<p><p><strong>Reference(s):</strong></p><p><em>Holmquist et al. (2003)<br>Ohio Department of Transportation (1998)</em></p><p><strong>Method Summary</strong></p><p>Verification Drilling is used as both a quality assurance technique and a quality control technique. When bulk infill grouting is selected as the mitigation method, Verification Holes should be performed and accurately logged. During verification drilling, additional holes are drilled throughout the mitigated areas and if roof contact in the voids is not demonstrated, grouting is continued.</p><p><strong>Accuracy and Precision</strong></p><p>This method is quite accurate in determining adequacy of grout penetration at certain points in a project area.</p><p><strong>Adequacy of Coverage</strong></p><p>A single Verification Drilling can only measure adequacy of grout penetration at one point therefore numerous Verification Drillings could possibly be needed for a single project. No Bulk Infill Grouting references provide guidance on how many Verification Drillings should be performed at a given project.</p><p><strong>Implementation Requirements</strong></p><p>Some experience and special equipment is necessary</p><p><strong>General Comments</strong></p><p>Verification Drilling can be used to determine the adequacy of grout penetration for use in quality control and quality assurance.</p></p>