What is the difference between elastic calculation method and classical calculation method in soil mechanics calculation?

In the calculation of soil mechanics, the main difference between elastic calculation method and classical calculation method lies in the understanding of the interaction between soil and structure and the establishment of its mathematical model.

Classical calculation methods, such as equivalent beam method, usually simplify the supporting structure as a fulcrum, and regard the effect of passive soil on the pile as passive earth pressure, regardless of the stiffness of the pile. This method usually simplifies the structure into a static or statically indeterminate beam, and analyzes the response of the structure by solving the internal force and displacement of the beam. This method is effective in dealing with simple structures, but its accuracy may not be enough in the face of complex soil-structure interaction.

The elastic calculation method, or spring method, simplifies the anchor point as a spring, and the passive soil is equivalent to the spring acting on the pile, considering the stiffness of the pile. This method transforms the interaction between the structure and the geotechnical medium into a series of independent spring connections, and simulates the deformation of soil and the response of the structure through the compression of springs. Elastic calculation methods can usually provide more accurate analysis results, especially when dealing with complex soil-structure interaction.

Generally speaking, the elastic calculation method considers the deformation coordination between structure and rock mass, and the calculation result is more accurate. However, this method needs to accurately select elastic parameters (such as m value), and usually needs to be solved by numerical calculation methods (such as finite element method). Although the classical calculation method is sufficient in some cases, it may require more assumptions when dealing with complex situations, and its accuracy may not be as good as that of the elastic calculation method.