# Settlement Prediction and Differential Settlement Criterion for Heightening and Thickening Leveee
## 3 Case Study
### Case Introduction
#### 3.1.2 Material Parameters  
To obtain soil parameters, we performed a site soil test and laboratory test. The soil parameters awe obtained at the Hohai University laboratory. The soil parameters included density, Young's modulus, and other factors. The main apparatuses were balance, cutting ring, high pressure consolidation apparatus, and triaxial apparatus. The three main test procedures were as follow:  
1. For the determination of dry weight, the main test apparatuses included cutting rings, balances, and ovens. The specific test steps were as follow: Step 1: Cutting rings and balances were used to get the density of samples; Step 2: Ovens were used to get the water content of samples; Step 3: Calculate the dry density of soil samples using the Equation (14): \[\gamma_{d}=\frac{\rho g}{1+\omega}.\] (14) where \(\omega\) is water content; \(\rho\) is density of samples; \(g\) is acceleration of gravity;
2. For the determination of the shear strength index, such as the cohesive and internal friction angle, the main test apparatus was a triaxial apparatus. The triaxial test was consolidated and undrained. The reasons for the selection are follow: 1. The soil at the scene belongs to normally consolidated soil; 2. After completion, there are a large number of vehicles loads on the top of the HLT. In the consolidated-undrained test, the specimen has been consolidated to a certain water content under the consolidation pressure and then sheared with constant water content.
3. For the determination of [PERSON]'s modulus, the main test apparatus was a high pressure consolidation apparatus. The specific steps are as follows: Step 1: Assembly and commissioning of samples and apparatus; Step 2: Initial pressure (1 kPa) is applied to ensure good contact and record initial data; Step 3: Apply pressure (12.5 kPa, 25 kPa, 50 kPa, 100 kPa, 200 kPa, 400 kPa) at all levels and record data; Step 4: Processing test data. The main formula is in Equations (15)-(19)  
\[e_{0}=\frac{G_{s}\rho_{w}}{\rho_{d}}-1 \tag{15}\]  
\[e_{i}=e_{0}-\frac{1+e_{0}}{h_{0}}\Delta h_{i} \tag{16}\]  
\begin{table}
\begin{tabular}{c l} \hline \hline
**Type of Levee** & **Characteristics** \\ \hline Earth levee & Good compactness, permeability coefficient \(10^{-5}\) cm/s, good impermeability. \\ Sand levee & With sand and gravel, the allowable bearing capacity is greater than 100 kPa, and the permeability stability is good. \\ Mixed levee & Upper layer is silty soil and clay. The down layer is poorly graded sand, gravel with poor permeability \\  & stability. \\ \hline \hline \end{tabular}
\end{table}
Table 3: Levee characteristics.  
\[a_{v}=\frac{e_{i}-e_{i+1}}{P_{i+1}-P_{i}} \tag{17}\]  
\[E_{S}=\frac{1+e_{0}}{a_{v}} \tag{18}\]  
\[E_{0}=\frac{(1+\mu)(1-2\mu)}{1-\mu}E_{S}, \tag{19}\]  
where \(G_{s}\) is relative density; \(\rho_{w}\) is density of water; \(\rho_{d}\) is dry density of soil; \(e_{0}\) is initial void ratio; \(h_{0}\) is initial height of soil sample; \(e_{i}\) is void ratio corresponding to load at each level; \(P_{i}\) is load at each level; \(a_{v}\) is compression coefficient of soil; \(E_{S}\) is compression modulus; \(E_{0}\) is Young's modulus; and \(\mu\) is Poisson ratio of soil.  
Table 4 lists the material parameter results.