Progress in research and applications of trenchless horizontal directional drilling equipment and technology in China

Horizontal directional drilling (HDD) technology is widely used in the construction and maintenance of municipal lifeline projects, the laying of long-distance oil and gas pipelines, and directional survey of mountains. It is one of the important technologies in the trenchless engineering field. Nearly 30 a of development of China’s HDD technology has made significant progress in the research and application of equipment and technology, creating a world record. The present work presents literature research considering 6 aspects: HDD equipment technology, detection and informationization technology of underground lifeline engineering, bi-directional crossing technology, large caliber HDD technology, HDD drag force calculation model, surface deformation and mud spillover. Moreover, this work analyzed the HDD research and applications progress of equipment and technology. In terms of the HDD equipment, the world’s largest drag force (20000 kN) electric drive drilling rig has been designed and developed. Based on the material properties of underground lifeline systems, electromagnetic induction methods are widely used for geospatial detection of existing lifelines. However, data analysis and accuracy improvement under complex interference still need to be investigated. Based on three-dimensional data, integrating building information modeling with artificial intelligence, big data and other technologies, and learning from the US “811” system the informatization of underground lifelines has been partially completed. Long distance underground lifeline engineering has been laid using bi-directional crossing technology. Process-based HDD process parameters, equipment parameters, and the control and monitoring technology have been widely used to effectively improve the HDD applications’ risk identification capabilities. The drag force calculation under different stratum conditions provides a basis for the equipment selection and facilitates HDD multidisciplinary research. In addition, preliminary explorations on hotspots with difficulties, such as slurry eruption under complex geological conditions, have been conducted. Theoretical, experimental, and numerical analysis models have also been constructed to provide a basis for improving the application efficiency and quality of HDD. Based on the abovementioned progress, this paper further analyzes the development trends of HDD technology.