A Large-Scale Soil-Structure Interface Testing Device

Abstract

A large-scale testing device for the experimental investigation of soil-structure interactions was developed. It allows an observation of the evolution of deformations and the measurement of the stresses in the soil-structure contact zone under 1 g-conditions. The tests are designed as boundary value problems for benchmark tests of numerical simulations. They can be used to validate contact formulations and constitutive equations for the soil. The dimensions (soil height >1.5 m) provide a sufficiently high stress level for simulations with constitutive models for soil. The major part of the device is an instrumented wall section with modifiable surface roughness representing, e.g., a part of a pile shaft or a steel sheet. This wall can be displaced quasi-statically relative to an adjacent soil body. The distribution of shear and normal stress and the wall displacements are measured. Digital image correlation (DIC) is used to evaluate the soil deformations. The paper focuses on the basic concept, the design, and the instrumentation details of the testing device. Additionally, some selected test results are shown.

Effects of Soil Deposition on the Initial Stress State in Model Tests: Experimental Results and FE Simulation

“…Within the realms of technical possibility, this was achieved by using glass plates or stainless steel for the inner surfaces. Nevertheless, a "silo effect" occurs in the test device [14]. Below a certain depth of about 0.5-1.0 m under the sand surface a significantly lower stress is observed compared to free field conditions.…”

“…The soil density can be controlled via variation of free fall height and intensity. The preparation methods for the Interface test device were already extensively described in [15] and are therefore not repeated here. A dry, uniform medium quartz sand was used as test material.…”

“…A dry, uniform medium quartz sand was used as test material. Detailed information can be found in [14,15].…”

“…It was designed to provide high quality experimental data for the validation of constitutive models and new simulation techniques. Details concerning the construction and test results can be found in [14,15]. The basic concept is schematically In the test, the device is filled with sand up to heights of 1.5-2.0 m. Integral part of the test device are four instrumented wall segments placed on one of the short sides.…”

“…Figure 13 shows the displacements occuring during the filling process in test V18-2 (internal denotation) compared with the associated simulation using 17 soil layers á 0.1 m height. The configuration of this test was a 2D-pile (for details see [14]). This configuration is more challenging for numerical simulation due to the non-planar wall geometry.…”