<p><p><figure id='attachment_2536' style='max-width:552px' class='caption aligncenter'><img class="wp-image-2536 size-full" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Profile diagram of a site remediated using bulk infill grouting." width="552" height="555" /><figcaption class='caption-text'> Profile view of site remediated using Bulk Infill Grouting. From Ryan (1983).</figcaption></figure><h2>Basic Function:</h2>Bulk Infill Grouting is a grouting process where grout is used to fill large voids in order to prevent surface subsidence.<br><h2>Advantages:<em> </em></h2><ul> <li>Low cost per unit volume of materials when using cheap fillers</li> <li>Minimum disturbance</li> <li>Strength of grout can be tailored to fit the in-situ condition</li> <li>Essentially yields full roof contact</li> <li>Grout can penetrate all voids with no fear of the grout flowing, washing away, or settling</li></ul><h2>General Description:</h2>Bulk Infill Grouting is a process where large quantities of cement-based grout is used to fill subsurface voids such as karstic cavities in soluble rock or manmade cavities such as mines. The entire cavity can be filled in or low slump grout columns can be constructed to reinforce the roof of the mine.<br><h2>Geologic Applicability:</h2><ul> <li>Bulk Infill grouting of a gypsum cave system in not advised</li> <li>Can be used in karst topography, chalk deposits, and salt deposits</li> <li>All other soil and ground types are not related to Bulk Infill Grouting</li> <li>Water should be allowed to drain away from the treated area for optimum penetration of the grout</li></ul><h2>Construction Methods:</h2>Grout is injected at low pressures or by gravity to the base of the cavity. Water and air within the cavity is displaced as grout is injected to either fill the cavity or to create a stable support below the roof or between the surrounding ground and structure. Extensive exploratory and grouting program is needed in karst terrain to detect all subsurface cavities. Using Bulk Infill Grouting on mines involves drilling boreholes into the mine voids to inject the grout. The grout can either be a high slump grout to fill in all voids or a low slump grout to construct columns and support the roof. Types of grout columns include Conventional Grout Columns, Controlled Grout Columns, and Cylindrical Grout Columns. Bulk Infill Grouting can also be used to “pretreat” rock mass to permit other foundation systems to be built.<br><h2>Additional Information:</h2>The grout is typically of low cement contents but has high volumes of cheaper, readily available materials such as aggregate, flyash, or other industrial waste and is therefore low strength. Quality Assurance includes coring in mitigated areas to confirm the presence of the grout. Coring is not feasible for low cement content pastes. Test holes should be drilled and pressure tested with water or grout. Closed Circuit Television (CCTV) inspection of treated area shows good results. Grouting methods will not completely fill all the voids.<br><h2>SHRP2 Applications:</h2><ul> <li>Embankments Over Unstable Soils</li> <li>Roadway and Embankment Widening</li></ul><h2>Example Successful Applications:</h2><ul> <li>Mine Subsidence Control Using Foundation Grouting – PA</li> <li>Limestone Cavities Filled at the Southeast Paper Manufacturing – Dublin, GA</li> <li>Industrial Plant Site – Lakeland, FL</li></ul><h2>Complementary Technologies:</h2><ul> <li>Compaction Grouting</li></ul><h2>Alternate Technologies:</h2>Piles, drilled shafts, compaction grouting, jet grouting, curtain grouting, deep foundations, excavation and replacement, implosion of mine voids through use of explosives, and deep dynamic compaction.<br><h2>Potential Disadvantages:</h2><ul> <li>When filling all voids with grout, the technology can become cost prohibitive.</li> <li>Little control where the grout goes.</li> <li>Difficulty obtaining sufficient knowledge of cavity’s position, shape, and infilling.</li> <li>Cannot provide consistent reliable support in common karst conditions.</li></ul><h2>Key References for this technology:</h2>Bruce, D.A, Littlejohn, G.S. and Naudts, A.M. (1997). “Grouting Materials for Ground Treatment: A Practitioner’s Guide.” ASCE Geotechnical Special Publication No.66: Grouting: Compaction, Remediation and Testing, 306-334.</p><p>Elias, V., Welsh, J., Warren, J. and Lukas, R. (2001). “Ground Improvement Technical Summaries.” Volume II. Federal Highway Administration Publication No. FHWA-SA-98-086R.</p><p>Warner, J. (2004). Practical Handbook of Grouting: Soil, Rock, and Structures. Hoboken, New Jersey: John Wiley</p></p>