ABSTRACT
The article contains a detailed description of the peculiarities of the formation of the geofiltration regime on the northeastern side of the Koashvinsky quarry. In this area, the possibility of constructing a grout curtain is considered as one of the methods of controlling high inflows of water into the quarry. At the expectable construction site, the Quaternary age rocks, which are associated with the valley of the Vuonnemyok River, are developed and lying on the bedding crystalline rocks of ijolite-urtites; hydrogeological conditions are characterized as complex. Quaternary rocks, the influx from which is up to 2000 m3/h in normal time and up to 3000 m3/h in high-water periods, play the main role in the quarry watering. The water inflow into the quarry from crystalline rocks is approximately 500 m3/h.
Formed at the time being in the open field, the filtration flow has a complex three-dimensional structure due to the presence of three aquifers in the section and a fairly close location of several boundaries feeding groundwater. The filtration calculations of the projected grout curtain with the use of analytical methods will not make it possible to take into account fully the complex hydrogeological structure of the northeastern side of the Koashvinsky quarry. The efficiency of the planned grout curtain can only be substantiated using geofiltration modeling.
To create a numerical geofiltration model of the Koashvinsky quarry area, the Visual MODFLOW software complex was used. The model takes into account the filtration flows formed both in Quaternary and in crystalline rocks, the feeding of aquifers by means of rivers and lakes and through the infiltration of atmospheric precipitation, as well as by virtue of discharge into the quarry and existing drainage wells.
In the course of numerical experiments, various alternate layouts for the grout curtain have been considered both in plain view and in section. It has been established that when the grout curtain is erected in the moraine aquifer that is the first from the surface, a decrease in the water inflow into the quarry will be insignificant in comparison with the total quarry drainage. In the case of the construction of the grout curtain in the artesian aquifer that is second from the surface, there will be an increase in the filtration rates in the upper part of strongly fractured and weathered crystalline rocks, the filtration properties of which have not been studied properly.
As a result of the study of geofiltration processes, the optimum position of the grout curtain has been determined with the use of numerical modeling, the structure efficiency has been assessed, and recommendations have been developed for the further study of the hydrogeological structure of the site in question.
