Natural Weight Theory And Its Pplication In Safety Assessment In Coal Mines

The weight using in the existing safety assessment method all is the artificial constant-value weight. The main shortcoming of this kind of weight is it is invariability, lacks pointed as well as subjectivity at will, but its basic flaw is its artificial subjectivity. In view of the basic flaw of the constant-value weight, the natural weight concept has been proposed and given a thorough research to in this article.It is thought in this article that the factor affect the system safety state may finally always sum up to as "the human" and "the thing" two factors by summarizing and analyzing each kind of disaster origin theory, and according to this, "the theory of double factors" and "the theory of cross path" have been taken as the rationale of this article. Based on these rationales and the utilization stochastic process theory, the research work has been well done about the divisibility of the system assessment. It is believed that the risk rate of a system to occur an accident (Ti) in a fixed time (tO) and the risk rate of the system to occur an unsafe behavior that can induce this accident (Ti) in the same time(tO) become direct ratio,and its ratio (or called slope, the k value) namely the probability for the dangerous source of the system to be at highly critical condition to initiates this accident(Ti) in the same time(to).Considering to the difficulty of the probability analysis, this article analyzes the fuzziness that displays during people carry on the concrete description to the system running status. It is thought in this article that the dangerous degree is the fuzzy set based on the security risk rate, and the easy degree of the dangerous source to occur a disaster is the fuzzy set based on the probability of the source at highly dangerous condition, thus the calculates of the security risk rate and the probability of the dangerous source at highly dangerous condition have been transformed into the appraisal of the dangerous degree and the easy degree of disaster to occur. Based on this, the natural weight concept has been put out, it has been defined as the ratio of dangerous source occupies the share in the entire disaster system based on the easy degree of the dangerous source to occur a disaster.Based on the concept of the natural weight, this article proposed the natural weight direct determination method and the indirect determination method. The direct determination method of the natural weight is the method of obtaining the weight by using the direct assessment of the dangerous degree of disaster; the natural weight indirect determination method is the method of obtaining the weight by using the instead calculation of the easy degree of the dangerous source to occur the disaster (namely natural weight) from the concealment target through spatial analogy or the historical analogy. As an example, this article discussed in detail the easy degree of disaster to occur and the natural weight direct determination method of each common dangerous source in coal mine. These computational methods all are this methods and formula that are established based on the qualitative evaluation criteria of the present and the recognition appraisal to the coal mine mining engineering factor, as well as the rises half normal distribution function form.Depended on the establishment of the natural weight concept and the determination of the natural weight algorithm, this article proposed the safety assessment model that is based on the natural weight. This kind of assessment model decomposes the system safety assessment into the assessment of the thing condition and the human's behavior, namely the easy degree of disaster to occur of all dangerous sources (namely the natural weight) as well as the dangerous degree of the human's unsafe behavior.For the assessment of the dangerous degree of human's unsafe behavior, this article studied in every detail the personal behavior,the group behavior as well as the relations between they and the overall behavior of mine pit, and it is thought that the human's behavior seeks in their mind the security risk state of equilibrium (or calls expectation condition) follows "the security economical consumption lowest criterion" and "the security economic efficiency biggest criterion". But the recognized and the compulsory risk state of equilibrium are people's behavior standards, the behavior standards in coal mine already have even formed the legal laws and regulations and the compulsory technology standard. This article rested on these behavior standards to formulate the whole evaluation criteria and the method of the human's safe behavior and the safe measure in the coal mine.This article finally carried on the applied research to the assessment model. Through the contrast analysis, this article believes that the safety assessment model based on the natural weight have the characteristic of the pointed strong, at the right moment, and that this article solve quite well the problem of the subjectivity, the constant value, at the right moment, as well as the non-linear which the existing weight system existed, therefore it's a new method with a stronger practical weight which can solve the mine safety assessment.