scholarly journals A Novel Calculation Method of Process Load for Extra-Large Section Tunnels

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1228 ◽  
Author(s):  
Gao ◽  
He ◽  
Chen ◽  
Li
Keyword(s):  
Rock Pressure ◽  
Process Design ◽  
Calculation Method ◽  
Surrounding Rock ◽  
Large Section ◽  
Highway Tunnel ◽  
The World ◽  
Calculated Load ◽  
Surrounding Rock Pressure ◽  
Large Sections

The calculation of load and surrounding rock pressure of extra-large-section tunnels serves as an important premise for the design and construction of tunnel projects with extra-large sections. Based on the large-span section of the Shenzhen Liantang Tunnel (China), which is the largest highway tunnel in the world to date, this paper discusses the challenges existing in the calculation method of state load and surrounding rock pressure for extra-large-section tunnels and puts forward a novel calculation method for process load, which is suitable for extra-large-section highway tunnels. In the current work, we derived the related application correlations and improved the specific application steps, methods, and project models of the proposed calculation method. Both the rationality and feasibility of the calculation method were verified from a practical perspective by comparing the on-site data of surrounding rock pressure at the Liantang Tunnel with the calculated load, which provides a fundamental basis for the process design of tunnels.

Study on a Surrounding Rock Pressure Calculation Method for Super-Large Section Highway Tunnels

Symmetry ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1133 ◽  
Author(s):  
Gao ◽  
He ◽  
Chen ◽  
Li
Keyword(s):  
Rock Pressure ◽  
Calculation Method ◽  
Surrounding Rock ◽  
Underground Structures ◽  
Large Section ◽  
Main Challenge ◽  
The World ◽  
Lining Structure ◽  
Surrounding Rock Pressure ◽  
Universal Applicability

This paper presents new correlations for estimating the surrounding rock pressure of symmetrically shaped tunnels based on a symmetrical numerical model. Surrounding rock pressure is defined as the load acting on the support structure due to the deformation of the surrounding rock after tunnel excavation. Surrounding rock pressure is directly related to the selection of the lining structure and the determination of support parameters. The main challenge in designing and proceeding with the construction process is choosing a calculation method for the surrounding rock pressure for super-large sections, and this has been the focus of research among the tunnel research community. The excavation area of Liantang tunnel of Shenzhen Eastern Transit Expressway (China) is over 400 m2, making it the largest highway tunnel in the world so far. Based on this project, this paper analyses the applicability of various traditional methods of calculating the surrounding rock pressure for super-large section tunnels. In addition, based on the Tunneling Quality Index (Q), the factor of span is introduced into the method of calculating the surrounding rock pressure using the numerical simulation results of super-large symmetrical tunnels with different values of Q and different spans. Additionally, calculated correlations that could quickly estimate the surrounding rock pressure of tunnels are obtained. The comparison of surrounding rock pressures between the estimated and monitoring results of Liantang tunnel and more than 30 projects around the world effectively proves the rationality and universal applicability of the proposed correlations. This method could provide engineers and designers with a quick way to predict the surrounding rock pressure of deep super-large section underground structures during their design and construction stage.

Calculation Method of Surrounding Rock Pressure for Shallow and Unsymmetrical Tunnel under Deep Valley Terrain

2012 ◽  
Vol 170-173 ◽  
pp. 1382-1387
Author(s):  
Zhe Bai ◽  
Shun Chuan Wu
Keyword(s):  
Rock Pressure ◽  
Calculation Method ◽  
Retaining Wall ◽  
Surrounding Rock ◽  
Road Tunnel ◽  
Wall Model ◽  
Study Results ◽  
Critical Edge ◽  
Surrounding Rock Pressure ◽  
Current Code

Code for design of road tunnel provides the calculation method of surrounding rock pressure for shallow and unsymmetrical tunnel, however, which has the applicable condition. Based on code method, the critical edge width is derived which need satisfy when using code method. Then, by assuming the retaining wall model, the analytical solution of lateral pressure for shallow and unsymmetrical tunnel under deep valley terrain is deduced. At last, taking Lijiabao tunnel belonging to Zhangzhuo highway as engineering relying and combining with the field measurement of surrounding rock pressure, the conclusion is drew by comparisons that the value from method in this paper is more close to the reality than the code method. The study results provide references with the design and construction of similar engineering and offers favorable supplement for the current code.

Study on the Prediction Method of Tunnel Surrounding Rock Pressure Based on the Theory of Progressive Destruction

2012 ◽  
Vol 446-449 ◽  
pp. 1432-1436
Author(s):  
Suo Wang
Keyword(s):  
Rock Pressure ◽  
Characteristic Curve ◽  
Prediction Method ◽  
Surrounding Rock ◽  
Progressive Damage ◽  
Tunnel Excavation ◽  
Practical Engineering ◽  
Surrounding Rock Pressure ◽  
The Relationship ◽  
Rock Parameters

In order to predict tunnel surrounding rock pressure, this paper puts forward a series of dynamic numerical simulative model on the tunnel excavation. According to the change of rock damage in the construction program, it adjusts dynamically the mechanical material parameters of surrounding rock. So the model achieves the purpose which is controlling and simulating the process of tunnel progressive damage. In accordance with the numerical simulative results, it analyzes the relationship between the rock parameters with the plastic strain, radial displacement. Then this paper proposes a prediction method of tunnel surrounding rock pressure based on the theory of the progressive damage and method of characteristic curve. Finally, it compares the pressure on the numerical simulative models with on the site date, and it proves that the prediction method has practical engineering value.

FBG Earth Pressure Sensors Applied in Surrounding Rock Pressure of Tunnel

2013 ◽  
Vol 351-352 ◽  
pp. 1173-1178
Author(s):  
Zhou Chun Cai ◽  
Chuan Li ◽  
Yuan Yu Guan ◽  
Wu Fen Chen ◽  
Li Jun Guo ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Rock Pressure ◽  
Pressure Sensors ◽  
Earth Pressure ◽  
Surrounding Rock ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Stress Changes ◽  
Surrounding Rock Pressure

During the period of tunnel excavation, shoring, forming and long-term operation, stress changes of tunnel surrounding rock are complex, the real-time monitoring of surrounding rock pressure is the key factor in ensuring long-term stability in tunnel. Fiber Bragg grating earth pressure sensors apply in surrounding rock pressure of tunnel which can change the pressure of the surrounding rock into fiber Bragg grating wavelength shift. According to the feature of pressure and temperature in Tian Xin Tunnel, 40 earth pressure sensors are embedded in 20 representative sections and one earth pressure sensor is embedded in each arch shoulder. In addition, one temperature compensation sensor is embedded in each arch crown. During the 235 monitoring days, the biggest daily change of surrounding rock pressure reaches 800 KPa. In 3 months of the sensor installation, the average monthly variation is within 50 KPa. The long-term measurement results indicate that the changes of surrounding rock pressure are different in different locations. When the surrounding rock is close to the excavated and blasted surface the surrounding rock pressure changes largely.

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