Analysis on the Characteristics of Displacement Field Distribution around the Deep Buried and Great Complex Section Tunnel

2012 ◽  
Vol 446-449 ◽  
pp. 2251-2255 ◽  
Author(s):  
Sheng Xiang Lei ◽  
Bo Gao ◽  
Qing Hua Xiao
Keyword(s):  
Retaining Wall ◽  
Maximum Principal Stress ◽  
Surrounding Rock ◽  
Rock Deformation ◽  
Hydropower Station ◽  
Spring Back ◽  
Rock Stress ◽  
Large Section ◽  
Blasting Method ◽  
Underground Chamber

Taken the excavation of TBM assembly underground chamber with deeply buried super large and complex section in Jinping Ⅱ Hydropower Station as the background, apply theoretical analysis and experimental method to study the rock deformation and displacement analysis. The result shows that, drilling and blasting method is used for construction which is divided into four layers from top to bottom according to the excavation, they are 8.5m, 5.5m, 6.0m,7.0m from top to bottom, respectively. the displacement of surrounding rock generally moves toward the direction of the free surface. The rock possesses spring back deformation pointing to internal underground chamber. The displacements of arch crown and floor are mainly vertical, and displacement of retaining wall is mainly horizontal. This is significantly different from the rock deformation of underground chamber under general stress after excavation. The chamber displacement distribution under high crustal stress is closely related to stress direction. Location axis of underground chamber should parallel the direction of maximum principal stress. Under the complex and great deeply buried condition, excavation of large section tunnel by digging from the top layer can better release the rock stress, and the rock displacement changes gently, which is conducive to rock mass stability and structure security.

Analysis of Surrounding Rock Deformation Based on M-C Model and Cvisc Model

2013 ◽  
Vol 295-298 ◽  
pp. 2963-2966
Author(s):  
You Xiang Li
Keyword(s):  
Surrounding Rock ◽  
Rock Deformation ◽  
Hydropower Station ◽  
Deformation Characteristics ◽  
Diversion Tunnel ◽  
Software Application ◽  
Jinping Ii Hydropower Station ◽  
Coulomb Model ◽  
Plastic Zones ◽  
Surrounding Rock Deformation

According to the analysis of the surrounding rock deformation of the buried sandy slate, which is 1500-2000m depth of Diversion Tunnel Jinping-II Hydropower Station, the essay uses FLAC software application to analyze the deformation characteristics and plastic zones of the sandy slate, study comparatively the influence of Mohr-Coulomb model and Cvisc model to the surrounding rock, and then draw some conclusions, including that calculations derived by using Cvisc model is more in line with the actual engineering.

Study on Safe Distance between Cross-Cut and Lower Belt Tunnel

2011 ◽  
Vol 121-126 ◽  
pp. 3525-3529
Author(s):  
Xing Lin Wen ◽  
Chuan Lei Li ◽  
Fei Yu ◽  
Lin Hai Gao
Keyword(s):  
Minimum Distance ◽  
Mining Area ◽  
Surrounding Rock ◽  
Rock Deformation ◽  
Deformation Analysis ◽  
Rock Stress ◽  
Safe Distance ◽  
Mining Conditions ◽  
Surrounding Rock Stress ◽  
Surrounding Rock Deformation

In order to solve the question of safe distance between cross-cut and lower lane bolt tunnel and support, aim at geological and mining conditions of north mining area in sanjiaohe coal mine, and analysis mechanism of surrounding rock deformation, analysis the upper roadway surrounding rock stress, displacement and distruction of plastic by FLAC3D determine the minimum distance between the two tunnel and design support scheme on the basis of on-site roadway conditions. Result of this study can provide a reference not only in this mine but also for another similar situtions roadway.

scholarly journals Analysis on Characteristics of Surrounding Rocks of Roadway and Bearing Structure Based on Stress Regulation

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Ruofei Zhang ◽  
Guangming Zhao ◽  
Xiangrui Meng ◽  
Jian Sun ◽  
Wensong Xu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Mechanical Characteristics ◽  
Axial Ratio ◽  
Maximum Principal Stress ◽  
Surrounding Rock ◽  
Rock Stress ◽  
Rock Reinforcement ◽  
Bearing Structure ◽  
Surrounding Rock Stress

To address the prominent status of great deformation and difficult maintenance of the roadway under high stresses, this study investigated the mechanical characteristics of surrounding rocks and bearing structural stability in a roadway under adjustment and redistribution of stresses through theoretical analysis, numerical simulation, and engineering field test. Stability forms of the bearing structure of roadway surrounding rocks were analyzed by using the axis-changing theory from the perspectives of surrounding rock, mechanical properties of roadways, surrounding rock stress distribution, and mechanical mechanism of the bearing structure. It is suggested that the surrounding rock stress distribution state is improved and the bearing structure is optimized through unloading and reinforcement construction. A mechanical model of roadway excavation was constructed to analyze the influences of excavation spatial effect on the stress releasing and bearing structure of surrounding rocks. A rock postpeak strain softening and dilatation model was introduced to investigate the mechanical characteristics of the surrounding rock mass in the rupture residual zone and plastic softening zone in a roadway. Moreover, we analyzed the influences of unloading and reinforcement construction on the stress path and mechanical characteristics of the rock unit model, which disclosed the adjustment mechanism of the bearing structure of surrounding rocks by the failure development status of rocks. A numerical simulation on the distribution of surrounding rock stress fields and adjustment features of the bearing structure after roadway excavation and unloading and reinforcement construction was carried out by using the FLAC3D program. Results demonstrate that the unloading construction optimizes the axial ratio of spatial excavation in a roadway and the reinforcement zones on both sides are the supporting zones of the bearing structure. Moreover, the ratio between the distance from two side peaks to the roadway sides and the distance from the roof and floor peaks to the excavation space is equal to the coefficient of horizontal pressure. In other words, the final collapse failure mode of surrounding rock is that the long axis of the excavation unloading space points to the same direction with the maximum principal stress of the primary rock. Reinforcement forces the surrounding rocks to form a “Ω-shaped” bearing structure, which is in favor of the long-term maintenance of the roadway.

Mechanics Characteristic Analysis of Support Structure of Shallow-Buried Large-Section Loess Tunnel

2014 ◽  
Vol 926-930 ◽  
pp. 589-592
Author(s):  
Zhi Jie Sun
Keyword(s):  
Surrounding Rock ◽  
Rock Deformation ◽  
Structural Performance ◽  
Characteristic Analysis ◽  
3D Numerical Simulation ◽  
Large Section ◽  
Support Structure ◽  
Construction Methods ◽  
Mechanics Characteristic ◽  
Surrounding Rock Deformation

To research the mechanics characteristic of support structure of shallow-buried large section loess tunnel with different construction methods, 3D Numerical Simulation is applied and the large-section loess tunnel of highway is taken as an example. Comparing mechanics characteristic of support structure in three types of construction method conditions, the research results show that:The Benching stepping method which caused large surrounding rock deformation can reduce the value of structural performance. While the Both side heading is just opposite.

scholarly journals Intelligent Classification Model of Surrounding Rock of Tunnel using Drilling and Blasting Method

2020 ◽  
Author(s):  
Mingnian Wang ◽  
Siguang Zhao ◽  
Jianjun Tong ◽  
Zhilong Wang ◽  
Meng Yao ◽  
...  
Keyword(s):  
Surrounding Rock ◽  
Classification Model ◽  
Blasting Method

scholarly journals Study on instability failure mode and monitoring early warning standard of surrounding rock in fully weathered argillaceous sandstone section of large section tunnel

2019 ◽  
Vol 136 ◽  
pp. 04023
Author(s):  
Ming Zhao ◽  
Ke Li ◽  
Hong Yan Guo ◽  
KaiCheng Hua
Keyword(s):  
Limit State ◽  
Stable State ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Large Section ◽  
Rock Stability ◽  
Geological Conditions ◽  
Construction Step ◽  
The Face ◽  
The Stability

Based on the special geological conditions of a tunnel in Qingyuan section of Huizhou-Zhanzhou Expressway, FLAC3d numerical simulation software is used to simulate the rheological properties and instability of surrounding rock in large-section fully weathered sandstone section, and the stability and loss of surrounding rock are analyzed. The deformation of the dome and the face at steady state is analyzed. It is found that: 1) when the surrounding rock is in a stable state, the deformation curve of the dome is smooth. When the surrounding rock of the face is unstable, the front of the face appears ahead. Deformation should be first strengthened on the surrounding rock in front of the face. 2) The arched foot is an important part of the instability of the surrounding rock. In order to prevent the expansion of the collapsed part, the arched part should be reinforced. 3) In order to obtain the limit state of surrounding rock stability, the strength of surrounding rock is reduced, and the strength reduction coefficient corresponding to the displacement sudden point is taken as the safety factor of rock stability around the hole, and the stability safety coefficients of surrounding rock of each construction step are greater than 1.2. 4) The dynamic standard values of deformation control in the whole construction stage are obtained by analyzing the deformation curves of each data monitoring point with time in the corresponding time period of each construction step.

Study on the Truss Support Technology for Coal Side in a Soft Broken Coal Roadway Under High Stress

2012 ◽  
Vol 524-527 ◽  
pp. 360-363
Author(s):  
Shou Yi Dong ◽  
Qi Tao Duan ◽  
Fu Lian He ◽  
Qi Li ◽  
Hong Jun Jiang
Keyword(s):  
Production Condition ◽  
High Stress ◽  
Field Investigation ◽  
Surrounding Rock ◽  
Theory Analysis ◽  
Large Section ◽  
Cable Channel ◽  
Coal Roadway ◽  
Measurement Results ◽  
Steel Truss

The coal side deformation and sliding can not be effectively controlled by use of the traditional bolt or cable support in the high stress crushed surrounding rock and large section roadway. For solving this problem, the new prestressed truss support technology is put forward, and its supporting principles of roof and two walls are stated. The mechanical model of cable-channel steel truss is established, and then the tensile strength of the cable and the maximum deflection of the channel steel are derived. By way of field investigation, mechanics theory analysis and actual production condition, the scheme is defined and applied in the replacement roadway. Measurement results of surrounding rock behavior show that the coal side displacement is no more than 254mm and the roof convergence is less than 172mm. Apparent economic and technical profits have been achieved.

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