Introduction. When designing shallow drainage systems and the corresponding prevention of deformation of the road surface, it is important to know not only the time when water enters the road structure, but also the time needed to remove it from the base of the road clothing after the stop of the influx. This is particularly important in the case of surface infiltration during precipitation. The water captures the tiniest particles that accumulate at the places of concave vertical curves, as well as at the transition from the grooves to the mound.
Problem Statement. In the northern regions of Ukraine, where freezing extends to a depth of up to 1 m, the drainage system should be designed to prevent freezing of water in the drainage layer. For this purpose, it is necessary that the time when the water reaches the drainage layer does not exceed the allowable value. It is particularly important to ensure that water does not freeze during transition periods and thaw with a positive temperature during the day and at a negative night, when combined with precipitation or melting of snow and ice. With slow drainage, cyclic temperature variations can produce large amounts of ice lenses. The question of the study of the working conditions of the drainage system and its design parameters is scattered. One way to address this pressing problem is to carry out experimental studies that are most appropriate to the field conditions.
Purpose. The aim of this work is to determine the relationship between the water drainage intensity and the structural characteristics of shallow cross-sectional drains on the basis of experimental studies.
Materials and methods. For the pilot installation of a road structure in the Scientific Laboratory of the Department of Transport Construction and Property Management of the National Transport University has conducted research on the operation of shallow drainage structures with various fillers. In order to validate the experimental studies carried out, a comparison with the analytical method has been made, and a minimum and maximum value has been defined for the quantity of water flowing from the aperture.
Results. During the laboratory tests, the drainage intensity of the drainage structure with various filling materials was determined. On the basis of the results of the measurements, the influence of structural elements and characteristics of shallow transverse drains on the intensity of their water discharge work was analyzed. The limit values for the water discharge intensity of each of the drainage structures are obtained. The drainage intensity of the drainage structure with the filler coarse sand with the PVC tube is more in line with the calculated minimum threshold, and the drainage structure with the chipping kernel is more in line with the calculated maximum. Relative deviations of the mean discharge intensity of the transverse DMZ limits obtained by the analytical method. The difference in the results of the experimental studies with limit values is due to the fact that the analytical method does not sufficiently take into account the design features of the DMZ and drainage regimes.
Conclusions. Based on an analytical approach, limit values have been defined for the intensity of drainage. Drainage structure in which coarse sand with PVC tube is the filling material more meets the minimum water discharge threshold and the drainage structure with chipping kernel is the maximum.
A comparison of the results of the pilot studies on drainage intensity of drainage ditches with analytical limit values showed significant relative deviations ranging from 34% to 40%. For cross-sectional DMZ, an important parameter in the intensity of water drainage is not only the distance between the drainage slots, but also the properties of the filling materials, which are not fully considered in the analytical approach when designing drainage structures.
