excavation, the pixel points with the curvature of the outline pixel points suddenly changing to be below the curvature threshold value are used as arch feet.

Further, for the in-plane deformation, the reference points are specifically selected as follows:

dividing the tunnel face area into a middle triangular area and two side arc areas based on the arch crown and the arch springing;

for the middle triangular area, taking a vault and two arch feet as three reference points;

and regarding the arc areas on the two sides, taking the arc section middle point, the arch crown and an arch foot which is closer to the arc section middle point of the arc area as three reference points.

Further, for the bulging deformation, the extracting the palm surface region reference point specifically includes:

and identifying and obtaining the center point of the core area of the tunnel face as a datum point, and forming three datum points by taking the arch crown, the two arch springing and any two adjacent points in the two arc section center points of the arc area between the arch crown and the two arch springing as other two datum points.

Further, the specific calculation process of the three-dimensional space deformation of the reference point includes:

performing parallax calculation on two images by adopting an SGBM algorithm based on two contemporaneous images obtained by binocular shooting, and calculating to obtain three-dimensional space information of the images according to a geometric relationship of parallel binocular vision;

and calculating the three-dimensional space deformation of the reference point based on the comparison of the plurality of pictures.

The invention also provides a rapid detection device for tunnel excavation face deformation, which comprises a binocular camera and an industrial personal computer, wherein one or more programs capable of being executed are stored in the industrial personal computer, and the one or more programs comprise instructions for executing the rapid measurement method for tunnel excavation face deformation.

Compared with the traditional photogrammetry technology, the method does not need to arrange artificial mark points, adopts the digital image technology to automatically identify stable geometric characteristic points on the tunnel face, thereby quickly identifying the deformation of the tunnel face, and has the following beneficial effects:

(1) According to the method, the geometric characteristic points on the face are identified as tracking and calculating objects through a binocular shooting technical means, the mark points do not need to be set manually, frequent contact and long-time exposure of workers under the face are avoided, and the safety risks of measurement and personnel are reduced; meanwhile, the problems that the installation work of the area above the tunnel face is difficult, a large amount of time is needed to be spent, and the interference is generated to the normal tunnel construction operation are solved, the construction safety can be guaranteed, and the working efficiency is greatly improved.

(2) The invention adopts a double-camera shooting scheme, and stations are freely set in a fixed distance in front of the tunnel face, so that the invention does not interfere with the normal construction of tunnel engineering compared with a fixed station setting and timing shooting scheme. On the other hand, compared with the currently common single-camera measurement scheme, the binocular shooting technology can calculate the three-dimensional space coordinates of the face feature points, further calculate the accurate three-dimensional space deformation of the face, provide face swelling deformation data for subsequent evaluation of face front surrounding rock geological conditions and establishment of face stability criteria, and establish a more complete and reasonable face stability determination system.

(3) Compared with the traditional method for calculating the deformation of the tunnel face by using the binocular camera, the method disclosed by the invention has the advantages that the deformation of the datum point is calculated firstly, the deformation of any part is calculated based on the three-point coordinates and the deformation value, a large amount of calculation can be avoided, and the measurement efficiency is greatly improved.

Drawings

FIG. 1 is a schematic flow chart of the present invention;

fig. 2 is a schematic diagram of a connected domain (horizontal skeleton is taken as an example) of a pixel 8 at an end point of a gun hole skeleton, wherein (2 a) is a left end point, (2 b) is a middle point, and (2 c) is a right end point;

FIG. 3 is a schematic diagram illustrating the effect of fitting a profile of a normal endpoint cross section;

FIG. 4 is a schematic diagram illustrating the effect of fitting the abnormal endpoint cross-sectional profile;

FIG. 5 is a schematic diagram of an anomaly determination model;

FIG. 6 is a schematic diagram of the contour fitting and image segmentation extraction of a tunnel face, wherein (6 a) represents the trace of blast holes, (6 b) represents the extraction of a skeleton of the blast holes, (6 c) represents the contour fitting of the tunnel face, and (6 d) represents the region segmentation of the tunnel face image;

FIG. 7 is a schematic diagram of the calculation of the included angle;

FIG. 8 is a schematic diagram showing the coordinate relationship between points calculated by deformation in a plane;

FIG. 9 is a schematic view of a bulging deformation calculation partition;

fig. 10 is a schematic diagram illustrating the deformation calculation of the bulging of the palm surface.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

Interpretation of terms

A palm surface: the tunnel face is also named , which is a term in tunnel construction. I.e. a working face where the excavation of a tunnel (in coal mining, mining or tunnelling) is constantly propelled forward.

Binocular photogrammetry: two cameras are used for positioning. For a characteristic point on an object, two cameras fixed at different positions are used for shooting the image of the object, and the coordinates of the point on the image planes of the two cameras are respectively obtained. As long as the precise relative positions of the two cameras are known, the coordinates of the feature point in the coordinate system for fixing one camera can be obtained by a geometric method, namely the position of the feature point is determined.

Marking points: the device is arranged on the surface of a measured object and is used as a control point or a measured point in the measuring process, so that the measuring precision and reliability are improved.

Examples

The method is based on a binocular photogrammetry technology, does not set artificial mark points and scales, and adopts an image processing algorithm to automatically identify and track the key points of the tunnel face; on the basis of resolving the space deformation of a small number of key points, three-point deformation data are adopted to calculate the plane deformation and bulging deformation of any part in the palm surface area, and the rapid measurement of the three-dimensional space deformation of the palm surface is realized.

As shown in fig. 1, the present embodiment provides a method for quickly measuring deformation of a tunnel excavation surface, including the following steps:

s1, acquiring a complete palm surface image through binocular shooting.

Two cameras are respectively arranged on two sides of the tunnel for synchronous acquisition, the range of the cameras from 30m to 50m from the tunnel face is optimal, and the complete tunnel face image acquisition is ensured; the light supplement lamp is turned on in the shooting process, and the light supplement equipment is equipped if necessary, so that the whole tunnel face is clear and visible and is free of shadow coverage.

The three-dimensional space coordinates of the feature points of the tunnel face can be calculated by adopting a binocular shooting technology, and further the three-dimensional space deformation of the tunnel face is calculated; and the method provides face bulging deformation data for subsequent evaluation of the geological conditions of surrounding rock in front of the face and establishment of face stability criteria, and establishes a more complete and reasonable face stability judgment system.

And S2, preprocessing the palm surface image.

The image preprocessing mainly comprises the following steps: and carrying out image denoising processing and image size unification. The image noise can be divided into gaussian noise and impulse noise aiming at dust and light source interference generated by a severe construction environment in a tunnel and self interference of photographing equipment. The method adopts a combined means of Gaussian low-pass filtering processing and median filtering processing, firstly adopts a Gaussian low-pass filtering method to filter and eliminate Gaussian noise, and then adopts a median filtering method to filter and eliminate pulse noise. And finally, performing pixel transformation processing on the palm surface image subjected to filtering processing, and performing image size unification and format standardization.

And S3, extracting the profile of the palm surface.

Taking the post-blasting columnar blast hole traces as identification objects, extracting a framework of each columnar blast hole trace by adopting a framework extraction algorithm, and extracting framework end points positioned on the tunnel face outline; based on the curvature change characteristic of the fitting curve, a screening judgment standard is provided on the basis of an experiment, extraction end points are judged one by one, abnormal points such as sharp points and catastrophe points caused by block dropping and risk elimination are eliminated, and the palm surface contour fitting is carried out after screening.

As shown in fig. 6, the extracting of the palm surface profile specifically includes:

(1) Blast hole skeleton extraction

Adopting a K3M sequential iterative processing algorithm, gradually carrying out corrosion operation from the periphery of a target image to the center of the target until the target image is corroded to the width of a single-layer pixel, and then extracting a blast hole skeleton, wherein the main operation process comprises the following steps:

1) Operating a single blast hole, extracting and recording target contour points;

2) Sequentially detecting 8 pixel neighborhoods of the contour points, judging whether the 8 pixel neighborhoods only contain 3 connected pixels, if so, deleting the 8 pixel neighborhoods from the contour points, and corroding corresponding points in the target image;

3) Sequentially detecting whether 8-pixel neighborhoods of the rest contour points in the step 2) only contain 3or 4 connected pixels, if so, deleting the points from the contour points, and corroding corresponding points in the target image;

4) Sequentially detecting whether 8 pixel neighborhoods of the rest contour points in the step 3) only contain 3or 4or 5 connected pixels, if so, deleting the points from the contour points, and deleting and corroding corresponding points in the target image;

5) Sequentially detecting whether the 8-pixel neighborhood of the residual contour points in the step 4) only contains a 3or 4or 5or 6 connected pixel, if so, deleting the point from the contour points, and corroding corresponding points in the target image;

6) Sequentially detecting whether 8 pixel neighborhoods of the remaining contour points in the step 5) only contain 3or 4or 5or 6or 7 connected pixels, if so, deleting the points from the contour points, and corroding corresponding points in the target image;

7) And repeatedly executing the operation until no object capable of corroding exists, and ending the operation to obtain the blast hole skeleton.

By adopting the processing method, morphological pixel corrosion operation is carried out on all the identified blast holes one by one at a time, and the skeleton of each blast hole is obtained and extracted.

(2) Blast hole frame endpoint extraction

And based on the extraction result of the blast hole skeletons, operating one skeleton by one skeleton, extracting end points and preparing for subsequent section contour fitting.

1) Carrying out binarization processing on the blast hole skeleton image, wherein the skeleton is black, and the background is white; and 8, judging connected domains of all skeleton pixel points: if 2 black pixels appear, the black pixels are end points, and if the number of the black pixels exceeds 2, the black pixels are middle points; and acquiring end points of two ends of the framework, as shown in figure 2.

2) And (3) taking the central pixel of the shot picture as a reference, respectively calculating Euclidean distances from the two end points to the reference pixel, as shown in formula (1), comparing distance values, eliminating the end point with larger distance, and keeping the end point with smaller distance as a subsequent contour fitting point.

In the formula: d is the Euclidean distance between two pixels;

p-end point, pixel coordinate (x, y);

q-base, pixel coordinate is (s, t).

(3) Abnormal point screening method based on curvature change characteristics

According to the geometric characteristics of the cross section of the highway tunnel, the designed cross section of the highway tunnel is a standard three-center circle combination, the cross section of the tunnel cannot be deformed before blasting, and the initial contour basically keeps an arc shape. The blasting quality control has uncertainty, so that the end point of the blast hole has poor quality; meanwhile, due to the existence of joints, the top of the tunnel may have a block falling trend; all the reasons can cause the phenomena of sharp points and catastrophe points in the initial section fitting process. And by eliminating abnormal points, the fitting precision is effectively improved.

If B' is an abnormal point caused by the block falling from the top, the abnormal point is disturbed in the subsequent construction process and integrally slides down, and the abnormal point needs to be removed when the initial section is fitted.

As can be seen from FIG. 3, the normal section profile, from A to B to C, has smooth curves and small overall curvature variation; the curvature of the fitted curve with outliers varies greatly at points a, B', and C, as shown in fig. 4.

Therefore, the abnormal point can be determined according to the degree of curvature change. On the other hand, the curvature calculation is complex to directly carry out, and the judgment reference is not easy to determine, so that the method converts the curvature calculation into a method for judging the included angle of the vector to carry out judgment, and provides a quantitative judgment standard.

As shown in fig. 5, A, B, C are 3 adjacent points, and arc ABC is a color trace contour curve. And establishing a coordinate system as a figure, wherein the AC direction is an x axis, and the Y axis is established by taking the AC middle point as a coordinate origin O.

For the design profile, vector AB is at a positive angle of less than 90 degrees to the y-axis. Due to the problems of construction factors, geological factors and image processing technologies, the position of an actually extracted blast hole endpoint B ' changes, the curvature of a fitted arc AB ' C changes, and the forward included angle between a vector AB ' and a y axis also changes.

Based on a large number of fitting tests, the influence of curve fitting precision is considered to be small when the B' point is positioned in 1 st and 2 nd boundaries of a coordinate system, and the vector included angle theta is considered to be small at the moment ₁ Less than 90 degrees; when the point B' is located in the 3 rd and 4 th image limits of the coordinate system, the fitting result is poor and can be judged as an abnormal point, and the vector included angle theta is determined at the moment ₂ Greater than 90 degrees.

The following formula can be used for the calculation of the included angle:

(4) Palm surface contour fitting based on least square method

Based on the screened blast hole end points as fitting data, for the initial section profile, a least square method can be adopted to perform segmented circle fitting, and finally the tunnel section profile of the three-center circle is combined. For the subsequently deformed section, piecewise polynomial fitting can be adopted.

For least squares fitting of the circle, the following algebraic sum of squares of distances and their correction formula are used:

in the formula: x is the number of _i -fitting the data points abscissa;

y _i -fitting the data point ordinate;

x _c -fitting a circle center abscissa;

y _c -fitting the circle center ordinate.

And S4, extracting the palm surface datum points.

And extracting the key points of the profile of the tunnel section, including the arch crown, the two arch springing and the like, based on the extracted curvature change characteristics of the profile of the tunnel face. The method comprises the steps that a plurality of datum points are obtained based on key points of a tunnel section contour, the datum points are selected according to deformation types of three-dimensional space deformation, different datum points are selected according to different deformation types, and the deformation types of the three-dimensional space deformation comprise in-plane deformation and bulging deformation.

In order to grasp the convergence and deformation of the palm surface, the arch crown and arch foot point of the palm surface need to be extracted. For different construction conditions, the following regulations are made:

1) For the bench method excavation, only part of the tunnel face can be shot, and the intersection point of the side wall and the ground surface is used as an arch springing for deformation monitoring.

2) To full section excavation, can shoot whole section, carry out deformation monitoring with inverted arch and the junction of becoming strong as the hunch foot.

Accordingly, the determination of the arch crown and arch springing is specifically as follows:

(1) Vault determination

The vault is positioned at the uppermost end of the section, the characteristic can be directly adopted to judge the vertical coordinate value of each contour pixel point, and the pixel point with the largest vertical coordinate value is a vertex for subsequent section convergence calculation.

(2) Determination of arch springing

And identifying the arch crown and the arch foot by taking the curvature change characteristics as evaluation criteria for the segmented tunnel face image.

For the step method excavation, the arch springing is the junction of the circular arc and the ground. For full-section excavation, the arch springing is the junction of a circular arc and an inverted arch, and all the arch springing has obvious curvature change. And recording the catastrophe point of the curvature value by adopting a method of calculating the curvature value of the boundary pixel, and marking the catastrophe point as an arch springing.

The method comprises the following steps: as shown in fig. 7, at any point, two vectors, i.e., the front and rear vectors, are ω, and an angle θ between them is calculated. Namely: taking the ω -th point in front of the point and the ω -th point behind the point, and respectively forming 2 vectors v with the point ₁ And v ₂ Then v is ₁ And v ₂ The included angle of (c):

the arch springing determination method comprises the following steps:

1) For the step method, the ground is a straight line and the curvature is 0; when the curvature mutation is 0, marking as an arch springing;

2) For the full-section method, the inverted arch is obviously gentler than the arch crown, the arch shoulder and the side wall, and the curvature is obviously smaller; when the rate of ablation is abruptly changed to a smaller value and the subsequent curvature continues to remain at the smaller value, the mark here is the arch springing.

And S5, calculating the three-dimensional space deformation of the reference point based on image matching and coordinate calculation.

Based on two contemporaneous images obtained by binocular shooting, performing parallax calculation on the two images by adopting an SGBM algorithm, calculating to obtain three-dimensional space information of the images according to the geometric relation of parallel binocular vision, and calculating the three-dimensional space deformation of the reference point based on comparison of a plurality of images.

And S6, calculating the deformation of the tunnel face. In view of solving the three-dimensional space coordinates of each point on the tunnel face, the calculation amount is large, a large amount of time is consumed, and the requirement of timely monitoring in the engineering can not be met. In the embodiment, key points such as the arch crown, the arch springing, the center of the face and the like are used as calculation reference points, the face is divided into areas, and deformation values of all parts of the face are calculated by adopting deformation data of the three reference points, so that a large amount of calculation can be avoided, and the face deformation can be quickly obtained.

According to different deformation types, the deformation calculation of the tunnel face is realized based on three selected different reference points, which specifically comprises the following steps:

(1) In-plane deformation calculation method

1) Dividing the whole face into a middle triangular area and two side arc areas, as shown in fig. 8;

2) For the middle triangular area, the deformation of the arch crown and the arch feet at two sides can be taken as reference points which are respectively marked as A, B, C, and the deformation value of any point P in the middle triangular area is calculated;

3) And for the arc areas on the two sides, adding the middle point of the arc section as a reference point, recording as D, E, and calculating the deformation of the arc area by taking the arch crown, the arch foot and the middle point of the arc section as the reference points.

Taking the middle triangle area as an example, the transverse displacement u of the point A is known _A Longitudinal displacement v _A Transverse displacement u of point B _B Longitudinal displacement v _B C point lateral displacement u _C Longitudinal displacement v _C . The displacement (u, v) of any point P on the tunnel face can be expressed as a polynomial combination of coordinates:

for three reference points, there are:

v _C ＝β ₄ +β ₅ x _C +β ₆ y _C (6-2)

the horizontal and longitudinal displacements are arranged in a matrix form, and the P-point displacement can be obtained through transformation solving:

in the formula:

under the condition that the coordinate and the deformation value of the datum point A, B, C are known, the plane deformation value of any P point in the ABC area can be rapidly solved according to the formula.

For the arc-shaped areas on the two sides, the above formula can be adopted to solve according to the datum point A, B, D or A, C, E.

(2) Bulging deformation calculation method

For the bulging deformation of the palm surface, due to the fact that the size of the palm surface is large, the bulging deformation amount is small, although the bulging surface is arc-shaped, the curvature radius is large, the bulging deformation amount is approximate to a straight line, and an interpolation method is adopted for approximate calculation.

The division of the palm surface area is shown in fig. 9, the image processing means is adopted to identify the midpoint of the palm surface core area, marked as O, and set as one reference point, and any two adjacent points in the arch crown, two arch feet and the two arc segment midpoints of the arc area between the arch crown and the two arch feet are used as the other two reference points to form three reference points.

The specific calculation method is as follows:

taking the area OBD as an example, as shown in fig. 10, the plane ODB is an initial palm surface, and O ' D ' B ' is a deformed palm surface; under the condition that coordinates of O, D, B three reference points and bulging deformation are known, deformation is calculated by adopting a similar triangle principle.

Within the right trapezoid B 'BDD':

within the right trapezoid H 'HOO':

by the above formula, the length of PP' can be obtained, i.e. the amount of bulging deformation of the point P.

The above method, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

Example 2

The embodiment provides a rapid detection device for deformation of a tunnel excavation face, which comprises a binocular camera and an industrial personal computer, wherein one or more programs capable of being executed are stored in the industrial personal computer, and the one or more programs comprise instructions for executing the rapid measurement method for deformation of the tunnel excavation face according to embodiment 1. The binocular camera is arranged at appropriate positions on two sides of the tunnel through a support, preferably, two cameras can be arranged within a range of 30m-50m in front of the tunnel, and the cameras are connected with an industrial personal computer to realize local real-time return and processing of collected images.

In a preferred embodiment, the device further comprises a light supplement device for supplementing light to the tunnel face.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the prior art according to the concepts of the present invention should be within the scope of protection determined by the claims.

Claims

1. A method for rapidly measuring deformation of a tunnel excavation surface is characterized by comprising the following steps:

performing tunnel face contour fitting on the preprocessed tunnel face image based on the blast hole traces after blasting, and extracting a tunnel face contour to obtain a tunnel face area;

2. The method for rapidly measuring the deformation of the tunnel excavation face according to claim 1, wherein the preprocessing includes image denoising processing and image size unification.

3. The method for rapidly measuring deformation of the tunnel excavation face according to claim 1, wherein the step of performing tunnel face profile fitting on the preprocessed tunnel face image based on the blast hole traces after blasting specifically comprises:

and fitting the profile points as fitting data based on a least square method.

4. The method for rapidly measuring the deformation of the tunnel excavation face according to claim 3, wherein the screening to obtain the skeleton end points specifically comprises:

5. The method for rapidly measuring the deformation of the tunnel excavation face according to claim 3, wherein the abnormal point is obtained based on the judgment of a vector included angle, and specifically comprises the following steps:

and judging whether the included angle between the vector AB and the forward direction of the y axis is larger than 90 degrees, if so, judging that the point B to be judged is an abnormal point.

6. The method for rapidly measuring the deformation of the tunnel excavation face according to claim 1, wherein the method for extracting the vault comprises the following steps:

the extraction method of the arch springing comprises the following steps:

for the step method excavation, the pixel points with the contour pixel point curvature mutation of 0 are taken as arch springing;

7. The method for rapidly measuring the deformation of the tunnel excavation face according to claim 1, wherein for the in-plane deformation, the reference points are selected as follows:

dividing the tunnel face area into a middle triangular area and two side arc areas based on the vault and the arch springing;

8. The method for rapidly measuring the deformation of the tunnel excavation face according to claim 1, wherein for the bulging deformation, the extracting of the reference point of the face area specifically comprises:

9. The method for rapidly measuring the deformation of the tunnel excavation face according to claim 1, wherein the specific calculation process of the three-dimensional space deformation of the reference point comprises the following steps:

10. A rapid detection device for tunnel excavation face deformation, which is characterized by comprising a binocular camera and an industrial personal computer, wherein one or more programs capable of being executed are stored in the industrial personal computer, and the one or more programs comprise instructions for executing the rapid measurement method for tunnel excavation face deformation according to any one of claims 1 to 9.