## 2 Proposed Finite Element Model  
Previous researchers [6; 9; 17; 18] have used finite elements to determine and analyse the stresses produced by different external loads on pipelines, in order to determine different failure scenarios. This study analyses buried pipes subjected to external loads higher than those contemplated in the standards applying the finite element method with Abaqus/CAE 2019 software to identify the installation parameters that have the greatest influence on the stresses produced on the pipe and that could lead to failure.  
Experimental data from a test carry on at the University of Texas Arlington (UTA) in the Center for Underground Infrastructure Research and Education (CUIRE) by [PERSON] [16] were used to validate the finite element model.  
The procedure developed is summarized in the scheme shown in Figure 3. The following characteristics are taken into account:  
* The nonlinearity of the material, the contact and the geometry [15; 19; 20; 21];
* The linearity range of the pipe;
* The applied loads, including soil and surface loads as well as lateral loads produced by the compaction process of the layers during installation.  
During the construction process of installing pipes in trenches, the compaction of the soil in layers is contemplated, which progressively affects the deflection of the pipe. The lower layers affect the horizontal deflection, reducing the diameter; the upper layers reverse the result, causing the pipe to deflect horizontally toward the walls of the trench. Thus, using a procedure that considers the construction process in stages, proposed by [PERSON] et al. [10] and described in Section 2.3, results are obtained that better approximate reality.  
\begin{table}
\begin{tabular}{l c c} \hline \hline
**Vehicles** & **Payload (t)** & **Rear Axle Side Wheels (kPa)** \\ \hline CATERPILLAR models 793 F (Irving, TX, USA) & 240 & 1242 \\ CATERPILLAR models 797 F & 400 & 1248 \\ KOMATSU model 930 E (Tokyo, Japan) & 297 & 1246 \\ KOMATSU model 980 E & 360 & 1236 \\ \hline \hline \end{tabular} The pressure of the rear axle wheels. More details in the second and third tables of Section 3.  
\end{table}
Table 1: List of load capacities of heavy vehicles used in mining industry (Typical mining equipment—Peru).  
To approximate the nonlinear behaviour of soils, different constitutive models can be used, which model this behaviour based on the soil type and the nature of the problem. Among these models, the following stand out: the Mohr-Coulomb elastoplastic model with perfect plasticity, the plasticity model of [PERSON] (2016), the Cam clay model ([PERSON], 2017), the modified Cam clay model ([PERSON], 2017), [PERSON]'s hyperbolic model ([PERSON], 2017), [PERSON]'s nonlinear elastoplastic model with hardening ([PERSON], 2017), the soil model with hardening ([PERSON], 2017), the undrained soft clay model ([PERSON], 2017) and the Duncan-Selig ([PERSON], 2017). Considering the objectives set out in this article, it is necessary to measure the trends of increase in the stresses of a buried pipe, caused by changes in some variables of the installation, but a high accuracy in the plastic behaviour of the soil is not required. Taking into account these considerations, the Mohr-Coulomb elastoplastic constitutive model is used. Likewise, it is considered that the values required by this model, the friction angle \(\phi\) and cohesion c, can be easily obtained from a conventional and usual soil study in engineering projects.