Study On Performance And Engineering Application Of Long-distance Pumped Cement Mortar

Flexible Formwork and Pumped Concrete Supporting Technology(FFPCST)is a new type of practical support technology for the development of underground space and exploitation of underground resources.The support technology has a large construction area,and the structure has good integrity,high strength,high degree of mechanization and fast construction speed.The technology has prominent advantages in economic,normal environment and social benefits.At present,there are some deficiencies in the pumping concrete in the flexible concrete support technology:the strength of concrete support is low,which can only reach about 30MPa;the raw material of concrete is more,and the weight of the stone is large,it is not good for transportation,and the pump of concrete is low.Cement mortar has the advantages of simple material type,good pump ability,and can meet the requirements of supporting strength.Cement mortar is used to replace concrete in order to meet the high production and high efficiency production requirements of coal mine with the times.In order to select the mixture ratio of cement mortar with good pump property,the probability of pipe plugging event and the wear of the pipe in the pump concrete are reduced,and the support efficiency is improved without affecting the strength of the support.This topic uses the high concentration cement mortar instead of concrete,adopts the orthogonal test method,selects the evaluation index of the portability of cem ent mortar by using the fluidity,the bleeding rate,the setting time and the 1D,3D,14d strength.Through the statistical software SPSS,the test results are entered by the method of difference analysis,variance analysis and multiple linear regression analysis.Line analysis.Through the range analysis,the change of each index with factors and the ranking of the factors affecting the index are obtained.Through the analysis of variance,the significant factors and significant factors that affect each index are obtained.By analyzing the mean value of the marginal estimate of each factor,the interaction between the factors is determined,and the optimum mixing ratio of pump cement mortar under the condition of supporting the supporting strength is obtained.By fitting the test results,the linear regression equation of the pump cement mortar fluidity,the rate of bleeding,the setting time and the compressive strength of 1D,3D and 14d is obtained respectively.The linear regression equation can calculate the mixture ratio of cement mortar for the required performance,and provide the initial mix ratio for the cement mortar prepared by the subsequent engineering,reduce the workload and guide the actual construction of the project.At last,the construction design of cement mortar pumping project is carried out in the 28051 working face of Xinzhuang coal mine.The performance of cement mortar is not quite different from that obtained by linear regression equation.The practical value of the linear regression equation is verified,and its engineering meaning is proved.Righteousness.The research results of this paper have guided the actual construction of the project,and proved the engineering value of this topic.