# Deformation Study of Strongly Structured Clays Considering Damage Effects
## 3 Test Results and Analysis
### The Compressive Characteristics of Structurally Strong Clay at Different Disturbance Levels
(**a**) The relationship between the compression coefficient \(\text{a}_{v}\) and the disturbance degree \(D\), as well as the damage degree \(W\). (**b**) The relationship between the compressive modulus \(E_{s}\) and the disturbance degree \(D\), as well as the damage degree \(W\). soil samples, indicating that the _Es-P_ curves gradually converged towards the sample with \(D=100\%\). From Figure 4a, it can be observed that for the sample with a disturbance degree of \(D=10.4\%\), the compression coefficient initially increased and then decreased as the damage degree \(W\) increased, particularly when \(W<10\%\). This phenomenon occurred because, at low disturbance and damage degrees, the sample with a high void ratio was significantly affected by pressure, leading to a rapid decrease in void ratio and a slight increase in the compression coefficient. Subsequently, under the influence of structural effects and compaction, the compression coefficient gradually decreased. For samples with disturbance degrees \(D>38.4\%\), the compression coefficient steadily decreased with increasing damage degree, with a more pronounced reduction observed when \(W<20\%\); this trend was especially evident in samples with higher disturbance degrees. Regardless of the disturbance degree, all samples exhibited a similar compressibility at higher damage degrees. From Figure 4b, it is evident that when the damage degree \(W>20\%\), the compressive modulus significantly increased with the rising damage degree, particularly for samples with lower disturbance degrees, which showed a more pronounced increasing trend. This behavior can be attributed to the fact that, with a constant disturbance degree, samples with higher damage degrees experience a greater rate of change in void ratio, resulting in a reduction in the existing void ratio. This leads to closer particle contact and increased density of the soil sample, thereby enhancing its resistance to compression and consequently increasing the compressive modulus [28]. From Table 5, it can be seen that the correlation coefficients R\({}^{2}\) of the fitting curves for the compression coefficients of different disturbed soil samples with respect to the damage degree all reached 0.99, indicating a good fit. The relationship between the compression coefficient \(a_{v}\) and the damage degree \(W\) for the structurally strong clay from Zhanjiang conformed to an exponential function given by the equation: \(a_{v}=a*e^{\frac{b}{2c+c}}\), where \(a\), \(b\), and \(c\) are structural damage coefficients of the soil. Table 6 indicates that the correlation coefficients R\({}^{2}\) of the fitting curves for the compressive modulus of different disturbed soil samples with respect to the damage degree all reached 0.95, demonstrating a good fit. The relationship between the compressive modulus \(E_{s}\) of the structurally strong clay from Zhanjiang and the damage degree \(W\) conformed to the following exponential function: \(E_{S}=A_{1}W^{2}+A_{2}W+A_{3}\), where \(A_{1}\), \(A_{2}\), and \(A_{3}\) represent structural damage coefficients of the soil related to the disturbance degree. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Disturbance Degree D/\%** & **Fitting Curve Equation** & **R\({}^{2}\)** \\ \hline
10.4 & \(E_{S}=110.67W^{2}+20.99W+2.0\) & 0.99 \\
38.4 & \(E_{S}=91.58W^{2}+12.25W-0.24\) & 0.98 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Fitting results of the relationship between the compressive modulus \(E_{s}\) and damage \(W\) of samples with different disturbances.