Barrier Technologies for Environmental Management Summary of a Workshop (1997) / Chapter Skim
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A Field Test of Permeation Grouting in Heterogeneous Soils Using a New Generation of Barrier Liquids
A Field Test of Permeation Grouting in Heterogeneous Soils Using a New Generation of Barrier Liquids
Pages 150-161
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From page 150... ...
Pruess, Earth Sciences Division, Lawrence Berkeley National Laboratory ABSTRACT A field demonstration of permeation grouting was conducted at a gravel quarry near Los Banos, California, with the purpose of demonstrating the feasibility of the concept. Two grouts were used: a form of colloidal silica that gels after the addition of a gelling agent, and a polysiloxane that polymerizes after the addition of a catalyst.
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From page 151... ...
Furthermore, hydraulic conductivities could be reduced to 10-~° cm/s after a single injection. In collaboration with the manufacturers, new CS and PSX formulations were developed to meet battier fluid requirements (the CS formulation selected being unaffected by the soil chemistry, and the new PSX formulation having an initial viscosity low enough to allow injection using existing equipment)
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From page 152... ...
regulations for the first-level field test was obtained, due to the environmentally benign nature of the barrier fluids. In preparation for the field test, LBNE staff developed a design package for the application of the barrier fluid- technology using TOUGH2_, completed a preliminary evaluation of geophysical techniques for monitoring barrier performance and emplacement, identified a local site in California with a subsurface geology similar to that at Hanford, and obtained permission from the owner and the regulators to conduct the first-level test at that site.
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From page 153... ...
Following well completion, all the wells were fitted with appropriate tubing, and probes were punched through the bottom of the wells for air permeability measurements. Air permeability measurements included static single point permeameter tests using constant head air Injection tests, and a new dual probe dynamic pressure technique developed at LBNL for measurement of air permeability between wells (Garbesi, 19941.
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From page 154... ...
For all but two wells, the values ranged from 5.6 x 10-ti to 8.1 x 10-~ m2. Injections into holes API, CS1, and CS2 using the new dual probe dynamic pressure technique, yielded inter-hole permeabilities between 3.510-9 m2 and 1 10-i ~ m2.
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From page 155... ...
Both CS and PSX-10 had gelled/crosslinked in the subsurface satisfactonly. Despite the extreme soil heterogeneity, both the CS and the PSX-10 created fairly uniform plumes, indicating that the potential problem of flow along preferential pathways of high permeability (such as a gravel bed overlying a tight silty or clayey zone)
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From page 156... ...
D-138 BARRIER TECHNOLOGIES FOR ENVIRONMENTAL MANAGEMENT FIGURE 2 Excavated portion of the CS grouted soil. PSX-10 was singularly successful in grouting the extremely heterogeneous subsurface at the site.
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From page 157... ...
Unlike CS, PSX-10 imparted structural strength and elasticity to the grouted soil volume, and gave sufficient strength to incoherent gravels to permit vertical walls to stand. It ideally penetrated clean sands, which resisted disaggregation due to its considerable elasticity.
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From page 158... ...
Samples prepared in this manner represent the lower limit of permeability that could be achieved by injection in the field. The permeabilities of the grouted sand samples were measured using a Wykeham-Farrance flexible wall permeameter (Humboldt Equipment, Durham, North Carolina)
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From page 159... ...
Hydraulic Conductivity Measurements on Laboratory and Field Samples of Grouted Sand ~ Sal Iple~ Hydraulic ~ CellBias Sample Sample lope Icings Gradient Possum ~ (at.)
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From page 160... ...
Such side-flow effects are expected to be far more pronounced in the cored or carved field samples. In the case of field-grouted sand and pebbles, the observed hydraulic conductivities reflect incomplete saturation of the pore space.
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From page 161... ...
Vasco, and to members of the LBNL Geophysical Measurements Facility team (~m Dougherty, Ray Solbau, Phil Rizzo, and Don Lippert) for the planning, preparation, support, and flawless execution of the field test.
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