Volume-II of IV - GAIL

MECON LIMITED
REGD. OFF : RANCHI (BIHAR)
Document6
PROCESS & PIPING
DESIGN SECTION
NEW DELHI
TITLE MAINLINE CONSTRUCTION
(ONSHORE)
STANDARD SPECIFICATION
SPECIFICATION NO. PAGE 37 OF 53
MEC/S/05/62/01 REVISION A
10.4 When the trench has been dug through drive ways or roads, all backfills shall be
executed with sand or a suitable material as approved by COMPANY and shall
be thoroughly compacted. In certain cases, special compaction methods, such
as moistening or ramming of the backfill in layers may be required by
COMPANY. COMPANY and any public or private authority having jurisdiction
over a road, street or drive way may require that the surface of the backfill be
graveled with crushed rock or some other purchased material and the road shall
be repaved. In such instances, CONTRACTOR shall comply with said
requirements at no extra cost to COMPANY.
10.5 Trenches excavated in dykes which are the property of railways or which are
part of main roads shall be graded and backfilled in their original profile and
condition. If necessary, new and/or special backfill materials shall be supplied
and worked-up. The materials required may include gravel, special stabilization
materials or stabilized mixtures. However, special processing and/or compacting
methods shall require the approval of COMPANY and/or competent authorities.
10.6 The trench in irrigated and paddy fields shall be backfilled to within 300mm of
the top, then rammed and further backfilled until the trench is completely
backfilled. Surplus material remaining after the operation shall be spread over
the ROW as specified in Section 14.0 "Clean-up and Restoration of Right-of-
Way", of this specification.
10.7 At the end of each day's work, backfilling shall not be more than 500 meters
behind the head end of lowered-in pipe, which has been padded and approved
for backfill. The backfill shall be maintained by CONTRACTOR against
washouts etc., until the completion and final acceptance of the work by
COMPANY.
10.8 CONTRACTOR shall furnish materials and install breakers in the trench in steep
areas (slope generally 10% and more) for the purpose of preventing erosion of
the backfill. The type of breakers installed shall be as per the approved
drawings. Breakers shall be constructed of grout bags filled with a mixture of 4:1
Sand:Portland cement at COMPANY's direction. CONTRACTOR may propose
other methods such as foam dams etc. which shall be subject to approval by
COMPANY. Such works shall be at no extra cost to COMPANY.
CONTRACTOR shall pay attention to the direction of backfilling in such steep
areas.