Tractive force requirement of V-plow drain-pipe installation machine

Abstract: A V-shaped plow has widely been expected to serve as a cost-effective trenchless drain-pipe installation machine in the subsurface drainage over the decades of application in European countries, due to its simple structure, high working efficiency, and low operation cost. The unique characteristics make it particularly suitable for the construction of subsurface drainage systems in alluvial plains along the Yellow River, where the underground water table is shallow, and the soil is unstable. A prototype machine was firstly developed in China at the beginning of the 13th Five-Year Plan period in 2016. In this study, a systematic investigation has been conducted on the tractive force requirement at different depthes in the pipe installation, thereby verifying the performance of the machine. A dynamic analysis was made to clarify the working resistances (consisting of soil-cutting, soil-lifting, and soil-metal friction resistance), and the traveling resistance (consisting of soil compaction, bulldozing, and friction resistance) using the mechanical structure and working principle. Two major components also constituted the total requirement of tractive force. A mathematical model was then established to describe the relationship of tractive force requirement with the plow body specifications, soil physical properties, and drain-pipe depth. The model indicated that the tractive force requirement was the second power in the pipe installation depth, particularly with the primary and quadratic terms resulted from the plow working resistance and the constant term from the track traveling resistance. A prototype machine was used to collect the soil physical data from the Shantun Village, some 80 km to the lower reaches of Huanghe River in Shandong Province of China. A Finite Element Method (FEM) and Smooth Particle Hydrodynamics (SPH) were combined for the dynamic simulations at different installation depths. The results showed that the curve of working resistance was in good conformance to the general law of plow-body and soil interaction. Specifically, the plow working resistances were 35.65, 55.71, 111.06, 201.80, and 313.22 kN, respectively, at the installation depth of 0.4, 0.6, 0.8, 1.2, and 1.6 m. A regression analysis was also implemented to further verify the validity of the model. A field test was planned using a central composite design, where the installation depth of drain-pipe and working speed of machine were set as the factors, whereas the tractive force was as the response. The power consumption of hydraulic pump was measured to determine the requirement of tractive force for the driving and traveling speed of the machine. An entire ANOVA table showed that there was a significant effect of installation depth and square in a drain pipe on the tractive force requirement, as indicated in the theoretical model. The tested and simulated regression curves of working resistance fit quite well, with the maximum relative error smaller than 20%, indicating the acceptable simulated data. The data can be expected to serve as a basic guideline for the V-plow drain-pipe installation machine under various soil physical properties at varying drain-pipe installation depth and pipe diameter to be installed. The finding can further provide strong support to the structural design of a V-plow machine for the trenchless drain-pipe installation.