Advanced Materials Research Vols. 243-249

Abstract: With the construction of large quantities of shield tunnels, based on the consideration of the performance, disaster prevention, relief and tunnel drainage requirement, it becomes more and more important to set the connected aisle in the shield tunnel section. The shape of the connected aisle cross-section has an obvious effect on the deformation and stress of the connected aisle. In order to draw reasonable connected aisle type for the subway construction under high hydraulic conditions, the comparative analysis of stress state of the circular and horseshoe-shaped connected aisle section is applied based on the construction of the connected aisle in the shield tunnel across the Yangtze River in Wuhan subway. It is recommended that the horseshoe-shaped cross-section should be applied to connected aisle construction in the shield tunnel in Wuhan subway.

Abstract: With the aim of solving technical problems existing in the rehabilitation construction of butt-joint sect works with manual level freezing undermining method, under Huangpu River of Shanghai Underground Subway 4^# between Nanpu Bridge station and Pudong South Road Station, Group of large-scaled physical model tests had been performed adopting the Manual Level Freezing Undermining Method (MLFM in brief) in constructing double track tunnel. Firstly, the model design and test system integration were made; afterward, through model tests, the paper systematically studied the laws of stratum frost heaving, melting sedimentation rule and stratum displacement variations etc, during the undermining construction of tunnel being frozen. The results indicate: the Maximum displacement of frost heaving measured at the top of freezing wall during up line freezing process was 1.36mm, which is equivalent to actual work quantity of 29.92mm; the strata melting sedimentation displacement during forceful thawing is 54% less than what was during natural thawing, which illuminates that adopting forcing thawing can reduce melting sedimentation of soil blocks.

Abstract: The assessment of the interaction between a new tunnel and existing residential or office building is an important issue in urban area. In this study, special protection design for existing structures is introduced based on an actual engineering project of urban tunnel closely passing beneath an existing residential building. Cavern-pile construction method and deep grouting technique with ultra-advanced steel pipe are used in this project to efficiently control the settlement of the stratums on top of tunnel. Additionally, the effect of tunneling on the existing residential building is investigated through finite element calculations. The load condition, deformation and stability of the tunnel elements beneath building are also analyzed. Then, on the basis of calculated results, it is concluded that the new tunnel constructed by cavern-pile method causes small ground settlement, therefore it does not considerably affects the existing building. The safety of resident is guaranteed.

Abstract: Based on the conditions of Guanjiao tunnel, numerical analysis of air flow field is carried out by the finite element software—CFD in this paper. The results show that when the wind speed is 11m/s, the outlet to the face is less than 50m was better; if the speed is 8m/s ~ 4m/s, the distance is less than 40m better. Under the same conditions, the face wind speed of 40m is larger than of 30m. The faster of the speed, the greater of the attenuation along the way. The best distance from duct to the face is suggested according to different wind speed, which can provide a reference for the construction ventilation of the similar projects in the future.

Abstract: Under the action of stress and crack hydraulic pressure, the damage and rupture of jointed rock mass accumulate and extend simultaneously during the process of its crack occurrence and growth. The rock mass’s damage will be accumulated owing to its rupture, and the damage is closely related to the rupture. Taking into account comprehensive the stress intensity factors both of plane stress and plane strain for hydrous jointed rock mass, two new equations of crack propagation and the new crack length were built on the basis of energy criterion. Assuming the jointed rock mass as equivalent continuous mass with damage and introducing the damage constitutive equation of rock, the damage evolution of the hydrous jointed rock mass is simulated by the damage tensor and the damage strain. The model is used to simulate one tunnel. Through simulation, the waterhead contour is more smooth when the coupling is considered than is not considered, and the maximal displacement almost the same because the diversion tunnel was bulit.The simulate results can provide a reasonable recommendation to the engineering practices.

Abstract: The shaft is accessory structure of water-conveyance tunnel, so study on law of seismic response of water-conveyance with shaft is very necessary. This supply reliable criterion and reference for structural design of water-conveyance, and haves important significance.

Abstract: After a comprehensive review on the exploitation of information technology in geotechnical engineering and underground engineering, a concept of digital underground space and engineering (DUSE) is proposed. Research results show that DUSE is an innovative new information platform for the life cycle of underground space and engineering. DUSE is also a digital museum of the underground space and engineering. By employing the concept, the method and the techniques provided in DUSE, a more realistic and transparent underground space and engineering could be built; huge amount of data could be easily managed and effectively visualized. Therefore, useful information of these data can be processed, improving working efficiency and promoting the implementation of intelligent decision about the engineering project. In addition, some research topics that need to be further addressed are also discussed.

Abstract: Currently, there are no efficient, sustainable and adaptive means of producing large compound-curved cladding and facades in constructional and architectural engineering. This paper described a new and cost effective approach to achieving an integrated manufacturing system by employing innovative digitalised multi-point forming technology. The system integrated with CAD/CAM/CAE/CAT software enables rapid and flexible manufacturing functional and aesthetic panels of 3D freeform cladding and facades through die-less forming and fixture-less assembly.

Abstract: Aiming at the nuclear power plant structure and adopting time domain analysis approach, the seismic analysis of an intake tunnel for nuclear power plant is performed with FLAC3D in this paper. Contraposing the characters of the field rock of the nuclear plant, the internal force distribution of the tunnel under different wall rocks is researched and analysed, and the envelope diagram of inner force in the lining of the tunnel is drawn. The obtained law can provide the basis for the seismic response analysis of tunnels.

Abstract: Many tunnels are going to be driven in China. In order to reduce accidents, the effective measure is to carry out risk evaluation in advance. So it is necessary to study risk acceptance criteria for providing standard of risk evaluation. Individual risk and social risk acceptance criteria are mainly studied in this paper. Individual risk can be derived by the product of former average individual risk level and influence coefficient of national laws. The shape of FN-curve is determined by the combination of neutral and conservative utility theory. Parameters in the curve equations can be calculated by investigating former risk data and known conditions.