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Analytical study on dynamic response of cantilever flexible retaining wall

Yang Xiuzhu, Liu Xinyuan, Zhao Shuang, Yu Jun

Archives of Civil Engineering

2023

Vol. 69, nr 2

435--453

Based on wave mechanics theory, the dynamic response characteristics of cantilever flexible wall in two-dimensional site are analyzed. The partial derivative of the vibration equation of soil layer is obtained, and the general solution of the volume strain is obtained by the separation of variables method. The obtained solution is substituted back to the soil layer vibration equation to obtain the displacement vibration general solution. Combined with the soil-wall boundary condition and the orthogonality of the trigonometric function, the definite solution of the vibration equation is obtained. The correctness of the solution is verified by comparing the obtained solution with the existing simplified solution and the solution of rigid retaining wall, and the applicable conditions of each simplified solution are pointed out. Through parameter analysis, it is shown that when the excitation frequency is low, the earth pressure on the wall is greatly affected by the soil near the wall. When the excitation frequency is high, the influence of the far-field soil on the earth pressure of the wall gradually increases. The relative stiffness of the wall, the excitation frequency and the soil layer damping factor have a significant effect on the dynamic response of the flexible retaining wall.

Estimation of the upper flammability limits for alkanes in air at increased pressures

Wan Xin, Wang Min, Cao Chunyan, Zhao Shuang, Song Zhiguo

Polish Journal of Chemical Technology

2022

Vol. 24, nr 2

35--41

A method is proposed to predict the upper flammability limits for alkanes in air at increased pressures. The upper flammability limits for methane, ethane, propane and n-butane/air mixtures at ambient temperature and initial pressure of 0.3 MPa–2.0 MPa are identified through the adiabatic flame temperature calculation model. The association of calculated adiabatic flame temperature with pressure is presented to determine the upper flammability limit. Research shows the good agreement between the forecast upper flammability limits with pressure dependence and the experimental upper flammability limit values. The average relative error of the estimated upper flammability limits for alkanes in air at high pressures reaches 2.52%.