The Influence of Vegetation Succession on Bearing Capacity of Forest Roads Made of Unbound Aggregates

Abstract

The aim of the research was to verify a common opinion concerning a positive influence of plants on the bearing capacity and durability of forest roads made of unbound aggregates. The surface bearing capacity is defined as the ability to transfer traffic loads without any excessive deformations which would hinder regular use of the surface and shorten its durability. It is a significant functional feature of any road. The article analyzed the influence of road surface plant succession on its bearing parameters. The research was conducted on sections of experimental road constructed using macadam technology and reinforced partly with a biaxial geogrid. Measurements were taken with a lightweight Zorn ZFG 3000 GPS type deflectometer with a 300 mm pressure plate radius and 10 kg drop weight which allowed to measure dynamic deformation modulus (Evd) and s/v parameter regarded as an indicator of compaction accuracy of the studied layer. Evd values and s/v parameters, which were obtained by measuring the road pavement covered in vegetation and after having it mechanically removed (mowed), were submitted to the analysis; next, they were compared with the results of an analysis done on areas naturally deprived of the plant cover and located in the immediate vicinity of the measuring points. The conducted research has indicated unfavorable influence of vegetation succession on the bearing parameters of the analyzed sections. The greatest drop in the mean Evd value was 39%, and s/v parameter deteriorated as much as 9%. Hence, a regular mowing of the road surface (including the maneuvering, storage and passing areas) should be taken as standard and mandatory procedures of forest road maintenance.

Evaluation of Light Falling Weight Deflectometer for In Situ Measurement of Secondary Deformation Modulus of Various Forest Road Pavements

“…Strictly controlled laboratory conditions can also play an important role (Sulewska 2004, Alshibli et al 2005, Szpikowski et al 2005, Sulewska and Bartnik 2017. Forest roads are often built as thin-layered structures on variable road substrates with sometimes unobserved compaction standards and under different moisture conditions in vertical and horizontal directions (Trzciński 2011, Grajewski 2016, 2019.…”

Evaluating the Forest Road Systems Subjected to Different Loadings by Using the Finite Element Method

“…The forest roads, like any other type of construction, undergo a series of structural changes as a result of use [1][2][3][4], which are closely related to the level of traffic at which were exposed [5][6][7][8][9][10][11][12][13]. Because of this, the sizing and the design are in a strong relation to future requests [5,12,[14][15][16][17] and the materials used in construction [3,[18][19][20][21], but also with the compliance or non-compliance of the proper conditions of the objective's exploitation and use [12,[21][22][23][24][25][26].…”

“…In Romania, the forest roads are restricted to public traffic [4,15,52,53], and are classified into three categories (masterly, principal/main and secondary forest roads), depending on the traffic characteristics and the forested areas they serve [4,15,53]; accordingly, the road systems are usually selected based on the category of road [36]. In addition, most forest roads are made of flexible systems [20,54], which are sized based on the traffic requirements [11,15,17,55]. Gravel surfacing is the most common in Romanian forest roads [3,15,[22][23][24]56], and most of the forest roads were designed for a maximum permissible weight of 25 tones [57], before 1990 [58].…”