Horizontal Directional Drilling

Currently, China is experiencing perhaps the fastest worldwide economic growth. With numerous monumental construction projects underway and an ever increasing population growth, China is utilising sustainable principles and methods for addressing their infrastructure needs.

The eyes of the world are upon China as the country prepares for the 2008 Summer Olympics Games in Beijing, the 2010 World Expo in Shanghai, and the 2010 Asian Games in Guangzhou. These three major international events should be enough to continue the construction frenzy that the country is currently experiencing.

Even with its current growth, China’s safe water supply measures the second lowest in the world. Infrastructure-related issues such as this have driven the government to seek out emerging methods for installing and extending the useful life of existing underground utility networks. Underground utility networks are increasingly facing the need for upgrading and replacing; however, being out of sight generally results in a “reactive” solution for sustaining these systems. To meet this need, China is rapidly adopting trenchless technologies as an economical and minimally intrusive method for sustaining buried utilities. The most rapidly growing trenchless technology in China is Horizontal Directional Drilling (HDD).

Technique horizontal directional drilling

Over the past few years, three professional trenchless technology societies have been established in China including: the China Shanghai Society for Trenchless Technology (CSSTT); China Beijing Society for Trenchless Technology (CBSTT); and the China Guangdong Society for Trenchless Technology (CGSTT). These societies have mandates to promote the adoption of trenchless construction methods through educational initiatives. With a mix of government and industry participation, these societies have conducted excellent and informative technical seminars in recent years. One private firm in particular, Hong Kong-based Balama Prima-Vermeer (China) Company Limited, has spearheaded numerous educational efforts regarding horizontal directional drilling throughout China.

SUSTAINING UNDERGROUND NETWORKS WITH HDD

Globally, horizontal directional drilling has made a significant impact in both the utility and pipeline installation industries over the past decade. Currently, HDD is a multi-billion dollar a year industry with hundreds of contractors and thousands of drilling rigs operating on five continents. Industry applications range across the civil engineering spectrum from the installation of utility conduits and natural gas pipelines, through municipal applications (i.e. water mains, gravity sewers), to environmental and geo-construction applications such as the remediation of contaminated sites, geotechnical investigations and diversion channels. Presently, the fastest growing segment of the HDD market is China. It is estimated that there are over 1,500 HDD rigs currently operating in the country with between 25 to 30 local manufacturers (although the top five account for 80 per cent of the locally made machines). Foreign rig manufacturers including Vermeer Manufacturing, Ditch Witch, American Augers, Case, and TT Technologies have had varied degrees of success in penetrating the local market. Today, HDD rigs of all sizes can be seen across various regions of China.

Horizontal directional drilling presents several advantages over traditional open-cut construction methods. One obvious advantage is that it is a trenchless technology. Installation of underground utilities in congested urban areas using open trenching methods can prove to be rather expensive, as the contractor must cautiously dig around existing utilities in order to achieve the required depth, subsequently impeding the operation. Furthermore, sidewalks, pavements, brick paving, sod, or other surfaces must be repaired or replaced. In addition, open-cut construction is often associated with higher user costs, including the interruption of traffic and the disruption of nearby commercial activities. With China’s large, congested population, horizontal directional drilling is even more attractive.

Government officials in China’s most wired city, Shanghai, have begun the onerous task of burying much of its 20,000 km above-ground utility network including telephone, fibre-optics, and electrical lines. The goal is to bury 70 per cent of the network by the year 2010. This is a difficult task given the mandate to preserve historical and cultural sites. Subsequently, horizontal directional drilling is rapidly becoming a preferred installation method because of its minimally-disruptive nature.

HDD SUCCESSES

China’s HDD achievements are competing at world levels by undertaking some of the most ambitious projects in terms of complexity, diameter, and distance. For example, an American-made Robbins trailer-mounted drill rig was instrumental in the completion of a 1.7 km (5,538 ft.) crossing of the Yangtze River in which a 400 mm petroleum pipeline was installed in difficult soil conditions. To further demonstrate HDD successes, projects in Shanghai and Fuzhou are described in the following paragraphs.

A gas pipeline installation project, which is the main pipeline of the West-East Gas Pipeline Project entering the first section of Shanghai region, was installed using HDD. Two multiple installations of 720 mm and 325 mm diameter steel pipelines were installed distances of 356 m and 361 m, respectively. A total of ten 720 mm and eight 325 mm pipes were installed. Shanghai Win-Market Trenchless Technology Construction Company Ltd utilised a Vermeer D200x300 Navigator directional drill rig to complete this project. The project commenced on June 25, 2004 and was completed on July 27, 2004. By utilising HDD, the installations were completed rapidly with minimal disturbance experienced in this congested urban setting.

A second HDD project in Shanghai involved the installation of ten 220 mm diameter high density polyethylene electrical conduits over a distance of 800 m. A Vermeer D100x120 Navigator directional drill rig was used in this installation. By using horizontal directional drilling, these electrical wires are currently being installed with minimal disruption to surface activities and provide longer life due to lower longer term maintenance compared to above ground systems.

Horizontal directional drilling was used in Fuzhou, the capital of the Fujian Province, to install two potable water lines. A 500 mm steel pipeline and a 630 mm diameter high density polyethylene line were both installed a distance of 144 m across a river. This challenging project was completed using a Vermeer D33x44 Navigator directional drill rig. Using a trenchless method was the best approach in terms of preserving the environment due to minimal ecological disturbance during construction.

Source : http://trenchless-australasia.com/news/the_emergence_of_the_horizontal_directional_drilling_industry_in_china/001849/