Study On The Polymerization Process And Sand Fixing Performance Of Calcium Acrylate Slurry

Since the 21st century,with the construction of highway,railway,water conservancy and other infrastructure,a large number of engineering geological wounds have been formed.As a common type of slope,sandy soil slope or sandy slope has the characteristics of low clay content,loose structure,poor stability,easy deformation,etc.It is often subject to rain erosion and wind erosion,resulting in serious soil erosion and pavement cracking,uneven settlement and other engineering problems.And long-term creep deformation even lead to geological disasters such as landslides and mudslides,endangering the safety of traffic and personnel,and increasing maintenance and repair costs.It is a major disease in the operation and management of highway,railway,water conservancy and other facilities.At present,the commonly used methods of sand consolidation and slope protection can be divided into engineering sand consolidation method and vegetation sand consolidation method from the material and technical point of view.As one of the engineering sand consolidation methods,chemical sand consolidation method has achieved a lot of research results in recent years,which is mainly to apply chemical sand consolidation materials to the sandy soil slope through spray seeding,grouting and other ways,forming a consolidation layer after cementation,to stabilize the stratum and reduce water flow Erosion and wind erosion and achieve the purpose of sand consolidation and slope protection.The strengthening effect of chemical sand consolidation materials mainly depends on the performance of chemical sand consolidation materials and the suitability between materials and sand particles.According to the characteristics of calcium acrylate slurry,the single factor experiment and L₉（3⁴）orthogonal experimental method was used to study the influence of different raw materials and water on the slurry performance,and the rheological characterization and gelling characteristics of calcium acrylate slurry were studied from the point of view of physical mechanics and rheology;the sand-fixation effect of calcium acrylate slurry was comprehensively evaluated from three aspects of mechanical properties,hydraulic properties and durability,taking the laboratory self-made sand soil as the reinforcement object.The research contents and main achievements are as follows:（1）The basic physical properties of sand-soil were obtained by particle experiment and compaction experiment.The cohesion and internal friction angle of the samples with different density were obtained by direct shear experiment.It is found that the cohesion and internal friction angle of the samples with different density increase with the increase of sand density.（2）The single factor experiment and L₉（3⁴）orthogonal experiment were used to optimize the composition and water content of the calcium acrylate slurry,determine the basic mix proportion of the calcium acrylate slurry,and select the evaluation indexes including p H,apparent viscosity,gel-time,permeability and plastic strength of the gel.The results show that the change of the content of the main agent of the calcium acrylate slurry has a great influence on the apparent viscosity,and the change of the content of the initiator AP has a great influence on the gelation time and the plastic strength.Finally,the optimal mixture ratio of the slurry is 120 m L main agent,80 m L water,1g initiator AP,the apparent viscosity of the slurry is 1.2 MPa·s,the gelation time is 15.3 min,and the plastic strength is 0.652 k Pa.（3）The calcium acrylate slurry developed in this paper is light yellow at room temperature.It is a non-water-soluble substance after gelling and can contain several times of its own volume of water.The rheological curve of calcium acrylate slurry is compound type.According to its rheological characteristics,it can be divided into three stages:near Newtonian fluid,shear-expansion fluid and pseudoplastic fluid.Before gelatinizing,the viscosity of the slurry is at a low level.When it is near the gelatinizing point,the viscosity of the slurry rises rapidly.In addition,the volume shrinkage rate of cementitious materials decreased gradually with the increase of curing age,and the volume shrinkage rate was stable at 31.91%at 30 days;the change trend of plastic strength of cementitious materials showed the law of first decreasing,then stabilizing and finally increasing,which was closely related to the water loss law of cementitious materials.（4）In this paper,the uniaxial compression test,shear test,permeability test,disintegration test and water retention test were carried out to study the effect of three sand densities of 1.3g/cm³、1.5g/cm³、1.7g/cm³,the mixing ratio of 15%,20%,25%and 30%,and four water contents of 0%（dry）,5%,10%and saturation on the consolidation effect.The experimental results show that the reinforced specimens have a great improvement compared with the unreinforced specimens,and the reinforcement effect increases with the increase of the density of sand and the mixing ratio of slurry.At the same conditions,the influence of the mixing ratio of slurry is greater than that of the sand density.The reinforcement effect is closely related to the moisture content of the specimens.The lower the moisture content,the better the reinforcement effect of the specimens.On the contrary,the reinforcement effect is poor.（5）The freeze-thaw resistance and UV aging resistance of sand-fixation body with moisture content of 0%（dry）,5%,10%and saturated and the mixing ratio of15%,20%,25%and 30%were studied.The experimental results show that the lower the moisture content and the larger the mixing ratio of slurry,the lower the damage degree of the samples,and the earlier it reaches the stable state,showing good durability.In the ultraviolet aging experiment,the heat generated by the light source has a certain effect on the moisture content of the samples,and further affects the anti-aging property of the samples.Further research should be carried out in the subsequent experiments.