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.

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.

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.

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.

Construction Optimization of the Bridge-Tunnel Sections

2012 ◽  
Vol 430-432 ◽  
pp. 408-413
Author(s):  
Wan Li Chao ◽  
Xing Hua Wang
Keyword(s):  
Stress Concentration ◽  
Dynamic Analysis ◽  
Good Control ◽  
Construction Method ◽  
Surrounding Rock ◽  
Displacement Control ◽  
Running Speed ◽  
Vehicle Load ◽  
Joint Section ◽  
Construction Optimization

The construction method of the joint section connecting bridge and tunnel was simulated by FEM. After Calculating and comparing the result of stresses and effect of displacement-control in the surrounding rock under three methods of construction, it shown that the side heading method was very advantageous for the stress concentration, and the CRD method provided a good control of bottom heave, as for the top heave, the double side heading method was more favorable. From the dynamic analysis, the vehicle load is found to have, though small, wide influence. What’s more, the lapping distance between the bridge and tunnel is better more than 4m, and the influence from the high running speed should be paid attention to.

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 Tailings facility disclosures reveal stability risks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel M. Franks ◽  
Martin Stringer ◽  
Luis A. Torres-Cruz ◽  
Elaine Baker ◽  
Rick Valenta ◽  
...  
Keyword(s):  
Information Disclosure ◽  
Significant Risk ◽  
Construction Method ◽  
Facility Management ◽  
Alternative Technologies ◽  
Construction Methods ◽  
Comprehensive Survey ◽  
Engineering Standards ◽  
The Right ◽  
Stability Issues

AbstractTailings facility failures represent a significant risk to the environment and communities globally, but until now little data was available on the global distribution of risks and characteristics of facilities to ensure proper governance. We conducted a survey and compiled a database with information on tailings facilities disclosed by extractive companies at the request of institutional investors. Despite limitations in the data, this information disclosure request represents the most comprehensive survey of tailings facilities ever undertaken. The compiled dataset includes 1743 tailings facilities and provides insights into a range of topics including construction method, stability, consequence of failure, stored volume, and the rate of uptake of alternative technologies to dewater tailings and reduce geotechnical risk. Our analysis reveals that 10 per cent of tailings facilities reported notable stability concerns or failure to be confirmed or certified as stable at some point in their history, with distinct trends according to construction method, governance, age, height, volume and seismic hazard. Controversy has surrounded the safety of tailings facilities, most notably upstream facilities, for many years but in the absence of definitive empirical data differentiating the risks of different facility types, upstream facilities have continued to be used widely by the industry and a consensus has emerged that upstream facilities can theoretically be built safely under the right circumstances. Our findings reveal that in practice active upstream facilities report a higher incidence of stability issues (18.3%) than other facility types, and that this elevated risk persists even when these facilities are built in high governance settings. In-pit/natural landform and dry-stack facilities report lower incidence of stability issues, though the rate of stability issues is significant by engineering standards (> 2 per cent) across all construction methods, highlighting the universal importance of careful facility management and governance. The insights reported here can assist the global governance of tailings facility stability risks.

Bridge bearing solutions that facilitate quick and efficient bearing installation and bridge construction

2019 ◽  
Author(s):  
Simon Hoffmann ◽  
Amit Kutumbale ◽  
Danilo Della Ca'
Keyword(s):  
Load Distribution ◽  
Construction Method ◽  
Construction Process ◽  
Vital Function ◽  
Bridge Construction ◽  
Construction Methods ◽  
Efficient Construction ◽  
Critical Components ◽  
Bridge Bearing ◽  
Segmental Bridge

<p>A bridge’s bearings, arguably its most critical components, perform a vital function throughout the bridge’s service life, but the bearings used can also have a significant impact on the bridge construction process. Suitably designed adjustable bearings are an integral part of the incremental launch method of bridge construction, for instance, which can be a very efficient construction method. Adjustable bearings may also support other bridge construction methods, such as segmental bridge construction, where fixities/freedoms that applied during the construction phase require to be changed before the bridge enters service. Lifting bearings, the height of which can be increased, may enable a lack of precision in the structure to be tolerated, and measuring bearings may enable load distribution during bridge construction to be verified, where this is required by the construction method. Design features of otherwise standard bearings that support quick and high-quality installation can also contribute towards the efficiency of the overall bridge construction process, as can the use of bearing designs which minimize bearing size. Bearing solutions and features that facilitate bearing installation and bridge construction in ways such as these are described.</p>

Modeling and Identification of Elastomeric Bearing Characteristics for Large-Scale Simulations

1998 ◽  
Vol 120 (1) ◽  
pp. 63-73 ◽  
Author(s):  
K. N. Morman ◽  
E. Nikolaidis ◽  
J. Rakowska ◽  
S. Seth
Keyword(s):  
Large Scale ◽  
Dynamic Stiffness ◽  
Testing Procedure ◽  
Nonlinear Dependence ◽  
Model Parameters ◽  
Elastomeric Bearing ◽  
Nonlinear Viscoelastic ◽  
Component Test ◽  
Differential Type ◽  
Stiffness And Damping

A constitutive equation of the differential type is introduced to model the nonlinear viscoelastic response behavior of elastomeric bearings in large-scale system simulations for vibration assessment and component loads prediction. The model accounts for the nonlinear dependence of dynamic stiffness and damping on vibration amplitude commonly observed in the behavior of bearings made of particle-reinforced elastomers. A testing procedure for the identification of the model parameters from bearing component test data is described. The experimental and analytical results for predicting the behavior of four (4) different car bushings are presented. In an example application, the model is incorporated in an ADAMS simulation to study the dynamic behavior of a car rear suspension.

Study on Deformation and Damage of Rock Mass Subject to High In Situ Stress by Using a Elastoplastic Damage Model and Considering the Impact of Weak Planes

2013 ◽  
Vol 838-841 ◽  
pp. 705-709
Author(s):  
Yun Hao Yang ◽  
Ren Kun Wang
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Damage Model ◽  
Back Analysis ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
High In Situ Stress ◽  
Underground Caverns ◽  
The Impact

Large scale underground caverns are under construction in high in-situ stress field at Houziyan hydropower station. To investigate deformation and damage of surrounding rock mass, a elastoplastic orthotropic damage model capable of describing induced orthotropic damage and post-peak behavior of hard rock is used, together with a effective approach accounting for the presence of weak planes. Then a displacement based back analysis was conducted by using the measured deformation data from extensometers. The computed displacements are in good agreement with the measured ones at most of measurement points, which confirm the validities of constitutive model and numerical simulation model. The result of simulation shows that damage of surrounding rock mass is mainly dominated by the high in-situ stress rather than the weak planes and heavy damage occur at the cavern shoulders and side walls.

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