Contract No. HKI/2024/07 - Hydraulic Improvement of Stormwater Drainage System (SMH7010840) in Whitty Street Qurrn's Road West

2024 - 2025

Before

After

Project Overview

A targeted hydraulic improvement was carried out on a 600 mm diameter stormwater drain by replacing a short defective section using a fully trenchless coring method. All works were executed from the existing manholes, eliminating the need for open‑trench excavation at this busy urban junction.

Client
Drainage Services Department

Contract No.
HKI/2024/07 – Rehabilitation and Replacement at Hong Kong Island (Central and Western) (Package 4)

Location
Whitty Street / Queen’s Road West, Hong Kong

Pipe Diameter
600 mm

Length
2 m

Completion
August 2025

Key Technique – Trenchless Coring & Pipe Installation

  • Pre‑Works Survey – CCTV inspection and underground utility survey confirmed pipe condition and adjacent services.

  • Guide Wire Installation – A steel wire was propelled from the downstream manhole to the upstream manhole to maintain precise alignment and invert level.

  • Coring Machine Jacking – A coring machine (CABEL CSN‑6A) jacked steel coring pipes along the guide wire to clear any obstructions, protect the host pipe, and create a safe working channel.

  • New Pipe Installation – Replacement uPVC pipe sections (each 600 mm long) were jacked into position from the downstream manhole, connected via flexible spigot‑and‑socket joints with elastomeric seals, forming a smooth, durable new conduit.

  • Manhole Reinstatement – All coring equipment was removed and anchor points were sealed with high‑strength concrete grout.

  • Final Verification – Post‑installation CCTV survey confirmed correct alignment and structural integrity.

Highlights

  • Zero surface excavation – works accessed solely through two manholes

  • No traffic disruption on Whitty Street or Queen’s Road West

  • Rapid completion within a single shift, including reinstatement

  • Enhanced hydraulic capacity restored with seamless, joint‑minimised pipe structur