# An Investigation into the Influence of Sample Height on the Consolidation Behaviour of Dredged Silt
## 3 Test Results and Analysis  
### Compression Curve  
Figures 2 and 3 depict the _e-p_ and _e-_lgp_ curves for samples of varying heights. Both figures indicate that the compression curves across different sample heights exhibit a consistent pattern. The compression process of dredged silt can be categorized into three distinct phases:  
1. Initial Load Disturbance Phase (consolidation pressure \(p\leq\) 12.5 kPa): This phase features a pronounced compression curve with a high compression coefficient. Owing to the initially loose state of the dredged silt, significant deformation arises even under minimal consolidation pressure. Intense extrusion of inter-particle film water leads to a notable reduction in the void ratio. This behaviour distinctly contrasts with the compression characteristics typically observed in natural soft clays.
2. Elastic Deformation Phase: As the consolidation pressure rises (\(p\) = 25-150 kPa), the soil undergoes continuous compaction, establishing a renewed structural strength. This strength partially counters the added pressure, resulting in a gentler curve trajectory which aligns closely with a linear pattern. During this period, the soil's skeletal structure primarily experiences elastic deformation. With only a minor amount of film water being extruded, the deformation is significantly less pronounced compared to the first phase, and the compression coefficient remains relatively low.
3. Plastic Deformation Phase: With further escalation in consolidation pressure, the soil structure becomes compromised. Clay particles undergo relative slippage and adopt a tighter arrangement. Predominantly characterized by plastic deformation, the curve in this stage adopts a concave upwards trajectory. This effect becomes increasingly evident with rising consolidation pressures.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline _W (\%)_ & _p (g/cm\({}^{3}\))_ & _Gs_ & _e\({}_{0}\)_ & _w\({}_{\mathbf{L}}\) (\%)_ & _w\({}_{\mathbf{P}}\) (\%)_ & _I\({}_{\mathbf{P}}\)_ \\ \hline
95.7 & 1.480 & 2.759 & 2.666 & 51.2 & 22.5 & 23.6 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Average physical property indices of the soil samples.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline _Sample_ & _Sample Height_ & & & & \\ _Number_ & & **(cm)** & & & \\ \hline \multirow{2}{*}{S-1} & \multirow{2}{*}{2} & 5, 12.5, 25, 50, 80, 100, 200, 300, 400, 600, & & High-pressure \\  & & 800, 1200, 1600 & & Consolidation Test \\ \hline \multirow{2}{*}{S-2} & \multirow{2}{*}{2} & 5, 12.5, 25, 50, 80, 100, 120, 200, 300, 400 & 64 & Standard Consolidation Test \\ \hline \multirow{2}{*}{M} & \multirow{2}{*}{3} & 5, 12.5, 25, 50, 80, 120 & 64 & Standard Consolidation Test \\ \hline \multirow{2}{*}{L} & \multirow{2}{*}{4} & 5, 12.5, 25, 50, 80, 120 & 64 & Standard Consolidation Test \\ \hline \hline \end{tabular}
\end{table}
Table 2: Test loading scheme.  
During the initial phase, a significant shift in the void ratio was observed, with little to no variation attributed to differing sample heights. However, the void ratio's evolution in samples of different heights during the second and third phases demonstrated notable disparities. As the initial height of the sample increased, the drainage span under a specific consolidation pressure also augmented. Consequently, the rate of pore water discharge diminished, leading to a decreased rate of pore ratio change.