COMPACTION GROUTING

The authors in closing the discussion of this paper state that a distinction should be drawn between compaction grouting and other techniques, and the basic principle of compaction grouting is set forth. Theoretically if the work is performed thoroughly, and if settlement is the only problem, there should be no later movement in areas treated except in those cases where the settlement is taking place in the top 4 ft or 5 ft or immediately ajacent to a slope. This presumes a grid spacing of 10 ft. It is emphasized that depth of grouting must be sufficient to reach competent material. Observations are made related to the discusser's comments regarding pressures required to give uplift. It is significant that the geometry of the mass pushed is similar to the mass pulled up by pull-anchor tests. The calculated pressures give an "order of magnitude" and precise values should not be expected. It is emphasized that lift is dependent on the volume of grout pumped as well as the pressure, both of which are influenced by injection rate. In practice, grout is usually not injected at a point but rather for a stage of several feet. The area of uplift is smaller and the pressure is lower than indicated by the discusser. The latter phenomenon is probably due to the lesser volume being lifted and the tendency of soil to be weaker in horizontal layers so that grout expands into these giving a greater maximum or effective diameter than the calculated average. The rate of pumping probably also has an effect. In actual practice analysis will nearly always be hampered by the non- uniformity of the soil.

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  • Accession Number: 00080835
  • Record Type: Publication
  • Report/Paper Numbers: Proc. Paper 10973
  • Files: TRIS
  • Created Date: Mar 6 1975 12:00AM