Study On Preparation And Strength Growth Model Of Lightweight Foam Soil With High Performance

Poor stability and low strength of foam light soil are the key factors limiting its further development.Poor foam quality can easily lead to collapse of cement slurry and connected hole and deposition.In addition,the traditional fly ash foam light soil is difficult to solve the problem of its early low strength,and fly ash has also become a scarce material.In view of the above problems,this thesis systematically studies the preparation of high strength stability foam lightweight soil and its strength growth model.The main research work of this thesis is as follows:(1)The effects of various foam agents on foam properties were analyzed.Single and multiple foam agents were studied,and found that maltodextrin and coconut amide-based acetylbetaine(CAB)had significant effects on improving foam performance.It is recommended that 0.27wt%malt dextrin+0.15wt%CAB be selected as a foam stabilizing agent to improve foam quality and improve the stability of foam light soil.(2)Limestone powder was selected as a new admixture to replace part of the fly ash to improve the early strength of foam lightweight soil.U15*(15~7)was designed and the relationship between the ratio of foam light soil material and performance was established based on the test results using multiple regression analysis.Grey correlation analysis between the performance of foam light soil and the influencing factors was conducted based on gray theory.(3)The ideal point method in the evaluation function is used to solve multi-objective planning problems under constraints by MATLAB.The optimal mix ratio of foam light soil was determined and the performance of foam light soil was verified.(4)A prediction model for the strength growth of foam light soil is presented.The age is introduced into the cement hydration degree equation;the equivalent age of fly ash in different substitution rates and water glue ratio was calculated,and the influence of various factors on the hydration of fly ash were simulated.The Powers gel-space ratio theory was improved,and the foam light soil strength growth prediction model was finally obtained with the test data,and the effectiveness and accuracy of the model were verified.(5)The initial threshold and weight of BP neural network were optimized by genetic algorithm,and the neural network was applied to predict the compressive strength of new foam lightweight soil.Compressive strength prediction model of foam lightweight soil based on GA-BP neural network was established.The superiority of the optimized neural network is verified by MSE and correlation coefficient.The applicability of the two explicit and implicit models was analyzed.This paper has 59 pictures,25 tables and 103 references.