Method for determining mechanical strength of tailing cemented filling body

Abstract

The invention discloses a method for determining the mechanical strength of a tailing cemented filling body, which comprises the following steps of: acquiring a three-dimensional space structure of a filling stope, and determining geometric structure parameters of the filling body; mechanical parameters of a tailing cemented filling body material are obtained; according to the geometric structure parameters of the filling body and the mechanical parameters of the tailing cemented filling body material, a filling stope tailing cemented filling body physical similarity model is constructed; according to the filling stope tailing cemented filling body physical similarity model, a filling body demand strength mathematical model is calculated and established; and determining the mechanical strength of the tailing cemented filling body according to the mathematical model of the required strength of the filling body. According to the method, the influence of factors such as the geometrical shape of the filling body, material mechanics, the filling mining process and mining disturbance is comprehensively considered, the influence on the stability of the filling body is calculated through a physical similar simulation experiment, the mechanical strength model of the tailing cemented filling body is constructed, and the method for determining the strength of the filling body is simpler and more accurate.

Description

Technical Field

[0001] The invention belongs to the technical field of mine filling mining, and in particular relates to a method for determining the mechanical strength of a tailings cemented filling body. Background Art

[0002] Backfill mining is a technologically advanced green mining method that is widely used in various underground mines. By using backfill materials to fill the goaf, the deformation of the surrounding rock in the mine can be suppressed, the ground pressure activity in the mine can be controlled, a safe and stable production environment can be created for mining operations, and the ore recovery rate can be improved. Using waste rock, tailings and other mining solid waste to fill the goaf can not only reduce solid waste emissions, save land occupation, avoid environmental pollution, but also realize the resource utilization of waste rock and tailings.

[0003] The strength of the filling body is a key technical parameter of the filling mining process. In order to ensure the safety and stability of the filling body during the mining process, the filling body must have sufficient mechanical strength. Tailings cemented filling uses mineral processing tailings and cementitious materials (such as cement) to prepare filling slurry. The higher the strength of the tailings cemented filling body, the better the stability of the filling body, but the more cementitious materials are consumed, and the higher the filling cost. Therefore, determining an accurate and reasonable filling body strength is of great significance to ensuring the stability of the filling body and reducing the consumption of cementitious materials, which is of great significance to ensuring the safety of filling mining and reducing filling costs. This is also the difficulty of filling body strength design.

[0004] At present, the main methods for determining the strength of filling bodies include theoretical model (or empirical formula) calculation method, engineering experience analogy method and numerical simulation calculation method, as well as the combination of the above methods. These methods have problems to varying degrees, such as oversimplification of the filling body mechanical model, insufficient consideration of factors affecting the stability of the filling body, and large deviation between the calculation results of the filling body strength and the actual situation. Summary of the invention

[0005] The present invention provides a method for determining the mechanical strength of a tailings cemented filling body, which can reduce the complexity of filling body strength calculation, fully considers the stability factor of the filling body, and has high accuracy in determining the filling body strength.

[0006] The present invention provides a method for determining the mechanical strength of a tailings cemented filling body, comprising the following steps:

[0007] S1. Obtain the three-dimensional spatial structure of the filling stope and determine the geometric structure parameters of the filling body;

[0008] S2. Obtaining mechanical parameters of tailings cemented filling material;

[0009] S3. Constructing a physical similarity model of the tailings cemented filling body in the filling stope according to the filling body geometric structure parameters obtained in step S1 and the tailings cemented filling body material mechanical parameters obtained in step S2;

[0010] S4. Calculate and establish a mathematical model of the required strength of the filling body according to the physical similarity model of the tailings cemented filling body in the filling stope obtained in step S3;

[0011] S5. Determine the mechanical strength of the tailings cemented filling body according to the mathematical model of the required strength of the filling body obtained in step S4.

[0012] Step S1 is specifically as follows: mining the mine by filling method, the three-dimensional geometric structure of the filling stope is a cuboid, and the filling body formed after the filling of the goaf is the same as the cuboid, and the filling body geometric structure parameters are determined, and the filling body geometric structure parameters include the length L 0 , Width W 0 and height H 0 .

[0013] Step S2 specifically includes: obtaining the mechanical parameters of the tailings cemented filling material, including the density, elastic modulus, Poisson's ratio, compressive strength, cohesion and internal friction angle of the filling.

[0014] Step S3 specifically includes: based on the similarity principle, according to the geometric structure parameters of the filling body obtained in step S1, according to the preset similarity ratio, determining the geometric dimensions of the physical similarity model of the filling body; according to the mechanical parameters of the tailings cemented filling body material obtained in step S2, confirming the tailings cemented filling material, and then using the same tailings cemented filling material as the actual filling body to establish the physical similarity model of the filling body;

[0015] The geometric dimensions of the physical similarity model of the filling body are calculated and determined by the following formula:

[0016] l 0 =μL 0

[0017] w 0 =μW 0

[0018] h 0 =μH 0

[0019] Among them, l 0 is the length of the physical similarity model of the filling body; w 0 h is the width of the physical similarity model of the filling body; 0 is the height of the physical similarity model of the filling body; μ is the preset similarity ratio.

[0020] Step S4 is as follows: based on the self-weight stress distribution of the filling body, considering the influence of the filling body geometry, filling material properties and filling mining process on stability, a mathematical model of the filling body required strength is established, and the filling body required strength R is calculated using the following formula: req :

[0021] R req =αβγH

[0022] Among them, α is the geometric shape influence coefficient of the filling body stability; β is the material process influence coefficient of the filling body stability; γ is the bulk density of the filling body material; H is the distance between the filling body at different height positions and the top surface;

[0023] The geometric influence coefficient α of the filling stability is calculated using the following formula:

[0024]

[0025] A simulation experiment was conducted on the physical similarity model of the filling body, and the stress therein was detected; n stress monitoring points were set in the physical similarity model of the filling body, and the material process influence coefficient β of the filling body stability was calculated using the following formula:

[0026]

[0027] Among them, f(h i ) is the first parameter; is the second parameter; g(h i ) is the third parameter; is the fourth parameter and is calculated using the following formula:

[0028]

[0029] Among them, σ v (h i ) is the vertical stress monitoring result of the ith stress monitoring point; h i is the distance between the location of the i-th stress monitoring point and the top surface of the model;

[0030] Step S5 specifically includes: determining the required strength R of different layers of the filling body according to the required strength mathematical model of the filling body obtained in step S4. req ; Consider the disturbance of mining in adjacent stopes and other uncertain factors to determine the design strength R of the filling body des , use the following formula to calculate:

[0031] R des =F s R req

[0032] Among them, F s Design safety factor for filling strength;

[0033] Taking into account the requirements for mine filling slurry preparation and filling body quality control, the vertical layered structure of the filling body is divided according to the actual height of the filling site and the design strength of the filling body, the filling body layer height is determined, and then the required strength of the filling body in different layers is calculated.

[0034] The present invention discloses a method for determining the mechanical strength of a tailings-cemented backfill body, which comprehensively considers the influence of factors such as the geometric shape of the backfill body, material mechanics, backfilling and mining technology, and mining disturbance, calculates the influence of the mechanical properties of the backfill body material and the backfilling and mining technology on the stability of the backfill body through physical similarity simulation experiments, and constructs a mechanical strength model of the tailings-cemented backfill body, making the method for determining the backfill body strength simpler and more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the process of the present invention;

[0036] Figure 2 This is a calculation result of the filling body strength according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The present invention provides a method for determining the mechanical strength of a tailings cemented filling body, and its flow diagram is as follows: Figure 1 As shown, the following steps are included:

[0038] S1. Obtain the three-dimensional spatial structure of the filling stope and determine the geometric structure parameters of the filling body, specifically:

[0039] In a mine with backfilling method, the three-dimensional geometric structure of the backfilling stope is a cuboid. The backfill body formed after the backfilling is completed has the same geometric shape as the cuboid. The backfill body geometric structure parameters are determined. The backfill body geometric structure parameters include the length L 0 , Width W 0 and height H 0 .

[0040] S2. Obtain the mechanical parameters of the tailings-cemented filling material, specifically: obtain the mechanical parameters of the tailings-cemented filling material, including the density, elastic modulus, Poisson's ratio, compressive strength, cohesion and internal friction angle of the filling body.

[0041] S3. Based on the filling body geometric structure parameters obtained in step S1 and the tailings cemented filling body material mechanical parameters obtained in step S2, a physical similarity model of the tailings cemented filling body in the filling stope is constructed, specifically:

[0042] Based on the similarity principle, according to the geometric structure parameters of the filling body obtained in step S1, the geometric dimensions of the physical similarity model of the filling body are determined according to the preset similarity ratio; according to the mechanical parameters of the tailings cemented filling body material obtained in step S2, the tailings cemented filling material is confirmed, and then the tailings cemented filling material that is the same as the actual filling body is used to establish the physical similarity model of the filling body;

[0043] The geometric dimensions of the physical similarity model of the filling body are calculated and determined by the following formula:

[0044] l 0 =μL 0

[0045] w 0 =μW 0

[0046] h 0 =μH 0

[0047] Among them, l 0 is the length of the physical similarity model of the filling body; w 0 h is the width of the physical similarity model of the filling body; 0 is the height of the physical similarity model of the filling body; μ is the preset similarity ratio.

[0048] S4. Calculate and establish a mathematical model of the required strength of the filling body according to the physical similarity model of the tailings cemented filling body in the filling stope obtained in step S3;

[0049] Based on the self-weight stress distribution of the filling body, considering the influence of the filling body geometry, filling material properties and filling mining process on stability, a mathematical model of the filling body required strength is established, and the filling body required strength R is calculated using the following formula req :

[0050] R req =αβγH

[0051] Among them, α is the geometric shape influence coefficient of the filling body stability; β is the material process influence coefficient of the filling body stability; γ is the bulk density of the filling body material; H is the distance between the filling body at different height positions and the top surface;

[0052] The geometric influence coefficient α of the filling stability is calculated using the following formula:

[0053]

[0054] A simulation experiment was conducted on the physical similarity model of the filling body, and the stress therein was detected; n stress monitoring points were set in the physical similarity model of the filling body, and the material process influence coefficient β of the filling body stability was calculated using the following formula:

[0055]

[0056] Among them, f(h i ) is the first parameter; is the second parameter; g(h i ) is the third parameter; is the fourth parameter and is calculated using the following formula:

[0057]

[0058] Among them, σ v (h i ) is the vertical stress monitoring result of the ith stress monitoring point; h i is the distance between the location of the i-th stress monitoring point and the top surface of the model;

[0059] S5. According to the required strength mathematical model of the filling body obtained in step S4, the mechanical strength of the tailings cemented filling body is determined, specifically:

[0060] According to the filling body strength requirement mathematical model obtained in step S4, the filling body strength requirement R is determined. req ; Consider the disturbance of mining in adjacent stopes and other uncertain factors to determine the design strength R of the filling body des , use the following formula to calculate:

[0061] R des =F s R req

[0062] Among them, F s Design safety factor for filling strength;

[0063] Taking into account the requirements for mine filling slurry preparation and filling body quality control, the vertical layered structure of the filling body is divided according to the actual height of the filling site and the design strength of the filling body, the filling body layer height is determined, and then the required strength of the filling body in different layers is calculated.

[0064] The method of the present invention is further described below in conjunction with an embodiment:

[0065] The production scale of an iron mine is 5 million tons / a, and it mainly adopts the staged empty field and subsequent filling method for mining. For thick and large ore bodies, the stopes are arranged vertically to the ore body and divided into panels according to the length of 100m. The ore body in the panel area is divided into a mine room and a pillar stope for two-step mining. The stope width is 15-18m, the stope length is the thickness of the ore body, and the stope height is the middle section height. According to the mining design, the height of the middle section mine room is about 85-90m, and the length of the one-step stope is about 180-220m. The mine adopts a high-concentration full tailings cementing filling process. The filling slurry is prepared at the surface filling station, transported to the underground by gravity through the filling borehole, and then enters the corresponding stope through the pipelines of each middle section. The physical and mechanical properties of tailings cementing filling bodies with different ash-sand ratios are shown in Table 1.

[0066] Table 1 Physical and mechanical parameters of tailings cemented filling

[0067]

[0068] First, according to the three-dimensional geometric structure of the mine filling stope, the geometric structure parameters of the filling body are determined as follows: length L 0 220m, width W 0 18m, height H 0 It is 90m.

[0069] Combined with the actual height of the filling site and previous filling project experience, it is preliminarily determined that the maximum required strength of the tailings cemented filling body is about 2.5~3.0MPa, which is closest to the compressive strength of the filling body with a ash-sand ratio of 1:5. Therefore, the physical and mechanical parameters of the tailings cemented filling body in the filling site are taken from the physical and mechanical parameters test results of the filling body with a ash-sand ratio of 1:5.

[0070] According to the geometric structure parameters of the filling body, at a similarity ratio of 1:100, the geometric dimensions of the physical similarity model of the filling body are: length 2.2m, width 0.18m and height 0.9m. Tailings cemented filling material with a lime-sand ratio of 1:5 is used to establish the physical similarity model of the filling body.

[0071] Based on the established physical similarity model of the filling body and combined with the two-step mining process, a filling mining simulation test was carried out. The vertical stress inside the model was monitored and recorded using stress monitors set at 9 different heights inside the model. The results are shown in Table 2. In order to ensure the reliability of the similarity simulation test results, a total of 5 similarity simulation tests were carried out, and the average value of the stress monitoring results of the 5 tests was taken for subsequent calculations.

[0072] Table 2 Monitoring results of vertical stress inside the similar simulation test model of backfill mining

[0073]

[0074] According to the physical similarity model of the tailings cemented filling body in the filling stope, the mathematical model of the required strength of the filling body is calculated and established. The calculation process is as follows:

[0075]

[0076] Among them, the geometric shape influence coefficient α of the filling stability is calculated using the following formula:

[0077]

[0078] The bulk density γ of the filling material is the bulk density of the tailings cemented filling body with a lime-sand ratio of 1:5, and the calculation formula is:

[0079] γ=1.99g·cm -3 ×9.8m·s -2 ≈0.0195MN·m -3

[0080] The calculation process and results of the material process influence coefficient of filling body stability are shown in Table 3:

[0081] Table 3 Calculation process and results of material process influence coefficient of filling stability

[0082]

[0083]

[0084] Therefore, considering the disturbance of mining in adjacent stopes and other uncertain factors, the design strength of the filling body R des Use the following calculation:

[0085]

[0086] According to the calculation formula obtained, the required strength and design strength of the filling body are calculated at a height interval of 10m. The results are shown in Table 4:

[0087] Table 4 Results of required strength and design strength of filling body

[0088] Height to the top of the filling body H / m <![CDATA[Demand intensity R req / MPa]]> <![CDATA[Safety factor F s > <![CDATA[Design strength R des / MPa]]> 10 0.20 2.0 0.40 20 0.38 2.0 0.76 30 0.55 2.0 1.10 40 0.70 2.0 1.40 50 0.85 2.0 1.70 60 0.98 2.0 1.96 70 1.11 2.0 2.22 80 1.23 2.0 2.46 90 1.34 2.0 2.68

[0089] Considering the requirements for filling slurry preparation and filling body quality control in mines, the vertical layered structure of the filling body is divided according to the actual height of the filling stope and the designed strength of the filling body, the filling body layer height is determined, and then the required strength of the filling body in different layers is calculated. The results are as follows: Figure 2 As shown in Table 5:

[0090] Table 5 Layered strength structure and parameters of filling body

[0091] Height to the top of the filling body H / m Filling strength R / MPa 0～30 1.0 30～60 1.8 60～90 2.5

Claims

1. A method for determining the mechanical strength of a tailings cemented filling body, characterized in that: The following steps are involved: S1. Obtain the three-dimensional spatial structure of the filling stope and determine the geometric structure parameters of the filling body; S2. Obtaining mechanical parameters of tailings cemented filling material; S3. Constructing a physical similarity model of the tailings cemented filling body in the filling stope according to the filling body geometric structure parameters obtained in step S1 and the tailings cemented filling body material mechanical parameters obtained in step S2; S4. Calculate and establish a mathematical model of the required strength of the filling body according to the physical similarity model of the tailings cemented filling body in the filling stope obtained in step S3; S5. Determine the mechanical strength of the tailings cemented filling body according to the mathematical model of the required strength of the filling body obtained in step S4.

2. The method for determining the mechanical strength of tailings cemented filling body according to claim 1, characterized in that: Step S1 is specifically as follows: mining the mine by the filling method, the three-dimensional spatial geometric structure of the filling mining area is a rectangular parallelepiped, and the filling body formed after the goaf is filled is the same as the rectangular parallelepiped, and the filling body geometric structure parameters are determined, and the filling body geometric structure parameters include length L0, width W0 and height H0.

3. The method for determining the mechanical strength of tailings cemented filling body according to claim 1, characterized in that: Step S2 specifically includes: obtaining the mechanical parameters of the tailings cemented filling material, including the density, elastic modulus, Poisson's ratio, compressive strength, cohesion and internal friction angle of the filling.

4. The method for determining the mechanical strength of tailings cemented filling body according to claim 2, characterized in that: Step S3 specifically includes: based on the similarity principle, according to the geometric structure parameters of the filling body obtained in step S1, according to the preset similarity ratio, determining the geometric dimensions of the physical similarity model of the filling body; according to the mechanical parameters of the tailings cemented filling body material obtained in step S2, confirming the tailings cemented filling material, and then using the same tailings cemented filling material as the actual filling body to establish the physical similarity model of the filling body; The geometric dimensions of the physical similarity model of the filling body are calculated and determined by the following formula: l0=μL0 w0=μW0 h0=μH0 Among them, l0 is the length of the physical similarity model of the filling body; w0 is the width of the physical similarity model of the filling body; h0 is the height of the physical similarity model of the filling body; and μ is the preset similarity ratio.

5. The method for determining the mechanical strength of tailings cemented filling body according to claim 4, characterized in that: Step S4: Based on the self-weight stress distribution of the filling body, considering the influence of the filling body geometry, filling material properties and filling mining process on stability, a mathematical model of the filling body strength requirement is established, and the filling body strength requirement R is calculated using the following formula: req : R req =αβγH Among them, α is the geometric shape influence coefficient of the filling body stability; β is the material process influence coefficient of the filling body stability; γ is the bulk density of the filling body material; H is the distance between the filling body at different height positions and the top surface.

6. The method for determining the mechanical strength of tailings cemented filling body according to claim 5, characterized in that: The geometric influence coefficient α of the filling stability is calculated using the following formula: A simulation experiment was conducted on the physical similarity model of the filling body, and the stress therein was detected; n stress monitoring points were set in the physical similarity model of the filling body, and the material process influence coefficient β of the filling body stability was calculated using the following formula: Among them, f(h i ) is the first parameter; is the second parameter; g(h i ) is the third parameter; is the fourth parameter and is calculated using the following formula: Among them, σ v (h i ) is the vertical stress monitoring result of the ith stress monitoring point; h i is the distance between the location of the i-th stress monitoring point and the top surface of the model.

7. The method for determining the mechanical strength of tailings cemented filling body according to claim 6, characterized in that: Step S5 specifically includes: determining the required strength R of different layers of the filling body according to the required strength mathematical model of the filling body obtained in step S4. req ; Consider the disturbance of mining in adjacent stopes and other uncertain factors to determine the design strength R of the filling body des , use the following formula to calculate: R des =F s R req Among them, F s Design safety factor for filling strength.

8. The method for determining the mechanical strength of tailings cemented filling body according to claim 7, characterized in that: Taking into account the requirements for mine filling slurry preparation and filling body quality control, the vertical layered structure of the filling body is divided according to the actual height of the filling site and the design strength of the filling body, the filling body layer height is determined, and then the required strength of the filling body in different layers is calculated.

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