No materials are involved.
A. 
Excavation shall not be carried below the required level except where unstable soil is encountered. Whenever excavation has been made below the required level, it shall be replaced with three-fourths-inch crushed stone and shall be thoroughly tamped. The engineer shall determine the depth of removal of unstable soil encountered.
B. 
Excavation for manholes and other structures shall have a twelve-inch minimum clearance and twenty-four-inch maximum clearance on all sides. The width of trenches for pipe shall equal pipe outside diameter plus two feet unless otherwise approved by the engineer. Rocks and boulders present in excavation shall be removed within six inches of pipe. Excavations shall be confined within the narrowest possible level and made as nearly as possible in a vertical line, and any sheathing, shoring, bracing and timbering which is necessary to obtain this result shall be done as hereinafter specified. Preliminary excavation shall be made only to a depth of three inches above the final depth of any trench or other excavations. The remaining depth shall be carefully excavated, shaped, and formed with hand tools immediately preceding laying of pipe or placing concrete. Trench bottoms shall be accurately formed to receive and support the bottom of the barrel of the pipe. Additional excavation shall be made in pipe trenches at the pipe joints and to prevent any possibility of a pipe resting on the bell rather than the barrel.
Ground adjacent to the excavations shall be graded to prevent water from running in. The contractor shall remove any water accumulating in excavations by pumping or other suitable means.
The contractor shall do all bracing, shoring and sheeting necessary to prevent failure of the banks of the excavation and to protect the work, workmen, public, under and aboveground utilities and structures, pavements, and public and private property. No bracing, shoring or sheeting shall be placed below the bottom of the pipe or structure unless approved by the engineer. Shoring, sheeting and bracing of any kind shall be withdrawn as the backfilling proceeds, except that the engineer may require such bracing to be left in place if it has been placed below the bottom of any structure or pipe, or if he deems it necessary in order to protect adjacent structures, utilities or property.
The contractor shall provide, install and operate an adequate wellpoint system for dewatering when necessary to stabilize trench bottoms and banks or other excavations or when necessary to protect the work, workmen, public, under and above ground utilities and structures, pavements, and public and private property. The well-point system or portions thereof shall be removed by the contractor, upon the completion of backfill, and the holes remaining from the points shall be backfilled and thoroughly tamped.
After the structure has been completed, inspected and approved, or, in the case of pipe, after each joint has been made, inspected and approved, backfill shall proceed immediately. When the pipe has been laid, this shall be done in six-inch layers of loose granular material free from stones, each layer thoroughly tamped, to a height of 24 inches above the outside top of pipe. The remainder of the trench and the entire excavation for all structures other than pipe shall be backfilled in twelve-inch layers, loose measure, each layer thoroughly tamped. Dampening of the material to be tamped may be required by the engineer.
Compaction shall conform to Article 2.7.3 of the New Jersey State Highway Department Standard Specifications, except that puddling will not be permitted.