scholarly journals Numerical Calculation of Instability of Tunnel Surrounding Rock Based on Elastic Hole Theory

2019 ◽  
Vol 283 ◽  
pp. 012047
Author(s):  
Haobo Yang
Keyword(s):  
Numerical Calculation ◽  
Surrounding Rock ◽  
Hole Theory

Precise grading of surrounding rock based on the numerical calculation of the jointed rock mass

2022 ◽  
pp. 1-32
Author(s):  
Dan Huang ◽  
Xiao-Qing Li ◽  
Wen-Chao Song
Keyword(s):  
Rock Mass ◽  
Numerical Calculation ◽  
Calculation Method ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Surrounding Rock ◽  
Geological Survey ◽  
Survey Method ◽  
Synthetic Rock ◽  
Numerical Calculation Method

In this study, grading of surrounding rock was based on rock mass basic quality (BQ) values according to the specifications in China. Numerical approach was to construct synthetic rock mass (SRM) model to represent the jointed rock mass, and obtain the strength of the rock mass. It represented intact rock by the bonded particle model (BPM), and represent joint behaviour by the smooth joint model (SJM) to construct the discrete fracture network (DFN). In the Hongtuzhang Tunnel, the micro properties of granite cores with different weathered degrees were determined by the validation process, and the calculation representative elementary volume (REV) of surrounding rock was 15 m×15 m. Five slightly weathered, three slightly to moderately weathered, and two moderately weathered granite surrounding rock mass models were established based on the probability distribution of joint sets in each borehole, the conversion BQ value was acquired according by the calculated strength of rock mass model. It was discussed the differences of surrounding rock grades between the geological survey method and the numerical calculation method, and then found that the geological survey report is higher than the numerical calculation method predicted. And the numerical calculation is consistent with the actual excavation of rock mass at borehole A1388.

Influence of Structural Plane in Similar Soil Surrounding Rock on Excavation Stability

2010 ◽  
Vol 168-170 ◽  
pp. 1318-1324
Author(s):  
Qiang Chen ◽  
Wei Tao Chen ◽  
Guo Wei Meng
Keyword(s):  
Numerical Calculation ◽  
Surrounding Rock ◽  
Disintegration Time ◽  
Structural Plane ◽  
Research Results ◽  
Tunnel Stability ◽  
Excavation Stability ◽  
Shearing Strength ◽  
The Stability ◽  
Similar Soil

Lots of primary or secondary structural planes in similar soil surrounding rock are the main difference with Quaternary soil surrounding rock, but the particularity isn’t considered in the analysis of tunnel stability. The fact, which similar soil surrounding rock has most weak structural planes, is testified by engineering examples. The influence of structural plane in similar soil surrounding rock on excavation stability was analyzed through combining theory with disintegration test and numerical calculation. The research results show that there are a lot of structural planes in similar soil surrounding rock. The angle between structural planes and tunnel axes and shearing strength of structural planes control the stability of tunnel. Disintegration time of soil is shortened due to structural planes. On a certain condition, structural planes can induce local collapse in soil surrounding rock while excavating.

Influence Law of Structural Inclination for the Advanced Excavation Method of the Tunnel

2013 ◽  
Vol 368-370 ◽  
pp. 1464-1467
Author(s):  
Chao Gao ◽  
Lei Chen ◽  
Shang Lun Liu
Keyword(s):  
Numerical Calculation ◽  
Hard Rock ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Geological Condition ◽  
Construction Process ◽  
Rock Stability ◽  
Highway Tunnel ◽  
Calculation Results ◽  
Ground Stress

A deep-buried highway tunnel is constructed with complex geological condition which existing an alternation of soft and hard rock and having feature of high ground stress, and extrusion, fall-block and twisted phenomena of supporting structure appear in many places during construction which pose a serious threat to the safety of tunnel construction. In combination with the construction process of Shimenya tunnel, by using the finite difference software FLAC3D, the surrounding rock stability is simulated, and the numerical calculation results of advanced pilot excavation method with different structural inclinations. The conclusion can be used for reference for the design and research of similar tunnels.

A Method for Determining Second Lining Supporting Opportunity in Soft Rock Tunnel

2011 ◽  
Vol 243-249 ◽  
pp. 3644-3651
Author(s):  
Zhong Wen Wang ◽  
Jian Qin Fang ◽  
Cai Chu Xia ◽  
Yue Wei Bian ◽  
Kun He
Keyword(s):  
Numerical Calculation ◽  
Limit State ◽  
Soft Rock ◽  
Surrounding Rock ◽  
Burial Depth ◽  
Limit States ◽  
Rock Tunnel ◽  
Grade Rock

The determination criteria and methods are summarized for the reasonable supporting opportunity which is obtained from the numerical calculation of GeoFEM. It is the limit state of surrounding rock when the second lining undertakes 10 percent of load in Ⅳ grade rock(buried depth 121m), and the surrounding rock with burial depth 43meters reaches its limit state when the second lining bears 5 percent of load in Ⅴ grade rock. The reasonable supporting opportunity will be obtained from those two limit states with the criteria.

Optimization of Reasonable Interval of Parallel Tunnel

2012 ◽  
Vol 170-173 ◽  
pp. 1550-1553
Author(s):  
Li Guo ◽  
Hong Fang Li
Keyword(s):  
Numerical Simulation ◽  
Numerical Calculation ◽  
Stability Analysis ◽  
Stress Distribution ◽  
Simulation Models ◽  
Surrounding Rock ◽  
Major Task ◽  
Parallel Tunnel ◽  
Single Stress

To acquire the stress distribution of surrounding rock is the important mean of stability analysis and the major task of numerical simulation. But the breaking probability cannot be expressed by the magnitude of single stress straightly. Based on the Mohr-Coulomb theory, coefficient S was deduced and used for further treatment of the result of numerical simulation. Models of parallel tunnel with different interval were building and analyzed. The different distributions of coefficient S were compared and analyzed after numerical calculation. The more reasonable tunnel interval was given, which can be a reference for optimization of design of similar projects.

scholarly journals Study on Seismic Response and Damping Measures of Surrounding Rock and Secondary Lining of Deep Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Baoli Tang ◽  
Yongqiang Ren
Keyword(s):  
Numerical Calculation ◽  
Seismic Response ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Theoretical Research ◽  
Concrete Lining ◽  
Tunnel Construction ◽  
Geological Conditions ◽  
Safety And Stability

Tunnel construction is gradually developing to areas with high in situ stress; the deeper the tunnel construction, the more intense the earthquake disturbance. Under the background of frequent earthquakes, the seismic characteristics of tunnels become an important content related to the safety and stability of engineering structures. In view of the key problems of seismic response and vibration reduction measures for complex deep buried tunnels, the methods of advanced grouting and foam concrete aseismic are studied in this paper. Firstly, through geological survey, the in situ stress and geological conditions of the study area are analyzed. The structural characteristics of surrounding rock and related rock mechanics parameters are analyzed. The failure criterion of concrete lining under dynamic load is studied theoretically, and the relevant numerical calculation parameters are modified. A numerical model based on viscous boundary conditions is established. Through numerical calculation, the seismic response of tunnel surrounding rock and lining under different damping measures is analyzed. The research results have theoretical research value and social and economic benefits for ensuring the safety and stability of tunnel structure and improving the seismic fortification level.

Influence exerted by underground excavation shape and by effective stresses on the formation of a tensile strain zone at a depth greater than 1 km

2020 ◽  
pp. 67-75
Author(s):  
Van Min Nguyen ◽  
V. A. Eremenko ◽  
M. A. Sukhorukova ◽  
S. S. Shermatova
Keyword(s):  
Rock Mass ◽  
Cross Sections ◽  
Tensile Strain ◽  
Rock Fracture ◽  
Strain Analysis ◽  
Surrounding Rock ◽  
Underground Excavation ◽  
Secondary Stress ◽  
Principal Stresses ◽  
Mining Depth

The article presents the studies into the secondary stress field formed in surrounding rock mass around underground excavations of different cross-sections and the variants of principal stresses at a mining depth greater than 1 km. The stress-strain analysis of surrounding rock mass around development headings was performed in Map3D environment. The obtained results of the quantitative analysis are currently used in adjustment of the model over the whole period of heading and support of operating mine openings. The estimates of the assumed parameters of excavations, as well as the calculations of micro-strains in surrounding rock mass by three scenarios are given. During heading in the test area in granite, dense fracturing and formation of tensile strain zone proceeds from the boundary of e ≥ 350me and is used to determine rough distances from the roof ( H roof) and sidewalls ( H side) of an underground excavation to the 3 boundary e = 350me (probable rock fracture zone). The modeling has determined the structure of secondary stress and strain fields in the conditions of heading operations at great depths.

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