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4b f r' 1.3.3 The Contractor is required to bring to the attention of the Engineer any known design discrepancies with actual tunneling methods that the Contractor will be performing. This shall be stated in writing to the Engineer no later than the pre -construction meeting.. 1.3.4 Provide shop drawing submittal and sample of pipe, fused joint, and trace wire. PART 2 — EXECUTION 2.1 INSTALLATION 2.1.1 installation shall be in a trenchless manner producing continuous bores. 2.1.2 The turmeling system shall be remotely steerable and permit electronic monitoring of tunnel depth and location. Accurate placement of pipe within a ± 2 -inch window is required both horizontally and vertically. Turning capability of a 90 -degree radius in 40 feet is required. Continuous monitoring of the boring head is required, including across open water if necessary. 2.1.3 The directional boring Contractor shall submit certification, by a Professional Engineer or Professional Land Surveyor licensed in the State of Florida, that the directional boring has been performed in accordance to the construction drawings, and shall provide signed and sealed record drawings. Record Drawings (As -built) shall be provided both in electronic format and hard paper copy. 2.1.4 Tunneling shall be performed by a fluid cutting process (high pressure -low volume) utilizing liquid clay, i.e. bentonite. The clay lining will maintain tunnel stability and provide lubrication in order to reduce frictional drag while the pipe is being installed. In addition, the clay fluid must be totally inert and contain no environmental risk. The Contractor must also have a mobile vacuum spoils recovery vehicle on-site to remove L the drilling spoils from the access pits. The spoils must then be transported from the job site and be properly disposed of off the site. Under no circumstances shall the drilling i spoil be permitted to be disposed of into sanitary, storm, or other public or private r drainage systems. Spoils may be transgrted to the County's Solid wasrc Facilgy an the cost of disposal shall bg h f { 2.1.5 Liquid clay type colloidal drilling fluid shall consist of at least 10 percent of high-grade carefully processed bentonite to consolidate cuttings of the soil, to seal the walls of the hole, and to fumish lubrication for subsequent removal of cuttings. The slurry, which is t heavier than the surrounding material, is high in colloids of the bentonite type and it will deposit a thin filter cake of low permeability material on the walls of the bore. This will allow only a small amount of the fluid to pass into the surrounding soil and will also stabilize the bore. The colloidal content of the Fluid Imparts excellent lubricating qualities to the slurry, which Is a distinct aid to the removal or the soil cuttings. 2.1.6 Pneumatic or water -jetting methods will be considered unacceptable due to the possibility of surface subsidence. � r 02320-2 ttonsonut Urrum vil Untten= C lnem�llrr�r� t'YM11Y1tYeN[i - katrl�t'Sr,er Ixr„�nie•rem irlf:4 • IbneeM+I t►wceerrrr IMIW Ar>R