Special Project - Modification / Install of U/G A/C Cooling Water Intake Pipes by PipeJacking for China Insurance Building CIGB
2012-2013
Project Overview
Client
Harriman Property Management Limited
Location
Connaught Road Central, Hong Kong
Pipe Jacking Tunnel
DN1350 steel segment sleeve pipe – 40 m long
Carrier Pipes
Twin DN350 mild steel seawater cooling water pipes
Completion
August 2013
This landmark trenchless project delivered a new air‑conditioning seawater intake system for the iconic China Insurance Group Building, located on one of Hong Kong’s busiest thoroughfares. A DN1350 hand‑shield pipe jacking tunnel was driven 40 m beneath Connaught Road Central, completely avoiding open‑cut excavation. Inside this tunnel, twin DN350 cooling water pipes were installed, tested, and connected to the building’s existing plant room and seaward intake points.
Pipe Jacking Head
Flange jointed mild steel seat water cooling water pipe
Scope & Key Techniques
Hand‑Shield Pipe Jacking – DN1350 steel segment sleeves were jacked through mixed ground using a conventional hand‑shield method, with guidance from a precisely aligned steel guide rail.
Twin Cooling Pipe Installation – Two DN350 flange‑jointed mild steel pipes were laid inside the completed tunnel, connected to new valve pits and the existing cooling system, with full hydraulic pressure testing to 1.5 times working pressure.
Grouting of Abandoned Pipes – Old intake pipelines were safely decommissioned and backfilled by grouting.
Utility & Condition Surveys – Comprehensive pre‑construction utility surveys (HKIUS‑compliant) and building condition surveys were carried out to safeguard adjacent structures and dense underground services.
Traffic & Safety Management – Approved Temporary Traffic Arrangements (TTA) maintained pedestrian and vehicular flow throughout works; hoardings and safety plans protected the public and site personnel.
12105 Pipe Jacking & Pipe Cleaning at Clear Water Bay Road
2014 - 2015
Project Overview
Client
New World Construction Co., Ltd.
Location
Clear Water Bay Road / University Road, Hong Kong
Scope
Pipe jacking, mechanical cleaning, CIPP lining
Jacking Shield
DN900 hand‑shield
Carrier Pipe
DN225
Jacking Length
15 m
Total Pipe Cleaned & Lined
Over 540 m
Completion
June 2015
A severely degraded drainage network serving a new residential development was fully restored using a combination of trenchless pipe jacking, mechanical cleaning, and CIPP lining. The most critical section — a 15 m DN225 concrete pipe completely blocked with hardened grout and beyond repair — was replaced beneath University Road by hand‑shield jacking a DN900 steel sleeve and installing a new carrier pipe, all without opening the road. The remaining 540 m of the network was mechanically cleaned and then structurally lined, creating a jointless, corrosion‑resistant new pipe from manhole S6 to S220.
Before Pipe Cleaning
After Pipe Cleaning
Before Pipe Coring
After Pipe Coring
Before Pipe Lining
After Pipe Lining
Key Techniques
1. Pre‑Works CCTV & Manhole Survey
All 27 manholes and over 480 m of pipe were inspected, producing detailed condition reports that mapped grout‑filled sections and identified pipes requiring structural renewal.
2. Mechanical Cleaning of Grout‑Filled Pipes
Standard jetting was ineffective. A two‑stage process was used:
Mechanical Coring – Tailor‑made coring heads were winched between manholes to break up and extract the hardened grout without man‑entry.
High‑Pressure Water Jetting – After the grout was loosened, HPWJ flushed out remaining debris, restoring over 540 m to full flow capacity.
3. Trenchless Pipe Jacking (S6–S7A)
The unsalvageable 15 m section was replaced by constructing a sheet‑piled jacking pit and advancing a DN900 steel sleeve using a hand‑shield. A new DN225 carrier pipe was installed inside the sleeve, the annulus grouted, and the manhole backdrop rebuilt — with zero road excavation.
4. CIPP Lining (S6–S220)
The entire network was structurally rehabilitated with a close‑fit CIPP liner, pulled into place, inflated, and cured to form a jointless new pipe within the old conduit. Post‑lining CCTV confirmed full integrity and hydraulic performance.
Pipe Jacking in Progress
Pipe coring machine
Jetting head
Pipe Lining (S7A-S6) in progress
Construction of the concrete pipe
Highlights
Trenchless pipe jacking eliminated the need to open University Road for the 15 m replacement.
Mechanical coring cleared over 540 m of grout‑blocked pipe that had resisted conventional jetting.
Full‑length CIPP lining restored structural condition across the entire network, ensuring long‑term performance for the new development.