Applied Mechanics and Materials Vols. 580-583

Abstract: Through the site investigation of defects on a secondary highway tunnel portal in Guizhou Province and survey data, this paper aims to analyze the detection mechanism of all defects. Controlled by bias effect of tunnel portals, the defects of portal lining cracking and leakage are pretty serious. A fully understanding of these mechanisms can help to improve and fine design and construction of tunnel portal, reducing the production of defect.

Abstract: A model of risk trend assessment for metro tunnel crossing underground pipelines is proposed in this paper based on the partial connection number. This paper fully considered the certainty and uncertainty of the index and used "partial connection number method" to analyze the risk developing trend and its sort of metro tunnel crossing underground pipelines. A case study was performed on a metro tunnel engineering of Shenzhen Line 9. The results showed that this model considered the dynamic characteristics of risk, enriching the contents of risk assessment of underground engineering, which can provide a reference for the risk management.

Abstract: The Tanjiaba tunnel lies in Hurongxi highway in Hubei Province. There are some middle karstified soluble rocks and a fish pool above the tunnel. To avoid the disaster of water inrush into the tunnel, risk evaluation is necessary to guide the construction. Fuzzy mathematics model is put forward to distinguish potentially dangerous parts along the tunnel. Use the fuzzy mathematics model differentiated the tunnel into 4 ranks of dangerous parts according to risk index. It is applied in the Tanjiaba tunnel and practice approves that the model are useful.

Abstract: Two structural schemes of the Hong Kong-Zhuhai-Macau Immersed Tunnel were compared. In Scheme 1, the prestressed reinforcing bars were to be cut off after installation. And in Scheme 2, the prestressed reinforcing bars will be kept there as they were after installation. A finite element model for sections E12~E15 was built by using the finite element software PLAXIS with consideration to the construction process and different loading conditions to analyze both schemes. The calculation results show that they both meet the design requirements.

Abstract: Qingdao Metro Line 3 is the first subway line in Shandong province, some tunnels need to cross water-rich sandy layers. At the time of passing through the water-rich sandy layers, how to maximum the deformation characteristics of the tunnel during excavation becomes the critical problem of the design and construction. This paper studies Qingdao Metro Line 3, directs at water-rich sand layer section YK16+382, with the use of on-site monitoring and measuring instruments, analyses the characteristics of ground deformation of the cross section. And we calculated the deformation by Flac3D numerical simulation in YK16+382 cross section, studied the arch and surface subsidence and convergence deformadon variation of convergence. Finally compare site monitoring measurement with numerical computational results and then we can get the convergence of arch and surface subsidence and convergence deformadon, provide theoretical guidance for the actual construction.

Abstract: Pile Foundation Construction jobs are usually wet process has contaminated a large, long duration, the pile of inconsistent quality, cost out. And long bored piles to adapt to a variety of complex geological conditions, but not the impact of water table, is widely used in various projects of the foundation engineering, this according to subway construction in Kunming, the application of experience, a brief description length screw pile construction anti-interpolation technology.

Abstract: This research investigates the impact of the first metro line (Line 1) in Hangzhou on its station-area residential property values. A hedonic pricing model shows that Line 1 had a statistically significant and positive effect on residential prices in its operation period. Compared with its construction phase, the impact did not change significantly, indicating that metro rail transit had a long-term positive influence on the station-area property values. These findings suggest that such capitalization is likely to lead to high-density and transportation-oriented development. While planning the urban rail transit system, such impact should be fully considered.

Abstract: After have been analysed the initial dynamic cumulative damage mechanism of lining structure of the high speed railway tunnel,the conclusions have been gained that, under the effect of the long-term vibrating load of high speed train, When the damage energy accumulation reached a limit values, the damage zone caused by the initial crack which has been existed in the tunnel lining will be expansed further more. for the more, based on the accumulation damage theory linear elasticity and the analysis method dynamic finite element, The extension characters and calculation method of initail crack in the tunnel lining structures for the high railway have been proposed.

Abstract: How to establish the proper rheological model to describe and simulate the relationship between rock mechanic characteristics and time is one of the difficulties in the tunnel long-term stability analysis. In this paper, a numerical model to replicate the time-dependent deformation of rock mass was presented. In the model, the time-dependent deformation is described in terms of degradation of intrinsic physical and mechanical properties of rock and accumulation of mesoscopic damage inside the rock. Based on the model, uniaxial numerical experimentation and tunnel numerical model test are numerically constructed and investigated respectively. The model well reflects the initial creep, steady creep of rock and accelerated creep, which preliminary prove the validity of the proposed model. The results of the tunnel numerical model test show that the displacement curves from the numerical simulation were generally consistent with those from physical model tests. Furthermore, the macroscopic failure modes and local mesoscopic damage evolution of the tunnels were simulated.

Abstract: The use of the Analysis and calculation with elastic-plastic theory and Deep displacement of surrounding rock measurement determine the distribution range on broken zone of surrounding rock in Cha Zhen tunnel ; it verifies The stability of surrounding rock and the design rationality of bolting parameters ;Providing a theoretical base for the setting on broken zone of surrounding rock supporting parameters.