scholarly journals Stability control measures of soft and broken surrounding rocks of super-large section tunnel constructed using benching tunneling method

2021 ◽  
Vol 769 (3) ◽  
pp. 032082
Author(s):  
Fei Wan ◽  
Bo Wang ◽  
Chongtao Fu ◽  
Lei Li ◽  
Xuefeng Li
Keyword(s):  
Stability Control ◽  
Control Measures ◽  
Large Section ◽  
Tunneling Method

Study on a Flutter Stability Control Measure of Fabricated Steel Truss Bridge

2014 ◽  
Vol 620 ◽  
pp. 7-13
Author(s):  
Cheng Long Zhang ◽  
Qiang Wang ◽  
Xiao Hui He ◽  
En Jiang Bian ◽  
Jie He
Keyword(s):  
Control Measure ◽  
Stability Control ◽  
Control Measures ◽  
Two Dimensional ◽  
Flutter Speed ◽  
Steel Truss Bridge ◽  
Steel Truss ◽  
Flow Field Characteristics ◽  
Computational Fluid Dynamics Cfd ◽  
Truss Bridge

Abstract. To improve the flutter stability of a certain type fabricated steel truss bridge, a method of setting tuyere is put forward. Based on the two-dimensional 3 DOF coupling flutter method (2d-3DOF method), with the numerical wind tunnel established by computational fluid dynamics (CFD), the flutter stability control measures of tuyere is simulated. Through CFD numerical simulation, the flow field characteristics, flutter derivatives and critical flutter speed of origin and tuyere models are obtained. Through analysis, for the certain type fabricated steel truss bridge, the tuyere can improve its flutter stability. It illustrates the feasibility and reliability, and lays the foundation for further applied in practical projects.

scholarly journals Voltage Stability Of South Sulawesi Power System Using Fuzzy Logic Method Based On The Linguistic Variable

2019 ◽  
Vol 54 (6) ◽  
Author(s):  
Sugianto ◽  
Syarifuddin Nojeng ◽  
Yustinus Upa Sombolayuk
Keyword(s):  
Fuzzy Logic ◽  
Power Systems ◽  
Voltage Stability ◽  
Stability Control ◽  
Control Measures ◽  
Short Message ◽  
Linguistic Variables ◽  
South Sulawesi ◽  
Message Service ◽  
Human Thinking

This study aims to apply a new method for controlling voltage stability in electric power systems, using new modeling with linguistic variables of cryptic logic. The method can easily carry out appropriate control measures in accordance with human thinking and acting. The Fuzzy Logic Stabilizer periodically checks the voltage in real time at each bus and maps into linguistic variables, analyzes its control decisions, then calculates how much stability control is sent to all mobile operator numbers that have been registered at the short message service center, so that appropriate control measures are carried out on the On Load Tap Changer, or On Load Voltage Regulator at each substation, according to the contents of the short message it receives. Application of fuzzy logic stabilizer in the 46 bus electricity system of South Sulawesi will increase the quality of bus voltage from an average of 0.08% to 0.5% of the nominal voltage.

scholarly journals STUDY ON INTENSIVE DESIGN AND CONTROL OF CHAMBER GROUP UNDER THE CONDITION OF WEAK SURROUNDING ROCK

Mining Scince ◽  
2019 ◽  
Vol 26 ◽  
Author(s):  
Jun Yang ◽  
Shilin Hou ◽  
Kaifang Zhou ◽  
Bowen Qiao ◽  
Hongyu Wang ◽  
...  
Keyword(s):  
Stability Control ◽  
Field Application ◽  
Surrounding Rock ◽  
Control Measures ◽  
Wire Mesh ◽  
Rock Deformation ◽  
Control Effect ◽  
Obvious Effect ◽  
And Control ◽  
Surrounding Rock Deformation

In order to study the design and stability control of deep soft rock chamber group, taking ninth coal mine of Hebi Coal Power Co., Ltd. as the engineering background, The main problem in normal design is analyzed with the combined method of FLAC3D numerical simulation and field engineering test. and then puts forward targeted control measures and carries out field application. The results show that, compared with the conventional design, the intensive design can reduce the stress concentration degree and plastic zone range of the surrounding rock, as well as reduce the quantities. Compared with conventional supporting schemes, the surrounding rock deformation greatly reduces by more than 82% after adopting bolting and shotcreting with wire mesh + anchor cable + floor anchor supporting. Among them, the floor heave control has obvious effect, and the decreasing amplitude reaches more than 93%. The field application shows that the surrounding rock deformation of the main chamber is within the allowable range, and the chamber control effect is good. Therefore, the research results can provide reference for the design and control of similar chamber groups.

scholarly journals Stability Analysis of Surrounding Rock of Large Section Ultradeep Shaft Wall

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Cheng Li ◽  
Wang Chunlong ◽  
Wang Xi ◽  
Chen Kexu
Keyword(s):  
Control Method ◽  
Stress Test ◽  
Stability Control ◽  
Surrounding Rock ◽  
Main Shaft ◽  
Large Section ◽  
Masonry Construction ◽  
Temporary Support ◽  
The Stability ◽  
Shaft Wall

In order to study the stability of deep surrounding rock during the excavation of new main shaft in Xincheng gold mine, a construction method suitable for large section ultradeep shaft is proposed. A series of analyses were carried out in this study, including the in situ stress test, stress response of surrounding rock disturbance, deformation and failure characteristics, and numerical simulation. Based on the above analysis, the stability control method of surrounding rock in the process of deep excavation of the new main shaft is proposed. The results show that (1) the maximum principal stress of deep surrounding rock of new main shaft is horizontal stress, and the surrounding rock of the shaft has strong rock burst tendency after excavation; (2) the influence range of the deep shaft excavation disturbance is 6.4 times the shaft radius, in which the temporary support should be strengthened to avoid the influence of excavation disturbance on the stability of shaft wall rock; (3) the failure shape of surrounding rock of the deep shaft excavation was “ear” failure, and the failure depth was not more than 2.5 m; (4) after replacing the original “one-excavation and one-masonry” construction with “three-excavation and one-masonry” construction, the temporary support span of the main shaft was adjusted to 12 m, which can make the subsequent concrete shaft wall in the state of “no pressure bearing or slow low pressure bearing,” and the lining compressive safety coefficient was increased to 1.98, which meets the safety requirements.

scholarly journals Research on Mechanisms and Control Measures of Surrounding Rock Disaster in Large Section Roadway with Top Coal under the Influence of Tectonic Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Yang Yu ◽  
Jianfei Lu ◽  
Dingchao Chen ◽  
Yuxin Pan ◽  
Xiangqian Zhao ◽  
...  
Keyword(s):  
Damage Mechanics ◽  
Tectonic Stress ◽  
Surrounding Rock ◽  
Control Measures ◽  
Shanxi Province ◽  
Stress Effect ◽  
Large Section ◽  
Thick Coal Seam ◽  
Surrounding Rock Control ◽  
Seam Mining

Based on the research background of large section roadway with top coal (LSRTC) in thick coal seam mining in Wangzhuang Coal Mine, Shanxi Province, China, catastrophe characteristics of the surrounding rock of the LSRTC were investigated and summarized. Based on the principle of damage mechanics, the critical size discriminant of the LSRTC was deduced, and the induction mechanism of section size effect and tectonic stress effect on the roadway surrounding rock disaster was revealed. Accordingly, the roadway surrounding rock control principle with the basic idea of “stabilizing and controlling top coal, reconstructing the coal wall, and limiting floor heave” was put forward, and the roadway surrounding rock stability control countermeasures with the core technology of “strong pressure support for roof + grouting reinforcement for two sides + bolt barrier for floor angle” were developed, which solved the surrounding rock control problem of the LSRTC under the action of tectonic stress and provided a useful reference for the difficult problem of roadway surrounding rock control under similar conditions.

Research on Generator Tripping Value of Security and Stability Control

2014 ◽  
Vol 494-495 ◽  
pp. 1795-1800
Author(s):  
Hui Ping Zheng ◽  
Yu Long Yang ◽  
Shu Yong Song ◽  
Xin Yuan Liu ◽  
Min Xue ◽  
...  
Keyword(s):  
Steady State ◽  
Theoretical Analysis ◽  
Transmission Line ◽  
Stability Limit ◽  
Stability Control ◽  
Control Measures ◽  
Equal Area ◽  
Simulation Results ◽  
Steady State Stability

In this paper, the problem of the excessive generator tripping value of security and stability control after occurrence of the N-2 fault in the Shentou-Yantong transmission line of Shanxi DaTong Regional grid is studied. And the principle of security and stability control measures based on equal area criterion is analyzed. The reason leading to excessive generator-tripping value of security and stability control after the occurrence of the N-2 fault in Shentou-Yantong region is figured out, and it is that the steady-state stability limit of transmission section decreases and the accelerator power cannot be released. Finally, the results of theoretical analysis are verified by simulations. The simulation results indicate that too large generator-tripping value of security and stability control is mainly caused by decrease of the steady-state stability limit of the transmission section after occurrence of the fault in Datong. The conclusions in the paper have referential significance for the study on similar power concentrated send-out systems.

RESEARCH ON A FLUTTER STABILITY CONTROL MEASURE OF A FABRICATED STEEL TRUSS BRIDGE

2017 ◽  
Vol 41 (2) ◽  
pp. 181-195
Author(s):  
He Xiaohui ◽  
Wang Qiang ◽  
Zhang Chenglong ◽  
Zhang Shunfeng ◽  
Gao Yaming
Keyword(s):  
Control Measure ◽  
Stability Control ◽  
Control Measures ◽  
Two Dimensional ◽  
Flutter Speed ◽  
Steel Truss Bridge ◽  
Steel Truss ◽  
Flow Field Characteristics ◽  
Computational Fluid Dynamics Cfd ◽  
Truss Bridge

In order to improve the flutter stability of a certain type fabricated steel truss bridge, a method of setting guiding plates is proposed. Based on the two-dimensional 3 DOF coupling flutter method (2d-3DOF method), and by use of the numerical wind tunnel established by computational fluid dynamics (CFD), the flutter stability control measures of setting guiding plates are simulated. Through CFD numerical simulation, the flow field characteristics, flutter derivatives and critical flutter speed of original and guiding-plated models are obtained. It is found that for a certain type fabricated steel truss bridge, the guiding plates can improve its flutter stability. Thus, the feasibility and reliability of setting the guiding plates are proved, and the foundation for its further application in practical projects is laid.

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