1 Introduction
2 Methodology: Forensic Excavation of Rock Masses
2.1 Chemical Splitter and Operation Principle
2.2 Experimental Procedure of FERM
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Stage 1—Holes with diameter of 27 mm were drilled to follow the apparent planes of incipient discontinuities using a battery-powered drill and spacing of around 200 mm. Holes were terminated within the test blocks to prevent leakage of the chemical splitter.
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Stage 2—The expansive powder and water were mixed to the recommended ratio (3.3 kg/L).
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Stage 3—Holes were filled with the chemical splitter. A plastic cover was placed over the holes.
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Stage 4—The chemical splitter hardens gradually and expands to open up the incipient discontinuity, typically over 24 h. Secondary tools (an excavator, forklift, wedges and chisels) were used as necessary to complete the opening up of the incipient fractures initiated by the expansive grout.
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Stage 5—Joint surface examination and description.