1、Section 25 STEEL AND CONCRETE TUNNEL LINERS 25.1 SCOPE These specifications are intended to cover the installa- tion of tunnel liner plates in tunnels constructed by con- ventional tunnel methods. For the purposes of these Spec- ifications, tunnels excavated by full face, heading and bench, or multi
2、ple drift procedures are considered con- ventional methods. Liner plates used with any construc- tion procedure utilizing a full or partial shield, a tunneling machine, or other piece of equipment which will exert a force on the liner plates for the purpose of propelling, steering, or stabilizing th
3、e equipment are considered spe- cial cases and are not covered by these Specifications. 25.2 DESCRIPTION 25.2.1 This work shall consist of furnishing cold-formed steel tunnel liner plates or precast concrete plates con- forming to these specifications and of the sizes and di- mensions required on th
4、e plans, and installing such plates at the locations designated on the plans by the Engineer, and in conformity with the lines and grades established by the Engineer. The completed liner shall consist of a series of liner plates assembled with staggered longitudinal joints. Steel tunnel liner plates
5、 shall preferably be of a type which is commercially available. Precast concrete tunnel liner plates shall be such that their size and shape suits the method and equipment being used to install them. 25.3 MATERIALS AND FABRICATION Liner plates shall be fabricated to fit the cross section of the tunn
6、el. 25.3.1 General Steel liner plates herein described must meet the Sec- tional Properties of thickness, area, and moment of iner- tia shown on the plans. If not shown on the plans, the properties shall be as listed in Division I, Article 16.3. All steel plates shall be connected by bolts on both l
7、on- gitudinal and circumferential seams or joints and shall be so fabricated as to permit complete erection from the inside of the tunnel. Bolt sizes and properties shall be in accordance with the manufacturers standard but not less than those specified in Division 1, Article 16.7. Grout holes 2 inc
8、hes or larger in diameter shall be provided as shown on the plans to permit grouting as the erection of tunnel liner plates progresses. Precast concrete tunnel liner plates shall conform to the details shown on the plans and the requirements of Section 8, “Concrete Structures.” If such details are n
9、ot provided and the plans or the specifications allow the Contractor to propose the use of concrete liner plates, the Contractor shall submit working drawings and specifica- tions to the Engineer for approval. Such drawings and specifications shall describe materials to be used, plate dimensions, re
10、inforcement details, connecting details, and erection procedures. The fabrication of Contractor proposed types of concrete tunnel liner plates shall not begin until the working drawings have been approved. Such approval shall not relieve the Contractor of any responsibility under the contract for th
11、e successful completion of the work. 25.3.2 Forming and Punching of Steel Liner Plates All plates shall be formed to provide circumferential flanged joints. Longitudinal joints may be flanged or of the offset lap seam type. All plates shall be punched for bolting on both longitudinal and circumferen
12、tial seams or joints. Bolt spacing in circumferential flanges shall be in accordance with the manufacturers standard spacing and shall be a multiple of the plate length so that plates hav- ing the same curvature shall be interchangeable and will permit staggering of the longitudinal seams. Bolt spac
13、ing at flanged longitudinal seams shall be in accordance with the manufacturers standard spacing. For lapped longi- tudinal seams, bolt size and spacing shall be in accordance with the manufacturers standard but not less than that required to meet the longitudinal seam strength require- ments of Div
14、ision I, Article 16.3.2. 657 65 8 HIGHWAY BRIDGES 25.4 25.4 INSTALLATION 25.4.1 Steel Liner Plates All steel liner plates for the full length of a specified tunnel shall be of one type only, either the flanged or the lapped seam type of construction. Liner plates shall be assembled in accordance wit
15、h the manufacturer?s instruction. Coated steel plates shall be handled in such a man- ner as to prevent bruising, scaling, or breaking of the coating. Any plates that are damaged during handling or placing shall be replaced by the Contractor at own expense, except that small areas with minor damage
16、may be repaired by the Contractor as directed by the Engineer. 25.4.3 Grouting When directed by the Engineer, voids occurring be- tween the liner plate and the tunnel wall shall be force- grouted. The grout shall be forced through the grouting holes in the plates with such pressure that ali voids wi
17、ll be completely filled. Full compensation for back packing or grouting shall be considered as included in the contract price paid for tunnel and no separate payment will be made therefore. 25.5 MEASUREMENT The length of tunnel liner to be paid for will be the length measured along the tunnel liner
18、plate invert. 25.6 PAYMENT 25.4.2 Precast Concrete Liner Plates Installation of precast concrete tunnel liner plates shall not start prior to receipt of approval of working drawings and specifications submitted as required by Article 25.3.1. Installation shall conform to the specified or approved er
19、ection procedures. Payment for the length of each size of tunnel as deter- mined under measurement shall be at the contract unit prices per linear foot bid for the various sizes, which pay- ment shall include full compensation for furnishing all labor, materials, tools, equipment, and incidentals to com- plete this item, including the force-grouting of voids.
