Wyniki wyszukiwania - BazTech

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Experimental research on the removal characteristics of simulated radioactive aerosols by a cloud-type radioactive aerosol elimination system

Zhang Jiqing, Jia Ying, Lv Xiaomeng, Xiong Tiedan, Huang Yuanzheng, Shen Keke

Polish Journal of Chemical Technology

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2023

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Vol. 25, nr 4

10--18

EN

Radioactive aerosols in the confined workplace are a major source of internal exposure hazards for workers. Cloud-type radioactive aerosol elimination system (CRAES) have great potential for radioactive aerosol capture due to their high adsorption capacity, lack of cartridges and less secondary contamination. A CRAES was designed and constructed, and a FeOOH/rGO composite was directly prepared by a hydro-thermal method to characterise and analyse its morphology, chemical structure and removal efficiency for simulated radioactive aerosols. The results show that the FeOOH/rGO composite works in synergy with the CRAES to effectively improve the removal efficiency of simulated radioactive aerosols. A 30-minute simulated radioactive aerosol removal rate of 94.52% was achieved when using the experimentally optimized composite inhibitor amount of 2 mg/L FeOOH/rGO with 0.2 g/L PVA as a surfactant. Therefore, the CRAES coupled with the composite inhibitor FeOOH/rGO has broad application potential for the synergistic treatment of radioactive aerosols.

2

Mechanical characteristics of twin tunnel underneath construction on existing high-speed railway tunnel

Fei Ruizhen, Peng Limin, Zhang Chunlei, Zhang Jiqing, Zhang Peng

Archives of Civil Engineering

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2023

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Vol. 69, nr 1

403--420

EN

The running speed of high-speed trains in the tunnel is as high as 350 km, which is very sensitive to the construction disturbance of the new shield tunnel. Therefore, it is of positive significance to study the influence of shield tunneling on existing high-speed railway lines and tunnel structures and control standards. Combined with centrifuge test and three-dimensional numerical simulation, the dynamic response of shield tunnel undercrossing existing high-speed railway tunnel is studied, and the influence of settlement joint and steel pipe pile reinforcement on existing tunnel is analyzed. Studies have shown that the existence of existing tunnels will reduce the surface settlement caused by tunnel excavation, but this shielding effect will be reduced if the influence of construction joints is considered. Therefore, if the construction joint is not considered in the numerical calculation, the ground deformation will be underestimated and the mechanical performance of the existing tunnel structure will be overestimated. In addition, steel pipe piles can effectively control the settlement of existing tunnels.

3

Centrifuge model test of parallel shield underneath high-speed railway tunnel

Fei Ruizhen, Peng Limin, Zhang Chunlei, Zhang Jiqing, Zhang Peng

Archives of Civil Engineering

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2022

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Vol. 68, nr 3

661--677

EN

In order to study the ground disturbance and the influence relationship between the two tunnels during the construction of the new shield tunnel undercrossing the existing high-speed railway tunnel, the centrifuge test was used to simulate the construction of the parallel shield tunnel undercrossing the high-speed railway tunnel, and the variation law of the internal force, segment deformation and surface settlement of the existing high-speed railway tunnel undercrossing the shield was studied. It is found that the adverse effects caused by the later tunnel are less than those caused by the first tunnel excavation. For the existing tunnels without settlement joints, the longitudinal settlement of the inverted arch and the vault is U-shaped and anti-U-shaped respectively. The settlement value of the ground surface and the existing tunnel is increased by more than 100%. When the shield passes through the high-speed railway tunnel, the transverse bending strain is larger than the longitudinal, and special attention should be paid at the corner.