Gaponov O. Improving the efficiency of multi-scraper chain trench excavators based on critical depth soil blocked cutting

The dissertation is devoted to the solution of the topical scientific and applied problem of increasing efficiency of multi-scraper chain trench excavators at the expense of critical depth soil cutting with its cutters. The dissertation substantiates the relevance of the topic, formulates the object, subject, purpose and objectives of the study, describes the research methods, as well as the association of the paper with the scientific programs, plans, and topics. It also provides information on testing and publication of research results. Since the soil development with cutters in conditions of critical depth cutting can reduce energy consumption of the trenching process and increase the productivity of chain trench excavators, the topic of this dissertation should be considered relevant. The scientific novelty of the obtained results lies in the development of generalized theoretical dependences, which were first obtained to determine the basic parameters of the working body and operation modes of a chain trench excavator whose cutters work in conditions of critical depth cutting. In particular, the following results were obtained for the first time: – the preconditions for increasing the efficiency of chain trench excavators due to critical depth soil cutting are substantiated and the length of the ploughshare of the extreme side cutters for these conditions is determined; – the main parameters of the working body and the operation modes of the excavator are determined, which are: the distance between adjacent ground-excavating bodies, the number of cutting lines and the number of cutters in the face, the height of the scrapers, the speed of cutting and feeding, cutting strength and others; – the technique of carrying out experimental check of theoretical positions is developed and natural samples of a working body cutters and their combinations for the test in the soil channel and in field conditions are created; – the algorithm of engineering calculations is developed and the nomograms for definition of the basic parameters and operating modes of excavators depending on geometrical parameters of cutters, parameters of a trench and soil conditions are built; – the calculations confirm the economic efficiency of modernization of chain trench excavators with critical depth soil cutting due to the reduced energy costs of the process of soil development and increased productivity of trenching and the pace of work on laying underground utilities. The efficiency of chain-scraper excavators is ensured by the minimum energy consumption of the working process and the maximum productivity of the machine, which in turn depend on the shape of the cutters, their number and arrangement. The obtained results take into account both the technological aspects of the excavator operation and the physical and mechanical properties of the soils developed by the cutters in the conditions of the critical depth of their cutting. This distinguishes the research conducted in the paper from the previous ones. The obtained calculated dependences make it possible to consider and analyze the main factors affecting the processes of trench development and substantiate the parameters of the machine and its working equipment, which provide minimum energy consumption and maximum productivity of the excavator taking into account physical and mechanical properties of soils. Thus, it can be affirmed that an applied aspect of the use of the obtained scientific result is the possibility to improve the working equipment for designing more efficient scraper trench excavators. Reducing energy consumption and increasing productivity are important technical indicators that determine the cost of not only digging a trench, but also of laying linear-long sections of underground distribution utilities on the whole. The practical significance of the obtained results of the work includes the development of a methodology and creation of algorithm for determining the parameters and operating modes of chain-scraper trench excavators on the basis of critical deep cutting of soils. On the basis of the received engineering calculations the technical task for modernization of the ETC-208 excavator which was accepted in production by LLC SPE «Gaztekhnika LTD» and LLC SKTB «Hydromodul» was made. The machine was used in the development of trenches for laying underground communications by a specialized construction company «Kharkivspetsbud-1».