Load Calculation Method of Tunnels with Shallow Buried Depth and Unsymmetrical Pressure in Regions of Weak Fissured Surrounding Rock

2011 ◽  
Vol 243-249 ◽  
pp. 3364-3369 ◽  
Author(s):  
Chang Qun Zuo ◽  
Jian Ping Chen ◽  
Hui Liu
Keyword(s):  
Numerical Simulation ◽  
Calculation Method ◽  
Structure Design ◽  
Surrounding Rock ◽  
Road Tunnel ◽  
Potential Safety ◽  
Load Calculation ◽  
Modified Formula ◽  
Simplified Calculation ◽  
Weak Surrounding Rock

The key problem of supporting structure design is the load calculation in tunnels with shallow buried depth and unsymmetrical pressure in the situation of weak surrounding rock. The results of simplified calculation method recommended by Code for Design of Road Tunnel differ from the practical situations to a certain extent because of the neglect of load calculation range that makes the results less than the practical values, which will bring about potential safety hazard. Based on the calculation method of the Code, modified computational formulas of vertical load of internal and external sides and horizontal load are put forward based on new assumption conditions and load simplified model. The modified formulas were adopted in the calculation of the entrance of Huo-Cheling Mountain Tunnel with unsymmetrical pressure, and the results were compared with those obtained by the method of the Code and numerical simulation. The comparison show that the results of modified formula coincided with those of numerical simulation, while the values calculated by the Code were smaller.

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.

Restoration Design and Calculation of Shaft Joint in Complex Stratum

2011 ◽  
Vol 368-373 ◽  
pp. 1993-1996
Author(s):  
Xu Han ◽  
Yan Long Ren ◽  
Yang Xia
Keyword(s):  
Numerical Simulation ◽  
Support Effect ◽  
Surrounding Rock ◽  
Metal Mesh ◽  
Cable System ◽  
Weak Surrounding Rock

On account of the fracture status of shaft joint in complex stratum, we analyze the reasons causing damage, then put forward restoration plans, such as, controlling water and consolidate the weak stratum by grouting, and strengthen the shaft supporting. We also propose to enhance supporting shaft thickness reasonably through shaft calculation, checking, and numerical simulation. In addition, bolting support with metal mesh and cable system should be adopted in the combined support of weak surrounding rock, double bolt plates should be used to enhance the links between shaft and surrounding rock, and the support effect should also be monitored.

Study on the Theory and Methods of Bolt-Shotcrete Support for Weak Surrounding Rock Based on Reliability Analysis

2013 ◽  
Vol 444-445 ◽  
pp. 1446-1453
Author(s):  
Zhe Ou ◽  
Cong Xin Chen ◽  
Guan Wen Cheng ◽  
Yun Zheng
Keyword(s):  
Reliability Analysis ◽  
Support System ◽  
Design Method ◽  
Soft Rock ◽  
Reliability Evaluation ◽  
Structure Design ◽  
Surrounding Rock ◽  
Design Parameters ◽  
Weak Surrounding Rock ◽  
Analysis Equation

The evaluation of stability and reliability of support system for tunnel weak surrounding rock are difficult issues of concern in rock and soil engineering. Aiming at the problem of parameter design and reliability evaluation of tunnel weak surrounding rock and bolt-shotcrete support system, the deformation, failure mechanism and physical mechanical properties of weak surrounding rock are analyzed as well as the mechanism of bolt-shotcrete support in soft rock is studied. And the reliability analysis equation of bolt-shotcrete support in two kinds of weak surrounding rock (nearly horizontal layered mechanics medium and continuum mechanics medium) is established. The quantitative soft rock supporting theory is introduced into the reliability analysis equation. The calculation formula of two important design parameters of anchoring force and bolt spacing in bolt-shotcrete support is established. Finally an engineering example is adopted to prove the rationality of the calculation results. Therefor this paper provides theoretical basis and design method for supporting structure design and reliability evaluation of tunnel weak surrounding rock.

Structure Design and Antiknock Performance Analysis of New Mine Refuge Chamber

2014 ◽  
Vol 945-949 ◽  
pp. 1227-1231
Author(s):  
Xiao Yan Gong ◽  
Xin Gao ◽  
Jun Guo ◽  
Jun Xu ◽  
Chao Ming Chen
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Performance Analysis ◽  
Coal Mine ◽  
Structure Design ◽  
Structure Model ◽  
Safety Problem ◽  
Impact Performance ◽  
Finite Element Software ◽  
Potential Safety

In order to solve the potential safety problem due to the explosion of coal mine caused the severe deformation of the front door not being opened normally and the emergency escape hatch was designed unreasonably, three types of structure model with emergency escape hatch being set in transition compartment as entrance and different locations of life supporting compartment as exit, which can avoid the potential safety problem above mentioned. Numerical simulation of antiknock impact performance of the three refuge cabins were calculated and analyzed by using the finite element software of LS-DYNA.The results indicated that the antiknock performance of structures could reach specifications, which could provide a new idea for the development of mine refuge chamber cabin.

A Simplified Calculation Method for the Wall Temperatures of Pressure Vessels With Insulating Layers

2017 ◽  
Author(s):  
Fang Ji ◽  
Guide Deng ◽  
Liang Sun ◽  
Hongchao Suo ◽  
Junwei Yang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Calculation Method ◽  
Numerical Models ◽  
Convective Heat Transfer Coefficient ◽  
Pressure Vessels ◽  
Simplified Calculation ◽  
Simplified Calculation Method

Wall temperatures are a necessary part of the design conditions for pressure vessels. Thermal analysis by numerical simulation is widely used to compute the wall temperatures and thermal stresses of the pressure vessels, and insulation layers outside the pressure vessels are normally included in numerical models to predict more accurate results. However, modeling and meshing the insulation layers introduces more work to designers and more cost to enterprises. In this paper, a simplified calculation method for the wall temperatures of the pressure vessels with insulating layers is presented. An equivalent convective heat transfer coefficient between the outside walls of the pressure vessels and circumstances is derived by theoretical analysis, which takes into account the thermal resistances of the insulation layers and the convective heat transfer coefficient between them and the circumstances, then it can be used in numerical models of the pressure vessels without the insulation layers to compute the wall temperatures. Results of comparative analysis show that the wall temperatures of the pressure vessels by the simplified calculation method agree very well with those using the numerical simulation with the insulation layer models.

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