METHOD AND PNEUMO-PERCUSSIVE DEVICE FOR FORMATION OF BOREHOLES IN GROUND Russian patent published in 2002 - IPC

FIELD: process of civil engineering work, applicable for construction of pedestrian underpasses under roads, buildings and other structures. SUBSTANCE: the method consists in sinking of a pioneer borehole, laying of a flexible coupling in it for connection of the pneumo-percussive device to the power member, connection of the pneumo- percussive device to the additional power member by means of a returning flexible coupling, cycling sinking of the borehole comprising the delivery of the pneumo-percussive device to the face by the power member and feeding flexible coupling, face displacement and extraction of the pneumopercussive device from the face and borehole by the additional power member and returning flexible coupling. The action of the power members on the pneumo- percussive device by means of the flexible couplings is oriented with respect to the borehole design axis, setting-up a new connecting duct of the power member to the pneumopercussive device by cutting-through the ground by the feeding flexible coupling. At a displacement of the face prepacking of the face central part, subsequent destruction of the face in the periphery with a simultaneous consolidation of the destructed ground around the borehole edges and by-pass of the destructed ground to the obtained bore-hole are carried out. The device has a pneumo-percussive mechanism consisting of a body and a striker, and a working member including a bush connected to the shell by means of ribs, the outer surface of the shell central part is coaxial with the pneumo-percussive mechanism. The working member is installed on the body of the pneumo-percussive mechanism for rotation and longitudinal displacement limited by stops. An even number of ribs is provided. EFFECT: enhanced stability of the bore-hole of the preset direction and reduced cost of energy for its formation. 3 cl, 9 dwg