scholarly journals Review on Early Warning Methods for Rockbursts in Tunnel Engineering Based on Microseismic Monitoring

2021 ◽  
Vol 11 (22) ◽  
pp. 10965
Author(s):  
Shichao Zhang ◽  
Chunan Tang ◽  
Yucheng Wang ◽  
Jiaming Li ◽  
Tianhui Ma ◽  
...  
Keyword(s):  
Early Warning ◽  
Formation Process ◽  
Structure Type ◽  
Microseismic Monitoring ◽  
Research Progress ◽  
Construction Methods ◽  
Methods Development ◽  
Evolution Characteristics ◽  
Geological Conditions ◽  
Rockburst Probability

Due to the different geological conditions and construction methods associated with different projects, rockbursts in deep-buried tunnels often present different precursor characteristics, bringing major challenges to the early warning of rockbursts. To adapt to the complexity of engineering, it is necessary to review the latest advancements in rockburst early warning and to discuss general early warning methods. In this article, first, microseismic monitoring and localization methods applicable under tunneling construction are reviewed. Based on the latest engineering examples and research progress, the microseismic evolution characteristics of the rockburst formation process are summarized, and the formation process and mechanism of structure-type and delayed rockbursts are analyzed. The different methods for predicting the risk and level of rockbursts using microseismic indices are reviewed, and the implementation methods and application cases for predicting potential rockburst areas and rockburst probability based on a mechanical model are expounded. Finally, combined with the new practice in early warning methods, development directions for the early warning of rockbursts are put forward.

scholarly journals A Case Study of Damage Energy Analysis and an Early Warning by Microseismic Monitoring for Large Area Roof Caving in Shallow Depth Seams

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Like Wei ◽  
Qingxin Qi ◽  
Hongyan Li ◽  
Bin Zhang ◽  
Yongren Wang ◽  
...  
Keyword(s):  
Early Warning ◽  
Damage Mechanics ◽  
Coal Pillar ◽  
Microseismic Monitoring ◽  
Energy Model ◽  
Field Application ◽  
Shallow Depth ◽  
Large Area ◽  
Cumulative Energy ◽  
Damage Level

Shallow depth coal seams are widely spread in Shendong mining area, which is located in the Northwestern region of China. When working face is advanced out of concentrated coal pillar in upper room and pillar goaf, strong strata behaviors often cause support crushing accidents, and potentially induce large area residual pillars instability and even wind blast disaster. In order to predict the precise time when the accident happens, guaranteeing life-safety of miner, microseismic monitoring system was for the first time applied in shallow coal seam. Based on damage mechanics correlation theory, the damage energy model is established to describe relationship between damage level and cumulative energy of microseismic events. According to microseismic monitoring data of two support crushing accidents, the damage energy model is verified and an effective early warning method of these accidents is proposed. The field application showed that the early warning method had avoided miners suffering from all support crushing accidents in Shigetai coal mine.

scholarly journals Construction Technology of Composite Cofferdam for Main Pier Bearing Platform of Dongjiang Lichuan Bridge

2020 ◽  
Vol 165 ◽  
pp. 04047
Author(s):  
Jianping Wang
Keyword(s):  
Steel Sheet ◽  
Economic Benefits ◽  
Construction Technology ◽  
High Quality ◽  
Rock Stratum ◽  
Advantages And Disadvantages ◽  
Construction Methods ◽  
Bored Pile ◽  
Geological Conditions ◽  
Pile Cap

Dongjiang Lichuan Bridge in Dongguan City is a curved tower curved beam cable-stayed bridge with a main span of 138m and no back cable. The main pier cap is located on the bank slope of Dongguan Waterway on one side of Nandi Road. The cushion cap is dumbbell type, and the left and right cushion caps are connected by tie beams. In most areas, the top of rock stratum is above the bottom of bearing platform. The rock stratum within the buried depth of bearing platform is moderately to strongly weathered argillaceous siltstone. The geological conditions are complex and the construction is difficult. In line with the principles of speeding up the construction process and improving economic benefits, comprehensive analysis and weighing advantages and disadvantages, the main pier cap adopts a composite cofferdam of filling soil to build an island and combining bored pile rows and steel sheet piles. The construction task of bearing platform of main pier has been completed with high quality. Compared with other cushion cap construction methods, this construction method has the advantages of fast construction, high quality, simple safety, energy saving and environmental protection. This paper briefly introduces the design scheme of composite cofferdam, expounds in detail the operation steps of steel sheet pile construction and the problems needing attention in construction, and provides good reference experience for similar pile cap construction.

Engineering Feasibility Study on the Beijing East 2nd Ring Underground Road

2013 ◽  
Vol 353-356 ◽  
pp. 1495-1501
Author(s):  
Jin Gang Wu ◽  
Ren Dong Chen ◽  
Qiang Bi ◽  
Hua Guo
Keyword(s):  
Large Diameter ◽  
Technical Difficulty ◽  
City Center ◽  
Technical Standards ◽  
Construction Methods ◽  
Geological Conditions ◽  
Solid Foundation ◽  
Complex Construction ◽  
Underground Transportation ◽  
Construction Organization

The Beijing East 2nd Ring underground road is one of the three horizontal and four vertical underground expressways, and it is an important part of Beijing's expressway system. Technical standards, engineering line location, geological conditions, construction methods, construction organization, controlling conditions of the project are illustrated in the paper. Research and demonstration of the feasibility of the projects is carried out. The conclusions are as follows: (1) The overall line location conform to the city's underground transportation system planning. (2) The overall project layout is correct. Underground space is used reasonably. The urban expressways system can be improved. The technical standards of the expressway project can be satisfied. (3) The project connects Puhuangyu Expressway and Beijing-Chengde Highway. Cross-border traffic is solved. That plays an important role to ease the traffic pressure of city center road network. (4) Large diameter shield construction program is feasible. (5) The large cross-section of proposed tunnel, complex construction environment, high technical difficulty, could be included in the forefront of the construction of city tunnel at home and abroad. Scientific and technological research and research projects are proposed to carry out, laying a solid foundation for the smooth implementation.

Construction Method and Numerical Analysis on the Bearing Capacity of the Large Diameter and Abyssal Pile Located in Complex Karst Area

2013 ◽  
Vol 639-640 ◽  
pp. 688-693
Author(s):  
Jin Yi ◽  
Guo Jing He ◽  
Si Si Liu ◽  
Zhi Yong Li ◽  
Zu En Zheng
Keyword(s):  
Bearing Capacity ◽  
Load Transfer ◽  
Large Diameter ◽  
Construction Method ◽  
Karst Area ◽  
Karst Region ◽  
Pile Capacity ◽  
Construction Methods ◽  
Geological Conditions ◽  
Transfer Method

This paper introduced construction method for deep pile of Zishui bridge through karst region and the checking results of the pile bearing capacity. Firstly, main structure of Zishui bridge was simply introduced. Secondly, according to the special geological conditions, construction methods for bored piles in water and drilling platform were described. The discussion focused on the problem of boring and grouting in karst foundation and their solutions. Finally, to ensure that the pile capacity can meet the design requirements, load transfer method was used on the part of pile foundation to calculate the bearing capacity. Results showed that pile bearing capacity meet the requirements, and the feasibility and correctness of construction method of Zishui bridge was also verified,which provides references for the design and construction of the same civil engineering.

Establishment and Application of Microseismic Monitoring System to Deep-Buried Underground Powerhouse

2013 ◽  
Vol 838-841 ◽  
pp. 889-893
Author(s):  
Biao Li ◽  
Feng Dai ◽  
Nu Wen Xu ◽  
Chun Sha
Keyword(s):  
Rock Mass ◽  
Monitoring System ◽  
Wave Velocity ◽  
Microseismic Monitoring ◽  
Surrounding Rock ◽  
P Wave ◽  
Monitoring Method ◽  
Underground Powerhouse ◽  
Geological Conditions ◽  
The Stability

The right bank underground powerhouse of Houziyan hydropower station is a typical deep-buried type with high geostress and complicated geological conditions. To monitor and analyze the stability of surrounding rock mass during continuous excavation of the powerhouse excavation and locate the potential failure zones, an ESG (Engineering Seismology Group) microseismic monitoring system manufactured in Canada was installed in April, 2013. The wave velocity of the monitoring system was determined through fixed blasting tests. And the average location error is the minimum while P-wave velocity is 5700m/s, less than 10m and meeting the system request. By combining the temporal and spatial distribution regularity of microseimic events with field excavation, micro-crack clusters and potential instability zones were identified and delineated. The results will provide a reference for later excavations and supports of the underground powerhouse. Furthermore, a new monitoring method can also be supplied for the stability analysis of surrounding rock mass in deep-buried underground powerhouses.

scholarly journals Preliminary Discussion on Comprehensive Research Method for Rock Burst in Coal Mine Based on Newton’s Second Law

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Jianping Zuo ◽  
Hongqiang Song ◽  
Yunqian Jiang ◽  
Shankun Zhao ◽  
Meilu Yu ◽  
...  
Keyword(s):  
Rock Mass ◽  
Rock Burst ◽  
Research Method ◽  
Surrounding Rock ◽  
Research Progress ◽  
Field Energy ◽  
Second Law ◽  
Preliminary Discussion ◽  
Geological Conditions ◽  
Newton's Second Law

Rock burst is one of the major dynamic disasters that directly threaten production safety in coal mines. According to the current research, the occurrence of rock burst can be described by the generalized Newton’s second law with three elements which are research object, force condition, and motion state. These three elements refer to the coal and rock mass in the mining area, concentrated static and dynamic loads, and dynamic instability of surrounding rock, respectively. On this basis, a comprehensive rock burst research method involving the three elements of Newton’s second law was proposed, which especially focuses on the investigation into geological conditions of mining areas. The research procedure of this method specifically includes the detailed exploration of engineering geological bodies, the classification and stability evaluation of surrounding rock, the measurement and inversion of in situ stress, the evolution analysis of mining-induced stress field, energy field, and fracture field, the study of multiscale failure mechanism of coal and rock mass, the establishment of theoretical failure model of coal and rock mass, the real-time monitoring and warning in potentially dangerous areas, and the reasonable prevention and control in key risk zones. As a preliminary discussion, the significant research progress in each aspect mentioned above has been reviewed and the feasible research directions of rock burst are presented in this paper.

Study on Early Warning of Slope Safety Based on Field Monitoring

2012 ◽  
Vol 204-208 ◽  
pp. 3499-3502
Author(s):  
Jian Hui Sun ◽  
Long Jiang ◽  
Wan Shun Wang
Keyword(s):  
Monitoring System ◽  
Early Warning ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Lateral Deformation ◽  
Strength Reduction Factor ◽  
Geological Conditions ◽  
Deformation Amount ◽  
Slope Treatment ◽  
Slope Safety

The paper has systematically studied stability, deformation property and early warning of high engineering slope in depth, and established the early-warning monitoring system of slope. The results show that: ① The time of displacement deformation is more consistent with the slope treatment, as well as the position of dislocation more consistent with geological conditions, and displacement deformation is less below the position and basically unchanged below a certain depth. ② Lateral deformation increases with increasing reduction factor. Lateral deformation has smaller increment with smaller strength reduction factor, and has a larger increment with larger strength reduction factor. ③ The early-warning monitoring system of slope safety based on deformation amount and safety factor is established.

Effect of Staged Excavation on Retaining Structure in Soft Soil Area

2012 ◽  
Vol 170-173 ◽  
pp. 633-636 ◽  
Author(s):  
Jie Liu ◽  
Xin Guang Xu
Keyword(s):  
Soft Soil ◽  
Horizontal Displacement ◽  
Structure Type ◽  
Operating Conditions ◽  
Deep Soil ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Retaining Structure ◽  
Geological Conditions

Based on a deep foundation pit in Tianjin, the authors introduced the retaining structure type, surrounding conditions, and the geological conditions of proposed field. According to the engineering characteristics, the excavation was divided into three typical operating conditions. Based on the monitoring of staged excavation of deep foundation pit, analysis on horizontal displacement, deep soil displacement, column settlement and bracing axial force was carried out. The general rules of the deformation and internal force of retaining structures induced by staged excavation were given, which will provide the references for similar engineering.

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