CN104750940A - Dynamic design method for strength of cemented filling body of underground mining stope - Google Patents

Abstract

The invention discloses a method for dynamically designing the strength of a cemented filling body in an underground stope, which belongs to the field of filling method mining. The design method includes the following steps: (1) According to the burial depth of the stope, calculate the top force value and lateral force value of the stope filling body through the hydrostatic pressure theory; (2) The interaction between the filling body and the surrounding rock Simplified to the three-dimensional stress problem with the same lateral pressure, the failure of the stope filling body follows the Hoek-Brown empirical strength failure criterion; (3) According to the quality requirements of the cemented filling body in the filling stope under different conditions, determine the integrity of the cemented filling body (4) Comparing the strength value of the cemented filling body meeting the specific filling quality requirements with the strength value meeting the self-supporting requirements of the stope filling body at the same time, and taking the maximum value between the two. The present invention is characterized in that it not only considers the stress condition of the top of the cemented filling body in the actual stope and the filling quality on site, but also can dynamically design the strength value of the cemented filling body according to the size change of the stope.

Description

A dynamic design method for strength of cemented filling body in underground stope

technical field

The invention relates to the field of filling method mining, in particular to the strength design of the filling body for the filling method mining of large underground ore deposits.

Background technique

Mining operation is a dynamic evolution process, the stress environment of the filling body is complex and changeable, and it is a nonlinear complex multiphase medium body. The relationship between filling body and surrounding rock is not only related to factors such as stope mining strength and mining depth, but also related to filling body proportion and filling quality. Therefore, the selection of filling body strength is a process of dynamic matching design. The proportion and strength of filling body is one of the key factors to save filling cost and ensure safe operation of stope, especially some filling mining methods that require high early strength of filling body; in terms of determining the strength of filling body in stope, foreign filling The strength value is about 1-2MPa, and the domestic non-ferrous metallurgical mine operation specification clearly stipulates that the filling body strength of the downward filling method must be above 5.0MPa; for the selection of filling body strength values of various other filling mining methods Design institutes and related scientific research units usually recommend filling body strength of 4-5MPa (Jinchuan nickel ore selection 4.5MPa) based on experience, so the strength of domestic filling bodies is usually higher than the strength value selected abroad, which directly leads to high filling costs in domestic mines At present, there is no accurate and suitable design method to determine the strength of stope filling body.

The three-dimensional stress state of the filling body is often ignored by researchers, who believe that the filling body itself only needs to satisfy self-supporting properties, which will affect the study of the relationship between the filling body and the surrounding rock, thereby affecting the selection of the filling body strength. Therefore, according to the influence of the mining depth, mining intensity and filling quality on the interaction characteristics of the filling body and the surrounding rock, the mechanical model of the interaction between the filling body and the surrounding rock is simplified to a three-dimensional force problem with the same lateral pressure, and different models are designed. The dynamic determination method of filling body strength under the conditions of mining intensity and mining depth aims to provide reasonable guidance and basis for mine design.

Contents of the invention

The purpose of the present invention is to provide a method for designing the strength dynamics of cemented filling bodies in underground stopes. According to the mining depth, mining strength and filling quality of the ore deposit, the method simplifies the mechanical model of the interaction between the filling body and the surrounding rock into a three-dimensional force problem with the same lateral pressure, and dynamically designs the strength of the cemented filling body in the stope, and The strength of the designed cemented filling body can not only meet the three-dimensional stress conditions of the filling body, but also maintain its own stability.

A dynamic design method for strength of cemented filling body in underground stope, characterized in that it includes the following steps:

(1) According to the burial depth of the stope, calculate the force value and lateral force value on the top of the stope filling body through the theory of hydrostatic pressure;

The object of the design method is random, and the top and lateral force values of the filling body can be calculated according to the actual burial depth of any stope. According to the hydrostatic pressure theory, the surrounding stress state of the stope can be calculated by the following formula,

Force formula on top of filling body:

_σv = γH (1)

In formula (1), γ is the density of overlying strata in the stope;

H is the burial depth of the stope;

Lateral force formula of filling body:

${\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

In formula (2), λ is the construction coefficient, usually 1.1~1.3;

Wherein, in said formula (2), with The ratio of is used as the correction factor for the lateral force of the filling body;

(2) The mechanical model of the interaction between the filling body and the surrounding rock is simplified to a three-dimensional force problem with the same lateral pressure, and the failure of the stope filling body follows the Hoek-Brown empirical strength failure criterion;

A. When filling the empty area of the underground stope, ensure that the filling body is in good contact with the surrounding rock of the stope, and is completely connected to the top of the surrounding rock;

B. Decompose the force of the filling body placed in the underground stope: the top is subjected to vertical stress, and the side is subjected to horizontal stress of the same lateral pressure;

C. The external force σ _v and the lateral pressure σ _a generated by the top rock mass in the mechanical model are respectively regarded as the maximum principal stress and minimum principal stress when the filling body fails, and satisfy the following criteria:

${\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; m</span>}{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}{{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In formula (3), σ _c is the uniaxial compressive strength of the filling body;

m and s are dimensionless parameters, which represent the integrity of the filling body, and are related to the type of filling particles, friction angle, filling quality and mining intensity, usually s=0~0.9, m=0.0001~25.0.

D. When the mining intensity of the stope is constant, the mining disturbance is certain to cause the energy change of the surrounding rock. The function of the filling body only needs to provide enough to compensate for the deformation energy generated by the mining to maintain the stability of the surrounding rock.

(3) Determine the integrity index of the cemented filling body according to the quality requirements of the filling stope under different conditions for the cemented filling body;

A. Classify the filling body quality;

B. According to the type of stope filling mining method, the integrity index of the filling body required on the site is given;

(4) Comparing the strength value of the cemented filling body meeting the specific filling quality requirements with the strength value meeting the self-supporting requirements of the stope filling body at the same time, and taking the maximum value between the two.

A. Substituting the determined index into formula (3) to calculate the filling body strength.

B. The underground stope filling body must also meet its self-supporting requirements, and the calculation formula is as follows:

${\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&rho;h</span>}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; w</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

where _σd is the vertical stress acting on the bottom of the filling body;

h the height of the filling body;

w The width of the filling body;

ρ filling body weight.

C. Select the maximum value calculated by the two methods, and this value is the optimal value required for the stope filling body.

The core of the step (1) is to clarify the top force and lateral force of the filling body through the hydrostatic pressure theory, so as to realize the standardization of the actual stress state of the filling body; determine the stress state of the filling body and the buried depth of the stope. connect.

The core of the step (2) is to require the failure of the cemented filling body to follow the Hoek-Brown empirical strength failure criterion.

The step (3) can give the filling body an integrity index according to the requirements of different filling method types for the filling body; different filling body integrity indexes reflect different filling body strength values, and the better the filling quality, that is, The more complete the filling, the smaller the required strength value of the filling.

The core of the step (4) is that the dynamic strength of the designed filling body must meet the following two conditions: the first criterion is to meet the stability requirements of the filling body itself; the second criterion is to meet the three-dimensional stress intensity criterion under the condition of multiple factors, and take the maximum value between the two.

The invention has the beneficial effect of overcoming the defect that the existing filling body strength design is limited to empirical formulas, and providing a quantitative and dynamic filling body strength design method. The invention considers the burial depth of the filling stope and the filling quality factors to design the strength of the filling body in the stope, not only can specify the strength value of the filling body required by any stope, but also can ensure that the strength of the designed filling body can ensure the safety of the stope operation. More importantly, it can avoid the increase of mine mining cost due to the high strength of the filling body selected by the empirical method, which affects its economic benefits.

Description of drawings

Fig. 1 is a flow chart of the method for dynamic design of filling body strength according to the present invention.

Figure 2 is a three-dimensional simplified diagram of the filling body.

Detailed ways

The present invention will be further described below, but the protection scope of the present invention is not limited to the scope of the specific embodiments described below.

Combined with the design flow chart provided by the present invention, the present invention will be further described. The advantages and disadvantages of the method for designing the strength of an underground stope cemented filling body according to the present invention will be illustrated below through specific examples.

In this example, the subsequent filling stope of the Hemushan Iron Mine stage is located at -187m level, the surface elevation is +30m, the stope width is 12.5m, the height is 37m, and the ore block length is 50m. Full tailings cemented filling is used, and the bulk density of the overlying rock mass is λ =3.2t/m ³ .

Fig. 1 is a flowchart of the method for dynamic design of filling body strength according to the present invention. In Figure 1, step 1: find out the burial depth of the filling stope.

Step 2: According to the burial depth of the filling stope, the bulk density of the overlying rock mass in the stope, and the geological structure coefficient, calculate the top and lateral force values of the filling body through the hydrostatic pressure theory.

Step 3: Determine the stope method of the filling body used in the stope, and propose the required level of filling body strength (see Table 1), so as to put forward specific requirements for the filling body strength.

Step 4: According to the quality requirement indicators m and s of the cemented filling body in the filling stope under different conditions (see Table 1), determine the filling quality integrity level.

Step 5: After determining the top and lateral force values of the filling body and the integrity index value of the filling quality, the strength failure of the filling body must meet the Hoek-Brown empirical strength criterion.

Step 6: Using the Hoek-Brown Empirical Strength Criterion Formula The strength values of the stope filling body under different conditions are calculated (see Table 2).

Step 7: The use of stope filling body must meet its self-supporting requirements calculation formula When the height of the filling body is 37m, the self-supporting strength value is 0.25MPa (see Table 2).

Step 8: Compare the filling body strength values calculated in Step 6 and Step 7, and select the maximum value calculated by the two methods, which is the optimal value required for the stope filling body.

Table 1 Strength classification of filling bodies

Table 2 Relationship between filling body strength and filling mass constant when mining depth is 180m and stope length is 25m

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person familiar with the technical field can easily think of changes within the technical scope disclosed in the present invention. Or replacement, all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (5)

1. a underground mining stope cemented fill dynamic changes of strength method for designing, is characterized in that, comprise the following steps:

(1) according to stope depth of burial, stope filling body top stress value and lateral force value is gone out by hydrostatic force theory calculate;

Described method for designing to as if random, obturation top and lateral force value can be calculated according to the actual depth of burial of any stope, theoretical according to hydrostatic force, calculate stope edge stress state by following formula,

Obturation top force bearing formulae:

σ _v＝γH (1)

In formula (1), γ is the density of Overlying Strata In A Face;

H is the depth of burial of stope;

Obturation lateral force formula:

${\mathrm{\&sigma;}}_a={\mathrm{\&sigma;}}_v\frac{(1-\mathrm{\&lambda;})(1+\mathrm{\&lambda;})}{2(1+2\mathrm{\&lambda;})}---\left(2\right)$

In formula (2), λ is structure coefficient, usually gets 1.1 ~ 1.3;

Wherein, in described formula (2), with ratio as the correction factor of obturation lateral force;

(2) be the identical stressed problem of three-dimensional of side pressure by obturation and the model simplification of country rock interaction mechanics, the destruction of stope filling body follows Hoek-Brown experience Strength Criterion for Ceramics;

A, when filling is carried out to underground mining stope dead zone, ensure that obturation contacts well with stope peripheral rock, connect top completely with top country rock;

B, the obturation stressing conditions being placed in underground mining stope to be decomposed: top is subject to perpendicular stress, and side direction is subject to the horizontal stress of identical side pressure size;

C, the external force σ that top rock mass in mechanical model is produced _vwith lateral pressure σ _abe considered as major principal stress when obturation generation destroys and least principal stress respectively, and meet following criterion:

${\mathrm{\&sigma;}}_v={\mathrm{\&sigma;}}_a+\sqrt{m{\mathrm{\&sigma;}}_c{\mathrm{\&sigma;}}_a+s{{\mathrm{\&sigma;}}_c}^2}---\left(3\right)$

σ in formula (3) _cfor obturation uniaxial compressive strength;

M, s are dimensionless group, represent the integrality of obturation, relevant with pack grain type, angle of friction, filling quality and mining rate, usual s=0 ~ 0.9, m=0.0001 ~ 25.0.

D, when stope mining rate one timing, exploitation disturbance be certain to causing country rock energy variation, the effect of obturation only need provide enough make up exploitation produce deformation energy just can keep country rock stablizing.

(3) according to the filling stope of different condition to the quality requirements of cemented fill, determine the integrity metrics of cemented fill;

A, to Quality of filling body grade classification;

B, give the integrity metrics of on-the-spot required obturation according to stope filling mining methods type;

(4) by the cemented fill intensity level met under specific filling quality requirement with to meet the intensity level that stope filling body supports oneself when requiring simultaneously and contrast, maximal value between both getting.

A, the index determined substituted in formula (3) and carries out strength of filling mass calculating.

B, underground mining stope obturation also must meet its independence requirement, and computing formula is as follows:

${\mathrm{\&sigma;}}_d=\frac{\mathrm{\&rho;h}}{1+(h/w)}---\left(4\right)$

σ in formula _dact on the perpendicular stress bottom obturation;

The height of h obturation;

The width of w obturation;

ρ obturation unit weight.

C, the maximal value selecting two kinds of methods to calculate, this value is the optimum value needed for stope filling body.

2. a kind of underground mining stope cemented fill dynamic changes of strength method for designing according to claim 1, it is characterized in that: the core of described step (1) is stressed by the theoretical clear and definite obturation top of hydrostatic force and lateral force, realizes the standardization of obturation actual forced status; There is contact in the buried depth of the force-bearing situation and stope that determine obturation.

3. a kind of underground mining stope cemented fill dynamic changes of strength method for designing according to claim 1, is characterized in that: the core of described step (2) is that the destruction of requirement cemented fill follows Hoek-Brown experience Strength Criterion for Ceramics.

4. a kind of underground mining stope cemented fill dynamic changes of strength method for designing according to claim 1, is characterized in that: described step (3) can according to for different stowing method types to the requirement of obturation, give the integrity metrics of obturation; Different obturation integrity metrics, the strength of filling mass value of embodiment is different, and filling quality is better, and namely obturation is more complete, and the intensity level of required obturation is also less.

5. a kind of underground mining stope cemented fill dynamic changes of strength method for designing according to claim 1, is characterized in that: the core of described step (4) is that the obturation resistance to vibration designed must meet following two conditions: criterion one to meet the requirement of obturation self stability; Criterion two is the three-dimensional stress criterion of strength met under multifactor condition, and gets the maximal value between the two.