Detection Evaluation And Prediction Strength, Frost Resistance Of The Service Mold-Bag-Concrete Lining Canal In Cold Northern Region

Hetao irrigation district of Inner Mongolia is one of the largest designed irrigation area.in China.Water conveyance canal is an important hydraulic structure for irrigation, with scarce water resources, in order to reduce the water resources in the transportation process of loss, Hetao irrigation district of Inner Mongolia gradually used mold-bag-concrete as lining material in the channel.At this point,it is very necessary to test, evaluate and predict the strength and frost resistance of mold-bag-concrete lining canal which has been finished or is in service.In this paper, firstly,from the shen wu irrigation fields, ulan buh irrigation field and Urat irrigation field in hetao irrigation district, a total of 25 sampling point,to drill mold-bag-concrete core samples.After processing,the mold-bag-concrete core samples mechanical performance test and freezing resistance performance test was carried out,using the Grubbs test and t-test to calculate the mold-bag-concrete strength estimate value and the t-test is better than the Grubbs test, through analyzing the stress-strain curve of mold-bag-concrete to establish the constitutive equation,using environmental scanning electron microscopy analysis of mold-bag-concrete microstructure, proves the mold-bag-concrete strength test results,and discuss the physical and chemical mechanism of the internal of the mold-bag-concrete by the freezing and thawing cycles.Then,the BP neural network and RBF neural network are used to establish the prediction model of compression and frost resistance. Chose eight factors as the input variables to predict the strength of mold-bag-concrete, choose four factors as the input variables to predict the frost resistance of mold-bag-concrete.The results show that,the BP neural network prediction results and the measured results more consistent, can better reflect the real situation of mold bag concrete.On the basis of analyzing the influence factors on the sensitivity of the mold-bag-concrete strength,the results showed that,various factors affecting the sensitivity to predict strength from high to low is dosage of cement, age,specimen quality, specimen size, sand ratio, admixture;Using BP network to forecast the relative dynamic elastic modulus is superior to the prediction of quality loss rate, and more representative of the mold-bag-concrete frost resistance.