Deep draw shaft material level height determining method and system based on bottom standing stress threshold value

Abstract

The invention belongs to the technical field of high draw shaft material level control, and particularly discloses a deep draw shaft material level height determining method and system based on a bottom standing stress threshold value, and the method comprises the steps that a safety threshold value interval of deep draw shaft bottom standing stress is obtained; on the basis of the safety threshold interval, a candidate material level height interval is obtained through inversion calculation; ore drawing operation is carried out based on the candidate material level height, and the actual standing stress of the bottom of the draw shaft is monitored in real time in the ore drawing operation process; and the candidate material level height interval is dynamically adjusted according to the actual standing stress, and the optimal material level height meeting the safety threshold value interval is obtained. According to the method, the problems that the bottom is compacted and hardened due to the high shrinkage working condition in the deep and large draw shaft, the blocked draw hole is difficult to treat, the blowout accident caused by sudden pressure release is easily induced, and major potential safety hazards are brought are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-silo well level control, and particularly relates to a deep-silo well level height determination method and system based on a bottom static stress threshold value. BACKGROUND

[0002] As the key infrastructure for vertical material transportation in underground mines, the stability and continuity of the operation of the silo are crucial to the overall production efficiency and safety of the mine. However, as the mining of mineral resources advances to the deep, the depth and scale of the silo continue to increase. For example, in a certain iron mine, the production silos in use and to be built are mostly deep or super-deep shafts with a depth of more than 100 meters. This change in engineering geological conditions makes the challenges faced by traditional silos even more severe.

[0003] In the conventional management of the silo, the main risks are concentrated in the temporary blockage caused by the jamming of large blocks of ore or poor ore fluidity. Therefore, the operation mode of reserving a certain ore level at the bottom is usually adopted to form a buffer pad to reduce the impact of ore falling on the shaft wall and bottom equipment. However, for deep and large silos, this "high ore" working condition can cause a more fundamental and intractable risk: bottom compaction and hardening.

[0004] Under the huge static pressure generated by the high ore column, the ore at the bottom of the silo, especially when containing a certain proportion of fine ore and moisture, will be subjected to long-term compaction, causing changes in its physical properties, gradually densifying and hardening to form a stable "compacted layer" or "pressure arch". Once this structure is formed, it will completely block the ore pass, and its stability far exceeds that of ordinary blockage, making it extremely difficult to handle, and it is extremely easy to induce "jetting" accidents caused by sudden pressure release, posing a major safety hazard. SUMMARY

[0005] The purpose of the present application is to solve the problem of deep and large silos that high ore working conditions can cause bottom compaction and hardening, block the ore pass, make it difficult to handle, and easily induce "jetting" accidents caused by sudden pressure release, posing a major safety hazard. A deep-silo level height determination method and system based on a bottom static stress threshold value are proposed.

[0006] The technical solution of the present application is as follows: in the first aspect, a deep-silo level height determination method based on a bottom static stress threshold value, comprising the following steps: obtaining a safety threshold interval of the bottom static stress of the deep silo; based on the safety threshold interval, obtaining a candidate level height interval through inversion calculation; based on the candidate level height interval, carrying out ore drawing operation, and monitoring the actual static stress at the bottom of the silo in real time during the ore drawing operation; The candidate stock level height interval is dynamically adjusted according to the actual static stress, and the optimal stock level height meeting the safety threshold interval is obtained.

[0007] Preferably, the safety threshold interval is [0.1 Mpa, 1.0 MPa].

[0008] Preferably, based on the safety threshold interval, the method for obtaining the candidate stock level height interval through inversion calculation is as follows: An initial stock level height range is calculated based on a first-order static approximation formula and the safety threshold interval. A discrete element numerical simulation software is used to establish a discrete element numerical model of the deep draw well, and the ore drawing process under different stock level heights is simulated, and then the candidate stock level height interval is selected from the initial stock level height range.

[0009] Preferably, the first-order static approximation formula is as follows:

[0010] wherein, represents the bottom static stress, represents the bulk density of the ore, represents the stock level height.

[0011] Preferably, when the candidate stock level height interval is selected from the initial stock level height range, the bottom static stress, the macroscopic fluidity of the ore and the dynamic impact load are used as the criteria for selection.

[0012] Preferably, the bottom static stress is the main criterion, and specifically, the bottom static stress is within the safety threshold interval. The macroscopic fluidity of the ore and the dynamic impact load are the auxiliary criteria, and specifically, the macroscopic fluidity of the ore is greater than a preset fluidity threshold, and the dynamic impact load is less than a preset impact threshold.

[0013] The present application has the following advantages: The present application proposes to control the bottom static stress within the "mechanical target interval" of 0.1-1.0 MPa, which can avoid hardening and maintain stable ore flow, and then accurately invert the optimal stock level height meeting the stress interval through the combination of theoretical preliminary calculation, numerical calculation based on the model and field measurement, so as to fundamentally avoid major risks such as well blockage and well blowout, and ensure the continuity of ore drawing operation and the safety of shaft structure. The present application establishes the internal relationship among "stock level height-bottom stress-flow state", and finally realizes the scientific, dynamic and intelligent closed-loop control of the stock level of the high draw well.

[0014] In a second aspect, a deep draw well stock level height determination system based on a bottom static stress threshold is provided, comprising: The safety threshold determination module is configured to obtain a safety threshold interval of the static stress at the bottom of the deep draw well. The candidate interval calculation module is configured to obtain a candidate material level height interval by inversion calculation based on the safety threshold interval. The operation monitoring module is configured to perform ore drawing operation based on the candidate material level height interval, and monitor the actual static stress at the bottom of the draw well in real time during the ore drawing operation. The material level height determination module is configured to dynamically adjust the candidate material level height interval according to the actual static stress, and obtain an optimal material level height that satisfies the safety threshold interval. In a third aspect, an electronic device is provided, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method of the first aspect.

[0015] In a fourth aspect, a non-transitory computer-readable storage medium storing computer instructions is provided, and the computer instructions are used to enable a computer to perform the method of the first aspect.

[0016] In a fifth aspect, a computer program product is provided, comprising a computer program, and the computer program, when executed by a processor, implements the method of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 A flowchart of a deep draw well material level height determination method based on a bottom static stress threshold provided by embodiment 1 is shown.

[0018] Figure 2 A landfill simulation and a schematic diagram of random distribution of different particle sizes of ores provided by embodiment 2 are shown.

[0019] Figure 3 A schematic diagram of a pre-filled situation in the well provided by embodiment 2 is shown.

[0020] Figure 4 A schematic diagram of the contact force distribution of the ores on the well during the ore falling provided by embodiment 2 is shown.

[0021] A schematic diagram of the contact force distribution of the ores on the well during the ore falling provided by embodiment 2 is shown. Figure 5

[0022] A schematic diagram of the contact force distribution of the ores on the well during the ore falling provided by embodiment 2 is shown. Figure 6 DETAILED DESCRIPTION

[0023] ​​Exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be understood that the embodiments illustrated and described herein are merely exemplary of the principles and spirit of the present application, and are not intended to limit the scope of the present application.

[0024] Embodiment 1 The present application provides a high-slip well optimal material level height determination scheme with bottom static stress as the core control index. By establishing the internal relationship among "material level height-bottom stress-flowing state", the scientific, dynamic and intelligent closed-loop control of high-slip well material level is ultimately realized. The primary risk source of high-slip well, especially when it is greater than 100m, is the compaction and hardening caused by the huge static pressure at the bottom. Therefore, the bottom static stress must be controlled within a "mechanical target interval" that can both avoid compaction and maintain stable ore flow. Research and simulation verification show that 0.1-1.0 MPa is the key threshold interval. The present application accurately inverts the optimal material level height that meets the stress interval by combining theoretical preliminary calculation, numerical calculation and field measurement, thereby fundamentally avoiding major risks such as well blockage and well blowout, and ensuring the continuity of ore drawing operation and the safety of shaft structure. As shown in FIG. 1, a deep-slip well material level height determination method based on bottom static stress threshold value includes the following steps: Figure 1 S1. Obtain the safe threshold interval of the bottom static stress of the deep-slip well; wherein the safe threshold interval is [0.1 Mpa, 1.0 MPa].

[0025] S2. Based on the safe threshold interval, obtain the candidate material level height interval by inversion calculation; Specifically, calculate the initial material level height range based on the first-order statics approximation formula and the safe threshold interval. The first-order statics approximation formula is:

[0026] wherein, represents the bottom static stress, represents the bulk density of the ore, represents the material level height; ​A discrete element numerical simulation software is used to establish a discrete element numerical model of the deep draw well, and the ore drawing process under different material level heights is simulated. The bottom static stress, ore macroscopic fluidity and dynamic impact load are used as criteria to select a candidate material level height interval from the initial material level height range. The bottom static stress is the main criterion, and the ore macroscopic fluidity and dynamic impact load are the auxiliary criteria. The bottom static stress is in the safety threshold interval, the ore macroscopic fluidity is greater than a preset fluidity threshold, and the dynamic impact load is less than a preset impact threshold. When the low material level height is low, it is mainly affected by the ore drawing impact, and the threshold is 0.1 MPa. When the low material level height is high, it is mainly affected by the static load of the ore, and the threshold is 1 MPa.

[0027] S3. Based on the candidate material level height, the ore drawing operation is carried out, and the actual static stress at the bottom of the draw well is monitored in real time during the ore drawing operation; S4. The candidate material level height interval is dynamically adjusted according to the actual static stress, and the best material level height that meets the safety threshold interval is obtained.

[0028] In this embodiment, the actual static stress is compared with the safety threshold interval. If the actual static stress is in the safety threshold interval, the system is normally operated. If the actual static stress deviates from the safety threshold interval, the actual material level height is dynamically adjusted by controlling the ore drawing equipment, so that the actual static stress is in the safety threshold interval, and a closed-loop control is realized.

[0029] In this embodiment, the main risk of the high draw well in the long-term high material level stacking state does not come from the fluidity of the upper ore, but from the stress concentration and compaction effect in the well bottom area. The bottom powder ore particles will rearrange, compact and even locally deform plastically under the action of a large static pressure, thereby producing physical or chemical cementation, and finally forming a high-strength hardened layer at the bottom of the draw well, or causing a blowout due to sudden stress release under the disturbance of ore drawing.

[0030] Quantitative reveal the direct correlation between the bottom static stress and the ore drawing behavior:

[0031] <0.1 MPa: The amount of reserved ore in the draw well is too small, and the bottom of the draw well is not only affected by the static stress, but also by the impact of the ore drawing process at the top of the draw well. The amount of reserved ore is too small, and the bottom ore drawing speed is too fast, which will produce a strong impact on the discharge plate of the bottom vibrating ore drawing machine.

[0032] ​>1.0 MPa: This is a high-risk state. The huge pressure makes the bottom particles, especially the fine ore, be over-pressed, and the bonding effect between particles is significantly enhanced, forming a "quasi-solid" hardened layer. This hardened layer is difficult to start, and even if it is destroyed under external disturbance, it may cause a severe blowout accident due to the instantaneous release of the huge elastic energy stored.

[0033] In the interval [0.1 Mpa, 1.0 MPa]: This is the ideal "stable flow window". In this stress range, the ore is moderately compacted, avoiding loose arching, and maintaining good inter-particle flowability, and is not easy to form permanent hardening. The ore drawing process is characterized by smooth start, continuous flow, and high controllability of risk.

[0034] In this embodiment, the main source of the static stress at the bottom of the draw shaft is the gravity compaction of the several meters or even hundreds of meters of ore column above it. For a vertically regular geometric draw shaft, in the ideal state of ignoring the "silo effect" (i.e. the friction between the ore and the shaft wall shares part of the gravity), the vertical stress at the bottom can be estimated using a first-order statics approximation formula:

[0035] wherein, is the bottom static stress (Pa), is the bulk density of the ore (N / m³), is the height of the material level (m).

[0036] In actual engineering applications, it must be recognized that the formula has limitations. The moisture content of the ore will significantly increase the bulk density of the ore ; the powder / block ratio will affect the stress transmission path between particles; and the shaft wall friction (silo effect) will make the actual bottom stress slightly lower than the theoretical calculation value, and this effect becomes more and more obvious as the depth-diameter ratio increases. However, this formula is still a valuable theoretical basis for preliminary estimation of the height of the material level, rapid assessment of the risk level, and understanding of the basic relationship between the material level and the stress.

[0037] In-depth study of the flow behavior of ore in a high draw shaft reveals that it presents a typical functional zoning phenomenon from bottom to top in the static and ore drawing states, which further illustrates the importance of controlling the bottom stress: Zone I: Static accumulation zone (core zone of hardening risk): adjacent to the bottom of the draw shaft and the ore drawing port, the ore particles in this area hardly move during ore drawing, and it is the area where stress is most concentrated. Long-term static pressure makes this area the main place where compaction and hardening occur.

[0038] Zone II: Transition zone: Located above the static zone, the particles in this zone move slowly and non-uniformly during ore drawing. The internal force chain structure is constantly destroyed and reorganized, which is the key area for the transition of stress state from static to dynamic.

[0039] Zone III: Continuous flow zone: Located in the middle, the particles in this zone exhibit ideal and continuous "piston" or "funnel" flow during ore drawing.

[0040] Zone IV: Intermittent flow zone (core area of arching risk): Located at the upper part of the draw shaft stock column, the flow in this zone is discontinuous, and is affected by both top feeding and bottom discharging, which can easily form a temporary "pressure arch" between the shaft walls, affecting the continuity of the flow.

[0041] Therefore, the higher the stock level, the greater the static pressure in the bottom I zone, and the size and instability of the upper IV zone also increase. Therefore, the core idea of the present application is to directly suppress the hardening risk in the I zone by precisely controlling the bottom static stress, and indirectly affect the stability of the II and III zones, thereby achieving stable operation of the entire draw shaft system.

[0042] The present application directly links the primary risk of high draw shaft (compaction and hardening) to a measurable physical quantity (bottom static stress), and determines its safe threshold interval [0.1 Mpa, 1.0 MPa]. Secondly, through "theoretical rough calculation → numerical precise calculation", the candidate stock level height interval that meets the stress criterion is scientifically and efficiently screened out, and then combined with the real-time monitoring data, the candidate interval is verified and closed-loop corrected, and the only optimal stock level height h* under specific working conditions is dynamically locked, finally achieving the ideal state of stable ore drawing and minimizing the compaction and hardening, arching and clogging risks in high draw shaft operation.

[0043] The present application establishes a new risk criterion for high draw shaft - "bottom static stress threshold window". For the first time, the core compaction and hardening risk of high draw shaft (especially in complex conditions such as deep, broken and water-containing) is directly quantitatively related to a physical quantity that can be accurately measured and simulated - "bottom static stress". The present application directly determines the compaction and hardening risk level by monitoring or simulating the bottom static stress of the draw shaft. After a large amount of scientific research and simulation verification, the specific and universally applicable safety stress threshold of [0.1 Mpa, 1.0 MPa] is obtained.

[0044] The present application determines the "three-step three-verification" high chute well optimal material level height determination process based on core criteria. The process establishes a standardized working method from theory to practice, layer by layer, and cyclically verifies the standardization working method, solves the fundamental defects of the traditional material level determination depending on experience and lacking scientific basis, constructs the complete closed loop process of "theoretical preliminary calculation-numerical precise calculation-site measurement correction", and the scientific logic of "first using a simplified model to frame the range, then using a fine model to optimize and screen, and finally using field data to calibrate and lock", and the methodology proposed by the present application can maximize the balance between calculation efficiency and result accuracy.

[0045] To improve the overall reliability of the scheme, the numerical simulation of the present application does not investigate stress alone, but constructs a multi-objective collaborative optimization model mainly considering stress, and considering fluidity and impact effect. When simulating by using PFC2D software, three key indicators of bottom static stress, ore macro fluidity and dynamic impact load are monitored and evaluated at the same time, and comprehensive screening is carried out on the basis of the three indicators. At the same time, the specific criterion combination of "main criterion (stress within threshold value) + auxiliary criterion (good fluidity and small impact)" is proposed.

[0046] The present application improves the static material level design scheme to an intelligent solution with long-term operation, real-time feedback and automatic adjustment capability. The intelligent control method dynamically maintains the bottom stress in the safety window by real-time monitoring the bottom static stress of the chute and comparing it with the preset threshold value, and then automatically or semi-automatically controlling the ore drawing or ore feeding equipment.

[0047] Example 2 On the basis of example 1, the present application example studies the optimal ore retaining height of a certain iron mine production chute, and details the method proposed in example 1.

[0048] The certain iron mine production chute is mainly located in the west of the lower part of the river, the ore body is large in scale, rich in reserves, and good in continuity, but the surface environment is complex, the geological conditions of the ore body and surrounding rock are variable, joints and fractures are widely developed, and faults may be activated, thereby increasing the uncertainty of the mining risk. What is particularly important is that the Qingshan River on the surface, as an important tributary of the Yangtze River, is closely related to the hydrogeological conditions of the underground mining area. Once the overlying rock layer deforms greatly, it will cause the connection of the surface water body and the underground tunnel, leading to serious water inrush accidents, which threatens the safety of the mine. The safety of the existing and under-construction ore drawing chute is very prominent.

[0049] According to the actual situation of the mine at the present stage and in the future, in order to ensure the safety of mine production and achieve the goal of stable production, the mine carries out the excavation work of super deep chute (more than 100m), and the related problems of the ore retaining height of super deep chute may occur during its use. More ore will be left in the shaft, the shaft wall will be more damaged, the static load on the shaft bottom baffle will be greater, and the impact load on the vibrating ore pass machine will be greater at the instant of ore drawing.

[0050] Establishing the ore drawing model: In order to accurately simulate the ore drawing process of clumps (ore) in the shaft, a two-dimensional particle dynamics simulation model is established based on the particle flow numerical simulation platform PFC2D, taking a mine 4-1# draw shaft as the engineering prototype. The model realizes the dynamic restoration of the whole process of ore particle movement by the discrete element method, including the accelerated movement in the free settling stage, multidirectional collision and energy dissipation with the shaft wall and the existing accumulation body, turbulent diffusion migration in the confined space, and finally forming a dense accumulation structure. The stress concentration evolution pattern and the development law of the inter-particle micro-bonding force in the shaft bottom area under different working conditions are studied, which provides theoretical support for preventing the harmful hardening phenomenon.

[0051] The model is constructed based on the geometric framework of the 183m total depth of the 4-1# draw shaft and the 3m standard shaft diameter vertical shaft, fully combining the field geological exploration data and shaft wall deformation monitoring results, and simplifying the shaft wall as a rigid boundary, as shown in Figure 2 In the initialization stage of the simulation, a clump (ore) pre-filled area with a height of about 100m is preset in the shaft, as shown in Figure 3 , and the particle size of the clump is randomly distributed between 0.01 and 0.6m. This not only provides a static basis for the subsequent dynamic settling process, including the initial stress field, pore structure and support arch form, but also accurately restores the typical working conditions of mine draw shaft ore drawing. By running in advance, the pre-filled area reaches a state of static force balance, ensuring the authenticity of the inter-particle contact force network and stress distribution, laying a physical foundation for subsequent dynamic simulation.

[0052] Modeling of draw shaft ore drawing: PFC2D particle flow software is used to establish a numerical simulation model of production draw shaft ore drawing. In order to more realistically simulate the nesting, engagement and contact behavior between particles in the gravel backfill process, the embodiment of the invention adopts a random graph generation algorithm written in Python to pre-design and output eight representative irregular clump structures. Each structure is saved in DXF format, with clear boundary lines, polygon outlines and characteristic corners, which can effectively simulate the irregular shape characteristics of natural gravel in terms of particle size distribution and structural characteristics. These DXF templates provide a basic data source for subsequent particle template replacement.

[0053] In view of the systematic influence of the board stress threshold, which is a core control parameter, on the ore drawing behavior of the ore pass, embodiments of the application rely on the established 4-1# discrete element model of the ore pass to carry out fine comparison tests. By setting three characteristic bonding force threshold conditions of 0.1 MPa, 0.5 MPa and 1.0 MPa (corresponding to the low alert value, the recommended running value and the high pressure bearing value in the project respectively), the whole life cycle evolution process from initial filling to board triggering is completely restored.

[0054] Each type of scene adopts strict variable control: the same shaft geometry constraint (such as a diameter of 3 m), clump template and environmental parameters are maintained; the difference is concentrated in the bonding threshold setting and the optimization level of the feeding strategy.

[0055] Numerical simulation of the ore drawing process: static stress The feeding is stopped when the bottom bonding force reaches 0.1 Mpa. Due to the continuous feeding, the ore flow is too fast, which leads to the non-convergence of PFC2D calculation, and thus an error is reported. From the simulation process, it can be seen that due to the low threshold value, after the ore is continuously fed to a certain stage, the particles quickly settle and begin to form a structural support network, which promotes the rapid rise of the bottom particle bonding force. In the simulation, it is observed that due to the rapid increase of the bottom stress exceeding the set value, the PFC2D solving process appears non-convergence, the system reports an error and the calculation is terminated. It shows that under the condition of low board threshold, the ore pass is prone to cause calculation non-convergence due to the too fast flow of ore particles in a short time.

[0056] Static stress The scenario is set to the recommended control standard, aiming to verify the stability of the feeding and the bottom evolution behavior under the medium stress threshold. The single round feeding height is maintained at 10-15 m, and the feeding interval is simulated for 5 minutes. During the simulation process, the ore particles gradually settle to the bottom, form nested contact with the original pile, and are accompanied by slight rearrangement and particle sliding effect, and the overall stress slowly rises but does not appear dramatic fluctuations.

[0057] Figure 4 The evolution curve of the bottom bonding force is shown, and it can be seen that the stress peak is stable at about 0.43 MPa, which does not break through the set threshold of 0.5 MPa, and the filling result is shown in Figure 5 , the clump is filled to 121 m, indicating that the bottom structure is in a critical stable state. More importantly, during the whole filling process, the feeding rhythm, particle rearrangement and stress evolution form a good synergistic mechanism, which can not only maintain high filling efficiency, but also effectively avoid stress concentration and board triggering at the bottom. This "continuous feeding-dynamic settlement-stable stress" model is more close to the dual requirements of safety and efficiency in actual engineering operation, and is suitable as a guiding working condition for subsequent field application.

[0058] From the perspective of ore trajectory and contact network evolution, the ore particles can be fine-tuned and rebalanced through their own displacement, slip and stress release after each round of release, without showing any instability behavior such as arching and impact compaction, which reflects the good self-organization ability under the medium threshold, that is, the smooth ore extraction.

[0059] Resting stress To test the upper limit of the system's bearing under high bonding tolerance and the risk of impact, the invention embodiment increases the single height of the release to 35 m to simulate a high-intensity loading scenario. After the release starts, a large amount of ore falls into the shaft in a short time, forming a concentrated impact with high quality and high momentum. The simulation results show that before entering the second round of release, the first batch of ore immediately causes a rapid rise in local bonding force after settling at the bottom of the shaft, with a maximum value of 1.32 MPa, which obviously breaks through the set threshold, as shown in Figure 6 The system determines that serious bonding has occurred at the bottom of the shaft and automatically terminates the release operation.

[0060] The ore particles accumulate into a high-density compaction zone at the bottom of the shaft due to the concentrated landing, short downflow path, and insufficient rebound space. This area has strong particle bonding and stress locking effects due to the overlapping of particles and the concentration of contact centers, even before entering multiple rounds of release, a "hard shell" structure has been formed at the bottom of the shaft, which seriously affects the continuity and safety of subsequent filling. Although a high threshold setting has a larger bearing capacity, its triggering method is often "concentrated compaction", which is easy to exceed the compaction limit in a short time, bringing the risk of ore spraying, arching and particle rebound.

[0061] Therefore, 1MPa can withstand large release quantities, but the control requirements for release rhythm and speed are extremely high, and without real-time monitoring and feedback mechanisms, it is not recommended to be used in actual projects.

[0062] Visualization analysis of stress distribution during ore release process: resting stress For this scenario, the ore falls rapidly and continuously during the simulation, forming a high-density accumulation state. Since the force chain cannot effectively diffuse, the contact force between particles rises sharply, causing the PFC2D model to fail to converge and automatically interrupt near the critical state. This numerical error actually reflects the nonlinear limit state of the particle system in a short time due to high stress concentration.

[0063] Resting stress When the bottom adhesion threshold is set to 0.5 MPa, the simulation shows that the particles at the bottom of the well first experience a large concentrated stress after the first round of ore placement. According to the stress variation trend during ore placement, at the initial stage of placement, the newly added ore rapidly settles under the action of gravity and violently contacts the heap at the bottom, forming a temporary high-density compaction zone in the local area, and the adhesion force instantaneously rises to about 0.43 MPa, close to the set threshold. However, as the collision, sliding and redistribution process between particles gradually proceeds, the stress is quickly released under the action of microstructure reconstruction, and the adhesion force falls to about 0.2 MPa and remains in a relatively stable state.

[0064] This phenomenon shows that under certain landfill thickness and particle accumulation conditions, the gravel system has good "self-organizing ability" and can complete stress rebalancing and local structure optimization without triggering cementation. Through the adjustment of dynamic contact between particles, a relatively stable support network is formed, effectively dispersing stress concentration and avoiding continuous stress accumulation caused by high-strength accumulation. This stress falling mechanism is of great significance to actual engineering, indicating that appropriate placement rhythm and particle movement space can significantly reduce the risk of cementation and achieve efficient and safe backfilling operation.

[0065] Resting stress In the simulation, when the bottom adhesion threshold is set to 1 MPa, the system allows higher stress accumulation to accommodate larger volumes or faster ore placement. To test the system's response ability under high threshold, the present embodiment performs a first round of high-strength placement based on the 92-meter ore that has been filled, with the single placement height increased to 35 m to simulate the placement strategy in actual engineering that aims to speed up the progress and reduce the number of rounds. However, the results show that due to the rapid falling of newly placed ore under the action of gravity, it concentrates on the bottom in a short time, forming a high-density, high-momentum transient impact zone, causing the adhesion between the bottom particles to instantaneously rise to 1.3 MPa, exceeding the set cementation threshold of 1 MPa. The system thus triggers the cementation criterion, and the simulation is forced to stop, prohibiting subsequent placement.

[0066] This phenomenon reflects an important engineering law: when no sufficient compaction pretreatment is performed or no buffer layer is set to absorb the initial impact energy, the first round of placement of large volumes of ore is likely to form a short-time high-pressure area at the bottom, triggering local adhesion chains and rapidly closing, causing the entire force chain system to lose adjustable space and triggering cementation. The interruption of placement caused by "transient impact compaction" poses a serious threat to the continuity and efficiency of actual engineering construction.

[0067] The results further verify that under different bonding force threshold settings, the settling trajectory of the ore, the contact network construction speed, and the force chain transmission capacity are the key control elements that determine whether to form a cake. Although a lower threshold is responsive, it is too sensitive to local stress fluctuations and is prone to false positives and interruptions in the drop; an intermediate threshold (such as 0.5 MPa) can achieve smooth settling based on natural particle rearrangement and stress diffusion, and is the recommended solution closest to actual working conditions; while a high threshold allows for greater load in theory, it also significantly increases the requirements for initial drop strategy, compaction preparation, and drop rhythm control. If not handled properly, it can easily cause irreversible cake formation in the early stages of drop. Therefore, the feasibility of a high threshold strategy is highly dependent on the careful design of supporting engineering measures and drop plans.

[0068] Through this embodiment, the following can be obtained: 1. The stress criterion-based identification of cake formation has good feasibility. By setting a reasonable bonding force threshold (such as 0.1 MPa, 0.5 MPa, or 1 MPa), it can effectively determine whether the drop leads to particle compaction and cake formation at the bottom of the well, providing a reliable engineering criterion for drop control during construction.

[0069] 2. The mechanical behavior of the ore is highly dependent on the filling rhythm, physical properties of the ore, and dynamic evolution during the settling process. An appropriate drop rhythm can enable the system to achieve a relatively stable state after multiple rearrangements, preventing the ore from forming a stress peak before it has fully self-organized, thereby improving the backfill efficiency.

[0070] 3. The chute drop-sinking-stress feedback constitutes a dynamic closed-loop system, which contains typical nonlinear evolution laws. Stress fluctuations, ore structure reconstruction, and force chain evolution are coupled with each other, which is the fundamental reason for the occurrence of cake or non-cake states.

[0071] 4. The simulation framework proposed in this embodiment not only provides a verification basis for theoretical research, but also guides the optimization of chute backfill strategies, cake prevention and control, and the setting of safety criteria at the bottom of the well in practice. It is a typical case of the combination of granular mechanics and engineering applications.

[0072] 5. It is recommended to use a static stress of 0.45-0.55 MPa as the monitoring and control interval during actual drop in the 4-2# chute drop, to ensure the continuity, safety, and efficiency of the backfill operation. It is calculated that the corresponding stockpile height distribution of [0.45, 0.55] MPa is between [120, 130] m.

[0073] Embodiment 3: On the basis of embodiment 1, the present embodiment provides a deep chute stockpile height determination system based on a bottom static stress threshold, which can be used to implement the deep chute stockpile height determination method based on a bottom static stress threshold as described in the preceding embodiments. The system comprises: a safety threshold determination module configured to obtain a safety threshold interval of the static stress at the bottom of the deep draw shaft; a candidate interval calculation module configured to obtain a candidate material level interval by inversion calculation based on the safety threshold interval; an operation monitoring module configured to perform the ore drawing operation based on the candidate material level interval and monitor the actual static stress at the bottom of the draw shaft in real time during the ore drawing operation; a material level determination module configured to dynamically adjust the candidate material level interval according to the actual static stress to obtain an optimal material level that satisfies the safety threshold interval.

[0074] According to the embodiments of the present application, the present application further provides an electronic device, a readable storage medium and a computer program product.

[0075] In an example embodiment, the electronic device comprises at least one processor and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the deep draw shaft material level determination method based on the bottom static stress threshold as described in Embodiment 1 above.

[0076] In an example embodiment, the readable storage medium can be a non-transitory computer readable storage medium storing computer instructions for causing a computer to perform the deep draw shaft material level determination method based on the bottom static stress threshold as described in Embodiment 1 above.

[0077] In an example embodiment, the computer program product comprises a computer program which, when executed by a processor, implements the deep draw shaft material level determination method based on the bottom static stress threshold as described in Embodiment 1 above.

[0078] Program code for implementing the method of the present application can be written in any combination of one or more programming languages. The program code can be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, when executed by the processor or controller, causes the functions / operations specified in the flow diagrams and / or the block diagrams to be implemented. The program code can be entirely executed on the machine, partially executed on the machine, partially executed on the machine and partially executed on a remote machine or server, or entirely executed on a remote machine or server.

[0079] In the context of the present application, a machine-readable medium can be a tangible medium that can contain or store program for use by or in connection with an instruction execution system, apparatus, or device. Machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable medium can include, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of machine-readable storage medium would include one or more lines of electrical wire, portable computer diskette, hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or Flash memory), optical fiber, portable compact disc read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination of the foregoing.

[0080] To provide for interaction with a user, the systems and techniques described here can be implemented on a computer having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0081] The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), and the Internet.

[0082] The computer system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server can arise by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The server can be a cloud server, a server of a distributed system, or a server combined with a blockchain.

[0083] Those skilled in the art will appreciate that the embodiments described herein are presented for purposes of illustration and understanding of the principles of the application and should not be construed as limiting the scope of the application to such specifically enumerated embodiments. Various other specific adaptations and combinations of features can be made in accordance with the teachings of the application without departing from the spirit thereof and these adaptations and combinations are intended to fall within the scope of the application.

Claims

1. A method for determining the material level height in a deep chute based on a bottom static stress threshold, characterized in that, The method comprises the following steps: obtaining a safety threshold interval of a static stress at the bottom of a deep draw shaft; based on the safety threshold interval, obtaining a candidate material level interval through inversion calculation; based on the candidate material level interval, performing ore drawing operation, and monitoring the actual static stress at the bottom of the draw shaft in real time during the ore drawing operation; adjusting the candidate material level interval according to the actual static stress to obtain an optimal material level that meets the safety threshold interval.

2. The bottom standing stress threshold based deep draft well level height determination method of claim 1, wherein, The safety threshold interval is [0.1 Mpa, 1.0 MPa].

3. The bottom standing stress threshold based deep sump level height determination method of claim 1, wherein, The method for obtaining the candidate material level interval based on the safety threshold interval comprises the following steps: calculating an initial material level range based on a first-order statics approximation formula and the safety threshold interval; establishing a discrete element numerical model of the deep draw shaft by using a discrete element numerical simulation software, simulating the ore drawing process under different material levels, and then screening the candidate material level interval from the initial material level range.

4. The bottom standing stress threshold based deep draw well level height determination method of claim 3, wherein, The first-order statics approximation formula is: wherein, represents the bottom rest stress, represents the bulk density of the ore, represents the level height.

5. The bottom standing stress threshold based deep sump level height determination method of claim 3, wherein, When screening the candidate material level interval from the initial material level range, the bottom static stress, the macroscopic flowability of the ore, and the dynamic impact load are used as criteria for screening.

6. The bottom standing stress threshold based deep sump level height determination method of claim 5, wherein, The bottom static stress is the main criterion, and specifically, the bottom static stress is within the safety threshold interval. The macroscopic flowability of the ore and the dynamic impact load are auxiliary criteria, and specifically, the macroscopic flowability of the ore is greater than a preset flowability threshold, and the dynamic impact load is less than a preset impact threshold.

7. A bottom standing stress threshold based deep draw well level height determination system, characterized by, The method comprises: a safety threshold determination module configured to obtain a safety threshold interval of a static stress at the bottom of a deep draw shaft; a candidate interval calculation module configured to obtain a candidate material level interval based on the safety threshold interval through inversion calculation; an operation monitoring module configured to perform ore drawing operation based on the candidate material level interval, and monitor the actual static stress at the bottom of the draw shaft in real time during the ore drawing operation; a material level determination module configured to adjust the candidate material level interval according to the actual static stress to obtain an optimal material level that meets the safety threshold interval.

8. An electronic device, comprising: The method comprises: at least one processor; and a memory connected in communication with the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to cause the at least one processor to perform the method of any one of claims 1-6.

9. A non-transitory computer-readable storage medium having stored thereon computer instructions, wherein, The computer instructions are used to cause the computer to perform the method of any one of claims 1-6.

10. A computer program product, characterised in that, The computer program, when executed by the processor, implements the method of any one of claims 1-6.

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