# A Large-Scale Model of Lateral Pressure on a Buried Pipeline in Medium Dense Sand
## 2 Materials and Methods  
In this study, a large-scale model was developed to act as the buried pipe under the lateral soil movement effect. Plywood and steel structures were used to fabricate the  
Figure 1: Lateral ground movement on buried pipe (adopted from [PERSON] and [PERSON] [15]). model of a chamber 3000 mm long, 1000 mm wide, and 1600 mm deep. Movable steel plates with stainless steel roller wheels were placed on a frame of three steel, rounded bars in the middle of the chamber. A High-Density Polyethene pipe (3000 mm long and 90 mm diameter) was installed by simple supports at both ends of the chamber. A manual winch pulley was used to pull the movable plates forward out of the chamber, as shown in Figure 2. Five Earth Pressure Cell sensors (EPCs) of 28 mm diameter and 10 mm thickness were used to measure the pipe pressure developed by soil pressure. A wire displacement sensor with 1000 mm capacity was used to measure the movable plate displacement (soil displacement). Poorly graded sand (Sungai Perak sand) was utilized as the backfill material for this experiment. The materials' properties are listed in Table 1. A camera was placed adjacent to the model box to capture the digital image of surface deformation of the soil model. The five earth pressure cell sensors were tested and calibrated by applied known dead loads. The EPCs were placed at different positions on the spring line, one sensor placed in the middle of the pipe where the soil was unstable, two at the boundary of the movable plates, and the other two placed to the left and right of movable plates where the ground was stable, see Figure 3. The EPCs were well attached to the pipe using strong double-sided adhesive tape. The distance between one sensor and another was 500 mm. A flexible conveyor was used to transport the sand from/to the chamber. The chamber was filled with the first layer of backfill material (sand), as the first layer was located on the left and right sides of the movable plates (depth of 170 mm). A manual rammer was used to compact the soil layers to achieve medium density of the backfill (relative density equal between 35% and 65%). The second layer of sand was added (depth of 200 mm) above \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Soil** & \multicolumn{2}{c}{**HDPE Pipe**} \\ \hline
**Class** & **Poorly Graded Sand** & **Class** & **(HDPE) PN 16** \\ \hline \(D_{10}\) & 0.12 mm & & \\ \(D_{30}\) & 0.24 mm & Tensile strain (break) & 600\% \\ \(D_{60}\) & 0.51 mm & & \\ \hline Density & 1606 kg/m\({}^{3}\) & Density & 0.951 g/cm\({}^{3}\) \\ \hline Friction angle & 38.69\({}^{0}\) & Diameter & 90 mm \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The materials’ properties used in the research. Figure 2: The large-scale model of soil–pipeline interaction. the movable plate level. The High-Density Polyethylene (HDPE) pipe was placed in the middle of the chamber with the two ends fixed using stainless steel pipe clamps, as shown in Figure 4. The third and fourth layers of the soil were added, with a depth of 90 mm and 160 mm. All the layers were compacted well and tested by the sand replacement method [29] to achieve the medium density of the backfill. The backfill's top surface was marked with a red square-grid pattern to monitor the surface failure at the end of the experiment. The wire displacement sensor was installed on top of the movable plates and connected to a data logger to automatically record the plate displacement values. In addition, the EPCs were also connected to the same data logger to record the stress on the buried pipe. The movable plate was pulled out (displacement of 50 mm) using a manual pulley, and the data logger started to record the stress values from the earth pressure  
Figure 4: Placement of an HDPE pipe in the middle of the chamber used to assess lateral pipeline–soil interaction in sandy soil. Figure 3: Cross-section of the physical model used to assess lateral pipeline–soil interaction in sandy soil. sensors.