Effects of Stratification on Soil–Foundation–Structure Interaction: Centrifugal Observation and Numerical Simulation

It is essential to reduce structural damages caused by earthquakes in severe conditions, such as layered ground, especially when a soft soil layer is close to the surface. In this study, the kinematic and inertial interactions, two mechanisms of soil–foundation–structure interaction (SFSI), of different soil–foundation–structure systems (SFS) were investigated on uniform and layered grounds. Two layered soil profiles composed of a low stiffness layer laid over another were prepared in an equivalent shear beam container. Nine centrifuge experiments were carried out for three structures located on the surface of each ground and exposed to the Hachinohe earthquake while increasing the peak acceleration of the input motion. Numerical simulations were performed to simulate the centrifuge tests. It was found that roof motion (RM) of the tall structure increased in layered profile even though the free-field motion (FFM) decreased compared to homogeneous ground. The appearance of a soft layer beneath structures modifies the SFS system’s stiffness that causes kinematic and inertial interactions to alter to those on uniform soil profile.

Deformation prediction and anti floating analysis of a raft foundation

This paper mainly studies the deformation and stress of the concrete plat under the uniform load considering the thickness of the compression layer of layered ground. Firstly, the load characteristics and the ground strategy are discussed in detail to clarify the boundary condition. Then the deformation of the ground in each layer is calculated by GEO-Cal program and the final settlement and uneven deformation is also predicted using consolidation theory. Ground stress and settlement is also calculated by FEM to verify the previous calculation.

Analysis of deformation characteristics of layered ground under uniform load

For the layered ground in a large area, the deformation under uniform load is analyzed numerically. Considering the work property of the concrete plane, the uneven settlement is strictly restrained using different foundation. In the process of settlement calculation, according to the linear interpolation of multiple borehole elevations, the geological profiles with different soil layer thickness are formed, and the influence of compressed soil layer thickness on the total settlement and uneven settlement is fully considered.