Estimation of earth pressure against retaining walls with different limited displacement modes based on elastic theory

The earth pressure acting on retaining walls due to creep and consolidation is under limited equilibrium conditions(limited displacement). Linear elastic constitutive theory can be applied to determine earth pressure distribution along retaining walls under limited displacement condition. In addition,tangent modulus in Duncan-Chang nonlinear elastic model was introduced to reflect the variations of soil modulus with confining pressure, and boundary strains were derived from Rankine active earth pressure, Rankine passive earth pressure, static earth pressure and principal stress direction deflection.According to the above four boundary strains, earth pressure on retaining walls was divided into five state zones. By comparing the calculation results obtained from the equations proposed in this paper with those of experimental tests, the following conclusions can be drawn: earth pressure distribution was always nonlinear along retaining walls for translation displacement(T mode), rotation displacement around wall base(RB mode), and translation + rotation displacement around wall base(RBT mode). Also,calculated earth pressure distributions along with the depth of wall were found to be consistent with measured values under three displacement modes.Additionally, a parametric study was carried out to evaluate the effects of internal friction angle and backfill soil cohesion on earth pressure. It could be seen from the above series of studies that the earth pressure equations derived in this work could be well applied in practical engineering in designing retaining walls.

Quantum nonlocality evolution for two entangled mesoscopic fields under decoherence

Investigation of the nonlocality evolution of entangled mesoscopic fields under decoherence not only is important for understanding the quantum–classical transition,but also has relevance to quantum communication and quantum computation protocols based on continuous variables.According to previous formulations of Bell inequalities,the system loses nonlocal features far before the disappearance of entanglement.We here construct a new version of Bell signal based on rotated and displaced on–off correlations,with which the Bell inequality is violated as long as there remains entanglement and the field state components keep quasiorthogonal.Consequently,the nonlocal character revealed by our formulation decays much slower compared with those based on previous ones.More importantly,there exists a wide regime where the Bell inequality is restored with previous formulations but remains to be violated based on our correlation operators.

Multiple damage detection in complex bridges based on strain energy extracted from single point measurement

Strain Energy of the structure can be changed with the damage at the damage location.The accurate detection of the damage location using this index in a force system is dependent on the degree of accuracy in determining the structure deformation function before and after damage.The use of modal-based methods to identify damage in complex bridges is always associated with problems due to the need to consider the effects of higher modes and the adverse effct of operational conditions on the extraction of structural modal parameters.In this paper,the deformation of the structure was determined by the concept of influence line using the Betti-Maxwell theory.Then two damage detection indicators were developed based on strain energy variations.These indices were presented separately for bending and torsion changes.Finite element analysis of a five-span concrete curved bridge was done to validate the stated methods.Damage was simulated by decreasing stiffness at different sections of the deck.The response regarding displacement ofa point on the deck was measured along each span by passing a moving load on the bridge at very low speeds.Indicators of the strain energy extracted from displacement influence line and the strain energy extracted from the rotational displacement influence line(SERIL)were calculated for the studied bridge.The results show that the proposed methods have well identified the location of the damage by significantly reducing the number of sensors required to record the response.Also,the location of symmetric damages is detected with high resolution using SERIL.