Horizontal Directional Drilling (HDD) is the fastest growing trenchless technology for the installation of pipes,conduits,and cables in underground bore-path construction.This is can be referred to the suitability of the technique for different soil conditions (hard and loose soils),applicability in crossing natural barriers such as rivers,lakes,and valleys,and artificial barriers such as highways and airport runways.Also,the technique has the less construction and restoration cost of new water and wastewater pipes and for rehabilitation of failing pipes in urban areas where excavation is unrequired or impossible.The 12 HDD operational units in 1984 increased to 2,000 HDD operational units in 1995.Approximately,17,800 HDD unites were manufactured and sold during the period between 1992 and 2001 in the North America.About 32,135 units has been manufactured and sold worldwide including the year 2011 (projected statistics for 2011),80％ (25,708 units) were manufactured in USA.In this paper,HDD survey was conducted to get the current market and industry position of HDD technology by analyzing 14 responses from HDD contractors and consultants in USA.Topics studied included observed HDD applications in different soil conditions,project parameters (diameters,lengths,depths of boreholes,product pipe and materials),and HDD rig size and applications.
展开▼
