## 1 Introduction  
Presently, coal-fired power generation represents more than 40% of the world's total energy generation. It is anticipated that coal will continue to be a significant component of the global energy mix for a considerable period of time. Encountering the context of achieving carbon peaking and carbon neutrality, it is imperative for the coal industry to continuously advance towards high productivity, efficiency, and safety, necessitating constant development [1; 2; 3]. During coal mining operations, excavation and coal extraction represent the primary production stages. Initially, mining preparation tunnels are excavated using mechanical methods and blasting techniques. Subsequently, specialized coal mining machinery is deployed at the working face to facilitate longwall mechanized coal extraction. Given the rapid technological advancements, the mining and tunneling processes and equipment in underground coal mines require immediate development to meet the high demand for coal energy in China and fulfill the expectations of unmanned and intelligent underground operations. However, despite the rapid progress in mining technology, the development of tunneling technology has significantly lagged behind fully mechanizedmining methods. The speed of roadway excavation is considerably slower compared to mining, leading to a growing disparity between the two processes [4]. Since 2001, the mining-to-tunneling ratio has consistently increased from 1:2.25 to approximately 1:3.2, resulting in the inefficiency of tunneling hampering the speed and effectiveness of coal extraction [5]. Hence, it is imperative to elevate the level of tunneling technology and enhance the equipment used in underground coal mines to facilitate swift excavation and enhance both tunneling and mining efficiency. Currently, the lack of effective temporary support is the primary obstacle to the development of roadway boring speed, preventing simultaneous excavation and support operations [6; 7]. To address the issue of perimeter rock damage in deep roadways, the conventional operating method involves alternating between excavation and anchor support. However, this approach does not allow for a highly efficient parallel operation of the tunneling machine and support system, with support activities accounting for 70% of the overall cycle process [8]. Consequently, the excavation efficiency is significantly hampered, leading to frequent start-stop of the boring machine and increased demand for personnel, thereby impeding the progress towards underground intelligence and automation while compromising equipment and worker safety. The only way to solve the aforementioned issues is to introduce efficient and safe temporary support equipment at the tunneling face, thereby establishing a novel methodology that incorporates parallel operations of excavation, temporary support, and anchoring. Temporary support can be classified into two categories: non-repetitive temporary support and stepping repetitive temporary support. Non-repetitive temporary support involves a non-repetitive roof support approach, which mitiges any potential secondary damage. However, it often necessitates equipment relocation, resulting in operational complexity and spatial limitations. In light of these considerations, this study adopts the stepping temporary support technology approach, designs twin-link stepping temporary support equipment, and concurrently develops a comprehensive set of excavation, support, and anchoring equipment based on the twin-link stepping temporary support strategy. Consequently, a novel tunneling procedure is established, whereby excavation, temporary support, and anchoring operations are performed simultaneously, leading to significant improvements in both efficiency and safety. However, during the process of implementing stepped temporary support, repetitive supporting actions are carried out on the roof. This may lead to additional damages and significant safety concerns, particularly when the roof is weak or subject to high original rock stress.