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In acoarse-textured or rocky soil, it may be difficult to make a <br />suitable slurry from the existing soil. A slurry can be made using <br />silica flour, which is then used to establish good contact between <br />the ceramic cup and the soil. Fora 2-inch diameter hole, 1 lb. of <br />silica flour is needed, while a 4-inch diameter hole will require 4 <br />lbs. of silica. Mix the silica with water to produce a slurry with a <br />consistency of cement mortar. <br />Core the hole to the desired depth, and pour in about 1/4 of the <br />silica slurry. Insert the Soil Water Sampler and pour in the re- <br />mainder of the slurry so that the slurry completely covers the ce- <br />ramic cup. Backfill the hole with sifted soil (free of pebbles and <br />rocks), tamping continuously with a metal rod to prevent surface <br />water from channeling down between the soil and the body tube of <br />the Sampler (see Figure 8). <br />Access Tubes <br />`/ Tampetl Soil <br />Depth Siked <br />As Requiretl Backfill <br />200 Mesh Silica <br />Flour Slurry <br />Rigure 8. <br />To ensure that disturbed soil resulting from the installation of the <br />Sampler does not affect the movement of water to the Sampler, <br />Bentonite clay plugs can be installed. Core the hole a few inches <br />deeper than the desired depth, and pour in several inches of wet <br />Bentonite clay (see Fig. 9). This will isolate the Sampler from the <br />soil below. Pour in 1/4 of the slurry, either of soil or of Silica, and <br />insert the Soil Water Sampler. Pour the remainder of the slurry <br />around the cup of the Soil Water Sampler. Backfill with native soil <br />to a level just above the Soil Water Sampler and again add suffi- <br />cient Bentonite as a plug to further isolate the Soil Water Sampler <br />and guard against possible channeling of water down the hole. <br />Backfill the remainder of the hole slowly, tamping continuously <br />with a metal rod using native soil, free of pebbles and rocks. <br />SOILMOISTURE EQUIPMENT CORP. 12 ^" <br />P.O. Box 30025, Sonto Borboro. ColiFornio 93105 USA <br />Phone: 18051 964-3525 ~ Fox: (805) 683-2189 SOILMOISTURE <br />e-moil: solesQsoilmoislure.<om • Web: http://wwwsoilmoisture.<om <br />