CN102926810A - Forecasting method of coal and gas outburst - Google Patents

Abstract

The invention provides a forecasting method of coal and gas outburst, which is based on a coal mine safety monitoring system. The method comprises the following steps of: mainly utilizing the coal mine safety monitoring system to extract an average value of gas density, a maximum value of gas density, a maximum confidence value of 95% of gas density, and a difference value of gas density for the last three times, wherein the values are transmitted by a sensor located at a position 40-60m away from an early-warning target heading face and processed by the coal mine safety monitoring system; and obtaining an index value of drilling cutting quantity and an index value of drilling cutting gas desorption by performing gas outburst prevention detection for the last times extracted by the mine safety monitoring system, calculating an index value of drilling cutting quantity and an index value of drilling cutting gas desorption in a current state by a specific algorithm, and comparing the index values with corresponding forecasting judgment indexes to realize continuous forecasting of the coal and gas outburst. Advantages of a contact-type forecasting method and advantages of a non-contact-type continuous forecasting method are integrated into the method provided by the invention, thus reliability and credibility of the forecasting can be improved, and an adaptive capacity is stronger.

Description

The Forecasting Methodology of coal and Gas Outburst

Technical field

The present invention relates to safety of coal mines guard technology field, be specifically related to the continuous prediction method of a kind of coal and Gas Outburst.

Background technology

Mine safety accidents is often sent out, and brings the massive losses of life and property.Coal and gas burst accident are one of multiple accidents in colliery.Current coal and gas outburst mechanism comprehensive supposition are thought, coal and Gas Outburst are the results of geostatic stress, gas and physical and mechanical properties of coal three comprehensive function, be the high speed pay-out that is gathered in a large amount of potential in country rock and the coal body, and think that high pressure gas plays a decisive role in outstanding evolution.Static contact interruption Forecasting Methodology is adopted at present domestic prediction to coal and gas burst accident more, such as drilling gas gush out initial velocity method, R desired value method, method of drilling index etc." control coal and the Gas Outburst detailed rules and regulations " that China relevant department promulgates point out that the method that adopts method of drilling index to predict driving face coal and gas outburst risk is effectively and reliably, each large coal mine evacuation working face is widely used at home at present.Method of drilling index is by plaing the boring of 2 or 3 diameter 42mm, hole depth 8～10m at Driving Face in Coal Tunnel, the every dozen of 1m that hole measure coal powder quantity of bore once, measure a Desorption Index for Drill Cuttings every 2m, according to the maximum coal powder quantity of bore S of long every meter along the hole of each boring _MaxWith Desorption Index for Drill Cuttings K ₁Or △ h ₂The outburst hazard of prediction work face, the outburst danger threshold of indices should be determined according to the on-site measurement data, as without field data the time, can determine with reference to the data of table 1 coal and the Gas Outburst of work plane.

Table 1 is predicted the threshold of Driving Face in Coal Tunnel outburst hazard with method of drilling index

The advantage that adopts method of drilling index prediction development end coal and Gas Outburst is that prediction is relatively accurate, reliability and degree of recognition are relatively high, the weak point of this kind method is: each measurement all can spend a large amount of manpower and materials, affect easily normally carrying out of coal production, what is more important can not be accomplished the real-time continuous prediction.

In recent years, to the Real-Time Monitoring of coal and gas burst accident and continuously prediction day by day be subject to the attention of each side.Be the Chinese patent literature of CN 101532397A such as publication number, it discloses the real-time diagnosis method of a kind of coal and Gas Outburst, the method is by combining with coal mine safety monitoring system, combine coal and Gas Outburst three factors at the variation characteristic of distinguished and admirable middle gas density, realization is to real-time diagnosis and the prediction of coal and Gas Outburst, be characterized in accomplishing contactless continuous prediction, but the method some desired values to contact measurement in forecasting process do not relate to, and the Forecasting Methodology reliability and the degree of recognition that are compared to contact of predicting the outcome is more relatively low.

Thereby, to study and a kind ofly can realize real-time estimate, the Forecasting Methodology that can embody and consider again the coal of the high reliability of common contact Forecasting Methodology and degree of recognition advantage and Gas Outburst seems very necessary and is significant.

Summary of the invention

The objective of the invention is: for deficiency of the prior art, come protrusion-dispelling desired value under the dynamic prediction driving face current state to realize Forecasting Methodology to coal under the current state and Gas Outburst thereby provide a kind of distinguished and admirable middle variation ofgas density data of development end of utilizing Real-time Collection and historical protrusion-dispelling to detect index parameter.

Technical scheme of the present invention is: the Forecasting Methodology of coal of the present invention and Gas Outburst is based upon on the coal mine safety monitoring system basis; Described coal mine safety monitoring system stores coal powder quantity of bore desired value and the drilling cuttings desorption of mash gas desired value that obtains by the reality detection and receives in real time and store the gas data of mine development ends and carry out respective handling, it is characterized in that: mainly may further comprise the steps:

1. extract by mine safety monitoring system and be arranged on apart from early warning target development end 40～60m position firedamp sensor following real-time gas data transmission and after safety monitoring system carries out respective handling:

Gas density average C: the average of gas density in forecast interval or the work cycle; Wherein, nearest three sub-value C ₁, C ₂, C ₃, currency C ₀

Gas density maximum value M: the maximum value of gas density in forecast interval or the work cycle; Wherein, nearest three sub-value M ₁, M ₂, M ₃, currency M ₀

Gas density 95% is put letter maximum value F: the maximum value of gas density 95% confidential interval in forecast interval or the work cycle; Wherein, nearest three sub-value F ₁, F ₂, F ₃, currency F ₀

Gas density difference D: in the certain hour or the gas density difference of patrolling and examining for twice; Wherein, nearest three sub-value D ₁, D ₂, D ₃, currency D ₀

2. extract the nearest three times mash gas outburst prevention of early warning target development end by mine safety monitoring system and detect desired value:

Wherein, coal powder quantity of bore desired value S for the first time _Max1, the second sub-value S _Max2, be worth S for the third time _Max3Current coal powder quantity of bore desired value S _Max

Drilling cuttings desorption of mash gas desired value K for the first time ₁₁, the second sub-value K ₁₂, be worth K for the third time ₁₃Current drilling cuttings desorption of mash gas desired value K ₁

3. will by step 1. with step 2. the data obtained carry out following calculating:

$\left\{\begin{array}{c}{A}_1{C}_1+A_2(M_1+F_1)+A_3{D}_1=K_{11}\\ A_1{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HDA00002418518500022.png"\; state="\{\{state\}\}">C</figure-callout>}}_2+A_2({\mathrm{<figure-callout\; id="2"\; label="M"\; filenames="HDA00002418518500022.png"\; state="\{\{state\}\}">M</figure-callout>}}_2+F_2)+A_3{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="HDA00002418518500022.png"\; state="\{\{state\}\}">D</figure-callout>}}_2=K_{12}\\ A_1{C}_3+A_2(M_3+F_3)+A_3{D}_3=K_{13}\end{array}\right\}---\left(1\right)$

Solve parameter A by equation group (1) ₁, A ₂, A ₃Value, bring these three parameter values into current forecast interval interior numerical value and carry out following calculating:

A ₁C ₀+A ₂（M ₀+F ₀）+A ₃D ₀=K ₁ （2）

Solve K under the current state by formula (2) ₁Value;

4. will by step 1. with step 2. the data obtained carry out following calculating:

$\left\{\begin{array}{c}{B}_1{C}_1+B_2(M_1+F_1)+B_3{B}_1=S_{\max 1}\\ B_1{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HDA00002418518500022.png"\; state="\{\{state\}\}">C</figure-callout>}}_2+B_2(M_2+F_2)+B_3{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="HDA00002418518500022.png"\; state="\{\{state\}\}">D</figure-callout>}}_2=S_{\max 2}\\ B_1{C}_3+B_2(M_3+F_3)+B_3{D}_3=S_{\max 3}\end{array}\right\}---\left(3\right)$

Solve B parameter by equation group (3) ₁, B ₂, B ₃Value, bring these three parameter values into current forecast interval interior numerical value and carry out following calculating:

B ₁C ₀+B ₂（M ₀+F ₀）+B ₃D ₀=S _max （4）

Solve S under the current state by formula (4) _MaxValue;

5. to the K under the current state that is 3. obtained by step ₁S under value and the current state that 4. obtained by step _MaxCarrying out following analysis judges:

Work as S _Max＜4.80kg/m(4.32L/m) and K ₁＜0.40ml/ (g.min ^1/2) time, predicting the outcome is safe condition;

Work as 4.80kg/m(4.32L/m)≤S _Max＜6.00kg/m(5.40L/m) or 0.40ml/ (g.min ^1/2)≤K ₁＜0.50ml/ (g.min ^1/2) time, predicting the outcome is threatened status;

Work as 6.00kg/m(5.40L/m)≤S _MaxPerhaps 0.50ml/ (g.min ^1/2)≤K ₁The time, predicting the outcome is precarious position.

The present invention has positive effect: (1) is by combining the distinguished and admirable middle variation ofgas density data of contact coal and gas outbursts Prediction index and the development end of Real-Time Monitoring, realized coal and the contactless continuous prediction of Gas Outburst, improve forecasting reliability and confidence level, opened up the domestic and international beginning in this field.(2) basic data extracted in gas density of Forecasting Methodology of the present invention is the dimensionless number certificate, revise used historical detect prominent index also be the boundary value that provides according to " control coal and Gas Outburst detailed rules and regulations " as the basis, thereby have stronger adaptive ability.

Description of drawings

Fig. 1 is the correlation schematic block diagram of coal of the present invention and each factor of gas outbursts Prediction;

Fig. 2 is the gas probe positions schematic diagram that the present invention gathers driving face coal and gas outbursts Prediction usefulness parameter;

Fig. 3 is prediction Smax value and actual measurement Smax value comparison diagram in the application examples of the present invention;

Fig. 4 predicts K in the application examples of the present invention ₁Value and actual measurement K ₁The value comparison diagram.

The specific embodiment

(embodiment 1)

The coal of present embodiment and the Forecasting Methodology of Gas Outburst, be based upon on the coal mine safety monitoring system basis, basic data mainly detects desired value two parts from coal mine safety monitoring system and historical protrusion-dispelling, and historical protrusion-dispelling detects desired value and obtains by the reality detection in daily headwork.

See Fig. 1, the impact analysis of the gas density during coal and Gas Outburst three elements stress state, physical mechanics state and coal seam gas-bearing capacity are distinguished and admirable to driving face under the coal mine is as follows:

1. stress state changes the impact on distinguished and admirable middle gas density:

The gas source of driving face mainly is comprised of following four parts: a. has exposed the tunnel Gas of rib all around; B. newly expose the Gas of tunnel rib; C. the Gas of coal breakage; D. newly expose the Gas of development end.Learn according to analysis, in a forecast interval, exposed that As time goes on the gas emission of rib is attenuation trend around the tunnel, and the new tunnel rib gas emission that exposes can be cancelled out each other substantially with the gas attenuation that has exposed the tunnel, belongs to the technology that has been employed.In the normal process that advances of work plane, the gas amount of coal breakage does not have larger change, and therefore only having the wall gas emission of new exposure is a parameter, and directly has influence on development end gas emission in each forecast interval.Driving face newly exposes the wall Gas and the stress state variation has direct relation, thereby when large variation did not occur the driving face air quantity, the variation of average gas density just can characterize stress state indirectly on the impact of Gas Outburst.Selection for forecast interval, can choose 8 hours, 12 hours, 24 hours or 48 hours, should select suitable forecast interval according to the development end operation orderliness in the middle of the application process at the scene, but forecast interval period maximum can not surpass 48 hours theoretically, and minimum can not be less than 8 hours.

2. coal seam gas-bearing capacity changes the impact on distinguished and admirable middle gas density:

Seam gas content changes the variation of high gas density of in the gas density sequence the most direct moment in distinguished and admirable when showing as coal breakage, and gas bearing capacity is higher in the coal seam, and the initial desorption of mash gas amount that records is larger, and gas concentration is just larger moment during coal breakage.So the variation of choosing two parameters of maximum value of the interior maximum gas concentration of forecast interval and gas density sequential value 95% confidential interval comes the variation of coal seam gas-bearing capacity in the characterized forecast interval.The maximum value of aforesaid 95% confidential interval according to the distribution pattern that the concentration data group meets, is calculated the scope of 95% confidential interval after referring to development end prediction sorted with the concentration data of gas probe, and the capping value is as the maximum value of 95% confidential interval.

3. the physical mechanics state variation is on the impact of distinguished and admirable middle gas density

At present, coal and gas outburst mechanism comprehensive supposition are thought, coal and Gas Outburst are the results of geostatic stress, gas and physical and mechanical properties of coal three comprehensive function, it is the high speed pay-out that is gathered in a large amount of potential in country rock and the coal body, and think that high pressure gas plays a decisive role in outstanding evolution, geostatic stress is to excite outstanding factor, and physical and mechanical properties of coal then is to hinder outstanding factor.The front has been found the relevant information that stress state changes and coal seam gas-bearing capacity changes well in the gas density sequence, in the physical mechanics state variation Forecasting Methodology of the present invention that hinders outstanding coal, adopt the maximum value of adjacent polling period concentration difference in the forecast interval to characterize.

Be explained as follows about in the coal mine safety monitoring system the distinguished and admirable middle gas density of development end uninterruptedly being carried out the method for monitoring:

See Fig. 2, usually in the coal mine safety monitoring system, all can the gas probe be set in development end, it also is gas concentration sensor, but, because the particularity that development end is ventilated, the distinguished and admirable disorder in heading end place, if certainly will bring larger error to predicting the outcome take the development end probe data as basic data, so through lab analysis and on-the-spot test checking, set up a firedamp sensor in distance development end 40～60m position, and follow the propelling of headwork and advance, this position had both fully taken into account distinguished and admirable stability and the abundant mixed problem of gas in distinguished and admirable, the again the least possible Gas that has comprised the digging laneway wall.Simultaneously because along with the propelling sensor that tunnels is also advancing, just guaranteed to a certain extent that gas density that this sensor detects has mainly comprised the Gas of gushing out of heading end gas and regular length wall, has controlled the value error of gas density to a certain extent.The real time data that Forecasting Methodology of the present invention is got is all from this firedamp sensor.

Based on above related description, the Forecasting Methodology of coal of the present invention and Gas Outburst is based upon on the coal mine safety monitoring system basis; Described coal mine safety monitoring system stores coal powder quantity of bore desired value and the drilling cuttings desorption of mash gas desired value that obtains by the reality detection and receives in real time and store the gas data of mine development ends and carry out respective handling, and Forecasting Methodology mainly may further comprise the steps:

1. by mine safety monitoring system extract be arranged on apart from the transmission of early warning target development end 40～60m position firedamp sensor and carry out following real-time gas data after the respective handling with safety monitoring system:

Gas density average C: the average of gas density in forecast interval or the work cycle; Wherein, nearest three sub-value C ₁, C ₂, C ₃, currency C ₀

Gas density maximum value M: the maximum value of gas density in forecast interval or the work cycle; Wherein, nearest three sub-value M ₁, M ₂, M ₃, currency M ₀

Gas density 95% is put letter maximum value F: the maximum value of gas density 95% confidential interval in forecast interval or the work cycle; Wherein, nearest three sub-value F ₁, F ₂, F ₃, currency F ₀

Gas density difference D: in the certain hour or the gas density difference of patrolling and examining for twice; Wherein, nearest three sub-value D ₁, D ₂, D ₃, currency D ₀

2. extract the nearest three times mash gas outburst prevention of early warning target development end by mine safety monitoring system and detect desired value:

Wherein, coal powder quantity of bore desired value S for the first time _Max1, the second sub-value S _Max2, be worth S for the third time _Max3Current coal powder quantity of bore desired value S _Max

Drilling cuttings desorption of mash gas desired value K for the first time ₁₁, the second sub-value K ₁₂, be worth K for the third time ₁₃Current drilling cuttings desorption of mash gas desired value K ₁

3. will by step 1. with step 2. the data obtained carry out following calculating:

$\left\{\begin{array}{c}{A}_1{C}_1+A_2(M_1+F_1)+A_3{D}_1=K_{11}\\ A_1{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HDA00002418518500022.png"\; state="\{\{state\}\}">C</figure-callout>}}_2+A_2({\mathrm{<figure-callout\; id="2"\; label="M"\; filenames="HDA00002418518500022.png"\; state="\{\{state\}\}">M</figure-callout>}}_2+F_2)+A_3{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="HDA00002418518500022.png"\; state="\{\{state\}\}">D</figure-callout>}}_2=K_{12}\\ A_1{C}_3+A_2(M_3+F_3)+A_3{D}_3=K_{13}\end{array}\right\}---\left(1\right)$

Solve parameter A by equation group (1) ₁, A ₂, A ₃Value, bring these three parameter values into current forecast interval interior numerical value and carry out following calculating:

A ₁C ₀+A ₂（M ₀+F ₀）+A ₃D ₀=K ₁ （2）

Solve K under the current state by formula (2) ₁Value;

4. will by step 1. with step 2. the data obtained carry out following calculating:

$\left\{\begin{array}{c}{B}_1{C}_1+B_2(M_1+F_1)+B_3{B}_1=S_{\max 1}\\ B_1{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HDA00002418518500022.png"\; state="\{\{state\}\}">C</figure-callout>}}_2+B_2({\mathrm{<figure-callout\; id="2"\; label="M"\; filenames="HDA00002418518500022.png"\; state="\{\{state\}\}">M</figure-callout>}}_2+F_2)+B_3{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="HDA00002418518500022.png"\; state="\{\{state\}\}">D</figure-callout>}}_2=S_{\max 2}\\ B_1{C}_3+B_2(M_3+F_3)+B_3{D}_3=S_{\max 3}\end{array}\right\}---\left(3\right)$

Solve B parameter by equation group (3) ₁, B ₂, B ₃Value, bring these three parameter values into current forecast interval interior numerical value and carry out following calculating:

B ₁C ₀+B ₂（M ₀+F ₀）+B ₃D ₀=S _max （4）

Solve S under the current state by formula (4) _MaxValue;

5. to the K under the current state that is 3. obtained by step ₁S under value and the current state that 4. obtained by step _MaxCarrying out following analysis judges:

Work as S _Max＜4.80kg/m(4.32L/m) and K ₁＜0.40ml/ (g.min ^1/2) time, predicting the outcome is safe condition;

Work as 4.80kg/m(4.32L/m)≤S _Max＜6.00kg/m(5.40L/m) or 0.40ml/ (g.min ^1/2)≤K ₁＜0.50ml/ (g.min ^1/2) time, predicting the outcome is threatened status;

Work as 6.00kg/m(5.40L/m)≤S _MaxPerhaps 0.50ml/ (g.min ^1/2)≤K ₁The time, predicting the outcome is precarious position.

(application examples)

See Fig. 3 and Fig. 4, take ore deposit, Shanxi N2105 adhesive tape crossheading development end as example, having chosen this ore deposit, totally ten days actual measurement gas outburst index value and the resulting gas outburst index value of Forecasting Methodology of the present invention compare 21 to 30 July in 2012.Because this ore deposit development end operation habit is to do the detection that a time protrusion-dispelling detects index every day, thus choose 24 hours as forecast interval, by the S that respectively 10 days the actual detection in this ore deposit is obtained _MaxValue and K ₁The S that value and every day obtain by Forecasting Methodology of the present invention _MaxValue and K ₁Compare, can be clear that coal of the present invention and gas outbursts Prediction method and traditional contact Gas Outburst detection method have good uniformity, forecasting accuracy is high.

In sum, Forecasting Methodology for driving face coal and Gas Outburst of the present invention, considered the variation characteristic of the distinguished and admirable middle gas density that larger ground pressure, coal seam gas-bearing capacity and the three kinds of factors of physical and mechanical properties of coal of driving face coal and Gas Outburst impact are brought, detected index with historical protrusion-dispelling and as revising the danger of driving face coal and Gas Outburst is predicted.Forecasting Methodology of the present invention had both had the continuous forecasting characters of non contact prediction method, combined again the high-reliability of this contact Forecasting Methodology of drilling cuttings index prediction method and the characteristics of degree of recognition simultaneously; And Forecasting Methodology of the present invention is the dimensionless number certificate in the gas density relevant rudimentary data of extracting, revise used historical detect prominent index also be the boundary value that provides according to " control coal and Gas Outburst detailed rules and regulations " as the basis, thereby have stronger adaptive ability.Thereby Forecasting Methodology of the present invention is all higher coal and Gas Outburst real-time predicting methods of a kind of prediction accuracy and degree of recognition.

Above embodiment and application examples are the explanations to the specific embodiment of the present invention; but not limitation of the present invention; person skilled in the relevant technique is in the situation that does not break away from the spirit and scope of the present invention; can also make various conversion and obtain the corresponding technical scheme that is equal to variation, so all technical schemes that are equal to all should be included into scope of patent protection of the present invention.

Claims (1)

1. the Forecasting Methodology of a coal and Gas Outburst is based upon on the coal mine safety monitoring system basis; Described coal mine safety monitoring system stores coal powder quantity of bore desired value and the drilling cuttings desorption of mash gas desired value that obtains by the reality detection and receives in real time and store the gas data of mine development ends and carry out respective handling, it is characterized in that: mainly may further comprise the steps:

1. extract by mine safety monitoring system and be arranged on apart from early warning target development end 40～60m position firedamp sensor following real-time gas data transmission and carry out respective handling through safety monitoring system:

Gas density average C: the average of gas density in forecast interval or the work cycle; Wherein, nearest three sub-value C ₁, C ₂, C ₃, currency C ₀

Gas density maximum value M: the maximum value of gas density in forecast interval or the work cycle; Wherein, nearest three sub-value M ₁, M ₂, M ₃, currency M ₀

Gas density 95% is put letter maximum value F: the maximum value of gas density 95% confidential interval in forecast interval or the work cycle; Wherein, nearest three sub-value F ₁, F ₂, F ₃, currency F ₀

Gas density difference D: in the certain hour or the gas density difference of patrolling and examining for twice; Wherein, nearest three sub-value D ₁, D ₂, D ₃, currency D ₀

2. extract the nearest three times mash gas outburst prevention of early warning target development end by mine safety monitoring system and detect desired value:

Wherein, coal powder quantity of bore desired value S for the first time _Max1, the second sub-value S _Max2, be worth S for the third time _Max3Current coal powder quantity of bore desired value S _Max

Drilling cuttings desorption of mash gas desired value K for the first time ₁₁, the second sub-value K ₁₂, be worth K for the third time ₁₃Current drilling cuttings desorption of mash gas desired value K ₁

3. will by step 1. with step 2. the data obtained carry out following calculating:

$\left\{\begin{array}{c}{A}_1{C}_1+A_2(M_1+F_1)+A_3{D}_1=K_{11}\\ A_1{C}_2+A_2(M_2+F_2)+A_3{D}_2=K_{12}\\ A_1{C}_3+A_2(M_3+F_3)+A_3{D}_3=K_{13}\end{array}\right\}---\left(1\right)$

Solve parameter A by equation group (1) ₁, A ₂, A ₃Value, bring these three parameter values into current forecast interval interior numerical value and carry out following calculating:

A ₁C ₀+A ₂（M ₀+F ₀）+A ₃D ₀=K ₁ （2）

Solve K under the current state by formula (2) ₁Value;

4. will by step 1. with step 2. the data obtained carry out following calculating:

$\left\{\begin{array}{c}{B}_1{C}_1+B_2(M_1+F_1)+B_3{B}_1=S_{\max 1}\\ B_1{C}_2+B_2(M_2+F_2)+B_3{D}_2=S_{\max 2}\\ B_1{C}_3+B_2(M_3+F_3)+B_3{D}_3=S_{\max 3}\end{array}\right\}---\left(3\right)$

Solve B parameter by equation group (3) ₁, B ₂, B ₃Value, bring these three parameter values into current forecast interval interior numerical value and carry out following calculating:

B ₁C ₀+B ₂（M ₀+F ₀）+B ₃D ₀=S _max （4）

Solve S under the current state by formula (4) _MaxValue;

5. to the K under the current state that is 3. obtained by step ₁S under value and the current state that 4. obtained by step _MaxCarrying out following analysis judges:

Work as S _Max＜4.80kg/m(4.32L/m) and K ₁＜0.40ml/ (g.min ^1/2) time, predicting the outcome is safe condition;

Work as 4.80kg/m(4.32L/m)≤S _Max＜6.00kg/m(5.40L/m) or 0.40ml/ (g.min ^1/2)≤K ₁＜0.50ml/ (g.min ^1/2) time, predicting the outcome is threatened status;

Work as 6.00kg/m(5.40L/m)≤S _MaxPerhaps 0.50ml/ (g.min ^1/2)≤K ₁The time, predicting the outcome is precarious position.

Images