Numerical Analysis of Reserving Core Soil with Annular Excavation Method Used in Loess Tunnel

2014 ◽  
Vol 1065-1069 ◽  
pp. 143-146
Author(s):  
Zhi Jie Sun ◽  
Zhong Ming Su
Keyword(s):  
Working Condition ◽  
Bending Moment ◽  
Surrounding Rock ◽  
Maximum Pressure ◽  
3D Numerical Simulation ◽  
Construction Methods ◽  
Core Soil ◽  
Secondary Lining ◽  
Pressure Stress ◽  
Primary Support

To research the deformation regularity of loess tunnel in reserving core soil with annular excavation method compared with other construction methods, 3D Numerical Simulation is applied and the loess tunnel of highway is taken as an example. The research results show that[1]：The deformation of surrounding rock affected by the area of core soil is small.The stress regularity of different support structure influence on the area of core soil is different. This is mainly reflected that the maximum pressure stress of primary support increases with the area of core soil’s increasing, but the minimum bending moment of secondary lining is not appeared in the working condition which the minimum core soil area is.

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.

Management Criterion for Large Deformation Tunnels

2012 ◽  
Vol 204-208 ◽  
pp. 1468-1471
Author(s):  
Su Min Zhang ◽  
Yong Quan Zhu
Keyword(s):  
Large Deflection ◽  
Reference Value ◽  
Bending Moment ◽  
Calculation Model ◽  
Support Structure ◽  
Simulation Calculation ◽  
Measured Displacement ◽  
Secondary Lining ◽  
Drill And Blast ◽  
Primary Support

The limit displacement was calculated with regard to a large deflection tunnel. The continuum calculation model was established with actual parameters of the surrounding rock of the tunnel as input. In the simulation calculation, the action occasion of the support structure was determined based on the ratio of the measured rock pressure to the geo-stress, and the bearing capacity of the R.C. compressive bending component of the support was expressed with the axial force and bending moment on losing capacity of the support structure in loading; The limit displacement of the tunnel wais determined finally combined with the measured displacement of control points on collapsed or gauge-intrusive sections and cracked primary support or secondary lining sections. Since the deforming rate is more concerned than the displacement in drill and blast tunnel construction, three-level-management of deflection and deforming rate was proposed based on the statistical analysis of measured deforming rate, and the safety requirement for deflection control in construction. The management criterion has reference value to other similar tunnels where difficulty is encountered due to large deflection occurring in construction.

Numerical Analysis of Construction Method in Shallow-Buried Large-Section Loess Tunnel

2014 ◽  
Vol 580-583 ◽  
pp. 997-1000 ◽  
Author(s):  
Zhi Jie Sun
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Ground Surface ◽  
Construction Method ◽  
Surrounding Rock ◽  
3D Numerical Simulation ◽  
Large Section ◽  
Research Results ◽  
Construction Methods ◽  
Ground Surface Settlement

To research the deformation regularity of large section loess tunnel in construction procession with different construction methods, 3D Numerical Simulation is applied and the large-section loess tunnel of highway is taken as an example. Comparing deformation regularity of surrounding rock in three types of construction method conditions, the research results show that:The CRD method takes precedence in the condition of the convergence of surrounding rock is large. The both sides heading method takes precedence in the condition of ground surface settlement is large.

scholarly journals Analysis of Construction Monitoring and Control of Tunnels Crossing Broken Faults and Water-rich Geology

2022 ◽  
Vol 2152 (1) ◽  
pp. 012019
Author(s):  
Jingang Fang
Keyword(s):  
Surrounding Rock ◽  
Monitoring Data ◽  
Monitoring And Control ◽  
Tunnel Engineering ◽  
Construction Monitoring ◽  
Construction Methods ◽  
The Poor ◽  
Secondary Lining ◽  
The Stability ◽  
And Control

Abstract In view of the poor geology such as tunnel engineering crossing faults or passing faults, the construction of surrounding rock and support is complicated. During construction, it is necessary to ensure the stability of the surrounding rock and supporting system, and ensure the timing of the secondary lining construction. For this reason, through the analysis and processing of monitoring data, the law of stratum change is mastered, and the supporting parameters and construction methods are adjusted and revised at the same time, so as to provide the best information for the tunnel surrounding rock and supporting lining construction.

scholarly journals Study on the Mechanical Behavior of Double Primary Support of Soft Rock Tunnel under High Ground Stresses and Large Deformation

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Zhe Liu
Keyword(s):  
Mechanical Behavior ◽  
Large Deformation ◽  
Design Method ◽  
Characteristic Curve ◽  
Soft Rock ◽  
Support Design ◽  
Deformation Amount ◽  
Secondary Lining ◽  
Rock Tunnels ◽  
Primary Support

Double primary support structures could effectively solve the problem of large deformation of surrounding rock for soft rock tunnels. However, the mechanical behavior of this new support structure is still incomplete, and the design method should be revised. Based on the theory of energy conversion, this paper analyzes the support characteristic curve of double primary support and puts forward the dynamic design method of double primary support. Considering that the secondary lining can be set after monitoring the deformation amount and deformation rate of the first primary support, its support parameters can be dynamically adjusted according to the actual situation. By applying the double primary support design method in the Maoxian tunnel of Chenglan Railway, the field monitoring results show that the double primary support has a significant effect on the energy release of surrounding rocks, greatly reducing the load acting on the secondary lining and ensuring the safety and reliability of the tunnel structure.

scholarly journals Rebound Mechanism and Control of the Hard Main Roof in the Deep Mining Roadway in Huainan Mining Area

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Denghong Chen ◽  
Chao Li ◽  
Xinzhu Hua ◽  
Xiaoyu Lu ◽  
Yongqiang Yuan ◽  
...  
Keyword(s):  
Slope Angle ◽  
Bending Moment ◽  
Main Roof ◽  
Mining Area ◽  
Calculation Model ◽  
Surrounding Rock ◽  
Tensile Failure ◽  
Damage Area ◽  
Critical Range ◽  
Working Face

Taking the occurrence conditions of the hard main roof in the deep 13-1 coal mining roadway in Huainan mining area as the research object, based on the mechanical parameters of the surrounding rock and the stress state of the main roof obtained by numerical simulation, a simply supported beam calculation model was established based on the damage factor D, main roof support reaction RA, RB, and critical range C (9 m) and B (7 m) at the elastoplastic junction of the solid coal side and mining face side (hereinafter referred to as “junction”). Considering that the damage area still has a large bearing capacity, the vertical stress of the main roof at the junction is K1γH (0.05γh, 0.15γh, and 0.25γh) and K2γH (0.01γh, 0.10γh, and 0.2γh). The maximum deflection is 21 mm, 324 mm, and 627.6 mm, respectively. According to the criterion of tensile failure, the maximum bending moment of the top beam is 209 mN·m at the side of the working face 3.1 m away from the roadway side when K1 = 0.15 and K2 = 0.10, and the whole hard main roof is in tensile failure except the junction. To control the stability of the top beam and simplify the supporting reaction to limit the deformation of the slope angle, RC and RD are used to construct the statically indeterminate beam. By adding an anchor cable and advance self-moving support to the roadway side angle, the problem of difficult control of the surrounding rock with a large deformation of the side angle roof is solved, which provides a reference for roof control under similar conditions.

scholarly journals Deformation Characteristics of the Surrounding Rock of a Six-Lane Multiarch Tunnel under Different Excavation Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Lina Luo ◽  
Gang Lei ◽  
Haibo Hu
Keyword(s):  
Three Dimensional ◽  
Class Ii ◽  
Surrounding Rock ◽  
Displacement Rate ◽  
Construction Technology ◽  
Deformation Characteristics ◽  
Highway Traffic ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Secondary Lining

Highway tunnel plays an increasingly prominent role in the development of high-grade highway traffic in mountainous countries or regions. Therefore, it is necessary to explore the deformation characteristics of the surrounding rock of a six-lane multiarch tunnel under different excavation conditions. Using the three-dimensional indoor model test and finite element analysis, this paper studies the dynamic mechanical behavior of a six-lane construction, reveals the whole process of the surrounding rock deformation process of class II surrounding rock under different excavation conditions, and puts forward the best construction and excavation method. The results show that the maximum displacement rate of excavation scheme III is the largest, and the maximum displacement rate of excavation scheme I is basically the same as that of excavation scheme II. Therefore, in terms of controlling the displacement rate of the surrounding rock, the effect of excavation scheme I is basically the same as that of excavation scheme II, while that of excavation scheme III is poor. In terms of construction technology, scheme II is simpler than scheme I and can ensure the integrity of the secondary lining. Therefore, in class II surrounding rock of the supporting project, it is recommended to adopt scheme II for construction.

Mechanics Analysis of Grade V Surrounding Rock Primary Support in Maanziliang Tunnel

2012 ◽  
Vol 164 ◽  
pp. 414-417
Author(s):  
Jia Ming Han
Keyword(s):  
Finite Element ◽  
Safety Factor ◽  
Surrounding Rock ◽  
Qinling Mountains ◽  
The Finite Element Method ◽  
Highway Tunnel ◽  
Geological Conditions ◽  
The Stability ◽  
Primary Support ◽  
Rock Section

Commonly used finite element strength reduction to calculate the safety factor of slope，to analyze the stability of the slope[1～3]. Recently it also proposed the methods to evaluate the safety factor for the stability of surrounding rock of underground chambers and supporting structural mechanics[4～6]. For Qinling Mountains of the complex geological conditions in the Maanziliang highway tunnel, this article use the finite element method from the bolt resist tension, bolt length, the force of sprayed layer of concrete to computing gradeⅤsurrounding rock section of primary support safety factor, to give evaluation to support mechanics of the Maanziliang tunnel.

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