Trench shields protect people in trenches from collapsing soil. They are usually set into already excavated holes or trenches. Therefore, they do not provide lateral support for the trench sides until a side collapses against the shield. The trench sides could collapse before the shield is placed into the hole and, even with the shield in place, there usually is a gap (over-excavation) between the soil and the trench shield (unless the contractor backfills the narrow gap, which they do not do). If the soil collapses before the shield is placed or even after the shield is placed, injuries and/or damages can occur to people, paving, structures, and underground utilities.
Because trench shields (and slide rail systems) are proprietary support systems with unknown structural components, you really can't analyze the trench shield side panels. You can analyze the pipe struts. All you can do is calculate the theoretical, lateral, active earth pressure and any lateral surcharge pressures and then compare the maximum lateral load per square foot of side area against the shield manufacturer's PE-certified load rating.

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