Change in reactive pressures and bending moments under the action of various external loads on the strip

Abstract

The problem of changing the reactive pressures acting on the strip interacting with the soil base is considered when using different soil models: a linear-deformable half-plane, a linear-deformable layer of finite thickness and the Winkler model. The goal is to compare the obtained results with the results of calculating the strip without taking into account its joint work with the soil. The methodology for calculating the "strip - soil" system is based on the method of B.M. Zhemochkin, for which the strip is divided into five equal length sections with a length of s=l/5=10/5=2 m. As a result of calculations it is proved that when any soil model is introduced, the reactive pressure curves will have a curvilinear shape with the highest values under the ends of the strip. The shape of the diagrams of bending moments both when using different soil models and when ignoring the joint work of the strip with the soil is identical. Positive bending moments when introducing a model of a linear-deformable layer of finite thickness are significantly greater than when calculating the strip without taking into account its joint work with the soil. The absolute values ​​of the negative bending moments in this case are significantly smaller than the similar moments obtained by ignoring the joint work of the strip and the soil. If Winkler models are included in the calculations, then the mentioned bending moments differ slightly from the moments obtained in the calculations of the strip in a primitive way. The originality of the work lies in the application of a unified approach to determining the stress-strain state of a strip located on soils described by various models of the "strip-soil" system. It is shown that if the model is applied incorrectly, it is possible to get false ideas about the stress-strain state of the system. For example, if the strip is considered as a strip on a linear-deformation plane, a stretched zone is obtained almost along the entire length of the strip in the lower zone, and in other cases both in the lower and upper zones, and this requires different reinforcement of the strip if it is designed with reinforced concrete. The practical value lies in the need for a serious justification for the use of a certain soil model, depending on soil conditions.