Lessons Learned on Geosynthetics Applications in Road Structures in Silesia Mining Region in Poland

Abstract

The paper aims at the research of pioneering applications of geosynthetic materials used for improvement of anthropogenic material for road contraction challenges in Poland. The presented case study concerns a road embankment construction process within an area of underground mining coal extraction for which significant deformations have been frequently recorded. To improve the bearing capacity of the structure base, the geosynthetic materials were used. The question; however, was how the anthropogenic materials, filling the embankment, will interact with each other over time. The assessment of the structural condition of the motorway surface was performed using the falling weight deflectometer and the calculated modules based on the back-analysis method. They confirmed the effectiveness of the geosynthetics used in the study. They also revealed that the mining exploitation, with simultaneous use of aggregate stabilization with geogrids, did not cause significant changes in the stiffness of the pavement layers. All observations, based on both field and laboratory tests, did not show any negative impact of anthropogenic soils on the structural behavior of geogrids.The present paper describes a case study on road construction works on post-mining areas. It concerns an underground mining coal extraction site where a new motorway was planned to be constructed. However, due to significant deformation of the ground surface, caused by former mining excavations, the sophisticated ground improvement methods were necessary to be applied. For the linear structures, like roads, or other geotechnical investments the mining activity is a major safety threat, thus the need of maintenance efforts increase significantly [14][15][16][17].Recently, a peculiar revolution in the field of understanding and describing the geogrid interaction with the unbound aggregate has been observed. It mainly concerns the road construction and ground mechanical condition improvement. An improved performance of the pavement due to the geosynthetic reinforcement and bearing capacity improvement [18][19][20][21][22][23] depends on main mechanisms [24][25][26]:

Finite Element Analysis of Geogrid-Stabilized Unpaved Roads

“…Sustainability 2020, 12,1929 2 of 11 different conditions [9][10][11][12][13]. The mechanisms of geosynthetics can be summarized as: (i) to restrain the lateral movement of the unbound materials (due to frictional interaction and interlocking between aggregates and the geosynthetic), (ii) to increase the stiffness and the shear strength of the unbound materials by providing additional confining stress, (iii) to improve the load distribution to the subgrade layer, and (iv) to reduce the shear stress in the subgrade (due to its stiffness, the geosynthetic exerts an upward force supporting the wheel load and thus improving the bearing capacity [14]; this is because it acts like a tensioned membrane [15]).…”

DEM-FDM Coupled Numerical Study on the Reinforcement of Biaxial and Triaxial Geogrid Using Pullout Test

“…In recent decades, as a kind of geosynthetic, geogrids are mainly used to strengthen and improve the overall performance of foundations, roads, and slopes [1][2][3][4][5]. In previous studies, theoretical analysis, experimental research, and numerical simulation have been used to study the mechanical properties of reinforced soil systems subjected to pullout forces.…”

Description of Limit States in the Subsurface Layer of Loosened Subsoil in View of Critical State Soil Mechanics

“…Figure 1 b presents the cracks across the road due to mining impact. Therefore, for many cases, it is necessary to use protection, e.g., geosynthetics [ 22 ] or geo-mattresses [ 23 ]— Figure 1 c—the cost of which is considerable [ 24 ].…”