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Underground Space Development and Tunneling Technology
Published in T. Adachi, K. Tateyama, M. Kimura, Modern Tunneling Science and Technology, 2020
A new law called “The Special Measures Act for Public Use of Deep Underground Space” has been enacted in Japan. This new law came into force on April 1, 2001. The deep underground is specified as the depth that is not normally used for construction basements, normally 40 m below the surface, or 10 m below the surface of the bearing layers of foundation piles. The main purpose of this law is to regulate the use of deep underground space in appropriate and rational manners for public purposes. Benefits are expected to include the smooth implementation of public projects, the selection of desirable routes which would shorten construction periods and reduce costs, the systematic use of deep underground space by cities, the creation of more and safer structures from earthquakes, the reduction of noise and vibrations on the ground surface, and the preservation of the landscape above the ground.
Japanese experiences
Published in Kuniyoshi Takeuchi, Integrated Flood Risk Management, 2023
Now the construction of underground rivers is underpinned by Special Law on Public Use of Deep Underground (Heisei 12 Law No. 87, 2000) enacted in May 2000 which provided a judicial framework for the public use of deep underground space for various purposes. This act aimed to respond the difficulty of developing new access to the central part of urban area, such as for railways, traffic roads and river courses. Here the deep underground is defined as the underground space below the ordinary use for basement (40 m) or foundation (supporting layer stronger than 2500 kN/m) plus safety distance (10 m) (MLIT, 2018). Under this jurisdiction, various underground river projects were revitalized.
A novel true triaxial test device with a high-temperature module for thermal-mechanical property characterization of hard rocks
Published in European Journal of Environmental and Civil Engineering, 2023
Chuan Wang, Zaobao Liu, Hongyuan Zhou, Kaixuan Wang, Wanqing Shen
In the near future, the equipment will be further upgraded to improve the coupling test function of deformation failure and seepage under high-temperature and true three-dimensional high stress, and expand the test capabilities of the equipment. The system can provide services for deep underground rock mass projects such as deep tunnels, deep geothermal, deep oil and gas, and geological disposal of high-level radioactive waste.
Viscoelastic-plastic constitutive model with non-constant parameters for brittle rock under high stress conditions
Published in European Journal of Environmental and Civil Engineering, 2022
Shuling Huang, Chuanqing Zhang, Xiuli Ding, Liu Yang
The deep underground engineering work required during large construction projects is undertaken in a high geostress environment over an extended period of time, resulting in increasingly significant problems concerning the operational safety of engineering caused by the long-term mechanical responses of the surrounding rock. To describe the rheological mechanical behavior of brittle rock under high geostress, a non-constant viscoelastic-plastic model was proposed. The following conclusions are drawn:The rheological mechanical behavior of hard brittle rock is related to the stress conditions. To describe the influence of stress conditions on the viscoplastic behavior of rock, a non-constant Newtonian fluid taking into consideration the influence of stress state was proposed. Moreover, the relationship between the viscosity coefficient of the non-constant Bingham body and stress level was established. Analysis revealed that the viscosity coefficient decreases with time, reflecting the law that the viscosity coefficient of rock gradually decreases due to crack propagation. The viscosity coefficient decreases with increasing stress level, a finding that can be used to describe the development of deformation in brittle rock at an accelerated rate under the effect of high stress. The nonlinear characteristics of the time-dependent deformation curves of rock become more and more significant with increasing viscosity coefficient. As the initial viscosity coefficient increases, the nonlinear characteristics of the acceleration phase of the time-dependent deformation curve become less and less obvious.Under lower stress, brittle rock rapidly changes to an attenuated time-dependent deformation stage after the initial stage. Steady-state time-dependent deformation behavior is only exhibited under higher stress conditions. The proposed non-constant viscoelastic-plastic constitutive model can well describe the attenuation behavior and steady-state behavior of rock under different stress conditions.