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Proučili smo nosilnost gozdnih prometnic, zgrajenih v Sloveniji v času od leta 2000 do 2010. Traktorske vlake so bile neutrjene, ceste pa utrjene z nosilnimi in obrabnimi plastmi, ki skupaj sestavljajo voziščno konstrukcijo. Usvojili smo gradbeniške postopke za terenske točkovne meritve nosilnosti vozišč gramoznih cest. Nosilnost vozišč smo leta 2009 na 18 prometnicah analizirali po postopku z dinamično obremenilno ploščo ZGF02 in dinamičnim deformacijskim modulom (Evd). Z dinamično ploščo smo lahko izmerili nosilnost vseh relevantnih kategorij gozdnih prometnic v Sloveniji v vseh fazah gradnje in rabe, razen v času zmrznjenega vozišča. Najnižja nosilnost je bila izmerjena spomladi na novih vlakah in to na kolesnici v nasipu (15 MN/m2), najvišja pa na starih glavnih gozdnih cestah v sušnem obdobju poleti (172 MN/m2). Nosilnost kolesnice v nasipu je značilno manjša od tiste na odkopni strani vozišča, a le na stranskih cestah na mešani podlagi. Po gradbenih merilih je ugotovljena velikost zmesi zrn obrabnih plasti ustrezna, velikost zmesi zrn nosilnih plasti pa neustrezna. Na stranskih cestah je bila povprečna nosilnost višja na karbonatni podlagi kot na mešani, kjer je povprečna nosilnost spomladi 2009 znašala 42 MN/m2, poleti 88 MN/m2 in jeseni 54 MN/m2. Na glavnih cestah je povprečna nosilnost znašala spomladi 54 MN/m2, poleti 125 MN/m2 in jeseni 78 MN/m2. Celoletne radarske meritve prometa na dveh odsekih glavnih gozdnih cest so skupno evidentirale 18.000 vozil, največ osebnih. Ugotovljena prometna obremenitev glavne gozdne ceste ʺRavnikʺ je 88606 NOO. To je po gradbenih merilih lahka prometna obremenitev. S celoletnimi meritvami nosilnosti nismo dokazali negativnega kratkoročnega vpliva prometne obremenitve na nosilnost in prečno ravnost cest. V sušni dobi je nosilnost vlak na trdi podlagi manjša od nosilnosti stranskih cest na mešani podlagi. We studied bearing capacity of forest thoroughfares, constructed in Slovenia between 2000 and 2010. Skid trails were unpaved while roads were paved with bearing and wearing courses that together consist pavement structure. We mastered civil engineering procedure for spot field investigation of bearing capacity on gravel roads. Carriageway bearing capacity has been analysed in 2009 on 18 thoroughfares with dynamic loading plate procedure and dynamic deforming module (Evd). With dynamic plate ZGF02 we measured bearing capacity of relevant categories of forest thoroughfares in Slovenia in all construction phases and road uses except during winter frost. The lowest values have been measured in spring on new skid trails at embankment rut (15 MN/m2) and the highest on old primary roads during dry period in summer (172 MN/m2). Bearing capacity of the embankment rut has been significantly lower from the rut on excavation side of the carriageway but only on secondary roads on mixed base. The aggregate sizes for wearing course have been found adequate, and inadequate for bearing courses. On secondary roads the bearing capacity was higher on lime base than on mixed base. There the average bearing capacity was in spring 42 MN/m2, in summer 88 MN/m2 and in autumn 54 MN/m2. On primary roads the average bearing capacity was in spring 54 MN/m2 in summer 125 MN/m2 and in autumn 78 MN/m2. One year traffic monitoring on two primary forest roads with radar traffic detector found 18000 vehicles, mainly personal cars. The calculated traffic annual loading for primary forest road ʺRavnikʺ is 88606 NAL. This is light traffic loading according civil engineering standards. All year bearing capacity measurements have not proven detrimental short term impacts of the traffic on road bearing capacity and transverse evenness. Bearing capacity of the skid trails on lime base in dry season have been lower that on secondary roads on mixed base in spring time. |
