THEORETICAL SOLUTION OF PILING COMPACTION AND THE INFLUENCE OF PILE-SOIL-BOUNDARY CURVE HYPOTHESIS

Research is ongoing to find theoretical solution to three-dimensional piling compaction. Considering the spacial-axis-symmetric characteristics, the boundary surface of pile-soil interaction is expressed by polynomials of different orders. First, the curve family parameter is introduced to construct the displacement and integral function. Then, the solution of pile-soil interaction is derived by combining the constitutive relation model of Duncan-Chang and the variational theory. Results of engineering computing show that the theoretical solution converges to the classical CEM and the limit equilibrium theory well at the corresponding computing area. Moreover, the effects of polynomial of different orders on the calculation results are not obvious. The conclusion in this paper can be used for reference in the derivation and application for other interaction of structure and soil problems.

Strength analysis of composite rotor helicopter blade, having percussive damage, by limit equilibrium theory

Authors model the limiting state of the helicopter «ANSAT» rotor blade at different flight modes, taking into account the possible damage to the blade in the butt section. The method of variation of elastic constants, based on the limit equilibrium theory and allowing to obtain both upper and lower limits of the limit load, is used to estimate the strength. The stresses in the layers determined in accordance with the deformation law of the associated limit yield surface of these layers, are expressed in terms of the six-dimensional vector of generalized forces. Analysis of the limit stress state is reduced to the analysis of the limit state in the space of the generalized forces. The safety factors of the blade’s butt section depending on the azimuth angle of rotation of the blade are determined for the case when all the generalized forces are proportional to one loading parameter. The possibility of making internal diagnostics of damage areas using x-ray computer tomography is announced. It is proposed to use medical Siemens x-ray tomograph to perform such diagnostics.

On Overloading Design Method for the Slope of Deep Foundation Pit with Layered Soil Braced by Soil Nail

Based on plastic limit equilibrium theory of soil, the suitable values of energy safety factor are discussed here from energy work rate, the new design method for vertical slope of deep foundation pit with layered soil braced by soil nail with even overloading on slope top is proposed and engineering example is given out.

Analysis of Rock Slope Stability on the Basis of Limit Equilibrium Method

To analyze the rock slope stability of open pit, limit equilibrium theory is used and the safety factor of slope stability is calculated by Geo-slope software. Then, the region where local instability or overall instability may occur is determined. Finally, some optimization plans and appropriate protective measures are suggested, providing a theoretical basis for engineering practice.