Improving rock mass quality using bio-grouting

Abstract

The aim of this project is to investigate the physical characteristics of bio-grouting that are being used to grout rock fractures. Tri-axial Compression tests are carried out on the host rock samples, which are made of Bukit Timah Granite, that are grouted with 2 different bio-grouting materials, normal bio-grout and bio-grout with sand. The test with sand is to see if there is a further decrease the permeability, thus, improving the performance of the grout.

To fully understand the physical characteristics of the different bio-grouts, multiple parameters are recorded and observed using test tubes with markings to collect the permeating agent, which is water, with differing stresses. Besides the main focus being stress-dependent permeability, average flow rates are also observed with varying inlet pressures and confining pressures.

The overall investigation reveals that the bio-grouts that are being tested are suitable materials to plug the fractures. It also shows that the permeability under the simulated stresses is comparable or even better than that of the host rock, Bukit Timah Granite. Lastly, it was also revealed the flow rates and permeability were affected by the changing confining and inlet pressures. There could be further and more extensive studies that could be done to determine the best material to use for bio-grouting.