Techniques of rotary hole-drilling for square anti-slide piles in complex formation and its application

To improve the hole-forming efficiency of square anti-slide pile excavation and study the rapid hole-forming technology suitable for rock landslides under complex conditions, this paper aims to study the hole-forming technology, the construction characteristics and the applicable system of hole-forming technology in different strata of square anti-slide piles by means of field investigation, theoretical analysis and engineering test.In this paper, a large rock landslide treatment project in eastern Chengdu with 101 large-section anti-slide piles is takens as the research object. The research shows that the new hole-forming technology of “rotary hole-drilling + manual excavation of the remaining earthwork” has greatly improved work efficiency and achieved a high efficiency of 2.0 m daily average footage in the anti-slide pile project. In the project, the new technology has successfully met the requirements of the construction period and solved the problem of slow hole-forming efficiency and backward technology. It is very important for disaster relief projects to choose the appropriate construction technology according to the conditions of landslides. For large-scale landslide treatment projects with good traffic conditions and high construction period requirements, the technology of “rotary hole-drilling + manual excavation of the remaining earthwork” is preferred. For small landslide treatment projects with poor traffic conditions and limited operation methods, we can use pneumatic picks to excavate the soil and use watermill drills to excavate the rock.