What challenges does the use of horizontal directional drilling (HDD) rigs (HWDs) in urban construction face?

Today, Drillto Trenchless Co., Ltd., a manufacturer of HWDs, will introduce HWDs. While the application of HDDs in urban construction offers significant advantages, they also face multiple challenges, including complex geological conditions, technically challenging operations, high equipment costs, stringent mud handling and environmental protection requirements, and a lack of standardized standards. A detailed analysis is provided below:
Complex geological conditions: Different geological conditions significantly impact the operation of HDDs. For example, in hard formations such as gravel and hard rock, drill bits are susceptible to wear, resulting in slow penetration rates and even equipment damage due to the high rock hardness. Furthermore, soft soil layers are prone to shrinkage, resulting in smaller boreholes and hindering pipeline installation. Quicksand layers can also hinder pipeline pullback due to adsorption forces. Therefore, detailed geological surveys and tailored construction plans are essential before construction begins.
High technical operational difficulties: HDDs require high precision, requiring a guidance system to monitor and adjust the drill bit direction in real time. However, underground conditions are often invisible, and the drilling process is easily affected by factors such as stratum fluctuations and uneven drill bit stress, leading to borehole deviation. Even minor deviations can significantly deviate from the planned trajectory, increasing construction risks. Furthermore, strict control of parameters is required during hole expansion and pullback, otherwise accidents such as drill bit sticking and drill pipe breakage can occur.

High Equipment Costs: Horizontal directional drilling rigs and their associated equipment (such as drill pipe, guide tools, and mud systems) are expensive and require regular maintenance and replacement of consumable parts. For small and medium-sized projects, equipment investment costs can be a limiting factor. Furthermore, the lack of highly skilled technicians increases training costs.

Mud Handling and Environmental Protection Requirements: Large quantities of mud are required during construction to stabilize the borehole wall and carry drill cuttings. However, mud loss or seepage can contaminate soil and groundwater, requiring strict control, especially in residential or ecologically sensitive areas. Furthermore, mud handling costs account for a significant portion of project costs, making efficient mud recovery and utilization a key factor in reducing costs. Lack of unified standards: Currently, there is no unified design and construction technical standard in the field of horizontal directional drilling rig construction, resulting in a lack of replicability between different projects and increasing construction difficulty and risk.