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 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 Stability Analysis of Shallow and Bias Loess Tunnel Based on Finite Difference Method

2019 ◽  
Vol 131 ◽  
pp. 01027
Author(s):  
Li Yongbing ◽  
Binglei Li ◽  
Guanyu Hua ◽  
Xinran Jia ◽  
Yanqiao Chen ◽  
...  
Keyword(s):  
Finite Difference ◽  
Shear Failure ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Failure Zone ◽  
Tunnel Face ◽  
Whole Process ◽  
The Earth ◽  
Practical Engineering ◽  
The Stability

Based on the Mohr-Coulomb elastic-plastic model and the practical engineering background of Mopanshan tunnel, this paper applies the finite-difference software FLAC3D to simulate and analyse the whole process of loess tunnel construction. Then, it analyses the stability of the surrounding rock and sup-port structure after partial excavation of the loess tunnel under the shallow burying and unsymmetrical load-ing condition. The study showed that in the absence of support, the shear failure occurred to the top/upper pilot tunnel of the tunnel face, the failure zone under tensile stress happened to the shallow soil of the earth surface, and the soil of tunnel face appeared to be damaged. Finally, according to the analysis results, a rea-sonable construction method suitable for the shallow and bias loess tunnel is determined.

Field Determination of Surrounding Rock Strength under TBM Construction in Zhongtianshan Tunnel

2012 ◽  
Vol 468-471 ◽  
pp. 1771-1774 ◽  
Author(s):  
Yu Suo Wang ◽  
Zheng Qun Wu ◽  
Ming Nian Wang ◽  
Hao Chen
Keyword(s):  
Rock Strength ◽  
Point Load ◽  
Surrounding Rock ◽  
Load Test ◽  
Construction Site ◽  
Analysis Method ◽  
Work Site ◽  
Support Measures ◽  
Key Factor

Rock strength is a key factor in the tunneling efficiency of TBM construction. An issue needing special attention on the work site is how to determine rapidly and accurately the strength of the surrounding rock which makes a crucial reference for the choice of TBM tunneling parameters and corresponding support measures. In the study conducted on the TBM construction site of Zhongtianshan Tunnel, point load test (PLT) of rocks is adopted to measure the rock strength and the data is compared with those of the uniaxial compressive strength (UCS). Finally, the correlation between the two is revealed through regression analysis method.

The Field Ultrasonic Test of the Disturbance of Surrounding Rock by the TBM Construction

2012 ◽  
Vol 446-449 ◽  
pp. 2101-2104
Author(s):  
Yu Suo Wang ◽  
Zheng Qun Wu ◽  
Mao Hong Li ◽  
Qi Xin Yang
Keyword(s):  
Stability Analysis ◽  
Ultrasonic Test ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Support Measures

Measurement of the loose zone of tunnel surrounding rock is of great significance in the determination of its support measures and stability analysis. By identifying the loose zone, the effective measures can be adopted to ensure a safe tunnel construction. The ultrasonic test is conducted to the TBM construction of Zhongtianshan Tunnel to specify the disturbance range of the TBM construction on the surrounding rock and the anchoring lengths of bolts.

scholarly journals Research on Construction Methods for Ultralarge Y-Shaped Tunnel Sections

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Shiding Cao ◽  
Yongli Xie ◽  
Wei Tang ◽  
Wei Wang ◽  
Qianru Zhou ◽  
...  
Keyword(s):  
Stability Criterion ◽  
Abrupt Change ◽  
Internal Force ◽  
Special Method ◽  
Large Section ◽  
Large Span ◽  
Construction Methods ◽  
Excavation Process ◽  
Clear Distance ◽  
The Stability

Many problems are encountered in the construction of bifurcated tunnels due the abrupt change in section, small clear distance, and large section. Progress in the direction of tunnel construction is limited by the large-span section; therefore, a special method of construction that involves constructing a guiding tunnel first followed by reverse excavation was adopted to construct the large-span bifurcation section of the Liantang tunnel of Shenzhen Eastern Transit Expressway in China. The stability criterion of the surrounding rock of the middle wall in the section of multiple arch and small clear distance is studied by theoretical analysis, and the internal stress and corresponding ultimate strength of the middle wall under different buried depths and widths of the middle wall are calculated by the stability criterion. In this study, 3D finite-difference software was used to simulate the excavation process under forward and reverse excavation conditions. The results show that the displacement field and internal force field distribution are similar for both excavation methods, and the tunneling first and reverse excavation construction method is safe and reliable.

scholarly journals Experimental Study on Structural Form and Excavation Model of Urban Metro Cross Transfer Station with Super Large Cross Section and Shallow Excavation

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhi Lin ◽  
Xiang Chen ◽  
Hongyun Yang ◽  
Chongguo Cheng ◽  
Huasong Wang ◽  
...  
Keyword(s):  
Large Scale ◽  
Ground Surface ◽  
Construction Method ◽  
Surrounding Rock ◽  
Structure Form ◽  
Large Section ◽  
Response Characteristics ◽  
Ground Surface Settlement ◽  
Transfer Structure ◽  
The Stability

The construction of urban underground cross-interchange transfer subway stations often encounters the difficulties of shallow-buried, different surrounding rock, large spans and heights, congested road traffic, and surrounding buildings sensitive to the construction sequence. Therefore, there is a need for an underground project that controls the stability of underground space and ground subsidence. Based on the construction difficulties of a certain station (the maximum excavation area over 760 m2), this paper conducts a comprehensive selection design of the structure, construction mechanics response, and control technology of this type of interchange station structure and construction excavation. First of all, based on the design experience of large-scale underground transfer transportation engineering and taking full consideration of the stratum conditions, an “arch-wall” cross transfer structure method is proposed. The refined numerical analysis shows that the structure can fully utilize the stratum conditions to reduce the ground surface settlement. Then, in view of the stability of surrounding rock during the construction of a large section, based on the traditional large section excavation method, a construction method of “cross rock beam + heading method” was proposed. In order to verify the effect of the construction method, the three-dimensional detailed numerical model was used to simulate the construction conditions, and the mechanical response characteristics and displacement changes of surrounding rock under each excavation step are explored. Simultaneous interpreting with the traditional large section excavation method, the results show that the new method has advantages in controlling the stability of the surrounding rock. Meanwhile, in order to ensure the safe construction of the project, the self-developed multifunctional engineering test system for traffic tunnels is used to carry out a large-scale physical model experiment to simulate the entire process of the “arch-wall” cross transfer structure construction response characteristics. By analyzing the data of measuring points, the results show that the structure form and the excavation method cause the ground surface settlement, stress, and structural forces meet the requirements for safe construction. Finally, the station can be safely constructed under the new structure form and construction method. Therefore, the structure form and method proposed in this paper can be adapted to the large-scale underground structure under construction in complex environments.

Study on Predictin of Surface Subsidence of an Exremely Shallow Large-Span Double-Arch Tunnel

2011 ◽  
Vol 396-398 ◽  
pp. 2245-2248
Author(s):  
Xin Zhi Li ◽  
Shu Cai Li ◽  
Shu Chen Li ◽  
Xian Da Feng ◽  
Chao Yuan ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Surface Subsidence ◽  
Tunnel Construction ◽  
Geomechanical Model ◽  
Large Span ◽  
Geomechanical Model Test ◽  
Construction Methods ◽  
Surface Subsidence Control ◽  
Great Wall

The Qi-Great Wall tunnel which crossed the Qi -Great Wall ruins was a large span double-arch tunnel with two-way and six-lane and the maximum depth was less than 5 meters, in order to protect the safety of thr surface ruins in the tunnel construction progress, surface subsidence control was particularly important. Through comprehensive geomechanical model test and numerical simulation , the surface subsidence wich generated in the process of construction according to construction methods of excavation and support was studied, the distribution of surface subsidence got through two methods was fitted well,and research results could provide guidance for the construction.

scholarly journals Research on Construction Optimization of Three-Connected-Arch Hydraulic Underground Cavities Considering Creep Property

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Bao-yun Zhao ◽  
Nian-chun Xu ◽  
Zi-yun Li ◽  
Tong-qing Wu
Keyword(s):  
Large Scale ◽  
Creep Property ◽  
Construction Method ◽  
Surrounding Rock ◽  
Creep Model ◽  
Secondary Development ◽  
Underground Cavity ◽  
Construction Methods ◽  
Nonlinear Viscoelastic ◽  
Construction Optimization

In order to prevent the creep of surrounding rock in long-term construction, with consideration of different construction methods and other factors during the construction of large-scale underground cavity, three different construction schemes are designed for specific projects and a nonlinear viscoelastic-plastic creep model which can describe rock accelerated creeping is introduced and applied to construction optimization calculation of the large-scale three-connected-arch hydraulic underground cavity through secondary development of FLAC3D. The results show that the adoption of middle cavity construction method, the second construction method, enables the maximum vault displacement of 16.04 mm. This method results in less stress redistribution and plastic zone expansion to the cavity’s surrounding rock than the other two schemes, which is the safest construction scheme. The conclusion can provide essential reference and guidance to similar engineering for construction optimization.

Study on Construction Method of Double-Track Tunnel on Passenger Dedicated Line by Numerical Simulation

2012 ◽  
Vol 204-208 ◽  
pp. 1527-1531
Author(s):  
Jian Guo Zhang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Construction Method ◽  
Surrounding Rock ◽  
Construction Process ◽  
Construction Methods ◽  
Operation Conditions ◽  
Stability Of Surrounding Rock ◽  
Double Track ◽  
Passenger Dedicated Line

In view of the double-track tunnel on passenger dedicated line with speed 250km/h, finite element programming has been employed to simulate dynamic construction process under shallow-buried and bias conditions with grade IV, including stony and soil, and grade V surrounding rock. Different construction methods under various operation conditions have been compared. Based on stability of surrounding rock and safety of primary and temporary lining, proper construction method under various operation conditions has been presented.

Stability Analysis of Large Underground Station Based on Coupled Fluid-Solid Theorem

2013 ◽  
Vol 748 ◽  
pp. 1104-1108
Author(s):  
Rui Lang Cao ◽  
Shao Hui He ◽  
Fang Wang ◽  
Fa Lin Qi
Keyword(s):  
Pressure Distribution ◽  
Pore Pressure ◽  
Surrounding Rock ◽  
Three Dimensions ◽  
Lagrangian Analysis ◽  
Principal Stresses ◽  
Construction Methods ◽  
Study Results ◽  
Underground Station ◽  
The Stability

Tunnelling may disturb the intrinsic balance of a stratum, and result in accidents like caving or gushing. In order to assess the security of underground station project, numerical analysis for the stability of surrounding rock was done with fast Lagrangian analysis of continua in three dimensions (FLAC3D), Multiple factors were considered, including surrounding rock classes, tunnel depths, groundwater tables, construction methods and initial supporting systems. According to the results of principal stresses, displacements, plastic zones, pore pressure distribution and the mechanical characters of supporting system including anchors and shotcrete, the seepage mechanism of underground station has been discussed. The pore pressure distribution of deep-buried tunnel was studied as well. The study results can provide a theoretical basis for the design of tunnel and underground works in aquifer strata.

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