Gravitational mass movements, such as rockfalls or landslides, represent geo-risks that require geotechnical safety measures in order to avert monetary damage and to protect human life. For the targeted stabilization and consolidation of rock masses, the gluing of rock which is known from mining and tunnel construction, is ideal. Here, an adhesive is grouted into the rock fissures which, when cured, hold the rock together by means of adhesive and cohesive forces. The selection of the right adhesive is of great importance, as it has a decisive influence on the mechanical properties of the rock and thus determines the success of the securing measure. Various adhesives such as resins and acrylate gel were examined in an extensive experimental laboratory program which was expanded to include numerical simulations with FLAC3D. The subject of the laboratory tests are jointed sandstone samples. The test program of the rock mechanical standard tests was supplemented by special tests, such as adhesive tensile strength tests to determine the adhesion between adhesive and sandstone. In order to assess the effectiveness of the adhesive bond, glued and intact sandstone samples were compared. Based on the experimental and numerical investigations, the application possibilities and limits of different polymer-based adhesives are shown and an application recommendation is given.
Solid rock is stored and structured differently depending on the history of its origin. The structure of the dividing surface allows the mountain range or individual blocks to move [1]. These represent geo-risks that require geotechnical safety measures in order to avert monetary damage and to protect human life. To prevent this, there are various ways of rock stabilization. Rock bolting, rockfall netting, rock anchors, rockfall control barriers and grouting are just a few of the possibilities [2][3]. For the targeted stabilization and consolidation of rock masses in this research work, the gluing of rock which is known from mining and tunnel construction, was considered more closely.
The material and in particular its surface properties as well as the internal strength of the adhesive are crucial for the formation of strong and durable bonded joints. Adhesion is determined by mechanical anchoring between the adhesive and the material (rock) (see Figure 1). Compared to the adhesive forces, which can be increased by cleaning/washing the rock surface, for example, the strength and functionality of the bonded joint is determined to a greater extent by the cohesive forces that develop inside the adhesive (see Figure 2). Especially thermosetting plastics, such as epoxy resin (EP resin) or polyurethane (PU resin), have a very high strength [4].