The grout migration height has a remarkable influence on the calculation of bearing capacity for post-grouting pile. Based on the time-dependent behaviors of power-law cement grout

a theoretical expression to calculate upward grout migration along the pile side was proposed with consideration of time-dependent behavior of viscosity. The methods to determine the parameters and to iteratively determine the grout migration height in the layered soils were presented

respectively. Moreover

based on post-grouting project of the connecting engineering of Taizhou Bay Bridge in Zhejiang Province

the reinforcement effect of post-grouting piles was analyzed by means of electromagnetic wave CT. The results show that the predicted results of grout migration height on the basis of fitting value of pressure loss along the grouting pipeline and time-dependent behaviors of viscosity are consistent with measured results

which verifies the rationality of proposed expression for grout migration height. However

an overestimated bearing capacity of post-grouting piles may be obtained when ignoring the influence of time-dependent behaviors of viscosity

which has an unfavorable influence on pile design. Additionally

the electromagnetic wave CT can detect the distribution pattern of the pile

injected grout and soil

and can also deduce the diffusion range of cement grout at pile tip

as well as the grout migration height along the pile shaft

which can be applied to assess the grouting effect of grouted pile. The research results can provide reference and guidance for design and effect detection of post-grouting piles.