Study On Construction Quota Compilation Method Of Cemented Sand And Gravel Dam

With the progress of social civilization and the increase of people’s 2 demand for a better life,higher requirements are correspondingly put forward for the design and construction of water conservancy engineering industry.Because of its environmental protection design and construction concept,the cemented gravel dam stands out and becomes a new dam type with great development potential.But at present,China has not yet implemented the special quota of cementitious sand gravel dam,and its cost management has always followed the relevant quota of RCC dam.However,there are great differences between cemented sand gravel dam and RCC dam in raw material mining,mixing and preparation,dam body filling,etc.,which makes it difficult to realize "reasonable determination and effective control" of the cost of cemented sand gravel dam.The construction quota is the basic productive quota,which provides the basis for the compilation of other pricing quotas.In order to improve the quota system of cemented sand gravel dam and promote the popularization of cemented sand gravel dam technology,it is urgent to carry out the research on the compilation method of construction quota of cemented sand gravel dam.Based on the research background of cemented sand gravel dam,this paper analyzes the construction technology of cemented sand gravel dam in detail,and summarizes its technical characteristics by comparing with RCC dam.This paper discusses the characteristics and principles of the construction quota compilation,and on the basis of summarizing and comparing the traditional quota compilation methods,puts forward the Monte Carlo method as the quota compilation method of the cemented gravel dam.Combined with the basic idea of Monte Carlo method,the steps of applying this method to quota compilation are summarized in detail.In view of the small sample of the construction data of the cementitious sand gravel dam at the present stage,this paper analyzes the influence of the accuracy of the parameter (?) and the parameter s in the Monte Carlo quota model.On the one hand,t-distribution is used to construct the relative error formula of (?),which can quantitatively explain the influence of observation times on the accuracy of parameter (?);On the other hand,the coefficient of variation is introduced to judge whether the deviation of parameter s is too large,and then the GM(1,1)model is selected to predict and modify the sample array with large deviation of parameter s.The results are as follows:(1)Based on the basic idea of Monte Carlo method,the consumption that has been produced and will be produced in construction is regarded as a random quantity determined by many factors.The collection of all consumption constitutes a population,and the on-site observation consumption is regarded as the sampling sample of the population.The distribution of the population is estimated by the distribution of observation values,so as to calculate the quota.Taking the normal distribution as the probability distribution model,the Monte Carlo quota compilation steps including data processing are formulated.Taking the measured data of a cemented sand gravel dam project as an example,the quota consumption of the project is calculated by Monte Carlo method.The analysis shows that Monte Carlo method can fully restore the distribution characteristics of data with high accuracy,which is helpful to improve the accuracy of quota calculation under different quota levels.(2)The relative error range estimation formula of parameter (?) is constructed by using t distribution.The formula shows that the relative error of parameter (?) and population μ is positively correlated with coefficient of variation and negatively correlated with observation times.The relative error between parameter (?) and population μ and the decreasing rate of relative error with each increase of observation times are listed when the coefficient of variation is 0.05-0.20 and the observation times are 8-30.Through the analysis of the two,it is concluded that the observation times which can control the relative error within 0.1 and have certain economy are 18-20.(3)The parameter s and the coefficient of variation are obtained δ.The coefficient of variation based on the sample data is proposed δ.Whether the value is in a reasonable range is a new idea to judge whether the parameter s deviates greatly from the true value.If coefficient of variation δ.If it is less than the lower limit of its reasonable range,it indicates that the quota consumption under extreme conditions has not been observed,so the influencing factors that may cause extreme conditions should be analyzed and the data should be supplemented;If coefficient of variation δ.If it is larger than the upper limit of the reasonable range,it is considered that there are too many unobserved data in the extreme value of the sample data.Further,the GM(1,1)model is used to predict the unobserved data in the extreme value,so as to reduce the error between the parameter s and the true value and improve the accuracy of the model.Finally,the feasibility of this method is verified by the calculation of an example.