Laserfiche WebLink
7. Maintain boring and jacking equipment in proper working order during entire duration <br />of boring and jacking work <br />D. Tolerances <br />1. Use extreme care to hold casing pipe to precise line and grade <br />2. Final position of casing pipe may only vary I inch in 40 feet, laterally or vertically <br />3. Any variation shall be regular an in only one direction <br />4. If any casing is shown to be constructed on a slope, the final grade of the casing pipe <br />flow line must be in the direction shown on the Drawings <br />E. Jacking and Auger Boring <br />1. Casing pipe hole shall be mechanically bored through soil by a cutting head on a <br />continuous auger inside of casing pipe. Excavated material shall be removed through <br />the casing pipe. The casing pipe shall be forced through the soil with hydraulic jacks. <br />Jetting will not be permitted. <br />2. Boring and jacking operations shall'be done simultaneously. After boring and jacking <br />is started, boring and jacking work shall proceed without interruption, In so far as <br />practical, until casing pipe is in final position. <br />3. Auger shall be proper diameter, configuration, and operating speed to remove <br />excavated material at rate appropriate to casing size and jacking rate. During boring <br />and jacking operations, exercise particular care to avoid over - excavation and to assure <br />the full circumference of casing pipe is bearing on surrounding soil. Auger shall <br />extend a minimum distance beyond end of casing pipe to preclude formation of voids <br />outside casing pipe. Do not allow auger to advance more than one foot ahead of <br />casing pipe. When material tends to cave in from outside of casing, the auger advance <br />shall be reduced or the auger shall be retracted into the casing, as required to control <br />formation of voids. <br />4. Use Bentonite slurry, as specified in this Section, during jacking to fill any void <br />between casing pipe and soil. Over - excavation in excess of I inch shall be pressure <br />grouted the entire length of casing pipe. <br />5. As casing pipe jacking proceeds, each additional section of casing pipe shall be full - <br />ring welded to preceding length of casing. Weld joints shall be equal in strength to <br />pipe. WeId joints shall be water tight. <br />6. Adequately protect casing pipe so that pipe is not crushed or otherwise damaged under <br />jacking pressures. Casing pipe strength and thickness specified is based on <br />superimposed loads and not upon stresses resulting from boring and jacking <br />operations. Any increase in casing strength or thickness required to withstand boring <br />or jacking operations shall be the responsibility of the Contractor. Provide backstops <br />that adequately distribute jacking thrust without causing deformation of soil or other <br />damage. Should the casing pipe be damaged replace damaged section as follows, at <br />no additional cost to Owner: <br />a. If damaged portion of casing is exposed in jacking pit, cut and remove damaged <br />portion of casing. Weld a new section of casing in place to replace damaged <br />section. <br />b. If damaged portion of casing is not accessible, abandon casing pipe in place. Fill <br />abandoned casing with Portland cement grout. Perform additional work as <br />required to install a replacement casing. Maintain jacking pit, receiving pit, and <br />casing pipe in a clean and orderly condition. Do not allow excavated material, <br />debris, slurry waste, or unused materials, equipment, or tools to accumulate or <br />33 05 23.16 - 5 <br />