the process of forcing special solutions into rocks. Plugging is used in mining and hydraulic construction to reinforce rock massifs, to waterproof and lay seepage barriers that prevent subsurface water from penetrating mining excavations (mine shafts, shaft bottoms, and drifts) and prevent seepage from penetrating the foundations of hydraulic structures, such as dams. In drilling wells, plugging is used to prevent outflow of water, petroleum, and natural gas from the wells. Plugging operations differ in the plugging solution used—cement, clay, bitumens, and calcium silicate (for rocks) and synthetic resins (for strengthening rock massifs). Combinations of substances are also used.
In mine construction, preliminary plugging is carried out prior to excavating. A specific plugging operation consists in injecting solutions under low pressure (up to 1 technical atmosphere) into the gap between the mine supports and the rock walls of shafts or other excavations to ensure the uniform transfer of rock pressure to the supports from all directions. In the construction of hydraulic structures, plugging is carried out through boreholes sunk into the foundation of the structure. Solutions can also be injected into friable, unstable rocks through pipes driven into the rocks.
An integrated method of plugging rocks by using clay mortars with small amounts of reagents (cross-linking agents), such as cement and sodium silicate (water glass), came into use in the USSR in the 1970’s. With this process it is possible to make engineering calculations of the plugging process from preliminary hy-drodynamic investigations of the rock massif.
IU. I. SVIRSKII