A. 
Excavation and backfill shall consist of the excavation and removal of all materials, including earth, boulders, concrete masonry, small structures, curbs, sidewalks, pavement, driveways and all other materials encountered of whatsoever nature necessary for the installation and construction of all structures and pipe. This item shall also include the disposal of excess backfill, the backfilling of a trench and the backfilling of materials in accordance with the grades as shown on the plans. Also, this item shall include all sheeting, bracing and dewatering necessary for the proper support of the sides of all trenches and excavations.
B. 
Excavation in a trench shall be made to the lines, grades and forms shown on the approved plans. In general, the earth shall not be plowed, scraped or dug by machinery so near to the finished subgrade so as to result in disturbance of the material below said subgrade, but the last of the material to be excavated shall be removed with pick and shovel just before the placement of the pipe.
Prior to any excavation, the contractor shall locate all water services, gas services, gas mains and water mains within 15 feet of the proposed work area. The location of utilities mentioned herein shall be performed prior to the commencement of any excavation.
A. 
The trench shall be dug so that all pipes and appurtenances as specified, where indicated on the plans, can be laid to the alignment and depth required. No trench shall be excavated more than 50 linear feet in advance of pipe laying unless authorized. The trench shall be so braced and drained that the workmen may work therein safely and efficiently. It is essential that the discharge of the trench dewatering pumps be conducted to natural drainage channels or drains.
B. 
The width of the trench shall be ample to permit the pipe to be laid and jointed properly and the backfill to be placed and compacted properly. Bell and coupling holes shall be provided at each joint to permit the jointing to be made properly.
C. 
Ledge rock, boulders and large stones shall be removed to provide a clearance of at least six inches below and on each side of all pipes.
D. 
The trench shall be excavated to the depth required so as to provide a uniform and continuous bearing and support for the pipe on solid and undisturbed ground at every point between bell and coupling holes. Any part of the bottom of the trench excavated below the specified grade shall be corrected with approved material, thoroughly compacted. The finished subgrade shall be prepared accurately by means of hand tools. In no case will blocking or wedging of the pipe be permitted.
A. 
In excavating, the contractor shall excavate his trench to the minimum width feasible.
B. 
Trenches in which the sewer pipe and all appurtenances are to be constructed shall be excavated in open cut from the surface and in all cases in such manner and to such depths and widths as will give suitable room for building the structure they are to contain. The trench width at the ground surface may vary with and depend upon its depth and the nature of the ground encountered. The sides of the trenches are to be kept as nearly vertical as possible.
C. 
The right is reserved by the Engineer to make changes in drain grades, elevations and locations necessary to overcome conditions and obstacles that may be encountered.
All trench excavation shall be maintained in good condition during construction so as not to hinder or injure any existing pipe lines or other structures adjacent to the proposed trench. All necessary precautions shall be taken to prevent movement of the sides of such excavations. The side slopes shall be such that the material will not cave or slide into the bottom, and any material sliding down at any time before the completion of the work shall be removed by the contractor.
A. 
The contractor shall be responsible for properly supporting the sides of all excavations five feet or more in depth in which employees are required to work, except when the excavation is in firm rock or the slope is not more than 45° with the horizontal or the material being excavated sloped to the angle of repose applying under existing weather conditions. The contractor may use either timber sheet piling, steel sheet piling or a trench shield properly sized and in accordance with the Construction Safety Code, Section II, issued by the State of New Jersey Department of Labor and Industry Bureau of Engineering and Safety, whichever may be required by the Engineer.
B. 
Timber sheeting shall be straight and sound, free from shakes, cracks, large or loose knots and other defects and be of adequate design, type, size and strength. All timber uprights, walers and cross bracing shall be squared to the required dimensions. In placing and driving the sheeting, proper workmanship and equipment shall be used to achieve a true alignment and close contact of the uprights. The contractor shall use only men of seasoned experience and judgment for this type of work. All timber sheeting shall be removed as the trench is refilled in such a manner as to avoid the caving in of the excavation. The void left by the sheeting shall be carefully refilled by ramming or other approved methods. When the sheeting is ordered left in place, the top of the uprights shall be cut off or driven at least 12 inches below the ground surface, unless otherwise directed.
C. 
Steel sheet piles shall be straight, sound and free from any defects which may impair their strength and durability and shall conform to the specifications of the manufacturer. The sizes and lengths of the steel sheet piles shall conform closely to the needs of the work. Walers and cross bracing shall be of adequate design, type, size and strength to properly brace, shore and support all steel-sheeted trench walls. Steel sheeting shall be driven at least three feet in advance of excavation, and, whenever possible, or when surrounding structures may be endangered, the sheeting shall be driven to full penetration before excavating. The contractor shall use a drop hammer or a pneumatic or steam pile driver and shall select a driver that strikes a heavy blow with low velocity at impact and is capable of supplying ample foot-pounds of energy to move the sheeting easily. The piles shall be driven a minimum of 18 inches below the subgrade. All excavations shall be backfilled to the existing surface elevation in accordance with the requirements of the backfilling item in these specifications before the steel sheet piling is withdrawn. The piles shall be withdrawn by a pile extractor, an A-frame or pulling beam or an inverted double-acting hammer.
D. 
Trench shields (protective cages) fabricated of steel plates and structural members may be used where satisfactory to the Engineer and shall be equivalent in strength to the sheeting requirements of the New Jersey Construction Safety Code. No person shall be in the excavation or shield during moving operations of the shield. A ladder shall be provided at the midway point of the shield.
E. 
The toe of slope of any excavated material or surcharge shall not be less than two feet from the outside edge of the sheet piling. Ladders shall provided, extending from the bottom of the excavation to two feet above, in such a manner as to prevent sliding, slipping, caving, squeezing or other movement of the face of the excavation that would endanger persons or structures in and adjacent to the excavation.
In case it is necessary to excavate below the subgrade to secure a good foundation, it shall be done as directed. In case the excavation has been carried below the grade approved, the bottom of the trench shall be filled to the required grade with a material satisfactory to the Engineer.
All excavated and other materials shall be so placed as not to endanger the work and so that free access may be had at any time to all parts of the trench and to all hydrants and gates on pipes in the vicinity and shall be kept neatly piled so as to inconvenience as little as possible public travel. Where required, fences and other structures in the vicinity of the work shall be protected and, if injured, shall be repaired or replaced. All trees in the vicinity of the work shall be protected in a satisfactory manner.
The contractor shall pump out or otherwise remove and dispose of as fast as it may collect any water, sewage or any other liquids which may be found at the site of the work or may accumulate in the excavation, regardless of whether it be water or liquid waste from its own or adjacent areas. Dewatering methods and equipment shall be subject to the approval of the Engineer, and all water removed from the work shall be disposed of in an approved manner without damaging adjacent property or other work. The contractor shall plug the upstream end of the sanitary sewer pipe to prevent entrance of water, silt and mud. The contractor shall, upon completion of laying and jointing pipe, flush out the sewer pipe prior to final inspection.
A. 
All materials used for backfilling shall be free from all perishable and objectionable materials and shall be moistened and well tamped or otherwise thoroughly compacted in such a manner as to prevent aftersettlement.
B. 
No backfilling shall be done by the contractor in any trench or excavation until the pipe or structure is inspected and approved by the Engineer. All backfilling shall be done in a careful manner and with such excavated material and in such order as may be directed by the Engineer.
C. 
If any material is encountered that, in the opinion of the Engineer, is unsuitable for supporting the pipe and/or any appurtenance, the contractor shall excavate the unsuitable material to such a depth until suitable material is encountered or to such a depth as to enable the placing of a broken stone subbase that will support the pipe and/or appurtenance.
D. 
Frozen earth will not be permitted to be used as backfill material. Any rocks or boulders that are encountered in the backfill material shall be placed so as to have adequate spacing between them that will prohibit the formation of voids.
E. 
Backfill shall be placed continuously by hand in layers not exceeding six inches in thickness and carefully and thoroughly consolidated by tamping simultaneously on both sides of the pipe to a height 12 inches above the top of the pipe. This backfilling must be done promptly and before any fill is deposited directly from a machine, bucket, truck or other vehicle. In no case will dumping from a bucket be allowed to fall directly upon a pipe, and, in all cases, the bucket must be lowered so that the shock of falling earth will not injure the pipe or structure.
F. 
All backfill shall be compacted as follows:
(1) 
By approved vibratory soil compactors if the backfill material is predominately sand or sand and gravel but contains more than 12%, by weight, of material that will pass a 200-mesh sieve.
(2) 
By approved vibratory soil compactors or by puddling material being predominately sand or sand and gravel and containing not more than 12%, by weight, of material that will pass a 200-mesh sieve.
(3) 
By approved flat-faced mechanical tampers if the backfill material is not predominately sand or sand and gravel.
G. 
Where mechanical tampers or vibrating soil compactors are used in accordance with the foregoing specifications, the backfill shall be placed and compacted in layers not more than 12 inches thick.
H. 
Where trenches are puddled in accordance with the foregoing provisions, the backfill shall be placed in successive lifts not more than four feet thick, and each lift shall be thoroughly puddled before the next lift is placed.
I. 
Approved flat-faced mechanical tampers may be substituted for vibratory compactors in the preceding subsections, where the use of vibrating compactors is deemed impractical due to bracing, shoring, existing utilities or other special conditions.
J. 
Surplus backfill material or unfit backfill material shall be removed from the site and deposited where directed by the Engineer.
K. 
All backfilling done where sheeting is withdrawn shall be done in a manner as to avoid caving of the trench or excavation. As the sheeting is withdrawn and the bracing removed, special care shall be taken to fill all voids created by the withdrawn sheeting.