Construction plan and supporting measures for HDPE membrane laying in slag yards

1. HDPE Geomembrane Project Overview & Core Objectives​

1.1 HDPE Project Background​

This plan applies to the anti-seepage engineering of waste dumps, aiming to install high-density polyethylene (HDPE) membranes as the core anti-seepage layer. The typical laying area covers the dump bottom, slopes, and surrounding catchment ditches, with the HDPE membrane thickness designed as 1.5-2.0mm. The key technical requirements include: permeability coefficient ≤1×10⁻¹³ cm/s, weld strength ≥80% of the base material strength, and zero leakage risks during service.​

1.2 Core Objectives​

• Quality Compliance: Achieve 100% integrity of the anti-seepage system with qualified third-party testing results.​

• Safety Assurance: Prevent membrane damage and leakage accidents; ensure safe operation in complex environments (e.g., methane accumulation areas).​

• Efficient Construction: Complete 800-1200㎡ of membrane laying per day, with the total construction period controlled within the planned schedule.​

• Cost Optimization: Keep material loss rate ≤2% (HDPE membrane) and rework cost ≤8% of the total project cost.

2. Pre-Construction Preparation​

2.1 Site Preparation​

• Base Treatment: The base surface must be compacted (compaction degree ≥95%) with flatness ≤5mm/2m. Remove all sharp objects (e.g., stones larger than 5mm, tree roots, concrete debris) to avoid membrane puncture. For soft soil foundations, replace with gravel and level the surface.

2.2 Transportation & Storage

Transportation: Use flatbed trucks with rubber mats (thickness ≥10mm) on the carriage. Stack rolls ≤3 layers with wooden boards (thickness ≥20mm) between layers. Avoid transportation during high-temperature periods (11:00-15:00 in summer) and cover with sunshades or rain cloths as needed.​

2.3 Equipment Preparation​

• Core Equipment: Double-track hot-melt welding machines (power 3kW, temperature range 180-220℃), extrusion welding machines (for repairs), spark leak detectors (30kV), universal testing machines, and vibration rollers (12t).​

3. Core Construction Procedures​

3.1 Laying Principles & Methods​

• Laying Sequence: Start from the bottom of the dump and proceed upward; lay slopes first, then the bottom. Align the HDPE membrane direction parallel to the maximum slope line.​

• Tension Control: Avoid over-stretching; reserve 1.5-2.0% slack to accommodate settlement and temperature changes.​

• Seam Arrangement: Longitudinal seams should be staggered by ≥1m and kept ≥1.5m away from slope bottoms or bends. Minimize seams at corners and irregular shapes.​

• Temporary Fixing: Use sandbags to press the membrane immediately after laying to prevent wind displacement. For slopes and curved surfaces, use straps or expansion bolts for temporary fixation.

3.2 Welding Construction​

3.2.1 Welding Conditions​

• Environmental Requirements: Construct when temperature is 5-40℃, wind speed , and no rain/snow. Avoid welding at noon in summer (temperature ≥35℃).​

• Preparación de la superficie: Clean the overlapping area (width ≥10cm) to remove dust, oil, and moisture (moisture content ≤5%).​

3.2.2 Welding Process​

• Test Welding: Conduct trial welding 7 days before formal construction in a 20㎡ test area. Determine optimal parameters through 3 groups of tests (recommended: temperature 200℃, speed 1.8m/min, pressure 0.35MPa).​

• Formal Welding: Adopt double-track hot-melt welding for main seams; use extrusion welding only for repairs. Ensure welds are continuous without virtual welding or missing welding OF HDPE.​

4. Supporting Measures​

4.1 Quality Control Measures​

• Document Management: Number each membrane roll and record the laying position, weld parameters, and inspection results.​

• Process Supervision: Assign full-time inspectors to monitor base treatment, welding, and inspection. Implement a three-party confirmation system (construction, supervision, and environmental monitoring) for key processes.​

• Defect Repair: Mark damaged areas immediately and repair with the same material. The repair lap width should be ≥200mm.​

4.2 Safety & Environmental Protection Measures​

• Safety Protection: Workers must wear anti-static clothing, gas masks, and non-slip shoes without sharp soles. Prohibit smoking and using sharp tools on the membrane.

4.3 Coordination & Collaboration Measures​

• Inter-Department Collaboration: Establish communication mechanisms between construction, supervision, design, and environmental departments. Hold daily technical disclosure meetings to confirm construction parameters.​

• Community Communication: Set up a communication group with surrounding communities to publicize deodorization measures and monitor data, reducing complaints.​

• Emergency Response: Prepare emergency plans for leakage, methane accumulation, and severe weather. Ensure emergency response time ≤20 minutes.​

4.4 Weather Adaptation Measures​

• High Temperature: Avoid construction at noon; store membranes in shaded areas to prevent thermal deformation.​

• Low Temperature: Compact membrane laying and use heating equipment for welding (if temperature is 0-5℃).​

• Wind & Rain: Stop construction when wind speed ≥5 levels or during rain. Install temporary drainage ditches (spacing ≤8m) in rainy seasons.

5. Construction Schedule & Resource Allocation​

5.1 Schedule Arrangement​

• Preparation Stage (7-10 days): Material inspection, equipment commissioning, site cleaning, and safety training.​

• Trial Construction (2-3 days): Test laying and welding in non-critical areas to optimize parameters.​

• Formal Construction (30-50 days): Complete HDPE membrane laying, welding, and inspection with a daily output of 800-1200㎡.​

• Acceptance Stage (3-5 days): Conduct third-party testing and rectify unqualified items.​

5.2 Resource Allocation​

• Personnel: 4-6 professional anti-seepage workers (with environmental operation certificates), 1 methane monitor, and 1 safety officer (trained in anti-toxic and explosion-proof skills).​

• Materiales: Reserve 5% of additional membranes and auxiliary materials for repairs.​

• Equipment: Equip backup welding machines and detectors to ensure continuous construction.