Innovative digital control minor-disturbance equipment for deep mixing

Considering the limitations of the current deep mixing (DM) methods and environmental constraints, there is an urgent need to develop DM equipment that is efficient, high-quality in construction, and environmentally low-disturbance. This paper introduces a digitally controlled minor-disturbance deep mixing technique, which consists of a rig frame platform, a mixing system, a digital construction system, an air supply system and an automatic slurry plant. The construction process is controlled by the digital construction system, which enables real-time tracking and feedback; it automatically adjusts air pressure and penetration/withdrawal speed when the monitored inner stratum pressure exceeds a pre-set threshold, thereby ensuring the minor-disturbance effect. Construction data is uploaded in real time to the cloud platform for monitoring and management. The proposed technique employs triple-channel hexagonal rods, whose unique geometry creates natural pressure-release pathways during rotation, thereby preventing pressure accumulation. In addition, a variable binder content mixing method is adopted, allowing automated adjustment of cement dosage in different soil layers according to preset parameters. Combined with inner stratum pressure control, these innovations effectively reduce the construction impact on the surrounding soil and improve installation efficiency and quality. A field test was conducted to ascertain the performance of the technology in question. The recorded construction parameters, including slurry flow rate, drilling speed, air pressure, and inner stratum pressure, were consistent with the required values. Both measured lateral soil displacement and ground heave induced by pile construction are less than 5 mm at a distance of 2 m from the testing pile. The measured 28-day unconfined compressive strength is uniformly distributed along the pile, exceeding a value of 1.1 MPa.