Table 1.
Basic physical properties of Zhanjiang Formation structural clay [14].
Table 2.
Parameters of vibration frequency and vibration duration.
Fig 1.
Stress-strain curves under different conditions.
Following the vibration disturbance, the stress-strain curve of the sample exhibits strain-softening behavior. The peak deviatoric stress is taken to be the unconfined compressive strength of the sample.
Table 3.
Unconfined compressive strength of disturbed samples [14].
Table 4.
Disturbance degree (RDq) [1].
Fig 2.
Typical stress-strain curve for soil.
Under the action of external forces, structural soil transitions to remolded soil, and the structural phase shifts to the damage phase.
Fig 3.
Energy balance relationship of structural soil.
The total input energy from external work is converted into elastic energy and dissipation energy.
Fig 4.
Work and dissipation analysis.
During the process of strain δε, the external force energy δW = σδε = δWe + δWΩ.
Fig 5.
Energy evolution laws of clay with varying disturbance degrees under unconfined compressive conditions.
In the figure, W represents the total energy input from external forces, We denotes the elastic energy stored within the soil, and WΩ indicates the dissipation energy. These quantities satisfy the relationship W = We + WΩ. The total energy W gradually increases with strain. Both the elastic energy We and the stress initially increase but subsequently decrease with strain. The dissipation energy WΩ can be divided into two phases: a slow initial growth period followed by a rapid growth stage.
Fig 6.
Locations of compaction points of clay with varying disturbance degrees.
Based on the variations in dissipation energy during the loading process, the compaction point is defined as the location at which the pores of the sample are completely closed, and the elastic energy begins to accumulate. The compaction point's location of the sample is then determined.
Fig 7.
Relationship between disturbance degree and strain at the compaction point.
As the disturbance degree increases, there is a corresponding rise in compaction strain, indicating a continual enhancement of the sample's ductility.
Fig 8.
Relationship between disturbance degree and dissipation energy at the compaction point.
As the disturbance degree increases, the dissipation energy at the compaction point escalates.
Fig 9.
Variations of energy parameters at peak stress of samples with different disturbance degrees.
The energy parameters depicted in the figure are as follows: W represents the total energy, We denotes the elastic energy stored in the soil, WΩ signifies the dissipation energy, and W = We + WΩ.
Fig 10.
Variation of elastic energy dissipation ratio.
The variation in logarithmic value of the elastic energy dissipation ratio can be divided into three stages: initial lgK > 0, lgK < 0 to (lgK)min, and rising from (lgK)min, where (lgK)min is considered the crucial turning point from the elastic to the plastic phase of the soil.
Table 5.
Critical turning point indicator.
Fig 11.
The (lgK)min threshold (11(A) (lgK)min values distribution, 11(B) The normal Q-Q plot of (lgK)min).
In 11(A), the □ symbol represents the distribution of (lgK)min values across samples with varying disturbance degrees. Assuming that (lgK)min adheres to a normal distribution, the analysis was performed using a normal Q-Q plot of (lgK)min, as shown in 11(B). This plot illustrates the alignment of the (lgK)min distribution with the theoretical normal distribution.
Fig 12.
Relationship between disturbance degree and stress indicators before failure of the disturbed samples.
Both σ(lgK)min and σ max demonstrate a linear decline as the disturbance degree increases, indicating that higher disturbance levels correspond to a gradual reduction in these stress indicators.
Fig 13.
Dynamic regulation is achieved by controlling the vibration duration and frequency of the disturbance source. In Fig 13(A)–13(C), as the duration increases, the collisions and friction between particles intensify, resulting in the formation and expansion of microcracks within the soil. In Fig. 13(D)–13(F), high-frequency vibrations exacerbate the collisions and friction between particles, promoting the rapid expansion of microcracks within the soil and swiftly transitioning into the macroscopic damage phase.