CREG's E-Series intelligent three-boom drill jumbo has recently been deployed on an extra-long expressway tunnel in East China, where the single machine is handling top-heading drilling operations across a challenging 17 m-wide large-span cross-section.
The tunnel geology is dominated by weak surrounding rock, fault fracture zones, and karst formations — primarily Class IV rock — and is being excavated using the benching method. At the tunnel face, the excavation width reaches 17 m with a height of 8 m, forming a single-tube three-lane cross-section that ranks among the largest-span highway tunnel profiles in the region.
The core design philosophy of this jumbo is the "compact body + high-reach booms" concept. Its drill booms cover an area of 17.5 m × 14 m, enabling the machine to complete all top-heading blast-hole drilling from a single parked position across the 17 m-wide face. In parallel, the body width has been narrowed to just 2.6 m, allowing the jumbo to navigate and pass between invert decks with ease, while also accommodating rock-bolt drilling, inspection holes, and auxiliary charging operations.
Field data shows an advance of approximately 4 m per shift, with post-blast overbreak and underbreak controlled within 15–20 cm. The equipment has operated continuously and stably, providing strong support for the project's schedule milestones.
