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1

Analytical study on dynamic response of cantilever flexible retaining wall

Yang Xiuzhu, Liu Xinyuan, Zhao Shuang, Yu Jun

Archives of Civil Engineering

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2023

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Vol. 69, nr 2

435--453

EN

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.

2

Investigations on a novel collector for anionic reverse flotation separation of quartz from iron ores

Fang Ji, Ge Yingyong, Liu Shunbing, Yu Jun, Liu Cheng

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 1

136--155

EN

It is necessary to exploit an easy and effective way to obtain flotation collector. In this paper, oleic acid was modified by oxidation reaction to obtain an excellent collector. The ﬂotation performances of oleic acid and its oxidation products were systematically investigated and a novel collector ((E)-8,11-dihydroperoxyoctadec-9-enoic acid, EDEA) was obtained. Single mineral flotation tests results showed that EDEA had strong flotation power towards quartz at pH＞11 and hardly floated hematite and magnetite at pH=8~13. The recovery of quartz could achieve 92.35% with 120 mg/L EDEA under the condition of pH=12 and dosage of CaCl2 60mg/L while the recovery was 62.44% with 120 mg/L oleic acid. Bench scale flotation tests results showed that EDEA had a preferable effect on separating quartz from iron ore especially at low flotation temperature (288K). The mechanism research revealed that EDEA attracted on quartz surface through electrostatic attraction and the neighboring EDEA molecules could form intermolecular hydrogen bonds which resulted in a closer alignment of EDEA on quartz surface.

3

Adsorption behavior and mechanism of an ether amine collector on collophane and quartz

Fang Ji, Ge Yingyong, Yu Jun

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 1

301--310

EN

The adsorption behaviors of an ether amine surfactant, N1-(3-((8-methyl-nonyl)oxy) propyl)propane-1,3-diamine, on collophane and quartz were studied. Batch adsorption experiments were conducted to characterize the thermodynamic behavior of the adsorption process and to calculate the maximum adsorption. Results demonstrated that the adsorption of the ether amine on quartz was greater than collophane. Adsorption mechanisms were studied by means of contact angle measurement, zeta potential measurement, FT-IR analysis, and X-ray photoelectron spectroscopy. The results showed that the adsorption of the ether amine surfactant on quartz surface was easier and more efficient than collophane. Micro-flotation tests testified that the collector can efficiently separate collophane from quartz at room temperature in neutral medium.