Slope Stabilization work between 9/0 to 10/0 and 33/0 to 36/0 on NH-58E

Scaling and controlled removal of loose, detached, overhanging and potentially unstable rock blocks from the highly fractured slope face, including inspection and marking of unsafe blocks; manual scaling; controlled splitting using pneumatic breaker and approved non-explosive expansive cracking agent where required; provision of rope access, temporary platform/ramp, lifelines, barricading and falling-rock protection; collection, loading, transportation and disposal of debris within a lead of 5 km; cleaning the face and road; all labour, plant, tools, safety appliances, leads, lifts and incidentals; complete as per approved method statement, drawings and directions of the Engineer-in-Charge.

Providing, drilling, supplying and installing self-drilling hollow rock anchors manufactured from 40Cr steel, 38 mm outside diameter and 19 mm inside diameter, having minimum yield load of 400 kN, suitable for simultaneous drilling through highly fractured rock/overburden, including 76 mm diameter sacrificial drill bit, hollow bars, couplers, centralizers where required, 10 mm thick bearing plate, dome/hexagonal nut, bolts and all system accessories. The item includes flushing and cement pressure grouting through the hollow anchor at approved water-cement ratio and pressure, including cement, approved admixture, water, mixer with agitator, grout pump, hoses, packers, connections, pressure gauge, wastage, refusal/top-up grouting and grouting records; working at all heights; rope access/platform; labour, machinery and T&P; proof/pull-out tests at approved frequency; complete as per approved design, drawings and directions of the Engineer-in-Charge. Preliminary anchor lengths are 6 m, 7 m and 9 m according to the height bands shown in the measurement sheet. Rate build-up includes 0.75 bag of cement grout per running metre; actual consumption shall be recorded and the adequacy of fixed and bond lengths shall be verified by design and field tests.

Supplying and installing a complete high-tensile rolled cable-net system for stabilization of fractured rock slopes, having aperture size not more than 300 mm in one direction, minimum longitudinal tensile strength of 100 kN/m and minimum puncturing resistance of 200 kN; fabricated from wire-rope cable of minimum 8 mm diameter with minimum breaking load of 40.7 kN and constituent wire tensile strength of 1770 N/mm². Corrosion protection shall be zinc coating Class A or 95% zinc + 5% aluminium alloy coating Class B in accordance with IS/ISO 17746:2016. The item includes net panels, boundary and support ropes, rope anchors where required by the proprietary system, connectors, shackles/clips, lacing, tensioning, overlaps, cutting, lifting, working at height, rope access, labour, T&P and all accessories for a complete installed system. The manufacturer shall have an in-house facility and carry out longitudinal tensile-strength and puncture-resistance tests during pre-dispatch inspection for each approved lot in the presence of the Engineer-in-Charge’s representative, complete as per approved drawings and system design.

Supplying and fixing double-twisted steel-wire mesh, mesh type 6x8 with nominal opening 60 mm x 80 mm; mesh-wire diameter 2.2/3.2 mm internal/overall including polymer coating where specified; mechanically edged/selvedged in accordance with EN 10223-3 and having at least 16 mesh openings per metre measured perpendicular to the twist. Wire tensile strength shall be minimum 500 MPa with minimum elongation of 10%. Minimum panel tensile strength shall be 34 kN/m, tolerance ±5 kN/m, parallel to the twist and 13 kN/m perpendicular to the twist, tested in accordance with IS 16014:2018. Zinc coating shall be heavy, soft type conforming to IS 4826:1972 and shall pass the specified adhesion test without flaking or cracking. The item includes compliant mesh panels, overlaps, lacing wire, clips, connections to the anchor/cable-net system, cutting, lifting, tensioning, rope access, labour, T&P, material testing and all incidentals, complete as per approved drawings and directions of the Engineer-in-Charge.

Providing and installing 75 mm internal-diameter perforated PVC/HDPE sub-horizontal drainage pipes in highly fractured rock, wrapped with approved non-woven geotextile filter, including setting out to intersect mapped water-bearing joints; drilling at the approved upward/sub-horizontal inclination and to the specified length; temporary casing where required; drill bits, rods, core barrels and consumables; flushing and cleaning the bore; perforating or supplying factory-perforated pipe of approved class and pattern; geotextile wrapping and securing; inserting the pipe; forming and protecting the outlet; connecting discharge to an approved toe/collector drain without re-infiltration; working at height, rope access, machinery, labour, T&P and flow testing; complete as per approved drawings, filter criteria and directions of the Engineer-in-Charge. Average drain length for this estimate is 10 m.