This paper presents a field and laboratory investigation of pullout resistance of steel anchors in rock. The field testing involved pullout tests of six steel anchors installed in rock by gravity grouting and pressure grouting. The laboratory testing involved unconfined axial compression tests of six grout specimens prepared in custom-made molds using the two grouting methods to investigate the effect of grouting method on the mechanical properties of grout. The pressure-grouted specimens had a higher density and compressive strength, which was a result of their denser microstructure with significantly fewer and smaller voids from air bubble inclusions than the gravity-grouted specimens. The field pullout tests suggest a progressive failure mechanism, which was manifested through the progressive elongation of the bond zone. The pressure-grouted anchors yielded higher pullout resistance than did the gravity-grouted anchors. The increase in rock-grout bond strength from pressure grouting is likely due to a combination of several factors, including the resultant higher grout strength, higher rock-grout contact stresses, and grout injected under pressure into the fractures/fissures that existed in the bedrock.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Geotechnical and Geoenvironmental Engineering|
|State||Published - Nov 25 2013|
All Science Journal Classification (ASJC) codes
- Geotechnical Engineering and Engineering Geology
- Environmental Science(all)