Study On Preparation Method Of Foamed Mixture Lightweight Soil Using River Sludge And Its Influence On Engineering Properties

River networks are numerous in our country.In order to maintain the smooth channel to ensure the normal operation of water conservancy projects,solve the environmental pollution to protect river landscape function and the residents along the river good living environment etc,the country spends a lot of manpower and financial resources on the river to conduct regular or irregular cleaning sludge every year.The use of sludge with high water content and the properties of good fluidity,by the light treatment,prepared to FMLSS which can meet the requirements of the actual engineering,realize the resource utilization of sludge,has important significance.FMLSS mainly uses silt as raw material,cement as curing agent,the bubbles made of different foaming agents as foaming materials,prepared by different foaming technology.The main purpose is to consider the foaming properties and adaptability of the foaming material.From the macro and micro point of view,the performance of different types of FMLSS is analyzed and evaluated,and the reference is provided for the practical application.The following is the main research content of the paper.(1)Through the bubble performance test,the comprehensive foaming factor and the half life of the bubble,the suitable dilution concentration of the protein foaming agent and the anionic type foaming agent K12 A was obtained.Through optimizing the anionic foaming agent,the compound foaming agent with better comprehensive performance was prepared.Through the comparative analysis,it is concluded that the K12 A concentration is small,the foaming ratio is large,but the stability is low.The protein foaming agent has good foam stability,but the ideal concentration is large,the foaming ratio is small,and the cost is large.Compared with the protein type,the compound foaming agent has less ideal concentration,and the stability of the foam and the foaming multiple are larger,compared with the K12 A,the foaming ratio is reduced,but the stability of the foam is improved obviously,so the comprehensive performance is better.(2)In order to investigate the foaming performance and adaptability of foamed materials.The preparation of FMLSS were used in two kinds of foaming process,including prefoaming and post foaming.Prefoaming type FMLSS includes anionic type(K type),protein type(D type),compound type(F type),and the bubble was prepared by the corresponding foaming agent at the appropriate dilution concentration.The type of post foaming(H type)FMLSS used hydrogen peroxide as the foaming agent.(3)In order to investigate the effect of mixing time on the properties of different typesof FMLSS and to determine the proper mixing time.The experiments showed that the performances of FMLSS were different under different mixing time.Suitable mixing time is helpful to the overall performance of FMLSS,and it should be paid more attention in practical engineering.The performance of FMLSS which was prepared by good Bubble is more obvious.(4)The performance of FMLSS under different matching conditions was compared and analyzed.The three factors of cement dosage,bubble volume and water content of raw soil were investigated.The study of cement content and air bubble volume is the key point of the research.The study found that the light effect was low,and the strength was small,the sample was generally brittle failure in the whole proportion of the conditions.The light effect of F type is good,and its strength and deformation were optimal.(5)The following is the investigation of the applicability of the foaming agent.The comprehensive performance of FMLSS prepared by hydrogen peroxide was poor,and did not meet the engineering application.The light weight of the selected protein foaming agent was poor and the cost was high,so the application value was low.The light effect of compound foaming agent and anionic foaming agent K12 A was good.When the preparation of low strength grade FMLSS,the performance of FMLSS was small.However,the applicability of K12 A is reduced in the preparation of high strength grade FMLSS or under low water content.The value of engineering application of compound foaming agent is high.(6)The microstructure parameters of different types of FMLSS were obtained by digital image technology.The correlation between microstructure and macroscopic properties was investigated.The failure mechanism of different types of FMLSS was summarized by comparing the changes of microstructure and the failure mode before and after the experiment.The scale of large pore in H type is too large,which leads to soil is quickly cracked after loading,which is not conducive to the strength and deformation.Compared to the K type,the size of micropore of the F type was small and it was uniform distribution in the soil,and the stress is evenly distributed on the wall of each micro hole,and the structure of the soil skeleton is more stable,which shows good characteristics of strength and deformation.The distribution of microporous of K type is not uniform,and the soil contains large number of micro pores is relatively more.The internal structure of the soil is destroyed after loading.Therefore,the performance of mixed soil is decreased.The failure mode of D type is similar to the F type in low density level.But because of the uneven distribution of the pore and bubble bleedingphenomenon,the overall performance of FMLSS is reduced.