Research On The Groutability And Application Of Permeation Grouting In Sand And Gravel Stratum

For rapid development of civil engineering construction, the engineerings of ground improvement in sand and gravel stratum will be more and more, and more complicated. At present, the method of ground improvement in sand and gravel stratum with grouting has been applied and got successful to some extent, however, there are some problems in engineering design theory. Because of grout flows are affected by so many factors and complexity in the inner structure of sand and gravel stratum itself, the research on grouting in sand and gravel stratum is very difficult. By now, there are no perfect design theory and methods for grouting in sand and gravel stratum. Many problems should be researched in the further engineering application.In the paper, author analyzed groutability of permeation in sand and gravel stratum from character of grouting grouts and internal permeation structure. From the aspect of grout, the paper analysis the penetration of cement grout and gain that main factor to penetration of cement grout is the size of cement particle and the rheology of grout. It put forward some effective method for improving the cement grout penetration. From the aspect of sand and gravel stratum, the paper consider that the penetration coefficient is necessary to groutability. Because of important relation of the penetration coefficient and the size of particle and content, the grain gradation and content should be analyzed in studing on groutability of sand and gravel stratum.While analysising the penetrantion of cement grout, it is found that the change of grout viscosity with time in researching fluidity of grouting grout is usually ignored. So it is necessary to study the character of cement grout inhere. In the paper, the character has been studied by test in lab and the connection curve and formula of the viscosity and the time is enduced by computer program.The paper analysed diffusion formula in sand and gravel stratum by all kind of grouting grout, and improved in diffusion formula of grouting basing on the relation of viscosity and time. It can be more accorded with the fact.Finally, the paper analysed and confirmed the feasibility and effect in improving sand and gravel stratum with grouting in engineering application.