Working in confined spaces is one of the most challenging conditions for excavator operation, requiring special equipment modifications, operational skills, and safety management. Below is a comprehensive solution for scenarios such as municipal pipelines, old neighborhood renovations, and indoor demolition.

I. Equipment Selection and Modifications

Machine Selection

• Prioritize 1.8-6 ton mini excavators

• Choose zero-tail swing design (reduces rear overhang by 40% or more)

• Wheeled excavators are recommended for municipal projects (quick relocation)

Essential Modifications

• Install full protective cages (to prevent falling object impacts)

• Replace with rubber tracks/tires (to protect paved surfaces)

• Equip LED panoramic cameras (blind-spot monitoring system)

• Install audible and visual alarms (automatic alerts during rotation)

Attachment Optimization

• Municipal pipelines: Use a 450mm narrow trench bucket

• Indoor demolition: Equip with hydraulic shears + thumb clamp (precision dismantling)

• Add a 1.5m short arm (improves control accuracy)

II. On-Site Layout Plan

Work Zone Planning

• Establish three-tier isolation zones:

• Core work area (3m radius) → Buffer transition zone (5m) → Safety Warning area (10m)

• Use foldable debris nets (to prevent flying Gravel)

Access Routes

• Minimum passage width = machine width + 1m (e.g., 1.8-ton machine requires 2.2m clearance)

• Conduct ground load-bearing tests (indoor areas must withstand ≥8t/m²)

Special Environment Handling

• Measure clear height (equipment height + 0.5m margin)

• Remove obstacles such as ventilation ducts

• Underground garage operations:

III. Precision Operation Techniques

Positioning Control

• Adopt the "three-point positioning method":

• Tracks parallel to the work surface

• Machine body ≥0.8m from obstacles

• Work equipment always within the operator’s line of sight

Movement Standards

• Pilot control lever operation limited to 1/3 of full travel

• Rotation speed restricted to ≤50%

• Decompose combined movements (no simultaneous rotation + lifting)

• Implement "millimeter-level micro-operations"

Typical Scenario Operations

• Pipeline excavation: Manually inspect pipes every 0.5m depth

• Wall scraping: Maintain a 15° angle between bucket and wall (prevents scraping)

• Parallel-to-wall digging: Use the arm’s side-shift function (avoids machine movement)

IV. Safety Monitoring System

Personnel Allocation

• Two-person team required:

• Operator (with special operation certification)

• Safety supervisor (directing with flags, positioned outside blind spots)

Smart Protection

• Install ultrasonic anti-collision systems (auto deceleration at 1.5m detection range)

• Use UWB positioning tags (auto shutdown if personnel approach within 0.5m)

Emergency Measures

• Equip emergency lowering devices (manual work equipment lowering in case of power failure)

• Check hydraulic line seals every 2 hours (prevents hose bursts)

V. Special Requirements for Municipal Engineering

Road Occupation Work

• Nighttime illumination ≥100 lux

• Noise control measures (machine noise ≤72 dB)

Heritage Protection Zones

• Use non-vibratory excavation techniques (e.g., vacuum suction)

• Reduce working pressure by 30% (minimizes accidental impacts)

VI. Prohibited Actions

• Never operate on slopes >5°

• Do not use bucket impacts for wall demolition

• Avoid single-track hang in the air operations

Conclusion: Confined space operations require an integrated approach of "equipment modification—precision operation—smart protection." BIM simulation rehearsals are recommended before construction. With these techniques, a Shanghai renovation project achieved 300 accident-free hours in a 3.2m-wide alley.