Bosna i Hercegovina ima pretežno brdsko-planinsku konfiguraciju terena, bogata je razvijenom hidrografskom mrežom. Pri projektiranju i izgradnji mreža šumskih cesta učestala je pojava presijecanja ...stalnih ili povremenih vodotoka pa je zato prijeko potrebno planirati i graditi vodopropusne objekte.Najrizičnija su mjesta, kada je u pitanju negativan utjecaj vodotoka na erozijske procese, upravo točke presijecanja šumske ceste rijekama i brdsko-planinskim vodotocima. Da bi se smanjio postotak neupotrebljivosti primarne mreže šumske transportne infrastrukture, treba pristupiti kvalitetnim rješenjima odvodnje površinskih voda i izgradnji prelazaka preko postojećih planinskih vodotoka. Vodna je erozija jedna od mogućih pojava, koja može nastati na kolničkoj konstrukciji, ako na odgovarajući način nije riješeno pitanje odvodnje površinskih i oborinskih voda.Procjena erozijskih procesa prilikom provođenja istraživanja utjecaja hidrografske mreže na primarnu mrežu šumske transportne infrastrukture obavlja se na osnovi terenskoga snimanja stanja vodopropusnih objekata i kolničke konstrukcije u njezinoj neposrednoj blizini.Prilikom istraživanja nisu analizirani tehnički elementi šumskih cesta (osim erodiranosti kolničke konstrukcije), aktivnosti su usmjerene na vodopropusne objekte, odnosno njihovo stanje i eventualni utjecaj na erodiranje kolničke konstrukcije. Istraživanja su provedena u GJ »Neretvica« u okviru ŠPP »Konjičko«.Analizirano je ukupno 129 različitih vodopropusnih objekata, od kojih su 16 mostova, 73 cijevna betonska propusta i 40 drugih tipova objekata. U okviru provedene analize vodopropusnih objekata obrađena je oštećenost i funkcionalnost vodopropusnih objekata te erodiranost kolničke konstrukcije u njezinoj neposrednoj blizini.
Water permeable structures on strip roads play a very important role in regulating the flow of surface water and rainwater. Although the
forestry operative of B&H does not use patterns that can be used to
correctly determine the dimensions of water-permeable structures, most often the selection of the dimensions of the structure that can ensure the smooth flow of water is done experientially.
Previous analyses show that investments in forest road infrastructure are insufficient (Sokolović and Bajrić 2011, 2013) and that this is the most common reason for the poor condition of forest road infrastructure. Erosion is a common occurrence on all unpaved roads, especially in heavy rain events and on steep slopes (Wang et al. 2021). Poor technical solutions, along with irregular maintenance of water-permeable structures, are a common cause of intensification of erosive processes and destruction of the road structure.
In the present study, a total of 129 water-permeable structures of various types were analyzed, of which 16 bridges, 73 concrete pipe culverts, and 40 ‘other’ types (improvised solutions of water-permeable structures, most often made of stone slabs). Bridges have the most efficient functionality, which allows water to flow freely through the flow profile. Also, concrete culverts of larger dimensions (Ø 80 and 100
cm) have better functionality than culverts of smaller dimensions (Ø 40
and 60 cm). Namely, in the case of specific small culverts, frequent partial blockages were observed, the maintenance of which was difficult due to the small dimensions of the culvert.
The worst functionality was observed with ‘other types’ of water-permeable structures, where collapses often occur, and as a result, they cannot be cleaned and have to be replaced instead. Of the total number of ‘other types’ of structures, 50% have difficult or disabled functionality, with 20% of the total number having disabled functionality. It is obvious that the choice of the type of water-permeable structures, as well as their dimensions, play a very important role when it comes to their future functionality.
Also, field research has determined the direct correlation between the functionality of water-permeable structures and the occurrence of erosive processes on the pavement structure in the immediate vicinity. That is, in the case of structures with impaired or disabled functionality, the water partially or completely overflows over
the pavement structure, whereby the surface rubs off the pavement and causes its erosion.
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