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hours to allow the grout to harden. Once 72 hours have passed,the <br /> remaining annulus can be grouted to the ground surface in one continuous <br /> operation. <br /> Grout injection shall be in accordance with ASTM D 5092. The tremie <br /> pipe shall be thoroughly cleaned with high pressure hot water/steam <br /> before use in each well. The bottom of the tremie pipe shall be <br /> constructed to direct the discharge to the sides rather than downward. The <br /> discharge end of the tremie pipe shall be submerged at all times. <br /> Additional grout shall be added from the surface to maintain the level of <br /> the grout at the land surface as settlement occurs. Work shall not be <br /> conducted in the well within 48 hours after completion of grouting. The <br /> Contractor shall visit the well 48 hours after the final grouting to inspect <br /> for grout settlement. If settlement is observed, additional grout shall be <br /> added to the annulus. Repeat process until no further settlement is <br /> observed and the top of the grout is flush with surrounding grade. <br /> 3.03.8 Protective Housing and Cow Barrier Placement <br /> A. Monitoring wells shall have a steel lockable protective housing set in the <br /> annular seal over the well casing. Keyed-alike locks shall be provided on <br /> the protective covers for all wells. A protective steel housing shall be <br /> installed around the well casingtriser pipe by placing the protective <br /> housing into the annular seal. The protective housing shall be cleaned <br /> with high-pressure hot water/steam prior to installation to ensure that it is <br /> free of any contamination. The protective housing diameter shall be at <br /> least 4 inches greater than the nominal diameter of the well riser. The <br /> protective casing shall be fitted with a locking cap and installed so that <br /> there is a maximum 0.2 foot clearance between the top of the in-place <br /> inner well casing cap and the bottom of the protective housing locking cap <br /> when in the locked position. The protective housing shall be positioned <br /> and maintained in a plumb position. The bottom of the protective housing <br /> shall extend a minimum of 2 feet below the top of the ground surface; and <br /> shall be anchored into the cement grout annular seal. Coarse sand or pea <br /> gravel shall be placed in the annular space between the protective casing <br /> and the riser pipe, above the drain hole,to within 2 feet from the top of the <br /> riser pipe. <br /> B. Install Cow Barrier as shown in the drawings. <br /> 3.03.9 Well Identification <br /> A. A corrosion resistant metal tag shall be affixed to the exterior and interior <br /> of the protective cover. The metal tag shall be stamped with the well <br /> Foothill Landfill Site Improvement Project 8 GROUNDWATER MONITORING WELLS <br /> San Joaquin County Public Works Section 02522 <br />