Rectangle piles have been widely used to stabilise problematic slopes with typically non-linear plastic deformation behaviour. This paper introduces analytic solutions to soil arching effect based on the slope soil and piles interaction. In view of stress condition of the passive piles subjected to the lateral force, the stress expression of arbitrary point of the soil behind the piles is derived from soil mechanics, elastic and plastic theories, and the mechanical model of soil arch is built. Stress isoline distribution of soil arch is found to be hyperbolic, shoulder expansion arch, saddle and domal. After the influence factors on soil arching effect are discussed in detail, the governing equation of maximum pile spacing is established based on the Mohr-Coulomb theory of soil shearing strength. Finally, a practical case of slope prevention engineering is given for the design of pile spacing to verify the rationality of analytic solution.

Commonly used model materials in structural model testing are gypsum, added-weight emulsion, added-weight rubber, PlexiglasTM, epoxy resin, and polyvinyl chloride PVC. These materials are viscoelastic and their mechanical properties are unstable, especially the elastic dynamic modulus. To discuss the principle of variation on the elastic dynamic modulus, the materials PlexiglasTM, PVC plastic, and added-weight rubber were chosen for dynamic testing; the factors of temperature effect, size effect, and the effect of loading modes are also discussed.

The properties of frequency response of five kinds of model materials in hydrotechnics are discussed and analyzed by the static tension test and the dynamic cantilever beam test. The frequency response and the changing of the modal dynamic modulus of elasticity are compared between linear elastic and viscoelastic materials. The results show that the modal dynamic modulus of elasticity for linear elastic material is insensitive to frequency and remains stable, while the modal modulus for viscoelastic material changes obviously with frequency, especially at low frequency, which leads to large simulation errors. In this paper, the line portion of the frequency response curve is suggested to be the working frequency, which can eliminate large simulation errors and result in ideal results.