Study On The Diffusion Law Of Fly Ash Slurry In Porous Media

During the construction of underground works,the threat of water and the influence of bad stratum are often encountered,and serious accidents are formed in a serious way,which leads to the stagnation of the project and causes great economic losses.Grouting technology is one of the important technical measures to control water disaster and reinforce weak stratum in underground engineering.Field grouting mostly relies on experience,and theoretical research lags behind engineering practice,so it is urgent to carry out relevant research.The grouting of the project is mostly uncontrolled grouting,which leads to the fact that the slurry can not be accurately predicted by the diffusion of the injected layer and the shape and size of the stone body after grouting.There are many factors affecting grout diffusion,such as the properties of grouting materials,physical and mechanical properties of rock and soil,grouting methods and so on.In this paper,the diffusion law of fly ash based slurry in porous media was studied by means of grouting material selection,slurry ratio test and numerical simulation.The main work and research results are as follows:(1)According to the composition,the activity of fly ash analysis,puts forward the selecting principle of several fly ash grout slurry: good stability,good fluidity,easy to control the injection performance;the grout strength,the high rate of stone;stone body stable chemical structure,durability;the energy saving and environmental protection;the wide range of applications.(2)According to the specific geological conditions of slurry grouting,ratio of fly ash based indoor grouting material test,considering the setting time and compressive strength of the two indicators,the water cement ratio of 3:1,with 67% fly ash grouting has good performance,the initial setting and final setting time are respectively 27 h and 72 h.The 14 d compressive strength of 0.66 Mpa.(3)Using the selected slurry ratio,the fluid dynamics simulation software Fluent was used to carry out numerical simulation.The slurry diffusion at different time,different depths,different water pressure and different grouting pressure was obtained.The slurry is columnar diffusion in homogeneous porous media.