Abstract
Micro-pile drilling technology is often used today for the reconstruction and repair of buildings whose foundations are heavily loaded. Once installed, the piles take up part of this load. They can also be used to improve the load-bearing capacity of building foundations before the upper floors are built on top of them or before additional underground floors are constructed. Construction of buildings and structures in areas with complex soils is a special case. Buildings constructed in such conditions as a result of underground mining operations, soil movement into the excavated space and formation of a displacement trough on the ground surface are subjected to uneven settlement and horizontal deformations during operation. This paper presents the results of field tests of unreinforced Franki micro-pile (B-4350) unreinforced pile for soil reinforcement. Based on the obtained data, it can be concluded that the use of micro-piles to reinforce the foundations of reconstructed buildings provides a reduction in construction costs, labor costs and construction time, and as a consequence demonstrates their undeniable effectiveness. Application of micro-piles at reinforcement of strip foundations, in comparison with the traditional reinforcement design gives reduction of the estimated cost of construction (by 8 %), mainly due to reduction of the cost of operation of machines (by 46 %) and reduction of wages (by 24 %), though with some increase in the cost of materials (by 28 %), which somewhat levels out the general tendencies of cost reduction.