Research On Method Of Check And Accept Concrete Strength Of Railway Engineering

The "Standard for Check and Accept Concrete Strength of Railway"(TB10425-94)has been implemented for more than 20 years.During this period,the preparation level of raw materials,the level of production equipment,the level of production management,mixing technology and quality control technology of railway concrete have already been greatly improved.If the previous assessment criterion is followed,unsafe or uneconomical problems will appear.Therefore,the most critical sampling inspection scheme in the evaluation criteria of railway concrete strength was studied by the Monte Carlo simulation method and the proposed revision plan was put forward in the paper.The main work and conclusions were as follows:(1)The 13534 sets of strength data from laboratory and the railway engineering site were respectively divided according to the source,quarter and location,and SPSS data analysis software was used to test the normal distribution of the data.The results showed that the strength of concrete divided by source,quarter,and location obeyed the normal distribution.(2)The reason why the qualified quality mean value,mean limit quality value,producer's risk,and consumer's risk respectively adopted fcu,k+1.645?,fcu,k,5.0%,and 5.0%in the mathematical statistics model of checking and accepting concrete strength of railway was explained.The influence of the sample size on the standard deviation and the acceptance probability was analyzed with the standard deviation was unknown by the Monte Carlo simulation method,and the result showed that it could be considered as the demarcation between large and small samples that the sample size was 10.(3)The result of the calculation and analysis of the producer's risk and consumer's risk of the "Standard for Check and Accept Concrete Strength of Railway"(TB10425-94)and the proposed revision plan under the mean condition indicated that it was more reasonable that the producer's risk and the consumer's risk of the proposed revision plan were both less than 5.0%when the standard deviation was known.The producer's risk of the proposed revision plan was larger than that of the "Standard for Check and Accept Concrete Strength of Railway"(TB10425-94),whereas the consumer's risk was smaller than that of the "Standard for Check and Accept Concrete Strength of Railway"(TB 10425-94),indicating that the proposed revision plan was controlled more safely,when the sample size was same with the standard deviation unknown.(4)The variable laws of the producer's risk and the consumer's risk of two schemes were simulated with the standard deviation by Monte Carlo,and the results showed that strength grade and the standard deviation had no effect on the producer's risk and the consumer's risk when the standard deviation was known,and that the existence of the minimum condition increased the producer's risk and decreased the Consumer's risk,and that the proposed revision was safer compared with "Standard for Check and Accept Concrete Strength of Railway"(TB10425-94)because its consumer's risk was smaller.The existence of the minimum condition had no effect on the producer's risk when the standard deviation was smaller,but it significantly increased the producer's risk when the standard deviation was larger with standard deviation unknown,and the producer's risk of the proposed revision was larger than that of"Standard for Check and Accept Concrete Strength of Railway"(TB 10425-94).The minimum condition had little effect on the consumer's risk,and the proposed revision plan was safer because its consumer's risk was smaller.