## Materials and Methods
### Model Soil Preparation  
The second important part of the model experiments is model soil preparation. It is reconstituted from undisturbed soil from a typical Shanghai construction site in Tang Town of Pudong New City, east from the Huangpu River. Construction in soft clay encounters issues associated with low permeability, thixotropy, and the rheology of the muddy clay [50; 51; 52; 53]. However, thermal properties are rarely considered. Representative and uniform soil samples were drilled out, sealed, and transported to the laboratory as soon as possible. They were kept in a curing room under constant temperature and humidity. Some soil samples used to measure the undisturbed basic parameters were penetrated by the thin-wall sampler carefully. They were shaped in a 30 cm-height and 10 cm-diameter cylinder under the best-undisturbed state. The physical and mechanical parameters are measured in Tables 2 and 3 to guide and control the preparation for reconstituted samples in model experiments. \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Soil** & **Soil Type** & **Thickness** & **Water Content \(w\)** & **Bulk Density \(\gamma_{0}\)** & **Specific Gravity \(G_{s}\)** & **Initial Void Ratio \(e_{0}\)** \\ \hline No.3 & Muddy silt clay & 4–9 & 39.2 & 18.3 & 2.73 & 1.08 \\ No.4 & Muddy clay & 12–20 & 49.9 & 17.2 & 2.74 & 1.39 \\ No.5 & Silty clay & 1–4 & 34.9 & 18.4 & 2.73 & 0.99 \\ \hline \end{tabular}
\end{table} 
Table 2: Physical properties of the model soils. Figure 3: The experimental system schematic. \begin{table}
\begin{tabular}{c c c c c c c} \hline  & **Soil Type** & **Coefficient of Compressibility** & **Coefficient of Volume** & **Coefficient of Permeability \(k_{v}\)** & **Cohesion \(c\)** & **Internal Friction \(q\)(\(\mathbf{c}^{\text{a}}\))**b** & **Friction \(q\)(\(\mathbf{c}^{\text{b}}\))**b** \\  & **\(\mathbf{a}_{v}\) (MPa\({}^{\text{a}}\))** & **a** & **m\({}_{v}\) (MPa\({}^{\text{a}}\))** & **a** & **(cm/s)** & **(\(\mathbf{c}\))** & **(\(\mathbf{c}\))** \\ \hline No.3 & Muddy silt clay & 0.59 & 0.28 & \(1.34\times 10^{-7}\) & 16 & 18.0 \\ No.4 & Muddy clay & 1.01 & 0.42 & \(4.22\times 10^{-8}\) & 13 & 10.0 \\ No.5 & Silty clay & 0.49 & 0.25 & \(3.84\times 10^{-6}\) & 16 & 14.5 \\ \hline \end{tabular}
\end{table} 
Table 3: Mechanical properties of the soils. Generally, there are two kinds of reconstitution methods for model soil, i.e., slurry deposition (SD) and moist tamping (MT). Due to the different soil properties, the SD method was chosen to reconstitute muddy clay since it is fine-grained, very soft, and has a water content as high as 50%. A slurry of the initial water content of 65% was made by mixing water and dry soil, thoroughly dried and pulverized from undisturbed soil, to be paved into the model box layer by layer in 2 cm. It is better to also be tamped together to remove air bubbles. The additional water was drained out by consolidation under 1 g self-weight dead load for 24 h with additional vertical stress of 165 kPa (pre-consolidation pressure). One pore pressure transducer was installed to monitor the consolidation process. Finally, the resulting water contents of model soils have been checked. It showed a good homogeny of 50% \(\pm\) 3% along the depth with a saturation level close to 100%. In contrast, the MT method was used for relatively coarse-grained soil, such as salts and sands, i.e., the muddy silty clay and silty clay layers in this research program, by compacting re-constituted soils to a specific density in layers. The undisturbed soils were thoroughly dried and mixed with a pre-calculated amount of water according to a designed water content value in a mixer of a specific volume, and then stirred a lot until homogenized; finally filled into the model box in step by compaction with a hand hammer. The desired density was controlled by the number of blows per unit of soil under the MT approach [55].