scholarly journals Evaluation of a tunnel in Yunnan using CRD construction method

2019 ◽  
Vol 136 ◽  
pp. 04020
Author(s):  
Jun Duan ◽  
Canrong Huang ◽  
Xiangyang Cui ◽  
Ke Li ◽  
Hongyan Guo
Keyword(s):  
Plastic Zone ◽  
Side Wall ◽  
Construction Safety ◽  
Construction Method ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Monitoring Point ◽  
The Right ◽  
Tunnel Monitoring

According to the surrounding rock conditions of Re Shuitang Tunnel NO.2, it is analyzed whether the CRD method is suitable for such surrounding rock conditions. By comparing and analyzing the distribution of plastic zone of surrounding rock during construction and the displacement deformation of tunnel monitoring point, the tunnel is constructed. The plastic zone of the middle arch and the arch is obviously changed, and should be reinforced. The settlement of the right vault and the side wall is larger than the left side, which is about 19.8% and 21.9%. According to the analysis results, the vault should be reinforced in advance during tunnel construction to prevent collapse and ensure construction safety, and provide reference for future construction.

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.

Monitoring Analysis on Tunnel Portal Shallow Burying Segment of Center Diaphragm Construction Method

2012 ◽  
Vol 238 ◽  
pp. 808-813
Author(s):  
Fei Zhou ◽  
Yong Li Xie ◽  
Jin Xing Lai
Keyword(s):  
Construction Method ◽  
Tunnel Construction ◽  
Ground Settlement ◽  
Normal Type ◽  
Highway Tunnel ◽  
Site Monitoring ◽  
Tunnel Monitoring ◽  
Tunnel Portal

Combined with highway tunnel monitoring measurement work of Bijia Mountain, the contents and methods of site monitoring and the analyzing methods for collected data of highway tunnel construction were studied. A comparative way was used to analyze the different curves of displacement with time on the two typical segments of ground settlement convergence and vault crown settlement. The result shows that the site monitoring curves of displacement with time can be divided into normal type and abnormal one. This article puts forward some feasible suggestions about how to guide the safe construction through the two types of curve. The aim of this article is to explore the changing of the abnormal curve before the dangerous accident occur, and give the causes of the reasonable analysis after collapse happened.

Numerical Analysis of Damage for Y-Shape Tunnel

2011 ◽  
Vol 368-373 ◽  
pp. 2517-2520
Author(s):  
Da Ming Lin ◽  
Yan Jun Shang ◽  
Guo He Li ◽  
Yuan Chun Sun
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Numerical Analysis ◽  
Plastic Zone ◽  
Comprehensive Analysis ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Deformation And Failure ◽  
Single Beam ◽  
Flac 3D

There are many effective researches about tunnel at home and abroad, because the complexity of design and construction for Y-shape tunnel, in public there is no research about it yet, with the background of nanliang-tunnel which merge two single-beam into a two-lane tunnel as Y-shape. This paper obtains the rock mass mechanics parameters on the basis of nonlinear Hoek-Brown criterion first, and has a numerical simulation according the tunnel construction with FLAC-3D. we arrange many monitor sections in this model and discuss the law of deformation and failure in different section, at last have a comprehensive analysis of displacement, stress, plastic zone of different sites which caused by tunnel construction and discover that: with the distance of two single tunnels decreased, the interaction caused by the merging increase together with the compressive stress, tensile stress. The displacements of surrounding rock increase corresponding, the amplitude of variation is up to 44.8%, After the two-lane tunnel is 15m long, the stress and displacements redistribution of surrounding rock become stable.

scholarly journals Study on Identification of Construction Method for Ultra-Large-Span Tunnel

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xu Chongbang ◽  
Qin Youlin
Keyword(s):  
Rock Strength ◽  
Construction Method ◽  
Surrounding Rock ◽  
Orthogonal Test ◽  
Tunnel Construction ◽  
Test Model ◽  
Large Span ◽  
Construction Methods ◽  
The Stability

Although the determination of tunnel construction methods is extremely critical for the construction of ultra-large-span tunnels, the determination of construction methods is still at a qualitative level, which relies on the engineering experience of on-site technicians and lacks rigorous and systematic theoretical basis and technical standards. By means of orthogonal test method, the proper construction method was established for the deep-buried ultra-large-span tunnel where the tunnel excavation span, tunnel surrounding rock strength, and rock integrity coefficient were set as the main control factors. The stability of tunnel surrounding rock under various test conditions was quantified according to the plastic zone properties calculated by the three-factor and five-level orthogonal test model. Meanwhile, the macro form and quantitative method of test combinations under different levels of various factors were proposed to obtain the influence of each factor on the stability of tunnel surrounding rock, and thus the functional relations between various factors and tunnel stability were obtained. On this basis, the identification and the criterion of the ultra-large-span tunnel construction method were established, which can quantitatively reflect the contribution of excavation span of the tunnel, the number of lateral drifts in cross section, surrounding rock strength, and rock integrity coefficient to surrounding rock stability of the tunnel. The construction method calculation results of the Malin tunnel, a practical underground project, are obtained according to the orthogonal test model calculation. Based on the method, Malin tunnel can be constructed safely and efficiently. The research results could provide the theoretical basis for the identification and selection of construction method for ultra-large-span tunnel.

scholarly journals Study on Safety Benchmark Value of Monitoring and Early Warning for Large Section Highway Tunnels

2019 ◽  
Vol 136 ◽  
pp. 04024
Author(s):  
Yuwen Wang ◽  
Xiang Yang Cui ◽  
Hongyan Guo ◽  
Ke Li
Keyword(s):  
Side Wall ◽  
Construction Method ◽  
Surrounding Rock ◽  
Large Section ◽  
Deformation Law ◽  
Initial Support ◽  
Under Construction ◽  
Monitoring And Measurement ◽  
Ultimate Displacement ◽  
Wall Method

Taking several tunnels under construction of a highway as the research object, the ultimate displacement of four buried depth sections of 0-50, 50-100, 100-300, 300-500 m in the surrounding rock of grade III, IV and V is numerically simulated by three-step and seven-step excavation method, middle-wall method, cross-middle-wall method and double-side-wall guide pit method for initial support of large-section highway tunnels. Through analysis, the deformation law of tunnel surrounding rock is obtained: under the same buried depth, the displacement ultimate displacement of the two-sided guide pit method and the cross-middle-wall method is the largest, the middle-wall method is the second, and the three-step seven-step excavation method is the smallest. Through the analysis and collation of the measured data obtained by monitoring and measurement of each construction method in the construction site, the surrounding rock deformation datum values of large-span and large-section tunnel under each construction method are obtained.

Stability Analysis of Highway Tunnel through Mined-Out Area during Excavation Process

2013 ◽  
Vol 838-841 ◽  
pp. 1352-1358 ◽  
Author(s):  
Zhi Hao Yang ◽  
Ge Cui ◽  
Ya Peng Fu ◽  
Yong Fang ◽  
Bin Yang
Keyword(s):  
Rock Mass ◽  
Plastic Zone ◽  
Axial Force ◽  
Construction Safety ◽  
Surrounding Rock ◽  
Two Dimensional ◽  
Highway Tunnel ◽  
Excavation Process ◽  
Caving Zone ◽  
Pass Through

Tianpingzhai Tunnel on Dazhou-Wanzhou Expressway passes through the mined-out area, the spatial position of the goaf changes constantly comparing to the tunnel during excavation, and broken rock mass of the caving zone is most likely to collapse, which affects construction safety in return. Two dimensional computation models were built by using finite differential software FLAC to simulate excavation process when the coal-mined area is right above or below the tunnel. In 2D models, goaf strata were regarded as horizontal, and buried depth and coal thickness were limited to 300 meters and 0.5 meter respectively. The displacement around the tunnel, forces of primary lining, axial force of bolts and plastic zone of surrounding rock have been analyzed under these circumstances that the distances between tunnel and goaf are 1m, 6m and 12m. According to the results, when the distance between goaf and tunnel is less than 12 meters,underlying goaf has greater impact on the displacement around the tunnel and average axial force of bolts than overlying goaf, as well as the size of plastic zone of surrounding rock. Its strongly suggested to avoid underlying goaf if the tunnel have to pass through the mined-out area.

A Study on the Influence by Karst on the Stability of Surrounding Rock in Neighborhood Tunnel

2012 ◽  
Vol 446-449 ◽  
pp. 2177-2181 ◽  
Author(s):  
Cheng Wang ◽  
Xiao Qiang Pi
Keyword(s):  
Side Wall ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Stability Of Surrounding Rock ◽  
Vertical Displacements ◽  
The Stability ◽  
Selection Of

Based on the Shuangbei tunnel, this paper studied influences on the deformation and stress of surrounding rock, regarding different Karst sizes and locations in such a neighborhood tunnel. The study indicates that variations of size and distance of the karst have prominent influence on the vertical displacements of vault and right side-wall in the tunnel near the karst, but have no influence on the horizontal displacement; while variation of karst size has prominent influence not only on the horizontal displacement, but also on the vertical displacement at the bottom of the tunnel far away from the karst; variations of size and distance of the karst have the prominent influence on the vault stress of the two tunnels. The results offer the reference to the tunnel construction and the selection of support type.

scholarly journals Displacement analysis of surrounding rock deformation of Baochang tunnel in Yunnan

2019 ◽  
Vol 136 ◽  
pp. 04018
Author(s):  
Lianghan Zhang ◽  
Xiaolong Li ◽  
Xinyun Ma ◽  
Hongyan Guo ◽  
Ke Li
Keyword(s):  
Horizontal Displacement ◽  
Construction Safety ◽  
Surrounding Rock ◽  
Tunnel Excavation ◽  
Partition Wall ◽  
Excavation Process ◽  
Tunnel Monitoring ◽  
Double Wall ◽  
Wall Method ◽  
Surrounding Rock Deformation

According to the problem of deformation of surrounding rock when the double-wall method is adopted in the tunnel, the five tunnel monitoring points are set in the tunnel vault, arch waist and arch foot to simulate the tunnel excavation process. The surrounding rock is deformed, and the excavation of the middle guide hole makes the deformation of the surrounding rock reach 7.2mm. After the removal of the middle partition wall, the deformation reaches the maximum, which is 8.4mm. The horizontal displacement starts to increase rapidly, and the maximum is 5.3mm. According to the analysis results, the surrounding rock above the tunnel should be reinforced in time, and the deformation of the surrounding rock after the removal of the middle partition wall should be paid attention to ensure the construction safety and provide reference for future construction.

Analysis of the Tunnel Construction and Monitoring Measurement under Complicated Geological Conditions

2011 ◽  
Vol 90-93 ◽  
pp. 2091-2095
Author(s):  
Zhan Fei Gu ◽  
Zhi Kui Liu ◽  
Hong Chi Chen ◽  
Ya Wei Wang
Keyword(s):  
Construction Method ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Low Level ◽  
Tunneling Method ◽  
Sandstone Rock ◽  
Geological Conditions ◽  
Single Block ◽  
New Austrian Tunneling Method

In view of certain areas of Guizhou are soft sandstone rock, where single block of rock's hardness is very low and easily crushed, complicated hydrogeology and low level of complex surrounding rock and geological conditions, geological radar prediction is used before the excavation of the tunnel, and New Austrian Tunneling Method was used in the construction. The process of construction segment had been monitored and measured, and the deformation of tunnel had been controlled. According to the situation during excavation and monitoring, the construction method was further improved. Through tracing and monitoring the tunnel construction of from zk40+430 to zk40+630 sections for two months, showed that the tunnel construction method is effective in this paper.

Stability Analysis of an Underground Pumping Station Group of China

2017 ◽  
Vol 865 ◽  
pp. 403-408 ◽  
Author(s):  
De Ping Chen ◽  
Li Peng Liu ◽  
Li Xin Zhao ◽  
Yang Zhang
Keyword(s):  
Plastic Zone ◽  
Side Wall ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Main Concern ◽  
Maximum Displacement ◽  
Pumping Station ◽  
Underground Caverns ◽  
Large Underground Cavern ◽  
Station Group

The stress and strain of surrounding rock and the development of plastic zone in the process of excavation of large underground cavern group have been the main concern of the design unit. The numerical simulation software is used to analyze the stability of caverns of an underground pumping station. The stress and displacement of the surrounding rock and the development of the plastic zone in the process of excavation are analyzed in detail. The results show that the tensile stress is easily generated in the side wall, and the maximum value can reach 4 M Pa. Correspondingly, the maximum displacement of the side wall part can reach 4 cm. The plastic zone is mainly concentrated in the surrounding rock near the side wall, the thickness can reach about 9 m. In general, the excavation of underground caverns is basically stable.

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