## 4 Discussion  
### Vibration Reconsolidation Mechanism  
The consolidation process and mechanism of soft clays under vibration loads differ significantly from those under static loads. The following examples illustrate this point:  
Case 1. Consider a soil specimen in a fully confined one-dimensional state, as shown in Figure 17a. The soil specimen has already undergone normal consolidation under a static load \(P_{0}\). The state of soil elements in the specimen can be represented by point A on the normal consolidation line (NCL). Now, a static load increment \(\Delta P\) is applied to the specimen, and the specimen begins to consolidate. During the consolidation process, the pore water pressure dissipation rate varies at different locations in the specimen, but the state paths of all soil elements can be represented by line segment AC. The pore water pressure \(u\) of the soil element starts from \(u_{0}=\Delta P\) and gradually dissipates, while the effective stress \(p\) continuously increases, and its state gradually moves from A along the NCL to C. The rate at which different soil elements move from state A to C varies, but after consolidation is complete, all soil elements reach state C.  
Case 2. Suppose that after the soil specimen has undergone normal consolidation under the static load \(P_{0}\), a vibration load \(Q\) is applied instead, and the specimen begins to undergo vibration consolidation. On the one hand, under the action of the vibration load \(Q\), the effective stress of the soil element tends to decrease due to the structural damage, and the pore water pressure increases accordingly. On the other hand, as the pore water pressure dissipates, the effective stress will rebound due to the compression hardening of the soil skeleton. Since the vibration load does not have an overall compressive or tensile tendency, the total stress remains constant at \(P_{0}\) during the consolidation process, while the effective stress \(p\) first decreases and then returns to the initial value \(P_{0}\), and the void ratio \(e\) decreases from the initial value \(e_{0}\) to the final value \(e_{1}\). A typical state path of a soil element is shown as curve AB in Figure 17b. During the consolidation process, the state paths of soil elements at different locations in the specimen vary. Soil elements near the drainage boundary have a faster dissipation rate of accumulated pore water pressure,and their state paths are relatively flat, as shown by the dashed line on the right side of curve AB; soil elements far from the drainage boundary are more likely to accumulate pore water pressure, and their state paths are relatively steep, as shown by the dashed line on the left side of curve AB. Different soil elements follow different state paths and rates of state change from state A to state B. However, all soil elements eventually reach state B upon completion of consolidation. Based on the above analysis, reference [18] provides a mathematical model that details the state paths and state change processes of soil elements during vibration consolidation. The vibration consolidation process is more complex than the static consolidation process, which is reflected in at least three aspects. Firstly, the static consolidation process is a process in which the pore water pressure, generated instantaneously and once, is continuously converted into effective stress, and the effective stress continuously increases during this period. The vibration consolidation process includes two factors at the same time: the decrease of effective stress caused by the structural damage effect of the vibration load and the increase of effective stress caused by the compression of the soil skeleton. The effective stress is completely consistent before and after the vibration consolidation. This phenomenon has also been noticed in the studies of Sakai [25] and Hyodo [26]. It can be considered that the structural damage effect of the vibration load dominates the entire vibration consolidation process.