Abstract: Foundation treatment and shield construction disturbance are the causes of squeezing soil which damages the initial structure and state, leads to the disturbance of soil, and changes the property of secondary consolidation. According to the squeezing disturbance of different levels caused by different preloads, a series of step-loading consolidation tests are conducted. The results indicate that, with the increase of preloads, the structure yield stress increases, compression index is almost the same when preload is less than structure yield stress, and decreases suddenly when preload is larger than structure yield stress; then it comes to a steady value. The secondary consolidation coefficient increases firstly, then decreases, finally gets to steady with the increase of pressure; and the secondary consolidation coefficient would decrease when disturbance increases; and a computational model for secondary consolidation coefficient is put forward; and the model coincides well according to the several testing data, and does well in predicting, which is useful for the prediction of post-load settlement.

Key words: structure, clay, disturbance, secondary consolidation