Introduction

This document outlines the comprehensive technical design specifications for the TKO Tunnel to Lam Tin project. The specifications cover all aspects of tunnel construction, mechanical and electrical systems, safety features, and operational requirements to ensure the highest standards of performance and safety.

The design specifications have been developed in accordance with international tunnel engineering standards and Hong Kong's specific regulatory requirements, incorporating best practices from similar major tunnel projects worldwide.

Tunnel Structure

Tunnel Dimensions

  • Total Length: 4.2 kilometers
  • Internal Diameter: 13.8 meters
  • Number of Bores: 2 (dual bore configuration)
  • Traffic Lanes: 3 lanes per bore
  • Maximum Depth: 60 meters below sea level

Structural Materials

  • Concrete Grade: C50/60 high-strength concrete
  • Reinforcement: Grade 500 steel reinforcement
  • Waterproofing: HDPE membrane system
  • Segment Thickness: 350mm precast concrete
  • Joint Sealant: EPDM gasket system

The tunnel structure utilizes a segmental lining system with precast concrete segments installed immediately behind the tunnel boring machine. Each ring consists of 6 segments plus a key segment, providing optimal structural integrity and construction efficiency.

Mechanical Systems

Ventilation System

Longitudinal Ventilation

Jet fan system with 48 reversible jet fans per bore, providing 150 m³/s air flow capacity.

Emergency Ventilation

Dedicated smoke extraction system with emergency fans capable of 200 m³/s extraction rate.

Air Quality Control

Continuous monitoring of CO, NO2, and visibility with automatic ventilation adjustment.

Drainage System

Tunnel Drainage

Comprehensive drainage network with pumping stations at low points, capacity 500 L/s.

Water Treatment

On-site treatment facilities for tunnel drainage water before discharge to marine environment.

Electrical Systems

Power Supply

  • Primary Supply: 11kV from CLP grid connection
  • Backup Supply: Diesel generators (2 x 2MW)
  • UPS Systems: 30-minute backup for critical systems
  • Distribution: 415V three-phase distribution network

Lighting System

  • Main Lighting: LED luminaires, 20 lux average
  • Emergency Lighting: Battery-backed LED system
  • Exit Lighting: Photoluminescent guidance system
  • Control: Automatic dimming based on traffic flow

Safety Systems

Fire Detection & Suppression

  • Linear heat detection cables throughout tunnel
  • CCTV-based fire detection system
  • Deluge sprinkler system with foam capability
  • Portable fire extinguishers every 50 meters

Emergency Communication

  • Emergency telephones every 100 meters
  • Public address system throughout tunnel
  • Radio communication system for emergency services
  • Variable message signs for emergency instructions

Escape Routes

  • Cross-passages every 250 meters
  • Emergency walkways in both bores
  • Pressurized safe areas in cross-passages
  • Emergency lighting and guidance systems

Traffic Management Systems

Surveillance Systems

Comprehensive CCTV network with automatic incident detection capabilities:

  • 120 CCTV cameras providing 100% tunnel coverage
  • Automatic incident detection algorithms
  • License plate recognition system
  • Traffic flow monitoring and analysis

Traffic Control

Advanced traffic management and control systems:

  • Variable message signs every 200 meters
  • Lane control signals above each lane
  • Speed limit enforcement system
  • Traffic signal coordination at portals

Materials & Standards

Applicable Standards

Component Standard Specification
Concrete BS EN 206 C50/60 grade, 28-day strength
Steel Reinforcement BS 4449 Grade 500 ribbed bars
Waterproofing BS 8102 HDPE membrane, 2mm thickness
Fire Safety NFPA 502 Road tunnel fire protection
Ventilation PIARC Guidelines Road tunnel ventilation

Quality Assurance

Comprehensive quality assurance program ensuring all construction and installation work meets the specified standards and requirements:

Construction Quality

  • Material testing and certification
  • Concrete strength testing program
  • Waterproofing integrity testing
  • Segment installation quality control

Systems Testing

  • Factory acceptance testing (FAT)
  • Site acceptance testing (SAT)
  • Integrated systems testing
  • Performance verification testing

Documentation

  • As-built drawings and specifications
  • Test certificates and reports
  • Operation and maintenance manuals
  • Warranty and guarantee documentation