Evaluation Of The Residual Load-Bearing Capacity Of The Existing Road Using Plate Loading Test

Abstract

In the last few years as the road construction budget has been decreasing in Latvia, the number of road construction reinforcement design and construction objects has been increasing. At the beginning of the project development of the existing road condition is assessed, taking into account various pavement evaluation criteria and it is determined on which road sections it is possible to reinforce the pavement and where full construction is required. The road pavement structure in Latvia is developed using “Recommendations for road design. Pavement” and inaccurately defining the bearing capacity of the existing foundation can significantly affect the service life of the designed structure. During the construction of the road, establishing that the bearing capacity of the existing foundation is lower than specified in the project incurs additional costs for the customer. Project changes are made, and special solutions are provided in order to achieve the bearing capacity on the mineral material layers defined in the project. One of the most accurate ways to determine the bearing capacity of existing road structural layers is the static plate test. However, the results of this test are also not 100% accurate and any of them may give unreasonable results due to various influencing factors. The aim of this work is to analyze the results of static plate test by determining the most important factors that affect the obtained load-bearing capacity values, identify biased/erroneous test results, and determine which results reflect the residual load-bearing capacity of the existing road structure.

Development of a static plate test finite element calculation model

“…Considering that the geotechnical investigation is carried out at the initial stage of the development of the road project, it is very difficult to define in which sections of the road it would be possible to envisage the construction of an incomplete pavement structure and at what depth it would be necessary to determine the residual bearing capacity of the existing foundation. In a previous study [1] (E. Virsis, A. Paeglitis and A. Zarins (2021)) it was determined that the results of the static plate test are significantly affected by trial test pit size because remaining asphalt layer affects the development of deformations in the base layer. The geotechnical research data do not give accurate results if a sufficiently large trial test pit area is not prepared, but taking into account the fact that it is not possible to create at least 1.5x1.5 m asphalt section during the research, then the engineer must estimate the approximate reduction in load-bearing capacity depending on the size of the trial test pit created during the geotechnical research.…”