FEATURES OF PERMEABILITY CALCULATION FOR CONCRETE-LINED FACING WITH SEALED SEAMS TAKING INTO ACCOUNT THE GROUND PERMEABILITY

Subject: calculation of filtration through concrete-lined facings with the subsequent construction of diagrams of excess pressure when sealing the seams. The considered case of water permeability of the sealed seam of the facing refers to a two-layer medium with a sealed screen and an underlying base in which three types of excess pressure diagrams can be formed depending on the ratio of the filtration coefficient of the ground-soil to that of the sealed layer. Research objectives: investigation of cases of water permeability of the sealed seam of the facing in a two-layer medium where the top layer constitutes a sealed screen of soil in which three types of excess pressure diagrams can be formed depending on the ratio of the filtration coefficient of the ground-soil to that of the sealed layer. Materials and methods: dependencies of specific flow through the sealed seam are considered. Results: for the analyzed cases of water permeability of the sealed seam, it was established that for the ratio of ground soil filtration coefficient to that of the sealed layer the following values are obtained: 1) when , the excess pressure would be positive and the filtration in the foundation would proceed with complete saturation of pores with water; 2) when , the diagram corresponds to such a degree of seam sealing, at which the excess pressure at its base falls to zero; 3) when , there is a negative excess pressure (i.e., vacuum), and the filtration with full pore saturation transitions to motion with partial saturation of pores. Conclusions: The obtained value of the speed of spreading of seepage flow under the sealed seam in the first case when is (1.0> 0.274 m/day), in the second case when - (1.0 ≅ 1.02 m/day), and in the third case, when - (1.0 < 2.48 m/day). These data confirm the nature of the filtration process in the ground-soil under the seam: in the first case - with complete saturation of pores, in the second case, there is a boundary with the transition from complete saturation of the soil to partially saturated soil, and in the third case - with partial saturation of the ground-soil, which corresponds to previously established concepts of filtration nature for infiltration basins.