Analysis of the correctness of methods of accounting temperature impact on metal struts of excavation retaining system and possibilities of its increase

In the design of deep excavation retaining structures, attention is not always paid to the temperature regime in which the strut system operates. However, even within one day the temperature can change by more than 10°C, which inevitably leads to a significant change in internal forces. If there is a change of season, the changes can be even more significant. The main problem with most of the existing techniques for accounting for temperature effects is that they are either quite complex or give a significant increase in forces, which turns out to be unrealistic. This paper analyzes the use of the THERMAL module in the software package PLAXIS 2D, including the author’s suggestions for modernization, in comparison with the two most well-known and relevant methods of accounting for temperature effects. For an excavation 6 m deep in a homogeneous soil mass with one tier of the strut element, a series of calculations were performed for different soil conditions, as a result of which the increment of forces according to the numerical method was found to be 1,2–3,1 times greater than for the other two methods considered. Despite the significant difference, the numerical method turned out to be the most universal and independent of structural solutions and is suitable for preliminary assessment when calculating the effect of temperature influence. The paper provides recommendations for more correct consideration of the temperature effect on the struts, as well as outlines the further development of the methodology.