Influences On Grotto Cultural Relies Caused By Engineering Construction Of The Porteetion project Of MoGao Grottoes In DunHuang

摘要

To protect the cultural relics of Mogao Grottoes in Dunhuang,and to eliminate unsafe hidden dangers,cliff strengthening,remedying and reconstructing the plank road alongside cliffs and integrated prevention and cure against sandstorms are projected.In these constructions,the effect caused by anchor eye drilling vibration during the process of cliff strengthening is difficult to avoid.In order to understand the propagation of the construction vibration of this kind and its effect extent on the grotto cultural relics,grotto rock masses dynamics parameters testing and anchor eye drilling vibration testing were performed in Mogao Grottoes.The test results show that the sympathetic vibration frequency of the cliffs of Mogao Grottoes is between 75 and 90 Hz,whenas the mechanical vibration frequency of horizontal drill adopted in China at present is within 6～7Hz,so it is easy to come to a conclusion that the anchor eye drilling construction will not cause sympathetic vibration damage to the cliffs and grottoes.Besides,the test results also show that most of the vibration peak values tested at a distance of 1m,2m or 3m from the anchor eye are above the protection standard which is 0.1mm/s,and the highest vibration speed of high-pressure drill impact reaches up to 6.01mm/s.It is clear that anchor eye drilling vibration may have harmful effect on the grotto relics,so this kind of vibration should be paid enough attention to.Only by 0.8～0.9MPa depression and 0.4m/min low-speed drilling,can the harmful effect caused by anchor eye drilling be reduced and the damage to grotto relics be avoided.