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. ; <br /> , � ' i <br /> - ' i <br /> Dr. Michael Caselnova's Office 3 j <br /> Geohazards Project No. 2008674 ; <br /> December 9,2008 ; <br /> j <br /> 7.0 PRESSURE GROUTING PROCEDURE � <br /> Pipe Installation i <br /> Grout pipes shall be installed to a depth sufficient to encounter bearing limestone or other bearing i <br /> material(e.g., dense sand), approximately 65 feet on average below the ground surface. If this ' <br /> estimated average depth is exceeded by more than 15 feet,the drilling procedure shall cease and the � <br />� Geotechnical Engineer notified. Drilling may continue at the Geotechnical Engineer's discretion. � <br /> The Contractor may rotary drill or drive the injection pipes to the refusal depth. However,the i <br /> method of installation shall ensure a good seal between the pipe and the surrounding soil. The i <br /> installation method may be modified subject to the Geotechnical Engineer or his or her <br /> representative's approval if grout seeps up around the outside of the pipe during injection. � <br /> � <br /> Grout Injection ' <br />' Following satisfactory installation of an injection pipe, grouting operations may begin. During the � <br /> grouting operation the injection pipes sha11 be incrementally raised to inject the entire zone between � <br /> depths of approximately 65 feet and 10 feet below the ground surface. If feasible,the sequence of � <br /> outin should be erformed at alternatin locations to a11ow sufficient time for the mix to set <br /> �' g P g <br />�, <br />� prior to drilling and grouting adjacent points. The rate of pumping shall not exceed twelve cubic � <br />� feet per minute. The pumping pressure at the top of the casing is planned to be in the range of 200 � <br />, to 300 psi or as required by the Geotechnical Engineer or his or her representative. � <br /> Unless otherwise directed by the Geotechnical Engineer or his or her representative, pumping sha11 I <br />� cease for at least a 24-hour period if a 1-foot zone takes 20 or more cubic yards of grout at a slump : <br /> of 4 inches. If this excessive pumping occurs,the grout pipe shall be raised and flushed to prevent i I <br /> the pipe from being cemented in place. Pumping can then proceed at another grout pipe location. I , <br />' Pumping may resume at the excessive grout pipe location and depth after a period of 24 hours has I � <br />, passed. The slump maybe reduced fiu-ther to 2 inches if a grout point fails to produce resistant � <br />' pressure during the pumping operation. Once a resistance pressure of 250—300 psi is reached,the I <br /> slump may be increased to not more than 6 inches to improve migration of the grout into the soil in , <br /> order to compact loose zones adjacent to the pipe. I <br /> { <br /> i <br /> Grouring procedures should be terminated once the grout point is filled to within 6-10 feet of the ( <br /> surface in order to minimize collateral damage to the structure. { <br /> Contractor Submittals � <br /> I <br /> Methods of the work: � <br /> a. Grout pipe installation procedures <br /> b. Proposed grout pipe locations, depths,and intervals � <br /> c. Increments of depth for installation of grout � <br /> d. Maximum grout quantities at each increment of depth f <br /> e. Grout pressures at depths i <br /> f. Equipment to be used in the work , <br /> g. List of vendors and suppliers ! <br /> h. Daily records � <br /> i. Grout mix design, design slump and tolerances <br /> I <br /> i <br /> � <br /> I <br /> � <br />