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34. Optimization Design and Experimental Study of a New Type of Hollow Grouting Anchor Rod Stopper Plug.

Author

XIE Biting, XIAO Mingqing, XU Chen, TIAN Qingfeng, and WANG Kejin

Subjects
GROUTING, TUNNEL design & construction, FIELD research, ANCHORS
Abstract

Anchor rods are widely used in tunnel construction to significantly improve the self-supporting capacity of surrounding rock and reduce structural stress. Hollow grouting anchor rods can greatly enhance their support effectiveness after grouting, and the quality of the grouting directly affects the load-bearing capacity of these rods. This study focused on the optimization design of a newly developed type of hollow grouting anchor rod stopper plug by conducting numerical simulations to refine its structural form and dimensions. The exhaust pressure stabilization effect of the newly developed stopper plug was tested through indoor model experiments and field trials. The results showed that the optimal dimensions for the stopper plug were an upper exhaust groove width of 8. 0 mm and depth of 1. 5 mm, a lower groove width of 11. 3 mm and depth of 1. 0 mm, an air-tight ridge height of 3 mm, and an outer stopper plug diameter of 51 mm at the opening and 50 mm at the far end. The grouting stopper plug was adaptable to various anchor rod hole diameters, and when the difference between the stopper plug and the anchor hole was 0 ~ 4 mm, it met the requirements for pressure stabilization and grouting performance. The experimental results showed that the stabilizing pressure of the new grouting stopper plug was between 0. 7 and 1. 2 MPa, with the anchor rod hole being fully filled and the grout compacted, demonstrating a significant grout-stopping effect. [ABSTRACT FROM AUTHOR]

Published
2024
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45. Design of Slip Ring Based on SSP Compensation and Variable Frequency Control

Author

FENG Xin, FU Zhuang, WANG Kejin, HAO Gaofeng

Subjects
non-contact slip ring, non-contact power transfer, series series parallel (ssp) compensation, phase difference detection, zero phase angle variable frequency control, Engineering (General). Civil engineering (General), TA1-2040, Chemical engineering, TP155-156, Naval architecture. Shipbuilding. Marine engineering, VM1-989
Abstract

In order to avoid the disadvantages of the traditional slip ring, such as easy wear and easy accumulation of static electricity, a novel slip ring design method based on series series parallel (SSP) compensation and variable frequency control is proposed. First, the magnetic circuit of the non-contact slip ring is modeled. The leakage inductance and the magnetizing inductance of the loosely coupled transformer, namely the primary side series compensation and secondary side series parallel compensation, are compensated respectively. Next, due to the influence of temperature and other factors, the sensitivity of some components is analyzed, and the relationship between component parameter variation and resonance frequency variation is obtained. After that, a phase difference detection method based on Hanning window fast Fourier transform is proposed, which can avoid the restriction of hardware performance and improve the anti-interference ability. Finally, according to the calculated phase difference and critical quality factor, a variable frequency control method based on zero phase angle is proposed to help the system work at zero phase angle, thereby reducing the loss of reactive power. The simulation results show that when the component parameters change, the proposed method based on SSP compensation and variable frequency control can quickly help the system work in zero phase angle state, and then improve the efficiency of the system. A prototype is designed to verify the proposed method, and the experimental results are basically consistent with the simulation results. Compared with no compensation method, the efficiency of the proposed method is increased by 5%. The research results show that the method proposed has a high robustness.

Published
2021
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