Tunnel Lining Segment Deformation and Cracking Mechanisms during Tunneling in Complex Mixed Grounds with the Combined Mining and Shield Tunneling Method

Tingjin Liu,Shuyi Zhang,Kepeng Yu,Hongyuan Liu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.1

The combined mining and shield tunneling method solves the challenge that shield machine is slow to excavate hard rock formations during tunneling in complex mixed grounds such as soft soils mixed with hard rocks, which, however, causes the deformation and cracking of tunnel segments. Both in-situ field measurements and three-dimensional numerical simulations are conducted in this study to analyze the segment deformation and cracking mechanism of a tunnel excavated in complex mix grounds with the combined mining and shield tunneling method. It is concluded that the segment deformation and cracking are caused by insufficient pea-gravel fillings and uneven grouting pressures. To ensure the tunnel ovality satisfying standards and minimize the segment deformation and cracking, the angle range of the tunnel wrapped in the pea gravel should be greater than 180° and the resistance coefficient provided by the filling layer after grouting should be greater than 20 MPa/m. Moreover, it is found that the difference between the grouting pressures at the top and bottom of the tunnel has a significant impact on the overall deformation and opening amount of the joints between the segments.

Research progress of single-atom coating and its application prospect in protective coatings

Chijia Wang,Qianqian Yin,Shuyi Liu,Jianxin Wang,Weihao Fan,Zhanjian Liu,Fatang Liu,Yize Liu,Huaiyuan Wang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.128 No.-

Coating technology is the most economical and efficient approach to retard metal corrosion, and newcomposite coatings prepared by adding monoatomic fillers to a polymer matrix have excellent corrosionresistance and good mechanical properties. The single-atom coating formed by the immobilization ofmetal atoms alone on the matrix or filler represents the maximum utilization of atoms at the presentstage, which has unique coordination properties, active sites, and synergistic effects with the support. Compared with traditional fillers, single-atom fillers not only have the advantages of supporting fillersbut can also provide monatomic metals to form passivation films, promote the progress of catalytic passivationreactions, and combine organic compounds to generate new composite materials. This paperfocuses on the preparation methods and mechanisms of single-atom coatings in the field of batteriesand catalysts as well as the application of composite materials prepared by combining single-atom materialswith polymer matrices in the field of metal protection. The preparation methods, application prospects,and coating characteristics of various single-atom composites were summarized. In addition,we discuss the potential applications of single-atom coatings in the design of future composite coatings.

Pile-sinking force modeling and analysis of anti-pull impact pile driver

Shuyi Yang,Deshun Liu,Yaobing Sun 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.8

A "Rigid body - spring - rigid body - elastic rod - rigid body - spring - elastic rod" impact system dynamics model for an anti-pull impactpile driver is established based on the Newton mechanics and stress wave theory. In the developed model, the force, velocity, andstress curves are acquired by solving the dynamic equations. Influences of system dynamics parameters on the maximum pile-sinkingforce are discussed. Results show that mass and velocity of the impact hammer, stiffness of buffer spring and pile cap have significantimpacts on maximum pile-sinking force, while mass of transmission box and platen have less effects. In engineering applications, maximumpile-sinking force can be controlled by rational allocation and design of pile cap and platen’s stiffness. This work can provide someguidelines for the future product optimization design. As a result, impact performance pile drivers with much better can be designed.

Modified organic reagent for deeply purifying crude TiCl4: an in-depth study on key component and mechanism

Yang Shuyi,Xing Zhenqiang,E Tao,Liu Lin,Qian Jianhua 한국탄소학회 2022 Carbon Letters Vol.32 No.3

Organic reagent is considered as one of the most promising reductants for deeply removing vanadium (V) trichloride oxide (VOCl3) from crude titanium tetrachloride (TiCl4). Nevertheless, indeterminate active component and unclearly removal mechanisms appear to be the obstacles to separate VOCl3 from TiCl4 using organic reagent. Herein we conduct the experiment to explore it. Firstly, the organic reagents are obtained from enterprise (noted as EOR1–EOR7), and then it is determined that carbon aromatic (CA) is the active component for removing VOCl3. Furthermore, modified organic reagents (noted as MOR1–MOR4) are prepared via adding aromatic hydrocarbon oil and stearic acid to EOR7, then indicating that MOR3 is endowed with the best capacity to remove VOCl3. In addition, the residues obtained from distillation experiment are comprehensively analyzed (using X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM) etc.), revealing that porous amorphous carbon that deriving from MOR, plays an excellent role in removing VOCl3 from TiCl4 system. Therefore, the removal mechanisms can be explained like that porous amorphous carbon reduces VOCl3 into insoluble vanadium (III) chloride (VCl3) and vanadium (IV) oxide dichloride (VOCl2), and then they are separated via adsorption process, with the help of porous amorphous carbon.

Experimental Study on the Longitudinal Mechanical Behavior of Shield Tunnel in Soft-Hard Uneven Strata and the Reinforcement Effect of Longitudinal Channel Steel

Tingjin Liu,Shuyi Zhang,Yongfeng Tang,Zhenwei Ye 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1

This paper investigates the longitudinal behavior and failure pattern of shield tunnel, as well as the reinforcement mechanism of longitudinal channel steel, using reduced-scale tunnel models assembled with 24 lining rings. The longitudinal behavior of the shield tunnel and the reinforcement effect are discussed in terms of vertical deformation, joint deformation, and concrete cracking. The results indicate that the shield tunnel without reinforcement longitudinallydeforms in a “bending and dislocation” mode, with the failure pattern dominated by bending deformation. In contrast, the failure pattern of the shield tunnel reinforced by channel steels is characterized by brittle shearing dislocation fracture of the circumferential joint. The load at which damage occurs in the reinforced tunnel model is 1.74 times and 2.04 times that of the non-reinforced staggered and straight jointed tunnels. The reinforcement reduces the horizontal convergence discrepancy of lining rings above the soft foundation spring and the adjacent lining rings, which improves the overall integrity of the tunnel structure.

The donor bound exciton states in wurtzite GaN quantum dot

Yaming Liu,Congxin Xia,Shuyi Wei 한국물리학회 2009 Current Applied Physics Vol.9 No.1

Based on the effective mass approximation, the donor bound exciton states in a wurtzite (WZ) GaN/AlGaN quantum dot (QD) are investigated by means of a variational method, including the strong built-in electric field effect due to the spontaneous and piezoelectric polarizations. Numerical results show that the donor bound exciton binding energy is highly dependent on the impurity position and QD size. In particular, we find that the donor bound exciton binding energy is insensitive to dot height when the impurity is located at the right boundary of the WZ GaN/AlGaN QD with large dot height. Based on the effective mass approximation, the donor bound exciton states in a wurtzite (WZ) GaN/AlGaN quantum dot (QD) are investigated by means of a variational method, including the strong built-in electric field effect due to the spontaneous and piezoelectric polarizations. Numerical results show that the donor bound exciton binding energy is highly dependent on the impurity position and QD size. In particular, we find that the donor bound exciton binding energy is insensitive to dot height when the impurity is located at the right boundary of the WZ GaN/AlGaN QD with large dot height.

Automatic Voltage Equalization Circuit Based on Multiple LC Resonant Units for Series-Connected Supercapacitor Strings

Zhang Xiaobing,Zhou Guohua,Liu Shuyi 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

The series-parallel switched-capacitor (SPSC) equalization circuit has high voltage stress on switch. To overcome this problem, an automatic voltage equalization circuit based on multiple LC resonant units is proposed for series-connected supercapacitor strings in this paper. The proposed equalization circuit shortens the equalization paths among cells and uses multiple LC resonant units, which improves the equalization speed. In the proposed equalization circuit, the maximum voltage stress on switch is only half of that in the SPSC equalization circuit. The configuration and operation principle of the proposed equalization circuit is presented. The power, equalization speed, and efficiency of the proposed equalization circuit are analyzed in detail. Based on the theoretical analysis, design considerations of the equalization circuit and design of modularized equalization circuit are proposed to optimize the equalization performance and to further decrease the voltage stress on switch. Simulation and experimental results are provided to verify the validity of the proposed equalization circuit. The results show that the proposed equalization circuit achieves fast equalization speed, high efficiency, and high equalization accuracy.

A Scheme of Real-Time Computer Architecture for Space Intelligent Robot

Bingrong Hong,Hong Liu,Chengfa Wang,Shuyi Wang 대한전자공학회 1993 International Conference on Electronics, Informati Vol.2 No.1

Identification of Dominant Microbial Community and Diversity in Continuously Cropped Pepper Fields

Hui Wang,Li Liu,Shuyi Yu,Tianshu Guan,Baihong Li,Qi Wang,Changyuan Liu 한국원예학회 2021 원예과학기술지 Vol.39 No.4

Pepper blight is the most significant soil-borne disease affecting the continuous cropping of peppers. To identify the effect of Phytophthora capsici infection on microbial flora, we isolated and counted the microorganisms collected from the rhizosphere soil of P. capsici-affected farms that continuously cropped pepper for 3, 6, and 9 years in Liaoning Province, China. The colony and cell morphology, physiological and biochemical characteristics, and 16S rDNA sequence of bacteria and actinomycetes were documented. In addition, colony and microscopic morphology of fungi and the rDNA-ITS sequence were analysed for classification. We observed that healthy and diseased peppers had the largest number of bacteria in the rhizosphere followed by actinomycetes and fungi. After infection, the number of bacteria and actinomycetes decreased with a corresponding increase in the number of fungi, leading to a reduction in the ratio of bacteria/fungi to actinomycetes/fungi. We identified 15 dominant bacterial strains, of which Bacillus represented the most abundant genus consisting of 7 strains followed by Flavobacterium and Staphylococcus. Furthermore, 15 of the 17 actinomycetes strains belonged to the genus Streptomyces. Among the six fungal strains, we found P. infestans, Fusarium, and Penicillium consisting of two strains each. This study elucidated the impact of pathogenic P. capsici on the composition of soil microbes over time and characterized several cultivatable dominant bacterial groups, which can provide a basis for practical intervention strategies to improve soil conditions for continuous cropping.

A SCHEME OF REAL-TIME COMPUTER ARCHITECTURE FOR SPACE INTELLIGENT ROBOT

Bingrong Hong,Hong liu,Chengfa Wang,Shuyi Wang 대한전자공학회 1993 ICEIC:International Conference on Electronics, Inf Vol.1993 No.8