The dissertation work presents the new decision of the current problem on methodology of design of transverse shallow drainage laying on the basis of the assessment of the quality condition of the road section which operates in wet conditions.
The discrepancy between the existing strength of the road and the constant increase in traffic tension and speed results in the destruction of road clothing, which makes it more water-resistant. In order to avoid long-term wetting of the structural layers of the cover and the base, it is necessary to prevent the accumulation of large quantities of free water in them by means of a shallow drainage system, which enables the water to be quickly removed from the road structure and ensures its strength. This also makes it necessary to measure the performance of shallow drainage structures, both in terms of drainage rates and vehicle vibration.
The work has developed a mathematical model of the quality of the road section, which takes into account its design and design parameters, in particular the shallow-level drainage. The conceptual model is based on a quamiletric method and a tiered hierarchical system of indicators. Weighting factors have been determined for each differential indicator of the quality of road structure elements and all objects situated within the withdrawal strip on the basis of cost and expert methods.
According to the method of finite elements, models of road construction with a drainage layer in three-dimensional elements with different types of tubular dredges are constructed on the basis of the modern software-calculation complex SCAD Office. According to the results of the numerical simulation, taking into account the technological features of the device of the drainage layer, a distribution of the normal voltage isofield and insulation is obtained, on the basis of which deformations of the road structure and directly in the body of two types of drainage pipes are determined. During the device of the drainage layer, deformation of concrete pipes may occur, which causes their destruction during the compaction thereof, as opposed to PVC pipes. The resulting deformations in the body of PVC pipes of class SN 8 are 2.3 per cent of the outer diameter, which does not affect drainage and confirms the advisability of their use as opposed to concrete pipes. Failure of concrete tube integrity contributes to moisture storage in road construction. The work also included a numerical simulation of the stress-strain condition of two types of road construction, with a drainage layer and with tubular drains below it, for two classes of tubes SN 2 and SN 8. The results obtained from three-dimensional numerical models justify the choice of strength characteristics of tubular drains.
The intensity of water drainage conditions of two structures of transverse drainage of shallow laying with different materials-fillers in the trench under influence and without the action of vibration was investigated. The experiment was conducted in accordance with the actual unfavourable meteorological conditions of the two shallow drainage constructions, with a rainfall intensity of 5 percent. The analysis of experimental studies suggests that the design of a cross-section drainage of shallow gravel core drains more water on average by 10% without vibration, and 14% more by vibration, over time, respectively, 7 and 11 times faster than the structure of a transverse drainage of a shallow laying with a tubular drainage. This gives rise to claims of greater efficiency. However, the intensity of drainage of the structure with the pipe is almost not affected by the vibration, and the effect of the vibration on the structure with the gravel core amplifies it due to a higher coefficient of filtration of the trench filler. On the basis of the results presented, correlation and regression relationships were obtained to determine the rate of drainage for each drainage structure in relation to the initial humidity of the ground. This makes it possible to adapt the results of experimental studies to in situ conditions with known changes in soil moisture from which the earth canvas will be constructed.
A target function has been defined to find the most optimal construction for the drainage of shallow laying base according to two groups of criteria: the estimated cost and the set of technical and technological indicators characterizing their performance. On the basis of the method of collective expert evaluation of the conduct of mathematical processing of the data of the questionnaire survey of experts in the field of road construction in order to identify and rank the totality of technical and technological parameters, determining the work of constructions of transverse drainage of shallow laying. Of the eight proposed designs, the best possible designs with the best technical and technological characteristics were justified and recommended for design with a minimum estimated cost.
