Numerical analysis of bearing behaviors of single batter piles under horizontal loads in various directions

The horizontal bearing behavior of a single batter pile(SBP)is vital to its application in practical engineering;however,the horizontal responses of SBPs change with the directions of horizontal loads,and this phenomenon is rarely investigated.Therefore,the directional differences in the horizontal bearing behaviors of SBPs are investigated in this study.Four model tests are conducted to preliminarily examine the effects of the skew angle of horizontal loads on the horizontal bearing capacities and distributions of the bending moments of the SBPs.Subsequently,the differences in the responses of the SBPs under horizontal loads in various directions at full scale are analyzed comprehensively via finite-element(FE)analysis.The effects of the skew angle on SBP-soil interaction are discussed.Moreover,an empirical design method is proposed based on the FE analysis results to predict the bearing ratios of SBPs in medium-dense and dense sand while considering the effects of the skew angle,batter angle,and pile diameter.The method is confirmed to be effective,as confirmed by the close agreement between the predicting results with the model test(reported in this study)and centrifuge model test results(reported in the literature).

Variational Solution of Coral Reef Stability Due to Horizontal Wave Loading

This paper proposes a theoretical method that can be used in calculating the stability of coral reefs or artificial islands.In this work,we employ the variational limiting equilibrium procedure to theoretically determine the slope stability of coral reefs covered with hard reef shells as a result of horizontal wave loads.A reasonable functional is proposed and its extremum is calculated based on the conservation of energy.Then,we deduce the stability factor Ns of coral reefs under combined vertical self-gravity and horizontal wave loads,which is consistent with the published results.We compare some classic examples of homogeneous slopes without hard shells in order to analyze the accuracy of results generated by this variational procedure.The variational results are accurate and reliable according to the results of a series of detailed calculations and comparisons.Simultaneously,some other influence parameters on the reef stability,including the top-layer tensile strength of coral reef,the amplitude of wave loading,and the tensile crack,are calculated and discussed in detail.The analysis results reveal that the existence of a hard reef shell could enhance the stability of reef slope and that there is a nonlinear relationship between the stability factor Ns,the shear strength,and the thickness Ds of the covered coral reef shell.Furthermore,the emergence of top-layer tensile cracks on the coral reefs reduces their stability,and the action of horizontal wave loads greatly decreases the stability of coral reefs.Thus,the hard shell strength and its thickness Ds,surface tensile crack,and wave loading require more careful attention in the field of practical engineering.

The Influence of Aerodynamic Unsteady Effect on Maneuver Load of Aircraft Horizontal Tail

In this paper, the unsteady effect of airflow is introduced into the calculation of aircraft maneuver load, and the results are compared with those obtained by quasi-steady method. Taking the steep pitch maneuver of an aircraft as an example, two methods are used to calculate the aircraft response after the rudder input is given according to the specifications. The calculation results show that if the peak overload of the aircraft is the same, the horizontal tail load increases by about 1% when the unsteady effect of the airflow is taken into account. If the rudder input of the two methods is the same, the unsteady calculation method will increase more. At the same time, the calculation shows that the bigger the deflection speed of rudder surface is, the bigger the difference between them is. Therefore, in order to improve the design quality of aircraft, it is necessary to introduce the unsteady effect into the calculation of loads in the detailed design stage of aircraft.