Micro Piles  |  Pressure Grouting  |  Rock Anchors  |  Permeation Grouting   |  Micropile
Soil Nailing  |  Compaction Grouting  |  Micropiles  |  Chemical Grouting   |  Soil Nail Wall

    SECTION 02300

    TUNNELING

   PART 1 - GENERAL

   1.1 SUMMARY

    A. This item shall include furnishing and installing 48 inch diameter tunnel with steel liner plates at three locations as indicated on the contract drawings and specified herein. Each tunnel is under the Nashville and Eastern Railroad.

   1.2 RELATED SECTIONS

    A. Section 02730: Sanitary Sewerage System

   1.3 UNIT PRICES

    A. Measurement for payment shall be by the linear foot as named in the Contact Documents. The quantity to be paid shall be the actual number of linear feet from face of tunnel to face of tunnel. The sewer carrier pipe to be installed inside the tunnel shall be included for payment under this item. The tunnel costs shall include the liner plates installed in place complete with all appurtenances including grouting, bulkheads, sandfill, unclassified excavation carrier pipe, strapping and all other items required to complete the tunnel.

   1.4 REFERENCE STANDARDS

    A. The sanitary sewer which is to be constructed by the tunnel method shall meet all the requirements of AREA specifications, Part 1, Chapter 4, Articles 4.17 and 4.18.

   1.5 SUBMITTALS

    A. The Contractor shall submit details of the lining for approval.

   1.6 PRODUCTS DELIVERY, STORAGE AND HANDLING

    A. Materials delivered to site shall be inspected for damage, unloaded and stored with the minimum of handling. Store materials on site in enclosures or under protective coverings. Store plastic piping and rubber gaskets under cover and protect from exposure to direct sunlight. Store materials above ground. Steel plates, nuts, bolts, and straps shall be kept free of dirt, debris and moisture.

    B. If the galvanized coating or the bituminous coating on any plate is damaged upon arrival field measures should be taken to prevent damage to the integrity of the plates. The areas shall be cleaned of any rust deposits and touched-up with a bituminous coating.

   1.7 PROVISION TO CONTRACTOR

    All working operations of the contractor and/or its subcontractor, must be subordinate to the free and unobstructed use of the track for the passage of traffic without delay or danger to life, equipment, or property. The contractor shall conduct its operations in such a manner that all work will be performed below track level and without obstructions on the roadbed. Tunneling shall be conducted on a 24 hour per day basis when working within 25 feet of the centerline of any track unless otherwise approved by Engineer. If work is stopped for any reason, the exposed face of excavation shall be fully protected with a bulkhead satisfactory to Engineer.

   PART 2 PRODUCTS

   2.1 GENERAL

    All materials shall be furnished by an established and reputable manufacturer or supplier. All materials shall be new and first class ingredients and construction, designed and guaranteed to perform the service required.

   2.2 MATERIAL

    A. Steel Plates

    1. The steel plates shall be galvanized, two flanged or four flanged steel plates 18 inches wide, each circumferential ring shall be composed of the number and length of plates to complete the required diameter. The minimum allowable plate thickness shall be 0.0746 inch for two-flanged plates and 0.1793 for four-flanged plates.

    2. Plates shall be punched for bolting on both longitudinal and circumferential seams or joints and shall be fabricated to permit complete erection from the inside of tunnel. The longitudinal seam shall have staggered bolt construction, so fabricated as to allow to cross-section of the plate to be continuous through the seam. All plates shall be of uniform fabrication and those intended for one size shall be interchangeable.

    3. After the plates are formed to shape and after all holes are punched, the plates shall be galvanized on all surfaces by the hot-dip process. A coating of prime western spelter, or equal, shall be applied at the rate of not less than two (2) ounces or more per square foot of surface in accord with ASTM A123-78. If the average spelter coating as determined from the required samples is less than the amount specified above, or if any one specimen shows a deficiency of 0.2 ounce, the lot shall be rejected. Spelter coating shall be of first-class commercial quality free from injurious defects such as blisters, flux and uncoated spots.

    All nuts and bolts shall be galvanized or sherardized.

    4. Plates shall be fabricated with grout holes to facilitate grouting above and around the tunnel liner. These grout openings shall be 2-inch I.P.T. half-couplings welded into a hole in the center corrugation of a plate and a galvanized C.I. plug shall be provided for each opening to permit tight closure after grout is pumped. All rings are to be provided with grout holes so that the spacing of holes will be on a maximum of 18-inch centers at the top of the tunnel and at the top quarter points, staggered with the holes at the top.

    When installing liner plate by the tunneling method, the excavation shall be performed in such a manner that voids between the undisturbed earth and the liner plate shall be maintained at a minimum. Any void occurring shall be filled with a Portland cement and sand grout pumped under pressure through grouting openings in the liner plate.

    5. Coating

    a. Tunnel liner plates shall be bituminous shop coated that meets the requirements of AASHTO Specifications M-190.

    b. Alternate:

    Field coating material shall be asphalt mastic, Trumbull 5X, or approved equal, and shall be applied with hydraulic spray equipment using a minimum of 2,400 pounds pressure at the nozzle tip. The material shall be supplied at spraying consistency and shall be applied both to the outside and inside of the liner plates.

    B. Grout

    1. The grout shall consist of Portland cement, water, sand and 2% approved additive (Bentorite, Septamine, Seaex, Hydrocide Liquid, etc.). One part Portland cement with additive shall be combined to four parts clean sand and sufficient water added to provide a grout having the consistency of thick cream when will mixed.

    C. Carrier Pipe (Refer to Section 02730 of these Specifications)

   PART 3 - EXECUTION

   3.1 INSTALLATION

    A. Excavation

    Excavation shall be unclassified and no distinction shall be made between rock and other materials excavated. The cost of excavation shall be merged in the unit price per linear foot of the tunnel. Blasting for the tunnel is acceptable only with expressed written approval by the Nashville and Eastern Railroad.

    Construction of the tunnel shall be carried on in such a manner that settlement of the ground surface above the tunnel shall be held to an absolute minimum. Where ground conditions are unstable, poling plates or poling boards shall be used to prevent caving of material above the tunnel before the liner plates can be installed. Steel liner plates shall be installed as soon after the excavation is removed as possible and excavation shall not be removed more than 24 inches ahead of the installed liner plates. Excavation shall be carried on in such a manner that voids behind the liner plates will be held to a minimum. However, should any boulders larger than one foot (1') in diameter be encountered, they shall be removed so that none are closer than 6 inches to the outer face of the liner plate.

    Where boulders are excavated below the invert of tunnel liner plates, the holes shall be backfilled with crushed stone as specified in Article 2.1, Section 02223 under crushed stone refill for sanitary sewers.

    When installing liner plate by the tunneling method, the excavation shall be performed in such a manner that voids between the undisturbed earth and the liner plate shall be maintained at a minimum. Any void occurring shall be filled with a Portland cement and sand grout pumped under pressure through grouting openings in the liner plate.

    B. Grouting of Voids

    The minimum provision for grouting openings shall be one (1) opening in a top plate of the tunnel at locations not to exceed 54 inches apart. Additional plates with grouting openings are to be installed at the top quarter points on each side between the top openings. The opening shall be staggered but shall not exceed 54 inches in any one line. Grout vent pipes will be required at a minimum of one per monolithic pour.

    A pump shall be provided for placing the grout which shall be capable of exerting sufficient pressure to assure the filling of all voids between liner plate and the undisturbed ground. Minimum acceptable pressure will be five (5) pounds per square inch.

    Pumping of grout shall be done (1) at the completion of the installation of approximately each 9 feet of liner plate, (2) at more frequent intervals than 9 feet if conditions indicate the necessity, and (3) at the end of a work shift or the stopping of work for any reason.

    C. Carrier Pipe

    1. The carrier pipe shall be of the size and materials specified in Section 02730 and as shown on the Contract Drawings.

    2. The carrier pipe shall be adequately strapped to the tunnel flanges behind each bell with 2" x 1/4" stainless steel strips.

    3. Sand shall be blown into the tunnel to fill the void between the inside wall of the tunnel and the outside edge of the carrier pipe to a depth of not less than two-thirds (2/3) of the outside diameter of the carrier pipe. Care shall be exercised to not completely fill the tunnel to prevent the external loads from being transmitted to the carrier pipe.

    4. Concrete or brick bulkheads will be placed at each end of the tunnel as shown on the Contract Drawings.

    D. Markers

    The Contractor shall provide markers at each railroad crossing as approved by the Engineer and the Nashville and Eastern Railroad.

   3.2 TESTING

    A. Test the carrier pipe according to the testing requirements set forth in Section 02730 of these Specifications.

    END OF SECTION