Effects of substrate materials and liner thickness on the adhesive strength of the novel thin spray-on liner

Lianjun Chen,Qizheng Dong,Xiangfei Cui,Huaixuan Cao,Guoming Liu,Zhi Zhou

doi:10.1177/1687814020904574

Lianjun Chen, Qizheng Dong + Show 4 more

Open Access

https://doi.org/10.1177/1687814020904574

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Abstract

In order to comprehensively investigate the influence of the thickness of thin spray-on liners on their adhesive strength with different surrounding rock environments, pull-off tests were employed to measure the adhesive strength of thin spray-on liners of different thickness on the surface of various substrates (granite, sandstone, concrete, and coal), which were used to simulate different surrounding rock environments. The results indicated that the failure mode was mainly liner material–substrate adhesion failure when granite, sandstone, or concrete was used as the substrate, while substrate failure was observed to occur more frequently when coal was used as the substrate. The variation rules of the adhesive strength ( σ) of thin spray-on liners, along with liner thickness ( t), for different surrounding rock environments were obtained: [Formula: see text] for granite, [Formula: see text] for sandstone, [Formula: see text] for concrete, and [Formula: see text] ( t < 4) and [Formula: see text] ( t≥4) for coal. Furthermore, analysis of the standard deviation of experimental adhesive-strength data suggested that the variation in adhesive strength decreased in the following sequence: coal > concrete > sandstone > granite. The achievements of the current study provide a theoretical basis for the on-site determination of thin spray-on liner thickness requirements, as well as the scientific and rational design of liner material structure.

Highlights

Thin spray-on liners (TSLs) represent an emerging support technology that originated in Europe and the United States in the 1990s.1,2 For this technology, novel spraying materials with special mechanical properties are employed to rapidly form super-thin liners (\10 mm) that play a role in projects such as roadway support and sealing.[3,4,5,6] In addition, TSL support technology has great significance for preventing mine disasters
In this work, we focused on the influence of substrate material and liner thickness, two important factors affecting the adhesive strength of liner materials
When sandstone was used as the substrate for pulloff tests, failure mode I accounted for 4.2% of failures, which all occurred with liners up to 2 mm thick

Summary

Introduction

Thin spray-on liners (TSLs) represent an emerging support technology that originated in Europe and the United States in the 1990s.1,2 For this technology, novel spraying materials with special mechanical properties are employed to rapidly form super-thin liners (\10 mm) that play a role in projects such as roadway support and sealing.[3,4,5,6] In addition, TSL support technology has great significance for preventing mine disasters. The variation of adhesive strength with temperature and humidity was obtained by experimentation (the curing time was 7 days, and the liner thickness was 5 mm), as shown in Figures 6 and 7.

Results

Conclusion