Unit test study on formation and influence factors of additional earth pressure during formation grouting
Soil grouting has become an important technology for deformation recovery of existing tunnels,in order to explore the formation mechanism and influencing factors of slurry diffusion and additional soil pressure during grouting,a unit test for ground grouting has been designed.The grout with different water contents has been injected into sandy soil and rubber particle formations respectively,to explore the diffusion mode of slurry and the formation law of additional soil pressure during the grouting process using model experiments.The test results are as follows.(1)Pore water pressure dissipation will occur after the grout is injected into the formation soil,and the larger the soil porosity is,the faster the water pressure dissipation rate will be.(2)During grouting,the diffusion mode of grout in the stratum soil is closely related to the soil porosity and water content of grout.(3)When the slurry is still,the static water pressure will dissipate,the slurry volume will gradually reduce,and the additional earth pressure value will also gradually decrease.(4)During deformation recovery grouting,the change of additional earth pressure shall be monitored in real time,and multi-point grouting technology shall be adopted when injecting grout with low water content into sandy soil layer.
tunnelling engineeringshield tunnelresume groutingadditional earth pressureunit bodymodel test
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