Reserves for increasing the productivity of an annular pneumatic impact machine during the construction of dowel fastenings of soil slopes

Abstract

   The essence of dowel fastening for ensuring the stability of the walls of deep pits, slopes of ravines or steep slopes of the earth's surface is considered. To implement this progressive type of support, especially in cramped construction conditions, during “spot development” in urban conditions, the possibility of using an annular pneumatic impact machine of the PUM type is being considered. Based on an analysis of the design features, the operating cycle of these machines and production tests, reserves for increasing operational productivity during the operation of the impact system as a whole were identified.
   Calculations have shown that even with insignificant mobility of the rod element driven into the ground, most of the energy of the first wave of the shock impulse (more than 75 %) is not spent on performing useful work. In addition, quite a lot of time is lost (up to 20 % of the driving cycle time) on the perception of the reactive recoil force, i. e. there is manually pressing the machine towards the face at the beginning of the insertion of the rod. There is additional time lost in replacing the wedge cams as they wear out.
   The feasibility of the development and implementation of a feeder is substantiated – a device for creating an external pressing force on the body of the impact machine, which allows you to select all the gaps that arise in the impact system and create optimal conditions for the operation of the clamping mechanism. The design of a quick-dismounting wedge clamping mechanism has been proposed, which allows replacing cams within 5...7 minutes.