Fracture Characteristics of Polyurethane Grouting Materials Based on Acoustic Emission Monitoring

Abstract

In this study, 16 groups of tests were designed by the orthogonal test method, and a PU grouting material was prepared, which can be used for the construction of sealing wall in mined-out area of coal mine. The basic properties of the material were measured. Firstly, the viscosity of four groups of samples with different polyether polyol contents was measured by a dynamic rheometer. Secondly, the uniaxial compressive strength of pure slurry samples and sand-containing samples was measured by a universal testing machine. Finally, the failure process of sand-containing samples was monitored by acoustic emission equipment. Through the above research and analysis, a PU grouting material with excellent performance has been obtained. That is, when the ratio of polyether triol:polyether tetraol:catalyst:surfactant:chain extender:plasticizer is 11 : 9 : 0.5 : 1.0 : 1.2 : 6.0, PU grouting material has higher injectability and ideal compressive strength, which has been proved in grouting experiments.

Study on the Gelation Process and Mechanical Properties of Organic Polymer Grouting Materials Applied to Fissure Sealing in Underground Mines

“…Figure 4 illustrates how the initial viscosity likewise falls exponentially with increasing the initial temperature, and the gel duration rapidly reduces as well. On the one hand, as the temperature rises, the volume of polyurethane expands, the molecular spacing increases and the intermolecular interaction force decreases, which reduces the intermolecular viscous force, and thus the viscosity decreases [ 26 , 27 , 28 , 29 ]. On the other hand, the increase in temperature increases the activity of the functional groups in the polyurethane molecules, thus accelerating the curing rate of the polyurethane.…”