scholarly journals Numerical Simulation Research on the Stability of Urban Underground Interchange Tunnel Group

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Shiding Cao ◽  
Shusen Huo ◽  
Aipeng Guo ◽  
Ke Qin ◽  
Yongli Xie ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Surrounding Rock ◽  
Distribution Characteristics ◽  
Large Area ◽  
Group Project ◽  
Simulation Research ◽  
Joint Construction ◽  
Tunnel Section ◽  
The Stability ◽  
The Right

Highway tunnel group has the characteristics of large span and small spacing, and the load distribution characteristics of surrounding rock between each tunnel section are complex. Based on geological prospecting data and numerical analysis software, the stress distribution characteristics along the characteristic section and the profile of the tunnel group were obtained. Taking Shenzhen Nanlong complex interchange tunnel group project as an example, the results show that (1) the excavation area of Qiaocheng main tunnel gradient section is large, and the grade of surrounding rock is poor, which leads to the phenomenon of large-area stress concentration on the right wall of this section. (2) The tunnels in the joint construction section of the tunnel group belong to the stress concentration area, and the influence of the right line excavation of Qiaocheng on the stability of the main tunnel of the right line of Baopeng is greater than that of the main tunnel of the left line of Baopeng. (3) The stress concentration of surrounding rock in the intersection section between the main tunnel and the ramp is caused by the too small distance between the main tunnel and the ramp of Baopeng. (4) The distance between the partitions in the K3 + 240 multiarch section of Qiaocheng is an important factor affecting the stability of the surrounding rock of the cave.

scholarly journals Analysis of suspension bridge tunnel-type anchorage construction on the stability of surrounding rock

2020 ◽  
Vol 198 ◽  
pp. 02006
Author(s):  
Nana Li ◽  
Yongqiang Zhou ◽  
Yanqiang Zhao ◽  
Guiju Li
Keyword(s):  
Suspension Bridge ◽  
Surrounding Rock ◽  
Construction Process ◽  
Analysis Model ◽  
Stability Of Surrounding Rock ◽  
Numerical Software ◽  
Left And Right ◽  
Simulation Results ◽  
The Stability ◽  
The Right

In order to study the interaction between the left and right tunnels of suspension bridge tunnel-type anchorage, the finite difference numerical software is used to analyze the mechanical properties of the surrounding rock during the construction process. A numerical analysis model based on FLAC3D is established to analyze the stress, displacement and plastic zone changes of the surrounding rock of right tunnel anchor cavern during the construction of left tunnel anchor cavern. The right tunnel anchor cavern is excavated firstly, and then the left tunnel anchor cavern is excavated. The numerical simulation results show that the main displacement of the right tunnel occurs in the construction stage of the anchor plug body and the rear anchor cavern of the left tunnel. During the excavation of the left tunnel, the plastic zones of the left and right tunnel anchor caverns are only connected above the middle of the waist wall. Therefore, it is suggested that during the construction process, especially in the excavation stage of the anchor plug body and the rear anchor cavern, the area above the middle of the tunnel waist wall should be strengthened in time to ensure the construction safety.

scholarly journals Numerical Simulation Research on Distribution Characteristics of Overlying Rock Stress Field in Floor Roadway

2021 ◽  
Vol 257 ◽  
pp. 03024
Author(s):  
Zhonghua Wang
Keyword(s):  
Stress Field ◽  
Field Distribution ◽  
Theoretical Basis ◽  
Surrounding Rock ◽  
Horizontal Distance ◽  
Distribution Characteristics ◽  
Rock Stress ◽  
Simulation Research ◽  
Location Selection ◽  
Coal Roadway

In order to explore the distribution characteristics of the overlying rock stress field in the floor roadway at different locations, FLAC3D software was used to simulate and analyze the surrounding rock directly above the floor roadway and the surrounding rock within 15m on both sides of the floor roadway when the distance between the floor roadway and the coal roadway and the horizontal distance were changed. The stress field distribution characteristics are obtained, and the stress field distribution characteristics of different areas directly above and on both sides of the floor roadway are obtained, which provides a theoretical basis for the location selection and support of the floor roadway.

Study on Design of Tunnel Section for Danba Diversion Tunnel

2014 ◽  
Vol 501-504 ◽  
pp. 1732-1735
Author(s):  
Jie Liu ◽  
Liang Tang ◽  
Ya Zuo ◽  
Jin Long Guo
Keyword(s):  
Stability Analysis ◽  
Plastic Zone ◽  
Cross Sections ◽  
Surrounding Rock ◽  
Hydropower Station ◽  
Diversion Tunnel ◽  
Rock Stability ◽  
Tunnel Section ◽  
Tunnel Design ◽  
The Stability

Analyzing and Evaluating the stability of the surrounding rock is an indispensable and important part in the tunnel design. In this paper, the surrounding rock stability of Danba hydropower station diversion tunnel is dealt with, FLAC3Dsoftware is used for stability analysis. Selecting three different cross sections for calculation models, comparing with the displacement and principal stress and the plastic zone which calculated by FLAC3D, we can evaluate their stability and get the best diversion tunnel design.

scholarly journals Assessment of Interaction Between A Waste Storage Dam And Instability In Downstream Right-Side Slope By 3D Numerical Analyses

2021 ◽  
Author(s):  
Candan Gokceoğlu ◽  
Berna Unutmaz
Keyword(s):  
Slope Failure ◽  
Slope Instability ◽  
Main Question ◽  
Large Area ◽  
Mining Operations ◽  
Waste Storage ◽  
The People ◽  
Before And After ◽  
The Stability ◽  
The Right

Abstract Waste dams (tailings) are used for storing the byproducts of mining operations and very common in mine industry. As the material they are storing can be harmful for the environment and the people in the vicinity, the construction of these dams is of high importance. During the construction phase, the topography of the site and geological- geotechnical parameters of the soils around the dam are as important as the stability and the leakage issues of the main dam body. In this paper, a nickel-ore waste dam located in Manisa-Gördes, Turkey is investigated in detail. At the downstream side of the dam, there was a slope instability at the right-hand side slopes due to improper loading on the top of these slopes. Whether this slope failure will affect the stability of main dam body or not is the main question of this study. Within these confines, 3D finite element analyses that cover a large area, including the dam, upstream and downstream sides and the waste have been performed before and after the planned downstream slope rehabilitation. The results show that after the rehabilitation of the slopes, the deformations decreased considerably and the waste dam became safer.

scholarly journals Study of the stability of tunnel construction based on double-heading advance construction method

2020 ◽  
Vol 12 (1) ◽  
pp. 168781401989696 ◽  
Author(s):  
Zhanping Song ◽  
Guilin Shi ◽  
Baoyun Zhao ◽  
Keming Zhao ◽  
Junbao Wang
Keyword(s):  
Numerical Simulation ◽  
Construction Method ◽  
Field Monitoring ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Successful Implementation ◽  
Simulation Results ◽  
The Stability ◽  
Sand Stratum ◽  
The Right

The deformation and significant settlement of surrounding rock often occur during tunnel construction with the condition of abundant water and weak cementing sand. In order to study the construction method and stability under such soft stratum, this article takes Taoshuping tunnel as the engineering background and puts forward a new tunnel construction method—double-heading advance construction method by comparing the advantages and disadvantages of various traditional construction schemes. The numerical simulation of tunnel construction process using this method is carried out to illustrate the rationality and feasibility of the method. The conclusions are drawn by comparing the numerical simulation results with the field monitoring data analysis. The numerical simulation results show that the maximum settlement value caused by excavation construction is in the parts 5 and 6 of the upper half-section and the part 7 of the central section. The settlement values of parts 5, 6, and 7 accounted for 32.4%, 24.3%, and 18.9% of the total settlement values, respectively. So, the supporting measures for double-heading advance excavation construction of these three parts should be strengthened properly. The stress of the right hance changes greatly before and after the demolition of temporary support. The maximum positive value of stress is 23 kPa and the maximum negative value of stress is −32 kPa. Therefore, the length of temporary bracing should be strictly controlled during construction and the monitoring of the right hance area should be strengthened. Furthermore, it is necessary to strengthen the supporting measures and monitoring in the right spandrel area as the surrounding rock pressure in the right spandrel area is higher than the left spandrel area. The optimum excavation height of the upper half-section in Taoshuping tunnel is determined to be 5.4 m and the reasonable excavation distance between parts 1 and 5 is determined to be 25–30 m by parameter optimization. Finally, the variation law of numerical simulation and field monitoring results is consistent, which shows that the double-heading advance construction method has a better effect on the stability control of surrounding rock, and the rationality and feasibility of this method are validated effectively. Therefore, the double-heading advance method is suitable for tunnel construction in the sand stratum with rich water and weak cementation, and the successful implementation of this method in Taoshuping tunnel also provides a reference for subsequent tunnel construction in the sand stratum with rich water and weak cementation.

scholarly journals Installation Time of an Initial Support for Tunnel Excavation upon the Safety Factors of Surrounding Rock

2020 ◽  
Vol 10 (16) ◽  
pp. 5653
Author(s):  
Yan-Jun Zhang ◽  
Kai Su ◽  
Hong-Ze Zhu ◽  
Zhong-Dong Qian ◽  
He-Gao Wu
Keyword(s):  
Safety Factor ◽  
Support System ◽  
Surrounding Rock ◽  
Engineering Practice ◽  
Tunnel Face ◽  
Tunnel Section ◽  
Initial Support ◽  
Global Safety Factor ◽  
The Stability ◽  
Installation Time

In engineering practice, the initial support system is commonly installed in the vicinity of the tunnel face after excavation, whereas the self-capacity of rock mass will fail to be utilized and the cost of the initial support system will be expensive. In this study, a methodology is proposed to determine the appropriate timing of initial support installation to find out the balance of tunnel safety and construction cost. Firstly, the global safety factor is introduced as the critical indicator to evaluate tunnel stability. Then, the comprehensive graphic relationship between the global safety factor and the distance to the tunnel face is established. Once the global safety factor decreases to an admissible value, the stability of the surrounding rock is in a critical state and the corresponding distance is the recommended location for installing the initial support. In these procedures, the installation time of the initial support at the typical tunnel section can be quickly designed and fed back by a direct indicator during construction. Meanwhile, several cases with different conditions have been carried out to discuss the regularity of the method.

Monitoring Analysis of the Underground Cavities in Guandi Hydropower Station during the Construction Period

2011 ◽  
Vol 368-373 ◽  
pp. 2925-2931
Author(s):  
Chun Yu Gao ◽  
Jian Hui Deng ◽  
Fan Li Meng
Keyword(s):  
Surrounding Rock ◽  
Hydropower Station ◽  
Water Control ◽  
Maximum Deformation ◽  
Monitoring Design ◽  
Geological Conditions ◽  
Underground Cavities ◽  
The Stability ◽  
Tail Water ◽  
The Right

The underground cavities of the Guandi Hydropower Station comprise four pressure division tunnels, a generator chamber, a main transformer chamber, a tail water control chamber and two tail water tunnels and arrange in the basalt mountain on the right bank of the dam. Based on the brief introduction of cavity arrangement, geological conditions, monitoring design and execution, the deformation magnitude and deformation characteristics of the three major cavities are focused on analyzing. The stability of the cavities is evaluated. The quality of the surrounding rock masses of the underground cavities of the Guandi Hydropower Station is good and the deformation is normally less than 30mm. However, some parts have large deformation due to the influence of the structure surfaces and the maximum deformation is 61.49 mm. Most of the parts with larger deformation are the middle and upper positions of the side walls and rock anchor beam positions. The structure surfaces have noticeable action for controlling the surrounding rock mass deformation. The stability of the cavities is good.

Analysis on Types of In Situ Stress Field and its Effect to Roadway in Deep Coal Mines

2011 ◽  
Vol 90-93 ◽  
pp. 353-358
Author(s):  
Chao Ru Liu
Keyword(s):  
Stress Concentration ◽  
Plastic Zone ◽  
Coal Mines ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Stress Fields ◽  
Different Types ◽  
The Stability ◽  
Two Sides

By analyzing a large number of in-situ stress data measured in underground deep coal mines, two types of in-situ stress fields exit in deep coal mines, σHvh and σvHh, which influences on the stability of underground deep roadways are analyzed by means of numerical simulation. The results show that the destruction of surrounding rock varies greatly in equal value stress fields with different types. In σHvh, the plastic zone of roof and floor of roadways is larger than the two sides, and stress concentration appears in front of heading face and in roof and floor of roadways, but not in two sides, more considerations should be given to the roof and floor supporting. In σvHh, plastic zone of two sides is larger than the roof and floor, and stress concentration appears in front of heading face and the sides of roadways, but not in the roof and floor, so more supporting considerations should be given to the two sides while protecting the roof.

Analysis of Monitoring and Measurement of Small Clear Spacing Tunnel in the Excavation by NATM

2012 ◽  
Vol 482-484 ◽  
pp. 581-584
Author(s):  
Dong Ming Zhang ◽  
Zi Xiong Chen ◽  
Xiao Han Qi
Keyword(s):  
Measured Data ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Distribution Characteristics ◽  
Ground Settlement ◽  
Tunnel Excavation ◽  
Construction Scheme ◽  
Study Results ◽  
The Stability ◽  
Monitoring And Measurement

Due to its convenience, quickness, cheapness and so on, NATM is widely used in the tunnel excavation. In order to guarantee security when tunnel construction and study the stability of tunnel surrounding rock, Supervision and measurement is essential in the tunnel excavation, the result of which may influence tunnel excavation directly. Based on the analyses of measured data, the distribution characteristics and variation laws of the ground settlement, crown settlement and convergence around the tunnel, the displacement of the interior of surrounding rock are all studied. The study results are drawn to provide the basis for modifying and optimizing the design and construction scheme.

Symmetrizable Difference Dchemes

2005 ◽  
Vol 5 (1) ◽  
pp. 3-50 ◽  
Author(s):  
Alexei A. Gulin
Keyword(s):  
Initial Data ◽  
Difference Scheme ◽  
Difference Schemes ◽  
Time Dependent ◽  
Stability Boundaries ◽  
Typical Representative ◽  
Variable Weight ◽  
The Stability ◽  
Conditions Of Stability ◽  
The Right

AbstractA review of the stability theory of symmetrizable time-dependent difference schemes is represented. The notion of the operator-difference scheme is introduced and general ideas about stability in the sense of the initial data and in the sense of the right hand side are formulated. Further, the so-called symmetrizable difference schemes are considered in detail for which we manage to formulate the unimprovable necessary and su±cient conditions of stability in the sense of the initial data. The schemes with variable weight multipliers are a typical representative of symmetrizable difference schemes. For such schemes a numerical algorithm is proposed and realized for constructing stability boundaries.

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