The presented results of scientific research are aimed at increasing the efficiency of trenching for laying the utility lines using new less energy-consuming technologies of excavating the soil with the working equipment of multi-scraper excavators. The proposed method of determining the efficient operating modes for excavators when digging a trench is based on the idea of cutting the soil with the blades at a critical depth level, which guarantees consumption of minimum specific energy and maximum efficiency of the machine. This becomes possible if the operation of such blades is provided with the absolute values and the ratio of the speeds of cutting and submitting the working body into the face. To determine the efficient modes of multi-scraper excavators and the size of their edge side blades, the conditions of their effective unloading were identified and the patterns of changing the soil movement over the surface of unloading scrapers depending on the time of unloading were determined. For the same purpose, the dependences of the blocked cutting speed on the trench width were determined and the technical performance of the excavator was specified on the basis of determining the soil bearing capacity for one group of blades. It is found that the time of unloading the soil from the scrapers very slightly depends on their angular velocity within its change in the unloading zone. On this basis, the maximum angular speed of the scrapers is determined. The identified indicators are related to the width of the edge side blades performing asymmetric locked cutting, whose dimensions were determined by calculations. The obtained efficient operating modes of scraper trench excavators and the size of their edge side blades allow developing practical recommendations for improving the working equipment of excavators of this type

The presented results of scientific research are aimed at solving the problem, which is associated with an increase in the productivity of the development of trenches for laying engineering communications due to the use of new less energy-intensive soil development processes with the working equipment of chain trench excavators. The aim of the work is to establish the regularities of the interaction of the working equipment of the chain scraper excavator with the soil, in which the cutters work in the critical cutting depth mode. Among the tasks that are directed to achieve the goal, it was necessary to establish the influence of soil development processes in these conditions on the technical parameters of the machine. The methodology for solving the problem is based on the idea of the theory of soil mechanics and the provisions on the critical depth of soil cutting.Applying this knowledge to the operation of the cutters of the chain excavator for cutters guarantees the consumption of the minimum specific energy and obtaining the maximum performance of the machine. Existing studies do not give a complete picture for calculating the parameters of trench excavators in which the cutters of the working body operate in the mode of critical cutting of the soil, which in turn does not allow carrying out a comprehensive calculation of the chain trench excavator and assessing the energy efficiency of its operation. The result of the research is the obtaining of theoretical dependencies for determining the cutting forces of the soil by the working body of the excavator under the conditions of the critical depth of the work of its cutters, as well as dependencies for calculating the energy indicators of the machine. The originality of the solution to the problem lies in an integrated approach, namely, it took into account not only the influence of the work of the cutters in conditions of a critical depth of cut on the technical parameters of the machine, but also the properties of the soils that are being developed. The practical significance of the results of the research is to obtain dependencies that can be used as the basis for the engineering methodology for the integrated calculation of chain-type trench eesquators in which the cutters operate in the critical blocked and half blocked cutting mode of the soil.