CN105067294A - Mining overburden separated strata allometry test monitoring system and analysis method - Google Patents

Abstract

The invention discloses a mining overburden separated strata allometry test monitoring system based on the digital speckle technology and an analysis method. The system comprises an experiment terminal, a monitoring terminal, and a processing terminal, the experiment terminal comprises an experiment table and an experiment model, the monitoring terminal comprises a high-speed camera, an industrial camera, a support, a white light source, and a calibrated scale, and the processing terminal comprises image acquisition cards, computers, and mobile hard disks. According to the method, simulation tests of similar materials are monitored based on the digital speckle technology, the allometry theory is employed for the analysis and measurement of the mining overburden separated strata caused by mining, the change condition of speckle points on the surface of an object is shot with the combination of the white light digital speckle method, deformation information of the object surface is obtained via the tracking of the movement of the points, micron-grade monitoring precision can be realized, the problem of difficult artificial capture is better solved, the allometry theory is firstly introduced for analysis, and quantified research of the development process is realized.

Description

A kind of mining overburden absciss layer allometry test monitoring system and analytical approach

Technical field

The invention belongs to mining safety monitoring technology field, relate to a kind of analytical approach of new mining overburden absciss layer evolution, particularly a kind of analytical approach of the mining overburden absciss layer allometry similar material simulation experiment based on digital speckle technology.

Background technology

Vast territory and abundant resources in China, and aboundresources variation, wherein energy resources also exist rich coal resources, the feature that oil, natural gas source are relatively less.Along with developing rapidly of economy, the demand of people to the energy is increasing, although the prosperity of science and technology creates some novel energies, the demand of coal resources is still in occupation of leading position.A large amount of demands causes people's transition to cut coal, thus has caused large-area settlement of stratum.China Subsidence Area adds up to nearly 12000Km ², accumulative economic loss is more than 60,000,000,000 yuan, and along with the continuous growth of coal in China industry and coal production, mining area's area that subsides also can constantly increase.

Exploitation Subsidence damage to be controlled and control is studied, be conducive to stable, social life stable of the development of coal in China industry, ecologic environment.In Coal Mining Subsidence theory, absciss layer is the key factor of impact, the factor such as size, locus, law of development of the size that overlying strata separation layer produces all can produce certain impact to the pests occurrence rule of mining subsidence, so further can improve mining subsidence theory to the research of mining overburden absciss layer generation rule, thus infringement that more effective control production depression causes.

At present, domestic scholars utilizes the methods such as theoretical analysis, Physical Experiment, numerical simulation to carry out large quantifier elimination to overlying strata separation layer, achieves great successes for the Production conditions of absciss layer, development characteristics, distribution range, the aspect such as the influence factor of absciss layer and the differentiation of absciss layer size.But for micro-macromechanics rule of complicacy, non-linear time and space idea, particularly wall scroll absciss layer different stages of development and the speed rule of different stages of development of absciss layer development, the Difference of different layers position absciss layer development is not enough; To the determining across scale feature understanding, the research of friction speed Characteristics of Development, quantitative description, mechanical behavior of absciss layer, Dynamic Evolution inverting, particularly consider problems not well research and the solutions especially such as mining overburden absciss layer allometry, therefore, the present invention is based on the overall process that equivalent material simulating scheme develops at laboratory reappearance mining overburden absciss layer, and the digital speckle technology of application of advanced has carried out comprehensive monitoring to the dynamic evolution of absciss layer, for the allometry theory of mining overburden absciss layer provides a kind of new research method.

Summary of the invention

The object of the invention is to overcome the deficiency in existing mining overburden absciss layer similar material simulation experiment, based on white light digital speckle correlation technique, the allometric experiment analytical method of a kind of absciss layer is proposed, improve artificial capture method difficult problem and the monitoring accuracy problem of absciss layer change in the evolution of mining overburden absciss layer, solve the problem that mining overburden absciss layer dynamic development process is difficult to quantitative description, the research for mining overburden absciss layer provides more scientific effective research method.

The present invention is achieved through the following technical solutions:

The invention provides a kind of mining overburden absciss layer allometry test monitoring system, this system comprises experimental terminal, monitoring terminal (data acquisition front) and processing terminal; Described experimental terminal comprises experiment table and empirical model; Described monitoring terminal comprises high speed camera, industrial camera, support, white light source and rule; Described processing terminal comprises image pick-up card, computing machine and portable hard drive.

Empirical model is fixed on experiment table, and high speed camera and industrial camera are fixed on empirical model front by support, and high speed camera connects image pick-up card I and Computer I successively, and industrial camera connects image pick-up card II, Computer I I and portable hard drive successively; White light source is arranged at empirical model front; Rule is arranged at the surface of empirical model, is positioned at the visual field of high speed camera and industrial camera.

Described white light source quantity at least 1.

Based on an analytical approach for above-mentioned mining overburden absciss layer allometry test monitoring system, step is:

(1) experimental terminal simulation that coal seam is excavated: make experiment table and empirical model with the material similar to mine, coal seam, and simulate the whole process of mine, coal seam excavation;

(2) monitoring terminal is to the collection of data: the absciss layer photographic intelligence being gathered experimental terminal by high speed camera and industrial camera, utilize digital speckle technology to carry out Taking Photographic to speckle, and the photographic intelligence collected is sent to processing terminal by data transmission link;

(3) processing terminal is to the treatment and analyses of data: computing machine utilizes DSCM (white light digital correlation speckle method) software to carry out computing to the speckle image photographed, according to image before being deformed after speckle gray feature change, distortion corresponding relation before and after image is set up obtains deformation information, obtain shear strain change cloud atlas and the related coefficient of mining overburden absciss layer, obtain the situation of change of stress according to the stress-strain relation of material; Introducing allometry is theoretical, the friction speed growth factor α that definition is relevant, calculates α value, and judges the growth conditions of certain one deck position absciss layer in certain moment according to α value.

Before on-test, the time synchro of utilization carries out the time calibration of two computing machines, ensures the synchronism of image data.

In step (2), for avoiding the skew due to high speed camera and industrial camera to make troubles to digital speckle correlation computations, controlled the switch of high speed camera and industrial camera by computing machine.

In step (2), demarcate empirical model with rule, rule is close to empirical model surface and is arranged, and takes the image of a width rule, according to the corresponding relation of rule length and pixel count in image, draw the conversion relation of pixel and long measure.

In step (2), test the initial stage the camera speed of taking pictures be 0.5-1.5 second/, test the middle and later periods the camera speed of taking pictures be 4-6 second/.

In step (3), when the distortion with Digital Speckle Correlation Method measurement model, first before and after model deformation occurs, take two speckle patterns respectively, be expressed as follows with gamma function:

Before distortion: F}={F (x, y), x=1 ..., M, y=1 ..., N}

After distortion: G}={G (x, y), x=1 ..., M, y=1 ..., N}

In formula: M × N is the size of speckle field, unit is pixel;

From the speckle pattern before model deformation, choose a zonule, and search for the particle structure matched in speckle pattern after deformation, obtain displacement and the deformation information in this region, the computing formula of the related coefficient C related to is:

$C=\frac{\mathrm{\Σ}\[f(x,y)-\stackrel{\‾}{f}\]\[g\left(x^{,}{,}^{,}y\right)-g\]}{\sqrt{\mathrm{\Σ}{\[f(x,y)-\stackrel{\‾}{f}\]}^2}\sqrt{\mathrm{\Σ}{\[g\left(x^{,}{,}^{,}y\right)-\stackrel{\‾}{g}\]}^2}}$

In formula: f}={f (x, y), x=1 ... i, y=1 ..., j} and g}={g (x, y), x=1 ... i, y=1 ..., j} is the gamma function of the sample image of two zonules; be respectively f (x, y), the average item of g (x, y).

The strain displacement of overlying strata separation layer development and derivative component thereof represent, its computing formula is as follows:

${\mathrm{\ϵ}}_x=\frac{\∂u}{\∂x}+\frac{1}{2}\[{\left(\frac{\∂u}{\∂x}\right)}^2+{\left(\frac{\∂v}{\∂x}\right)}^2\]$

${\mathrm{\ϵ}}_y=\frac{\∂u}{\∂y}+\frac{1}{2}\[{\left(\frac{\∂u}{\∂y}\right)}^2+{\left(\frac{\∂v}{\∂y}\right)}^2\]$

${\mathrm{\γ}}_{xy}=\frac{1}{2}\left(\frac{\∂u}{\∂y}+\frac{\∂v}{\∂x}\right)+\frac{1}{2}\left(\frac{\∂u}{\∂x}\frac{\∂u}{\∂y}+\frac{\∂v}{\∂x}\frac{\∂v}{\∂y}\right)$

In formula: u is the displacement component in x direction, v is the displacement component in y direction, ε _xfor the strain tensor in x direction, ε _yfor the strain tensor in y direction, γ _xyfor the shear strain of xy plane;

Absciss layer development presents allometry pattern, and the computing formula of speed ν is:

$v=\frac{W_{max}{e}^{-\mathrm{\β}x}(sin\mathrm{\λ}x+cos\mathrm{\λ}x)-\frac{p^{\′}}{24E^{\′}{I}^{\′}}{(x^2-d^2)}^2}{t}$

In formula: β is the fitting coefficient of curve, λ is the flexibility eigenwert of beam, W _maxfor the maximum sinking value of beam on elastic foundation, p ' is earthing body gravity load on rock beam, the bendind rigidity that E ' I ' is rock beam, and d is the boundary length of rock beam, and x is the horizontal range of calculation level apart from beam mid point, and t is the time that excavation is corresponding.

The formula that Allometric Relationships judges as:

In formula: represent the ratio of upper the next rock depression amount of a certain moment, its value is constant; W _underfor the sinking amount of deflection of the next rock stratum of absciss layer, W _onfor the sinking amount of deflection of the upper rock stratum of absciss layer.

Constant α according to calculating is friction speed growth factor, its reaction be the ratio of the relative growth rate of the next rock stratum and the relative growth rate of upper rock stratum, be worth size to judge according to α:

(1) as α >1, show as positive allometry result, the fall rate of the next rock stratum is greater than the fall rate of upper rock stratum, and absciss layer is in crack initiation, developing stage;

(2) when α=1, show as isogony result, the fall rate of the next rock stratum equals the fall rate of upper rock stratum, and now absciss layer develops into maximum;

(3) as α <1, show as negative allometry result, the fall rate of the next rock stratum is less than the fall rate of upper rock stratum, and absciss layer is in close stage.

The experimental terminal of the present invention material similar to mine, coal seam makes experiment table and empirical model, simulates the whole process of mine, coal seam excavation to greatest extent, closest to actual recovery process, therefore has important directive significance to actual exploitation work.

Monitoring terminal, for information such as the absciss layer photos that gathers, adopts Two-point distribution formula monitoring system, adopts high speed camera and industrial camera to carry out the dual collection of data simultaneously, and the enterprising row relax analysis of the computer system being transferred to two platform independent work.Adopt two cameras to process simultaneously and can effectively reduce the impact of unscheduled event for experimental precision, the data complement of two point form monitoring is simultaneously conducive to the accuracy improving interpretation.High speed camera and industrial camera are erected on fixed support, are the accuracies in order to the speckle pattern photographed, and need ensure that in whole experimentation, collecting device can not be moved.White light source is placed on empirical model front, ensures to illuminate whole model, by digital speckle camera work, carries out on-the-spot Taking Photographic to object of observation, gathers out the model surface image in experimentation, be sent to processing terminal by data transmission link.

Processing terminal has memory function and controlling functions concurrently, the image transmitting of high speed camera and industrial camera shooting is stored in computing machine and portable hard drive in order to process after image pick-up card carries out digitizing, computing machine utilizes DSCM (white light digital correlation speckle method) software to carry out related operation to the speckle photographed, according to image before being deformed after speckle gray feature change, distortion corresponding relation before and after image is set up obtains deformation information, and the precision of the experiment material surface displacement recorded by DSCM method can reach micron level.The change in displacement situation in absciss layer evolution clearly can be captured according to the shear strain cloud atlas obtained after digital speckle process.

After having tested, correlation computations is carried out to speckle image, the shear strain of mining overburden absciss layer, the change cloud atlas of principal strain and related coefficient can be obtained, the situation of change of stress can be obtained according to the stress-strain relation of material.Introducing allometry is theoretical, the friction speed growth factor α that definition is relevant, the growth conditions of certain one deck position absciss layer in certain moment can be judged according to relevant computing formula, when being calculated as positive allometry result, absciss layer is in crack initiation, developing stage, and when being calculated as isogony result, absciss layer develops into maximum, when being calculated as negative allometry result, absciss layer is in close stage.

Compared with prior art, the present invention adopts digital speckle technology as the monitoring means of mining overburden absciss layer similar material simulation experiment, its measuring principle is more reliable, determination techniques equipment is more advanced, whole system can observe the situation of change in the absciss layer crack of micron level more accurately, more easily catch the situation of change of absciss layer length and width in different evolution, better solving the problem of artificial capture method difficulty, is that conventional monitoring methods does not reach, the present invention is theoretical by allometry first to combine with the development of mining overburden absciss layer, mining overburden is considered as a total system, introduce the allometric concept of absciss layer, solve the problem being difficult to quantitative description in absciss layer evolutionary process, pass through computing, absciss layer crack initiation is disclosed from root, development and closed essence, fill up the theoretical blank in allometry of existing Coal Mining Subsidence, what provide a kind of quantification for later mining overburden absciss layer similarity simulation experiment researchs and analyses method, for the control of Coal Mining Subsidence disaster and control provide theoretical direction.

Accompanying drawing explanation

Fig. 1 is main process steps flow chart schematic diagram of the present invention;

Fig. 2 is similarity simulation experiment monitoring system schematic diagram;

Fig. 3 is the mechanics model of mining overburden absciss layer;

Fig. 4 is an absciss layer and No. two absciss layer matched curves in embodiment.

In Fig. 2,1-empirical model; 2-rule; 3-white light source; 4-high speed camera; 5-industrial camera; 61-image pick-up card I; 62-image pick-up card II; 71-Computer I; 72-Computer I I; 8-portable hard drive.

In Fig. 3, x-horizontal axis, the vertical coordinate axis of z-, the maximum boundary length of d-rock beam.

Embodiment

With reference to the accompanying drawings, the monitoring system of a kind of mining overburden absciss layer allometry simulated experiment based on digital speckle technology provided by the invention and analytical approach are described.

The present embodiment is based on digital speckle technology, similar material simulation experiment for mining overburden absciss layer is studied, for completing the allometric monitoring of absciss layer and analytical approach is described the specific embodiment of the present invention, as shown in Figure 1, concrete implementation step is as follows:

The first step: the making of observation experiment model

Using the deposition coal measure strata containing sandstone as simulated object, do aggregate with silica sand, mica, barite, do Binder Materials with lime, gypsum, borax does retardant, makes coal-bearing strata model.Similar to what happens under actual mining conditions for ensureing distortion, the destruction of model, rational affinity constant must be determined, according to affinity constant and prototype character, in conjunction with similarity theory and matching principle, draw the proportioning of simulation material.The affinity constant that this experiment is chosen is specific as follows:

Geometric similarity constant: a _l=l _m/ l _p=1:100

Unit weight affinity constant: a _r=r _m/ r _p=2:3

Acceleration of gravity affinity constant: a _g=g _m/ g _p=1:1

Time similarity constant: $a_t=t_m/t_p=\sqrt{a_l}=1:10$

Speed affinity constant: $a_u=u_m/u_p=\sqrt{a_l}=1:10$

Displacement affinity constant: a _s=a _l=1:100

Intensity, bullet mould, cohesive force affinity constant: a _r=a _e=a _c=a _la _r=3:500

Angle of internal friction affinity constant: $a_f=f_m/f_p=a_g\&CenterDot;a_r\&CenterDot;a_l^3=0.6\&times;{10}^{-6}$

According to affinity constant and prototype character, in conjunction with similarity theory and matching principle, show that the weight proportion of simulation material is as shown in the table:

Table 1 bill of material

The making of this empirical model adopts layering ramming, and the bottom is coal seam, lays multilayer sand layers above.Take institute's expense according to material mix proportion, add even mixing in the water containing retardant, and rapid patrix, every layer of laying depth is about about 2cm, and uniform compaction.For ensureing model forming, needing model to leave standstill after completing to dry, simulated experiment can be carried out by form removal.In order to collect good speckle pattern, require that speckle particle size is even, contrast is obvious, therefore after form removal, utilizes graphite to carry out the random spray of speckle point at model surface.

Second step: the arrangement of related experiment equipment

As shown in Figure 2, after empirical model 1 completes, be fixed on experiment table, experimental environment and measurement require to select and adjustment pen recorder.Here high speed camera 4 selects Canon 5DMARKIII, and industrial camera 5 selects BasleracA1600-20gc/gm, by A-frame, both is fixed on empirical model 1 front.High speed camera 4 connects image pick-up card I61 and Computer I 71 successively, and industrial camera 5 connects image pick-up card II62, Computer I I72 and portable hard drive 8 successively.Set up two white light sources 3 to throw light in empirical model 1 front, ensure to illuminate whole empirical model 1.According to circumstances select high speed camera 4 and industrial camera 5 corresponding aperture, focal length, final purpose is that to make to photograph speckle particle in speckle pattern clear, size to fit.

The data of monitoring gained are sent to processing terminal by transmission line.The image information that Canon 5DMARKIII high speed camera 4 and Basler industrial camera 5 gather is stored in respectively in two high-performance computers in order to processing in image card after A/D changes.Wherein the shoot function parameter of Basler industrial camera 5 is 10 frames/second, 1M/ frame, and namely storage capacity requirement can reach 36G/ hour, for ensureing the smooth storage of data, adopts portable hard drive 8 parallel memorizing of the additional seagate4T of Computer I I here.Make troubles to digital speckle correlation computations for avoiding due to the skew of collecting device (high speed camera 4 and industrial camera 5), controlled the switch of collecting device here by computing machine.

Adopt displacement that numerical value speckle correlation technique obtains in the present invention in units of pixel, finally will be converted into long measure and calculate, then need to demarcate empirical model 1.Be close to empirical model 1 surface to place one rule 2, and take the image of a width rule 2, according to the corresponding relation of rule in image 2 length and pixel count, the conversion relation of pixel and long measure can be drawn.After demarcation, just can not do any transfer to experimental system, otherwise need again to demarcate.

3rd step: the simulation of seam mining process

Before on-test, the time synchro of utilization carries out the time calibration of two computing machines, ensures the synchronism of image data.

This experimental simulation seam mining method adopts and is all caving formula, and be an excavation step with top overlying strata spontaneous caving, whole recovery process divide into six excavation steps altogether.At the test initial stage, the roof rock caused due to seam mining is caving obvious, rapid, then need higher data acquisition density, the speed of taking pictures being controlled high speed camera 4 and industrial camera 5 by Computer I 71 and Computer I I72 is respectively 1 second/, later stage in an experiment, absciss layer development deformation velocity slows down, camera take pictures speeds control be 5 seconds/.The mining in coal seam is with being all caving formula method, with top covering rockmass spontaneous caving be one excavation step, divide some excavations step, because the development of absciss layer is sometimes fast and sometimes slow in mining active process, therefore cause the difficulty of artificial capture method, the relevant monitoring that the present invention is undertaken by digital speckle technology then overcomes this shortcoming.

4th step: the computing of related data

When seam mining terminates, until top overlying strata are stablized, no longer there is slump distortion, then information acquisition end-of-job, the image of collection is gathered, select specific speckle image according to time sequencing and carry out correlation analysis calculating, the allometry rule of many absciss layers of wall scroll absciss layer and different layers position can be drawn.Mechanics model used as shown in Figure 3.

In order to carry out the allometric correlation analysis of overlying strata separation layer, the view data to collecting is needed to process.Utilize DSCM (white light digital correlation speckle method) software to carry out related operation to the speckle photographed at processing terminal, after computational analysis, obtain displacement field and strain field and the distribution of correlation coefficient field etc. of each state.By the conversion between pixel and unit length, length and the wide variety information of overlying strata separation layer can be obtained, according to the shooting interval of image, the temporal information of overlying strata separation layer development can be obtained, below just obtain two large key factors of research overlying strata separation layer allometry problem, just summed up in the point that the problem rate in overlying strata separation layer evolutionary process by the acting in conjunction of time and displacement.

When the present embodiment adopts the distortion of Digital Speckle Correlation Method measurement model, first before and after model deformation occurs, take two speckle patterns respectively, be expressed as follows with gamma function:

Before distortion: F}={F (x, y), x=1 ..., M, y=1 ..., N}

After distortion: G}={G (x, y), x=1 ..., M, y=1 ..., N}

In formula: M × N is the size of speckle field, unit is pixel.

From the speckle pattern before model deformation, choose a zonule, and search for the particle structure matched in speckle pattern after deformation, search for successfully, just obtain displacement and the deformation information in this region.The computing formula of the related coefficient wherein related to is:

$C=\frac{\mathrm{\&Sigma;}\&lsqb;f(x,y)-\stackrel{\&OverBar;}{f}\&rsqb;\&lsqb;g\left(x^{,}{,}^{,}y\right)-g\&rsqb;}{\sqrt{\mathrm{\&Sigma;}{\&lsqb;f(x,y)-\stackrel{\&OverBar;}{f}\&rsqb;}^2}\sqrt{\mathrm{\&Sigma;}{\&lsqb;g\left(x^{,}{,}^{,}y\right)-\stackrel{\&OverBar;}{g}\&rsqb;}^2}}$

In formula:

{f}＝{f(x,y),x＝1,...i,y＝1,...,j}

{g}＝{g(x,y),x＝1,...i,y＝1,...,j}

It is the gamma function of the sample image of two zonules; be respectively f (x, y), the average item of g (x, y).When two zonule speckle images are identical, C=1.The strain of overlying strata separation layer development can use displacement and derivative component thereof represent, its computing formula is as follows:

${\mathrm{\&epsiv;}}_x=\frac{\&part;u}{\&part;x}+\frac{1}{2}\&lsqb;{\left(\frac{\&part;u}{\&part;x}\right)}^2+{\left(\frac{\&part;v}{\&part;x}\right)}^2\&rsqb;$

${\mathrm{\&epsiv;}}_y=\frac{\&part;u}{\&part;y}+\frac{1}{2}\&lsqb;{\left(\frac{\&part;u}{\&part;y}\right)}^2+{\left(\frac{\&part;v}{\&part;y}\right)}^2\&rsqb;$

${\mathrm{\&gamma;}}_{xy}=\frac{1}{2}\left(\frac{\&part;u}{\&part;y}+\frac{\&part;v}{\&part;x}\right)+\frac{1}{2}\left(\frac{\&part;u}{\&part;x}\frac{\&part;u}{\&part;y}+\frac{\&part;v}{\&part;x}\frac{\&part;v}{\&part;y}\right)$

In formula: u is the displacement component in x direction, v is the displacement component in y direction, ε _xfor the strain tensor in x direction, ε _yfor the strain tensor in y direction, γ _xyfor the shear strain of xy plane.

The present invention introduces allometric analytical approach first in the research of mining overburden absciss layer, for analyzing the allometry characteristic of absciss layer, sets up relevant absciss layer mechanics model, the relational expression according to amount of deflection z and load q, foundation pressure p:

$EI\frac{d^{4}z}{{\mathrm{dx}}^4}=q-p=q-kz$

Show that the subsidence curve equation of beam on elastic foundation is:

z＝e ^-βx(C ₁sinλx+C ₂cosλx)

Another according to relevant border condition z/ _x=0=W _max=m η; c can be obtained ₁=C ₂=W _max.

In formula: β is curve coefficient, for the flexibility eigenwert of beam, k is the resistance coefficient of ground itself, and EI is the bendind rigidity of ground, W _maxfor the maximum sinking value of beam on elastic foundation, m is seam mining thickness, and η is rock depression coefficient, and x is the horizontal range of calculation level apart from beam mid point.

Therefore the subsidence curve equation of grade beam is:

z＝W _maxe ^-βx(sinλx+cosλx)(x≥0)

In like manner, for rock beam, the pass between amount of deflection z and load p ' is:

$E^{\&prime;}{I}^{\&prime;}\frac{d^4{z}^{\&prime;}}{{\mathrm{dx}}^4}=p^{\&prime;}$

According to boundary condition z/ _{x=± d}=0; can show that the subsidence curve equation of rock beam is:

$z^{,}=\frac{p^{,}}{24E^{,}{I}^{,}}{(x^2-d^2)}^2$

In formula: d is the boundary length of rock beam, the bendind rigidity that E ' I ' is rock beam, p ' is earthing body gravity load on rock beam.

The width that can obtain absciss layer is thus

$Z=z-z^{,}=W_{max}{e}^{\mathrm{\&beta;}x}(sin\mathrm{\&lambda;}x-cos\mathrm{\&lambda;}x)-\frac{p^{,}}{24E^{,}{I}^{,}}{(x^2-d^2)}^2(x\&le;0)$

Make Z=vt, can draw $v=\frac{W_{\max }{e}^{-\mathrm{\&beta;}x}\left(\sin \mathrm{\&lambda;}x+\cos \mathrm{\&lambda;}x\right)-\frac{p^{\&prime;}}{24E^{\&prime;}{I}^{\&prime;}}{\left(x^2-d^2\right)}^2}{t}.$ Wherein, t is the time that excavation is corresponding, because x is also variable, can find out As time goes on, speed and time disproportionate relation, this shows that the absciss layer speed of development is not at the uniform velocity, but in allometry.

The present embodiment to the data such as strain, time in the evolution of mining overburden absciss layer, is used for analyzing the allometry problem of mining overburden absciss layer based on digital speckle technical monitoring.The formula that the Allometric Relationships of the independent research wherein related to judges as:

In formula: represent the ratio of upper the next rock depression amount of a certain moment, its value is constant; W _underfor the sinking amount of deflection of the next rock stratum of absciss layer, W _onfor the sinking amount of deflection of the upper rock stratum of absciss layer.

Constant α according to calculating is friction speed growth factor, its reaction be the ratio of the relative growth rate of the next rock stratum and the relative growth rate of upper rock stratum, the size according to α value can judge:

(1) as α >1, show as positive allometry result, the fall rate of the next rock stratum is greater than the fall rate of upper rock stratum, and absciss layer is in crack initiation, developing stage.

(2) when α=1, show as isogony result, the fall rate of the next rock stratum equals the fall rate of upper rock stratum, and now absciss layer develops into maximum.

(3) as α <1, show as negative allometry result, the fall rate of the next rock stratum is less than the fall rate of upper rock stratum, and absciss layer is in close stage.

5th step: the Treatment Analysis of experimental result

Experimentally monitoring result can carry out the Allometric Analsis of different layers position absciss layer and the Allometric Analsis of certain wall scroll absciss layer.For the Allometric Relationships of research different layers position absciss layer, random selecting five absciss layers are analyzed, and are numbered an absciss layer, No. two absciss layers, No. three absciss layers, No. four absciss layers and No. five absciss layers successively from the bottom up to it.Research range is from absciss layer crack initiation to developing into maximum length, and the length chosen in each stage is research variable, and the different layers position absciss layer length value monitored is as shown in the table:

Table 2 different layers position absciss layer length value

Different absciss layer length is taken the logarithm, then gets different layers position absciss layer length logarithm as independent variable and dependent variable, fit regression curve, and then whether there is linear relationship between the absciss layer of checking different layers position.

(1) absciss layer and No. two absciss layer matched curves are as shown in Figure 4, with an absciss layer length logarithm for independent variable, No. two absciss layer length logarithms are dependent variable, its degree of fitting is 0.93, there is between two variablees obvious log-linear rule, its friction speed growth factor is 2.6618, and Regression Equations is:

y＝2.6618x-4.3456

In formula, x is an absciss layer length logarithm, and y is No. two absciss layer length logarithms.

Calculate the regression equation between other absciss layers respectively, result of calculation is as follows.

The regression equation of (2) absciss layers and No. three absciss layer matched curves is:

y＝1.4382x-1.2643

In formula, x is an absciss layer length logarithm, and y is No. three absciss layer length logarithms.

The regression equation of (3) absciss layers and No. four absciss layer matched curves is:

y＝0.3994x+1.9319

In formula, x is an absciss layer length logarithm, and y is No. four absciss layer length logarithms.

The regression equation of (4) absciss layers and No. five absciss layer matched curves is:

y＝1.7298x-2.3997

In formula, x is an absciss layer length logarithm, and y is No. five absciss layer length logarithms.

The regression equation of (5) No. two absciss layers and No. three absciss layer matched curves is:

y＝0.5069x+1.1543

In formula, x is No. two absciss layer length logarithms, and y is No. three absciss layer length logarithms.

The regression equation of (6) No. two absciss layers and No. four absciss layer matched curves is:

y＝0.1393x+2.6068

In formula, x is No. two absciss layer length logarithms, and y is No. four absciss layer length logarithms.

The regression equation of (7) No. two absciss layers and No. five absciss layer matched curves is:

y＝0.6044x+0.5207

In formula, x is No. two absciss layer length logarithms, and y is No. five absciss layer length logarithms.

The regression equation of (8) No. three absciss layers and No. five absciss layer matched curves is:

y＝1.1533x-0.7689

In formula, x is No. three absciss layer length logarithms, and y is No. five absciss layer length logarithms.

Above data analysis is known, and the development of different layers position absciss layer meets Allometric Relationships, and its Allometric Relationships is as shown in the table:

The long Allometric Relationships of table 3 different layers position absciss layer

Have analysis data known, the absciss layer between different layers position is different in the state of development of synchronization, presents allometric relation.

With wall scroll absciss layer for research object, the difference of the sinking amount of deflection of the next rock stratum in analysis, namely using the width of absciss layer development as analytic target, carries out the Allometric Analsis of wall scroll absciss layer.Analyze with the Monitoring Data of No. four absciss layers, as shown in the table.

Table 4 No. four absciss layer developments

Table 5 No. four absciss layer developments

Can find out that the speed that wall scroll absciss layer develops within each period there are differences, namely embody allometric feature.The growth feature of mining overburden absciss layer length is: along with the increase of time, and absciss layer length constantly increases, and when being increased to sometime, absciss layer length reaches maximal value, and its length no longer continues along with the time to increase.The rising characteristic of absciss layer width is: incipient stage absciss layer width constantly becomes large, until develop into maximum rating, absciss layer shows as positive allometry state, this absciss layer is in crack initiation, developing stage, after absciss layer width reaches maximal value, along with the increase of time, absciss layer width starts to reduce, absciss layer shows as negative allometry state, and this absciss layer is in close stage.Known according to analysis result, wall scroll absciss layer also exists allometric relation at different stages of development.

According to the above, the absciss layer friction speed growth factor monitor by experiment, calculated, absciss layer crack initiation, development and closed essence is disclosed, for wall scroll absciss layer provides quantitative decision method at the Allometric Relationships of synchronization between the Allometric Relationships and different layers position absciss layer of different stages of development from root.

The present invention is by adopting a kind of monitoring means based on digital speckle technology newly, study the development of mining overburden absciss layer, the problem of evolution, solve the difficult problem that the acquisition precision of personal monitoring in prior art is not high, achieve high-precision acquisition process work, make the measurement result of experiment more reliable.By the Allometric Analsis method of a set of mining overburden absciss layer of introducing, achieve the possibility of the quantitative description that absciss layer develops in mining overburden absciss layer similarity simulation experiment, for Coal Mining Subsidence theory provides a kind of more scientific, effective research method, and then in the control that can be used for instructing Coal Mining Subsidence disaster and control.

Claims (10)

1. a mining overburden absciss layer allometry test monitoring system, is characterized in that, this system comprises experimental terminal, monitoring terminal and processing terminal; Described experimental terminal comprises experiment table and empirical model; Described monitoring terminal comprises high speed camera, industrial camera, support, white light source and rule; Described processing terminal comprises image pick-up card, computing machine and portable hard drive; Empirical model is fixed on experiment table, and high speed camera and industrial camera are fixed on empirical model front by support, and high speed camera connects image pick-up card I and Computer I successively, and industrial camera connects image pick-up card II, Computer I I and portable hard drive successively; White light source is arranged at empirical model front; Rule is arranged at the surface of empirical model, is positioned at the visual field of high speed camera and industrial camera.

2., based on an analytical approach for mining overburden absciss layer allometry test monitoring system described in claim 1, step is:

(1) experimental terminal simulation that coal seam is excavated: make experiment table and empirical model with the material similar to mine, coal seam, and simulate the whole process of mine, coal seam excavation;

(2) monitoring terminal is to the collection of data: the absciss layer photographic intelligence being gathered experimental terminal by high speed camera and industrial camera, utilize digital speckle technology to carry out Taking Photographic to speckle, and the photographic intelligence collected is sent to processing terminal by data transmission link;

(3) processing terminal is to the treatment and analyses of data: computing machine utilizes DSCM software to carry out computing to the speckle image photographed, according to image before being deformed after speckle gray feature change, distortion corresponding relation before and after image is set up obtains deformation information, obtain shear strain change cloud atlas and the related coefficient of mining overburden absciss layer, obtain the situation of change of stress according to the stress-strain relation of material; Introducing allometry is theoretical, the friction speed growth factor α that definition is relevant, calculates α value, and judges the growth conditions of certain one deck position absciss layer in certain moment according to α value.

3. method according to claim 2, is characterized in that, before on-test, the time synchro of utilization carries out the time calibration of two computing machines, ensures the synchronism of image data.

4. method according to claim 2, is characterized in that, in step (2), is controlled the switch of high speed camera and industrial camera by computing machine.

5. method according to claim 2, it is characterized in that, in step (2), with rule, empirical model is demarcated, rule is close to empirical model surface and is arranged, and take the image of a width rule, according to the corresponding relation of rule length and pixel count in image, draw the conversion relation of pixel and long measure.

6. method according to claim 2, is characterized in that, in step (2), test the initial stage the camera speed of taking pictures be 0.5-1.5 second/, test the middle and later periods the camera speed of taking pictures be 4-6 second/.

7. according to the arbitrary described method of claim 2-6, it is characterized in that, in step (3), when the distortion with Digital Speckle Correlation Method measurement model, first before and after model deformation occurs, take two speckle patterns respectively, be expressed as follows with gamma function:

Before distortion: F}={F (x, y), x=1 ..., M, y=1 ..., N}

After distortion: G}={G (x, y), x=1 ..., M, y=1 ..., N}

In formula: M × N is the size of speckle field, unit is pixel; From the speckle pattern before model deformation, choose a region, and search for the particle structure matched in speckle pattern after deformation, obtain displacement and the deformation information in this region, the computing formula of the related coefficient C related to is:

$C=\frac{\mathrm{\&Sigma;}\&lsqb;f(x,y)-\stackrel{\&OverBar;}{f}\&rsqb;\&lsqb;g\left(x^{,}{,}^{,}y\right)-g\&rsqb;}{\sqrt{\mathrm{\&Sigma;}{\&lsqb;f(x,y)-\stackrel{\&OverBar;}{f}\&rsqb;}^2}\sqrt{\mathrm{\&Sigma;}{\&lsqb;g(x^{,},y_{,})-\stackrel{\&OverBar;}{g}\&rsqb;}^2}}$

In formula: f}={f (x, y), x=1 ... i, y=1 ..., j} and g}={g (x, y), x=1 ... i, y=1 ..., j} is the gamma function of the sample image in two regions; be respectively f (x, y), the average item of g (x, y).

8., according to the arbitrary described method of claim 2-6, it is characterized in that, in step (3), the strain displacement of overlying strata separation layer development and derivative component thereof represent, its computing formula is as follows:

${\mathrm{\&epsiv;}}_x=\frac{\&part;u}{\&part;x}+\frac{1}{2}\&lsqb;{\left(\frac{\&part;u}{\&part;x}\right)}^2+{\left(\frac{\&part;v}{\&part;x}\right)}^2\&rsqb;$

${\mathrm{\&epsiv;}}_y=\frac{\&part;u}{\&part;y}+\frac{1}{2}\&lsqb;{\left(\frac{\&part;u}{\&part;y}\right)}^2+{\left(\frac{\&part;v}{\&part;y}\right)}^2\&rsqb;$

${\mathrm{\&gamma;}}_{xy}=\frac{1}{2}(\frac{\&part;u}{\&part;y}+\frac{\&part;v}{\&part;x})+\frac{1}{2}(\frac{\&part;u}{\&part;x}\frac{\&part;u}{\&part;y}+\frac{\&part;v}{\&part;x}\frac{\&part;v}{\&part;y})$

In formula: u is the displacement component in x direction, v is the displacement component in y direction, ε _xfor the strain tensor in x direction, ε _yfor the strain tensor in y direction, γ _xyfor the shear strain of xy plane.

9. according to the arbitrary described method of claim 2-6, it is characterized in that, in step (3), absciss layer development presents allometry pattern, and the computing formula of speed ν is:

$v=\frac{W_{max}{e}^{-\mathrm{\&beta;}x}(sin\mathrm{\&lambda;}x+cos\mathrm{\&lambda;}x)-\frac{p^{\&prime;}}{24E^{\&prime;}{I}^{\&prime;}}{(x^2-d^2)}^2}{t}$

In formula: β is the fitting coefficient of curve, λ is the flexibility eigenwert of beam, W _maxfor the maximum sinking value of beam on elastic foundation, p ' is earthing body gravity load on rock beam, the bendind rigidity that E ' I ' is rock beam, and d is the boundary length of rock beam, and x is the horizontal range of calculation level apart from beam mid point, and t is the time that excavation is corresponding.

10., according to the arbitrary described method of claim 2-6, it is characterized in that, in step (3), the formula that Allometric Relationships judges as:

In formula: represent the ratio of upper the next rock depression amount of a certain moment, its value is constant; W _underfor the sinking amount of deflection of the next rock stratum of absciss layer, W _onfor the sinking amount of deflection of the upper rock stratum of absciss layer;

Constant α according to calculating is friction speed growth factor, its reaction be the ratio of the relative growth rate of the next rock stratum and the relative growth rate of upper rock stratum:

(1) as α >1, show as positive allometry result, the fall rate of the next rock stratum is greater than the fall rate of upper rock stratum, and absciss layer is in crack initiation, developing stage;

(2) when α=1, show as isogony result, the fall rate of the next rock stratum equals the fall rate of upper rock stratum, and now absciss layer develops into maximum;

(3) as α <1, show as negative allometry result, the fall rate of the next rock stratum is less than the fall rate of upper rock stratum, and absciss layer is in close stage.