Pile Driving by Electroosmosis

In the seven-year plan for development of the national economy of the USSR, bridge construction and the build­ ing of hydrotechnical structures occupy a prominent place. One of the most importa. nt operations in such construc­ tion is the laying of pile foundations. In recent years deep pile foundations have been developed, with heavy loads on the piling. This technique is necessary when penetrating dense sand-clay soils or when sinking the piles to hard rock. The operations are very laborious, requiring a. great expenditure of time and effort, and this Significantly low­ ers the time of productive work (actual driving of piles) and reduces the quality of the work. To improve the efficiency of pile driving under such conditions, it is desirable to use electroosmosis. By elec­ troosmosis we refer to the movement of pore water through the ground, directed from anode to cathode under the in­ fluence of direct current. This current, in passing through clayey sOils, causes drying of the soil at the anode and moistening of the soil at the cathode. Therefore, if a pile that is to be driven is connected to the negative terminal of a. direct-current generator, electroosmosis will cause a film of moisture from the soil to settle on the surface of the pile, and a zone of electroosmotically water-saturated soil will form about the pile. This situation permits a temporary diminution of the resistance of the ground to the sinking of the pile.