Application of displacement monitoring system in t

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Application of dump displacement monitoring system in safety production

I. Introduction

on August 1, 2008, a particularly serious cross collapse occurred in the dump of Jianshan Iron Mine in Loufan County, Taiyuan City, Shanxi Province, killing 45 people. More than ten years ago, a landslide event also occurred in the waste dump of Fuding basalt mine, causing certain casualties and property losses. How to prevent the collapse and landslide disasters of the mine waste dump and ensure the safety of people's lives and property has become a major issue for the operators of non coal mining enterprises. This technology can reduce the energy consumption by 15% ---- the president of TTT Tech Inc in the United States is a very serious major issue

due to the historical reasons in the early stage of mining in Fuding basalt mine, the waste quarry section is nearly 1000 meters long. Due to the failure to release the high-level potential energy of the waste quarry and the special geological conditions, the hidden danger of landslide is buried, which has become a major hazard source of the mine, and there are safety production accidents that may cause collapse and landslide at any time. Moreover, the risk probability of cross collapse and landslide in each section of the waste dump is random and uncertain

in order to make the formulation of emergency plans for eliminating major potential safety hazards have a scientific basis, take preventive measures, and effectively control the waste dump to avoid collapse and landslide disasters. In 2000, Fuding basalt mine established a set of displacement monitoring system for mine waste dump. Since the system was put into operation, it has been the only national engineering laboratory in the field of coating, adhesives and other surface materials in China. We have mastered the accurate information of the dynamic displacement of each section of the mine dump, which has provided a scientific decision-making basis for the accident treatment principle of giving priority to the treatment of major safety hazards. We have successfully predicted and prevented a potential landslide crisis in the dump and received good results

II. Introduction to the theoretical mechanism of displacement monitoring of waste dump

the displacement of waste dump is due to the kinetic energy of displacement obtained by the solid waste in the waste dump induced by external factors. According to the law of energy balance. The kinetic energy obtained by the sliding body is equal to the difference between the potential energy lost by the sliding body and the work done to overcome the frictional resistance of the sliding body

the friction coefficient f determines the anti sliding force of the sliding body of the waste dump. A sufficiently large friction coefficient is the prerequisite to ensure the implicit determination of the waste dump

The value of friction coefficient f is a variable. Due to the infiltration of atmospheric precipitation and the action of groundwater, a seepage flow is formed in the waste dump, which increases the hydrostatic pressure and hydrodynamic pressure in the waste dump soil and rock, so that the F value of the contact surface between the discharged solid waste and the soil and rock is gradually reduced, and the shear strength of the soil and rock is reduced; In addition, the original hillside vegetation of some waste dumps is developed, the residual soil layer is thick, and the separation of soil and stone is not paid attention to during the discharge process, so the hydrophilicity of the waste is enhanced, and it is easy to soften under the action of seepage water, forming a soft layer of sliding mass. Thus, the decreasing speed of F value is further aggravated. When the friction coefficient f drops to its critical point (i.e. f = TG), the whole landslide body will suddenly collapse and form an avalanche chain reaction, that is, debris flow collapse disaster

The change of

f value is not instantaneous. Its change has a transition process, and the displacement of sliding body caused by it also has a process from gradual change to sudden change. In this transition process, people can achieve the purpose of predicting the risk of collapse and landslide of the waste dump by accurately monitoring the dynamic displacement of the waste dump, so as to carry out scientific risk evaluation, determine the high-risk section from the uncertain risk field, and strive for enough time for emergency disposal in the transition process of landslide gradual change, so as to prevent and control the dangerous situation of the waste dump in time and effectively Landslide disaster was eliminated in the embryonic stage of the accident

III. application of monitoring system in safety production

according to the mechanism of waste dump landslide, in 2000, we established a set of dynamic displacement monitoring system for waste dump in the mine, established control points in the east slope, north slope and south slope of the mine, which are the sensitive parts of the waste dump dumped along the slope left over from the original history, and introduced the electronic total station imported from Japan, taking the three-dimensional coordinates of three fixed points as the measurement base points, Measure the three-dimensional coordinates of the control point. It is operated by a specially assigned person and measured periodically (once every ten days, and measured intensively after rainstorm). Through the measurement, the dynamic displacement is mastered, and the potential landslide hazard of a waste dump is successfully predicted and prevented, and good results are achieved

from December 2000 to February 2001, the detection data showed that the displacement of the original waste rock yard on the north slope was relatively obvious. The elevation of the waste dump is between +502m and +380m, the relative height difference between the front and rear edges is 122m, the axial length is about 250m, and the transverse width is about 150m. The artificially accumulated waste rocks are distributed on the slopes with relatively steep original slopes. In the early stage of mining, the waste rocks are arbitrarily discharged and accumulated along the slopes, forming an artificial stone cone group of about 300000 cubic meters. Its huge load produces huge horizontal and vertical thrust on the front edge and lower residual soil of the slope, resulting in nearly 300000 meters. The sliding body produces displacement and deformation. The monitoring data are shown in the following table (where point n is at the leading edge and points N4 and N5 are at the trailing edge)

accurate monitoring data show that the sliding body is currently in a limit state of equilibrium and imbalance. From the monitoring data table, it can be seen that within less than half a month from January 23 to February 4, the leading edge of the sliding body moved 0.4m to the north, while the trailing edge of the sliding body moved 1.2m to the north. The movement of both front and rear edges indicates that the displacement is not local collapse, but the overall sliding of the sliding body. And such a large range of displacement shows that the sliding body is bearing a huge horizontal thrust, and the sliding body may be in a critical state of overall collapse. If the emergency measures to eliminate major accident hidden dangers are not started in time, the gradual process of the sliding body may cause sudden decline under the action of heavy rainfall or continuous rainfall. The establishment of a scientific risk assessment mechanism has won us valuable time to deal with major potential safety hazards, and also provided us with a scientific decision-making basis for formulating plans to eliminate such major potential safety hazards. In the process of launching and handling the emergency plan, on the one hand, we have taken emergency measures such as timely reporting, announcing dangerous situations, blocking roads and close observation. At the same time, seek technical support, and entrust the Provincial Geological Engineering Survey Institute with rich experience in geological disaster treatment to carry out the following survey and analysis: (1) due to the urgency of time, the geological conditions of the waste rock yard should be ascertained to the greatest extent according to the current site conditions without using geophysical means. (2) By comprehensively analyzing the displacement monitoring data in recent time, the stability analysis and thrust calculation of the waste rock yard are carried out. (3) Put forward specific and operable advice on the feasibility of unloading and load reduction. Under the guidance of relevant experts from the Provincial Geological Exploration Institute, the characteristics of the landslide in the waste rock yard are analyzed, and then the causes of displacement and deformation are discussed. Finally, the following conclusions are formed: (1) the landslide body is composed of mineral ballast and residual slope soil, and the landslide surface is located in residual slope soil; (2) The landslide area is about 370000 m2, and the volume involved is about 370000 m3, which is a large-scale push type landslide; (3) At present, the sliding mass is in the limit state of balance and imbalance. Under the action of inducing factors, it may slide as a whole and form debris flow. According to the results of the analysis of the dangerous situation, the emergency treatment measures of unloading and reducing the pressure foot were immediately taken, and the hidden danger of landslide was completely eliminated in a few months

IV. conclusion

waste dump is one of the major hazard sources of open-pit mines. The dynamic displacement monitoring system of the waste dump is established in the mine, and the observed displacement and displacement rate of the waste dump are used to calculate the thrust and analyze the stability. According to the analysis results, it can be determined whether the waste dump has the risk of span collapse and landslide, and the corresponding technical measures are formulated to effectively prevent the waste dump from span collapse The method of landslide accident is one of the means for the global cereal packaging industry to move forward slowly

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