Study on Mechanical Properties and Application of a New Flexible Bolt

As mining depth extends continuously, complex geological environment and strong stress pose serious challenges against excavation safety higher demand for bolt support. To meet the challenges, a new type of flexible is developed that free from limitation height can be installed quickly. The bolts have tail structure which squeezed together by locking casing steel-strand rod. forms thread through rolling process, then quickly nut rotation type, avoids disadvantages cable tension installation. Through long bolts, thick anchoring layer roof constructed, control roadway realized. obtain optimal specifications, casings three diameters lengths were used to prepare samples static tensile test. Test results show when diameter fixed, peak resistance increases as length increases, but increased amplitude tends reduce gradually. When too large makes mechanical property unstable. Finally, are set at 120 30 mm, respectively. In addition, cyclic loading tests conducted, indicate does not change state within display stable property. Field achieve low damage surrounding rock maximum fracture 2.1 m, thus guaranteeing safety.