A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Compaction Grouting in Karst Terrain (A Test Program)
There are inherent risks associated with site development in karst terrain including: 1) highly variable rock conditions over short lateral distances, 2) solution cavities and voids resulting in acute or gradual subsidence problems, and 3) weak soil conditions characterized by decreasing soil strength with increasing depth. Disclosure of all subsurface features and conditions is not possible regardless of the extent of the subsurface exploration. Several ground improvement techniques can provide attractively priced alternatives to deep foundation systems and reduce the risks associated with construction in karst terrain. One such ground improvement method is Compaction Grouting. Compaction Grouting can economically reduce the risks of sinkhole development while improving the strength of weak soils. This paper presents a comparative field test study to evaluate the effectiveness of different Compaction Grouting techniques at shallow depths in karst terrain. Two specialty contractors donated the man-hours, materials, and equipment to conduct the field test. Each contractor was asked to inject their preferred low slump, low mobility, compaction grout. The grout was injected at rates of 0.043 meter3 per minute (1.5 cubic feet per minute), and 0.85 m3/min (3.0 cfm). A trench was excavated in the middle of the grid pattern and the diameter of the exposed grout columns was measured (in the exposed plane) at the top, middle, and bottom. The maximum distance the grout traveled from the point of injection was also measured. The typical volume injected was 0.47 m3 per linear meter (5 cf/lf), which equates to a 76 cm (30") diameter assuming a cylindrical shape. The ideal distance for grout travel from the injection point is 38 cm (15 inches), assuming 0.47 m3/m (5 cf/lf) injected and a cylindrical shape. The average distance the grout traveled from the point of injection was 104 cm (41 inches) and 53 cm (20.9 inches) for the S and D grout, respectively. The effectiveness of the grouting was evaluated and indicated that grout rheology has a profound impact on the grout mobility and resultant soil improvement. The mixture with a higher percentage of fines traveled farther from the point of injection, and in some cases, the grout was observed significant distances from the point of treatment. This is potentially problematic in areas where isolated, controlled, or targeted treatment zones are required.
Compaction Grouting in Karst Terrain (A Test Program)
There are inherent risks associated with site development in karst terrain including: 1) highly variable rock conditions over short lateral distances, 2) solution cavities and voids resulting in acute or gradual subsidence problems, and 3) weak soil conditions characterized by decreasing soil strength with increasing depth. Disclosure of all subsurface features and conditions is not possible regardless of the extent of the subsurface exploration. Several ground improvement techniques can provide attractively priced alternatives to deep foundation systems and reduce the risks associated with construction in karst terrain. One such ground improvement method is Compaction Grouting. Compaction Grouting can economically reduce the risks of sinkhole development while improving the strength of weak soils. This paper presents a comparative field test study to evaluate the effectiveness of different Compaction Grouting techniques at shallow depths in karst terrain. Two specialty contractors donated the man-hours, materials, and equipment to conduct the field test. Each contractor was asked to inject their preferred low slump, low mobility, compaction grout. The grout was injected at rates of 0.043 meter3 per minute (1.5 cubic feet per minute), and 0.85 m3/min (3.0 cfm). A trench was excavated in the middle of the grid pattern and the diameter of the exposed grout columns was measured (in the exposed plane) at the top, middle, and bottom. The maximum distance the grout traveled from the point of injection was also measured. The typical volume injected was 0.47 m3 per linear meter (5 cf/lf), which equates to a 76 cm (30") diameter assuming a cylindrical shape. The ideal distance for grout travel from the injection point is 38 cm (15 inches), assuming 0.47 m3/m (5 cf/lf) injected and a cylindrical shape. The average distance the grout traveled from the point of injection was 104 cm (41 inches) and 53 cm (20.9 inches) for the S and D grout, respectively. The effectiveness of the grouting was evaluated and indicated that grout rheology has a profound impact on the grout mobility and resultant soil improvement. The mixture with a higher percentage of fines traveled farther from the point of injection, and in some cases, the grout was observed significant distances from the point of treatment. This is potentially problematic in areas where isolated, controlled, or targeted treatment zones are required.
Compaction Grouting in Karst Terrain (A Test Program)
Miluski, Michael J. (author) / Bonita, Giovanni (author)
Proceedings of the Fourth International Conference on Grouting and Deep Mixing ; 2012 ; New Orleans, Louisiana, United States
Grouting and Deep Mixing 2012 ; 1612-1625
2012-08-17
Conference paper
Electronic Resource
English
Grouting , Highways and roads , Chemical grouting , Anchors , Cement , Compaction grouting , Cutoffs , Piles , Mixing , Risk management , Karst , Foundations , Hydraulic structures
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