(1. Key Laboratory of Mechanics on Disaster and Environment in Western China，Ministry of Education，Lanzhou University，Lanzhou，Gansu 730000，China；2. Dunhuang Academy，Dunhuang，Gansu 736200，China)
Abstract：Many grottoes are excavated in sandy conglomerate poorly consolidated with a little calcareous/ argillaceous cementation on the Silk Road in China，also many cracks can be found on those grottoes. The further development of those cracks into cliff will cause collapse and devastating damage of rock of caves. PS-F grouting material has a perfect effect on crack grouting of conglomerate grottoes in China，but the mechanism research of PS-F grouting material is comparatively lagging behind. By X-Ray diffractometer(XRD)，scanning electron microscopy(SEM) and other analytical tools，the main component and micro-morphology of fly ash，the physical mechanism of PS with different moduli，and the contractibility，mechanical property and micro- morphology of PS-F grouting material with different viscosities and moduli are studied. Comparing above results，it shows that PS-F has good groutability. The strength of PS-F grouting material changes with PS viscosity and modulus，and a reasonable interpretation of mechanism on the PS-F grouting material is presented.
