Kriging method-based creep model for anchor-soil interface considering grouting pressure

The long-term work performance of anchored systems depends on the shear creep behavior of anchor-soil interface. The technology of pressure grouting used in the construction of anchored systems is recognized to influence the creep behavior of anchor-soil interface greatly. A specially apparatus with capability of applying different grouting pressures is designed to investigate the impact of grouting pressures for the anchor-soil interface. The element-anchor specimens with different grouting pressures are made by using this apparatus. The time-history curves of pullout displacement are obtained in applying multi-stage loading to those prepared specimens by a specially designed creep pullout device. Chen’s method is adopted to transform those individual time-history curves of pullout displacement into a group of creep curves with varying loading stresses for each anchor specimen equivalently. Using the isochronal curve method the long-term shear strengths of anchor-soil interface are derived for the specimens with different grouting pressures. Aiming to improve the modelling precision, the creep curves with natural time coordinate are rebuilt to logarithmic time coordinates. The Kriging creep model for anchor-soil interface accounting for grouting pressure is established based on the Kriging method. Comparison between the predicted and the measured results for creep response validates that the proposed creep model has high precision in the fitting and prediction.