Diffusion Performance And Reinforcement Mechanical Properties Of Medium Sand Grouting

In order to explore the diffusion effect of medium sand grouting and the mechanical properties of reinforcement,based on the theory of sand grouting,the grouting diffusion and reinforcement test of medium sand layer was carried out by using ordinary silicate 42.5#cement(OPC),fly ash cement(FPC),early strength agent cement slurry(ESAPC)and cement-water glass double slurry(C-S)through the indoor medium sand layer grouting reinforcement test device.The maximum diffusion radius and grouting amount of slurry were measured,and the relationship between slurry diffusion radius and water cement ratio,fly ash content,water glass Baume degree and grouting pressure was analyzed.The ability of slurry to reinforce the sand layer under ideal conditions was obtained by uniaxial compressive strength test.The microscopic reinforcement characteristics of the sand-slurry interface were analyzed by SEM,and the essential reason for the difference of sand effect in different material reinforcement was revealed.The results show that :(1)Grouting material,particle size,water cement ratio and grouting pressure lead to the difference of grouting effect.Due to the different particle sizes of grouting materials,the difficulty of crossing medium sand is different.In general,the smaller the particle size of the material,the farther the diffusion distance.Due to the lubrication of free water,increasing the water-cement ratio can significantly increase the slurry diffusion distance.After reaching a certain grouting amount,the effective pore diameter of the pore channel in the sand is filled with the slurry,so that increasing the grouting pressure does not significantly increase the diffusion radius of the slurry.(2)Based on the relationship between the diffusion radius of OPC and ESAPC slurry and the grouting pressure and the relationship between the grouting amount of OPC,FPC and ESAPC slurry under different grouting pressures and time,the concept of “saturated slurry content” is proposed.It shows that the filling of medium sand pores by slurry and the maximum slurry holding capacity are determined by the properties of medium sand itself,which provides a theoretical basis for quantitative preparation of slurry.(3)The sand effect of different slurry reinforcement can be determined by uniaxial compressive strength test.Under ideal conditions,the compressive strength of FPC slurry is not much different from that of OPC slurry,and FPC cement can be widely used for medium sand grouting.The ESAPC slurry greatly improves the early compressive strength of the reinforced solids.(4)The engineering applicability of different grouting materials can be judged by SEM analysis of rock-pulp cementation reinforcement.The cementation degree of ESAPC rock-slurry is better than that of OPC and FPC,and it is closely arranged.It can form a large area of flake crystals without obvious cracks,which is suitable for the early reinforcement and water interception of water-rich sandy soil strata.