Installation of Corrugated Steel Culverts In Collapsible loess Area

(1) Prepare tools and accessories:Hexagonal wrenches (16-18 and 22-24 sizes), adjustable wrenches, small pry bars (ø16mm×50cm round steel), crowbars (ø50mm×1.8m steel pipes), hammers, chisels, flat-head screwdrivers, jacks, bolts, rubber sealing gaskets, and 0.5kg binding wire.

(2) Apply an epoxy resin anti-corrosion coating to both inner and outer surfaces of the corrugated steel culverts. Ensure the coating thickness reaches 0.5–1mm and allow it to dry completely before installation.

(1) Site Preparation:Clear and level the construction area. Arrange material storage zones and position machinery in advance.Mark the pipeline axis and foundation boundaries with lime lines based on design specifications.

(2) Sequential Installation:Begin installation from the downstream to the upstream end, aligning the first pipe section with the longitudinal centerline of the foundation.

(1) Seismic Energy Absorbers:Prefabricated with flat flanges, these devices are installed in high-fill sections of corrugated metal culverts to absorb settlement stress.

(2) Reinforcement Clamp Flanges: Split into upper and lower semicircular halves, these clamps wrap around the culvert flanges. Align with steel channels and secure with bolts to enhance deformation resistance.

Backfilling for Corrugated Steel Culverts Section from Inlet to J3 Inspection Well,Foundation Layer: A 60cm-thick lime-soil layer (3:7 ratio) and 50cm gravel cushion.Backfill Methods:

120° Wedge Zone: Compact sand and gravel using frog rammers or wooden piles. Sides and Top: Layer new loess in 15cm lifts, compacted to ≥96% density. Mark layers with red paint for precision. Compaction Rules:

Topfill Strategies:<50cm: Manual vibratory rollers.50–100cm: ≤6t rollers (15cm/lift). 100cm: 18t rollers (30cm/lift).

Position templates based on measured slopes. After concrete pouring, use vibrating screeds from the slope base to the top. Reinforce edges with insert vibrators.

(1) Gasket Inspection: Check rubber seals for cracks or defects before installation.

(2) Bolt Tightening: Recheck all bolts pre-backfilling.

(3) Leak Testing: Conduct hydrostatic tests by filling the culvert with water or blocking the outlet to check for leaks.

(4) Waterproof Layer: Install a 60cm lime-soil barrier beneath the foundation to block groundwater.

(5) Flexible-Rigid Joints: Weld short steel bars (≥10cm welds) between inspection wells and corrugated metal culverts, coated with anti-corrosion paint.

(1) Pre-Embedded Anchors: Fix pipes using 1m threaded steel bars (30cm exposed) welded to Φ10 steel hoops at 2m intervals.

(2) Layered Concrete Pouring: Pour the base layer first, allow initial curing, then add the second layer. Use excavators to suppress floating during pouring.

Corrugated steel culverts and corrugated metal culverts offer advantages such as lightweight design, rapid construction, and cost efficiency in collapsible loess regions. However, their success relies on strict quality control, including anti-settlement design, layered compaction, and advanced leak prevention. These measures ensure long-term stability and safety, particularly in challenging environments.