CN114511678A - Tunnel overbreak and underexcavation numerical value calculation method based on laser point cloud measurement - Google Patents

Abstract

The invention discloses a tunnel overbreak and underexcavation numerical calculation method based on laser point cloud measurement. The existing measuring method for tunnel overbreak and underbreak by utilizing laser point cloud is calculated aiming at a specific type of tunnel, and the universality is poor. Establishing an XOY coordinate system, connecting tunnel section excavation outlines on a tunnel section outline design drawing into a curve C, equally dividing the curve C, and connecting equally divided points into lines S in a clockwise direction; converting the laser point cloud data of the profile of the tunnel section into an XOY coordinate system; and searching a line segment closest to the jth laser point cloud on the S, and calculating the distance from the jth laser point cloud to the closest line segment, namely the overbreak numerical value of the jth laser point cloud. The method meets the extraction of the over and under excavation numerical values of various types of tunnels, can quickly acquire the over and under excavation numerical values, and provides guarantee for the tunnel construction quality.

Description

Tunnel overbreak and underexcavation numerical value calculation method based on laser point cloud measurement

Technical Field

The invention belongs to the technical field of laser point cloud measurement, and particularly relates to a tunnel overbreak and underexcavation numerical calculation method based on laser point cloud measurement.

Background

The tunnel construction process is influenced by factors such as geological conditions, surrounding rock structures, rock stratum structures, hydrogas and the like, and the phenomenon of over-underexcavation of the tunnel is frequently encountered. The formation process of the super-under excavation is that the excavation can collapse rock blocks, so that surrounding rock disturbance is caused, the stress state of the surrounding rock is changed, and when the shear strength of a rock mass structural plane is smaller than the downward sliding force, part of rock mass slides down, and the super-under excavation phenomenon is generated. The excessive excavation leads to the increase of primary support sprayed concrete, the quality defect of cavity formation appears after the primary support is excavated in excess at the cross section of the surrounding rock, and the amount of secondary lining concrete is increased, thereby increasing the cost. The underdigging directly affects the lining thickness, and the treatment wastes time and labor.

The existing method for measuring the tunnel overbreak and underbreak by utilizing the laser point cloud carries out sectional calculation according to an outer contour line member of a tunnel design drawing. Different tunnels, the outermost contour line of design is different, can only calculate to specific type's tunnel like this, and the universality is relatively poor.

The article of 'a method for rapidly obtaining measurement data of primary support overbreak and underbreak of tunnel' published by wainscot et al, the article calculates a tunnel section consisting of a plurality of sections of circular arcs, and calculates the overbreak and underbreak value of a point to be measured by combining simple programming of a Kasioh calculator and three-dimensional coordinates of a total station through a geometric method, wherein the overbreak and underbreak value of only one point can be detected at one time, and batch calculation cannot be carried out.

Patent [ CN108871268A ] a method for calculating an overbreak and overbreak numerical value of a tunnel based on laser point cloud, which provides a method for calculating an overbreak and underbreak numerical value of a tunnel based on laser point cloud, wherein the method can calculate overbreak and underbreak data of point cloud, and the method is only suitable for calculating the overbreak and underbreak numerical value of a tunnel consisting of arc segments.

Disclosure of Invention

In order to make up for the defects of the prior art, the invention provides the tunnel over and under excavation numerical value calculation method based on laser point cloud measurement, which can meet the extraction of various tunnel over and under excavation numerical values and provide effective guarantee for the tunnel construction quality.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a tunnel under-excavation numerical calculation method based on laser point cloud measurement comprises the following steps:

the method comprises the following steps: acquiring a design drawing of the profile of the section of the tunnel, and establishing an XOY plane coordinate system;

step two: connecting the tunnel section excavation outlines of the design drawing into a curve C;

step three: equally dividing the curve C obtained in the step two, and connecting the equally divided points in a clockwise direction to form a line S; the line S is composed of n vertices, which are set as: v. of₁，v₂……v_nEvery two adjacent vertexes form a line segment, and the distance of each line segment is respectively as follows: | v₁v₂|、|v₂v₃|……|v_n-1v_n|；

Step four: acquiring laser point cloud data of the profile of the cross section of the tunnel, converting the laser point cloud data into an XOY plane coordinate system, and calculating the coordinate azimuth angle alpha of each laser point cloud data_j；

Step five: searching the jth laser point cloud (x) on the line S_j,y_j) Nearest line segment s_jCalculating the jth laser point cloud (x)_j,y_j) To line segment s_jDistance d of_jI.e. byThe value of the underrun of the jth laser point cloud, d_jThe calculation method is as follows:

wherein d is_jIs the overbreak value, x, of the jth laser point cloud_jAs the abscissa, y, of the jth laser point cloud_jDistance (x) on line S as ordinate of jth laser point cloud_j,y_j) The nearest line segment is denoted as s_jLine segment s_jHas an endpoint coordinate of (x)_i,y_i) And (x)_i+1,y_i+1)，s_jThe straight line is marked as L_j，k_iIs L_jSlope of (b)_iIs a straight line L_jIntercept on the y-axis.

Specifically, the distance j from the jth laser point cloud (x) on the search line S_j,y_j) Nearest line segment s_jThe method comprises the following steps:

laser point cloud point j (x)_j,y_j) Is denoted by p_jCalculating the distance difference:

dist_n-1＝|p_jv_n-1|+|p_jv_n|-|v_n-1v_n|

calculating dist₁，dist₂……dist_n-1Get min { dist₁，dist₂……dist_n-1}，dist_n-1The line segment corresponding to the minimum value is the distance (x) on the line S_j,y_j) Nearest line segment s_j。

The invention has the beneficial effects that:

1) the method has a simple calculation principle and a wide application range, can meet the requirement of extracting various tunnel overbreak values such as straight wall arches, door-opening types, three-center round flat arch multi-vehicle with inverted arches, horseshoe-shaped tunnel shapes, circles and the like, can quickly obtain the overbreak values, can accurately obtain the overbreak values corresponding to the laser cloud, and provides an effective guarantee for the tunnel construction quality;

2) the plane coordinate system is reasonably established, the calculation method of the coordinate azimuth angle is reasonable and feasible, the calculation process can be simplified, accurate data information can be obtained, and the practicability is high.

Drawings

FIG. 1 is a bisector diagram of a tunnel plan outline composed of arbitrarily shaped lines;

FIG. 2 is a design excavation contour line and a point cloud chart of a door opening type tunnel;

fig. 3 is a graph showing the design excavation contour line and the point cloud of the arc tunnel.

Detailed Description

The present invention will be described in detail with reference to specific embodiments.

FIG. 2 is a graph showing the contour lines and point clouds in the design of the door opening type tunnel

In this embodiment, a portal tunnel is taken as an example to explain the present invention in detail, and the method specifically includes the following steps:

the method comprises the following steps: acquiring a design drawing of the profile of the section of the door opening type tunnel, and establishing an XOY plane coordinate system; the XOY plane coordinate system is specifically as follows: the center line of the tunnel is a coordinate origin at the designed elevation, the X axis is a horizontal line of the origin, and the Y axis is a straight line superposed with the center line of the tunnel;

step two: connecting the tunnel section excavation outlines of the design drawing into a curve C; the tunnel section of the design drawing generally comprises a plurality of sections of arcs or arcs and straight lines, wherein the arcs and the straight lines are independent entities, and the entities are connected into a curve, so that the shape of the curve is kept unchanged and no repeated point exists;

step three: as shown in fig. 1, equally dividing the curve C obtained in the second step, and connecting the equally divided points in a clockwise direction to form a line S; the line S is composed of n vertices, which are: v. of₁，v₂……v_nAnd each two adjacent vertexes form a line segment, so that the line S can be regarded as being composed of n-1 line segments, and the distances of the line segments are respectively as follows: | v₁v₂|、|v₂v₃|……|v_n-1v_nL. The length of the curve C is L, the line length tolerance before and after conversion is delta, and the conversion tolerance satisfies an expression 1);

n₀is a number of equal parts of curve C, where n₀The value is generally 1000;

step four: as shown in fig. 2, laser point cloud data of the tunnel section profile is obtained, and the laser point cloud data of the tunnel section profile can be obtained by vehicle-mounted laser, airborne laser or ground laser scanning; converting the laser point cloud data into an XOY plane coordinate system, and calculating the coordinate azimuth angle alpha of each laser point cloud data_jAzimuth angle of coordinate α_jValue range [ -pi, pi [ -pi [ ]]；

Coordinate azimuth angle alpha_jThe calculation method is as follows:

wherein: alpha is alpha_jIs the coordinate azimuth, x, of the jth laser point cloud_jAs the abscissa, y, of the jth laser point cloud_jIs the ordinate of the jth laser point cloud.

Step five: searching the jth laser point cloud (x) on the line S_j,y_j) Nearest line segment s_jCalculating the jth laser point cloud (x)_j,y_j) To line segment s_jDistance d of_jI.e. the super under-dig value, d, of the jth laser point cloud_jThe calculation method is as follows:

wherein d is_jIs the overbreak value, x, of the jth laser point cloud_jAs the abscissa, y, of the jth laser point cloud_jDistance (x) on line S as ordinate of jth laser point cloud_j,y_j) The nearest line segment is denoted as s_jLine segment s_jHas an endpoint coordinate of (x)_i,y_i) And (x)_i+1,y_i+1)，s_jThe straight line is marked as L_j，k_iIs L_jSlope of (b)_iIs a straight line L_jIntercept on the y-axis.

5.1 search for line segment s_j

Searching the jth laser point cloud (x) on the line S_j,y_j) Nearest line segment s_jThe method comprises the following steps:

laser point cloud point j (x)_j,y_j) Is denoted by p_jCalculating the distance difference:

dist_n-1＝|p_jv_n-1|+|p_jv_n|-|v_n-1v_n| 4)

according to equation 4), dist is calculated₁，dist₂……dist_n-1：

Laser point cloud point j (x)_j,y_j) Is denoted by p_jCalculating

dist₁＝|p_jv₁|+|p_jv₂|-|v₁v₂| 5)

|p_jv₁|、|p_jv₂|、|v₁v₂L is the distance between two points, dist₁Representing distance differences, and the like;

dist₂＝|p_jv₂|+|p_jv₃|-|v₂v₃| 6)

……

dist_n-1＝|p_jv_n-1|+|p_jv_n|-|v_n-1v_n| 7)

get min { dist₁，dist₂……dist_n-1}，dist_n-1The line segment corresponding to the minimum value is the distance (x) on the line S_j,y_j) Nearest line segment s_j；

5.2 calculation of k_i，b_iStraight line L_jEquation of straight line

k_i＝(y_i+1-y_i)/(x_i+1-x_i) 8)

b_i＝x_i-y_i/k_i 9)

y＝k_ix+b_i 10)

In this embodiment, 118 data points on the laser point cloud cross section are calculated, and the result is as follows:

such as the arc tunnel of fig. 3 and other types of tunnels, can be implemented according to the method of the present invention.

The invention is not limited to the examples, and any equivalent changes to the technical solution of the invention by a person skilled in the art after reading the description of the invention are covered by the claims of the invention.

Claims (2)

1. A tunnel under-excavation numerical calculation method based on laser point cloud measurement is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: acquiring a design drawing of the profile of the section of the tunnel, and establishing an XOY plane coordinate system;

step two: connecting the tunnel section excavation outlines of the design drawing into a curve C;

step three: equally dividing the curve C obtained in the step two, and connecting the equally divided points in a clockwise direction to form a line S; the line S is composed of n vertices, which are set as: v. of₁，v₂……v_nEvery two adjacent vertexes form a line segment, and the distance of each line segment is respectively as follows: | v₁v₂|、|v₂v₃|……|v_n-1v_n|；

Step four: acquiring laser point cloud data of the profile of the cross section of the tunnel, converting the laser point cloud data into an XOY plane coordinate system, and calculating the coordinate azimuth angle alpha of each laser point cloud data_j；

Step five: searching the jth laser point cloud (x) on the line S_j,y_j) Nearest line segment s_jCalculating the jth laser point cloud (x)_j,y_j) To line segment s_jDistance d of_jI.e. the super-under-dig value of j laser point cloud, said d_jThe calculation method is as follows:

wherein d is_jIs the overbreak value, x, of the jth laser point cloud_jAs the abscissa, y, of the jth laser point cloud_jDistance (x) on line S as ordinate of jth laser point cloud_j,y_j) The nearest line segment is denoted as s_jLine segment s_jHas an endpoint coordinate of (x)_i,y_i) And (x)_i+1,y_i+1)，s_jThe straight line is marked as L_j，k_iIs L_jSlope of (b)_iIs a straight line L_jIntercept on the y-axis.

2. The method for calculating the tunnel overbreak and underexcavation numerical value based on the laser point cloud measurement as claimed in claim 1, wherein: the j-th laser point cloud (x) on the search line S_j,y_j) Nearest line segment s_jThe method comprises the following steps:

laser point cloud point j (x)_j,y_j) Is denoted by p_jCalculating the distance difference:

dist_n-1＝|p_jv_n-1|+|p_jv_n|-|v_n-1v_n|

calculating dist₁，dist₂……dist_n-1Get min { dist₁，dist₂……dist_n-1}，dist_n-1The line segment corresponding to the minimum value is the distance (x) on the line S_j,y_j) Nearest line segment s_j。

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