The deep-buried tunnel has the characteristics of high in-situ stress, high osmotic pressure and rich sources of disasters. These factors can significantly increase the risk of water-inrush. Drilling-and-blasting excavation method must be adopted in some sections. The water-inrush in drilling-and-blasting excavated deep-buried tunnel are commonly characterized by concealment, complexity, suddenness and destructiveness and the disaster mechanism is more complicated. There are still some problems in the existing researches, such as the detection and identification of disaster source are inaccurate, the constructed disaster mechanism is unclear, the prevention and control of malignant disasters are inadequate. The existing theories and technologies are not fully applicable anymore, thus, the prevention and mitigation of geological hazards are the key scientific issues remained to be solved. The existing research status are analyzed from three aspects: the advanced geological prediction, the disaster mechanism of water-inrush, and the evolution and mitigation of constructed disaster. Three suggestions were put forward about the key points and directions of the research on the water-inrush in deep tunnel. First of all, it is necessary that comprehensive application of big data analysis and the latest research results of other subjects in order to achieve quantitative and accurate detection. Furthermore, the catastrophic model of disaster sources should be established from the perspective of energy storage and release. The occurrence conditions and emergency mechanism of engineering disasters need revealing. In addition, the method of calculating the safety of impermeable silt layers should be developed and the existing research results also should be applied to practical engineering. Last but not least, the risk assessment theory of the water-rich soft rock section of deep-buried tunnel should be studied seriously. According to the actual conditions of the tunnel, the different technologies of disaster control should be combined organically to maximize the benefits of technology, economy, resources and environment.

This research summarized the basic concepts of compressed air energy storage(CAES)underground caverns from an engineering perspective, analyzed the basic structure of caverns and the main load characteristics of caverns during operation. On this basis, the basic design concept of flexible sealing structure was put forward, and the reliability design method was suggested to be adopted in the construction of underground caverns, which also provided the guidance and design principles, operation, and maintenance of CAES underground caverns.

Due to the long length of the tunnel, the low efficiency of manual detection and the strong subjectivity, automated and information-based monitoring and detection methods were required for daily operation and management maintenance, and timely diagnosis and prevention. This study introduced several common defects in tunnels and several commonly used monitoring and detection technologies at home and abroad, and analyzed their respective characteristics and detection capabilities. Three common inspection system equipments- UAV, inspection vehicle, and inspection robot were presented, and the applicable conditions and environment were analyzed. The future development trend of tunnel intelligent monitoring and detection was prospected. It was proposed that the development of a variety of comprehensive detection technologies, combined with artificial intelligence and big data analysis is the future trend of intelligent development of tunnel monitoring and detection.

This paper made a comprehensive literature review on the topic of applying machine learning methods to shield tunnelling parameter predictions, stratum predictions ahead of a tunnel face, surface settlements prediction, shield attitude deviation and tool wear predictions. The selections of machine learning methods and the associated input and output parameters were analyzed, and the shortcomings and challenges of existing research were summarized. Some prospects were given, including the model generalization, multi-source heterogeneous data compression and assimilation, data-physics-based intelligent shield tunnelling, big data in shield tunnelling, in order to provide reference and guidance for the future research and engineering practice.

The construction of railway projects in China is still in the ascendant, and the construction of tunnel projects under complex geological conditions will face more and more challenges. Seven typical engineering disasters during the construction period of railway tunnels were introduced including water inrush, collapse, large deformation, rock burst, harmful gas, high ground temperature and frost damage. According to the types of disasters, a preliminary summary of each disaster case was given. In addition, for some typical disaster prevention and control cases in recent years, the disaster occurrence process, disaster mechanism and specific disposal methods were introduced detailedly to provide reference for future similar project disaster prevention and control. On the basis of summing up the experience and lessons learned from disaster prevention and control of railway tunnels, it was suggested that future disaster prevention and control should focus on the following areas, emphasis on the macro geological analysis of the tunnel site area, development 2019年 - 第1卷第2期田四明,等:中国铁路隧道建设期典型灾害防控方法现状、问题与对策 \=-of comprehensive advanced geological forecasting technologies, improvement of tunnel disaster monitoring and early warning systems, and improvement of the level of disaster risk information management and control, development of large-scale mechanized supporting construction, and reinforcement of the safety quality management of tunnel construction.

The prevention and treatment of tunnel drainage pipe crystal blockage is very important to the safety of tunnel structure and normal operation of tunnel. Based on the systematic review of domestic and foreign research data, the crystallization process and mechanism of tunnel drainage pipe were analyzed and summarized. The crystallization process in tunnel drainage pipe was summarized as three main stages: the penetration process of groundwater into shotcrete, the dissolution process of calcium in concrete, crystal deposition process in drainpipe. Meanwhile, based on the source of the crystalline material and the crystallization process, the factors affecting the clogging of the tunnel drainpipe were divided into internal and external factors. Internal factors include three types of groundwater quality, surrounding rock types, and shotcrete characteristics. External factors include the characteristics of the aqueous solution in the drainpipe(including the CO₂ content, pH value, salt content in the solution, flow velocity), environmental factors(temperature, pressure)and engineering factors, and elaborated in detail on them. In addition, the prevention technology of drainpipe crystallization blockage was discussed from the aspects of drainage system design, drainage pipe material and concrete mix ratio. Finally, the mechanical, physical, chemical, and biological disposal methods for the crystallization of the tunnel drain pipe were discussed and analyzed in detail. The research can provide a theoretical reference for the prevention and treatment of crystal blocking disease of tunnel drainage pipe.

The background of the invention of the double-mode shield machine/TBM was reviewed, the multi-mode shield machine/TBM was defined and classified. The working principle of the double-mode shield machine/TBM was explained. The applicable geology formation and environment of the double-mode shield machine/TBM was clarified. The effects of application of the double-mode shield machine/TBM were summarized. The paper has an important reference for the construction of tunnel boring machines under similar strata and environmental conditions.

Based on groundwater level data of 35 monitoring boreholes from 2015 to 2020 obtained from a large-scale underground water-sealed cavern project, the characteristics and causes of the changes in the groundwater level were systematically analyzed. Taking the construction progress of each cavern unit and geological structure information obtained from previous survey into account, those monitoring data revealed the influence of underground cavern excavation and artificial water curtain system on groundwater level, and the possible risk areas of low water pressure. According to the corresponding relationship between the temporal changes of groundwater level and construction progress, the monitoring boreholes could be divided into three types: water level maintains relatively stable,water level declines when adjacent tunnels were excavated; water level declines far after the adjacent tunnels were excavated. Combined with the spatial distribution of boreholes and the construction progress of underground caverns, it could be found that the groundwater level in the overall study area declined after the excavation of the underground caverns. However, benefited by the artificial water curtain, groundwater level in most area maintained higher than the safe water level(-25 m). Affected by faults F2, F3 and joint fracture zones L4, L8, local groundwater level in the southwest was still far below the safe water level(-25 m)at the end of monitoring, and it indicated a risk of insufficient water sealing. It indicated that the dynamics of the groundwater level in the study area was closely related to the construction progress and quality of the underground caverns, and the systematic monitoring of the groundwater level and timely analysis and feedback were essential. It is urgent to compile a specification for the underground water monitoring of the water-sealed cavern to promote more systematic monitoring of groundwater and improve the construction efficiency of the project.

With the development of urban accelerated construction, “urban disease” is becoming more and more prominent, and the development and utilization of underground space is more and more important. By transforming the mode of urban development, scientifically planning the development and utilization of underground space, drawing on international successful experience and paying attention to the development of quality, we can realize the multifunctional utilization of underground space development, realize the “urban diseases” such as urban disaster, traffic congestion, air pollution and urban inland inundation, and take the construction of underground pipe gallery and sponge city construction as an opportunity to resolve the existing problems in the construction of legal system and the reform of management system in a timely manner, realize the harmonious coexistence of man and nature, promote the construction of urban ecological civilization towards a new height, and promote the construction of beautiful cities.

Deep underground rocks are in a complex geomechanical environment featuring high in situ stress, high temperature, and high osmotic pressure. The mechanical responses and failure mechanisms of deep rocks under dynamic loading due to excavation, blasting and earthquakes cannot be explained by traditional rock mechanics theories due to these factors. In recent decades, significant progress has been made in the characterization of dynamic properties of rocks, including compression, tension, fracture and shear. Due to the complex geomechanical environment of deep rocks, extension of these investigations to deep rocks is desirable by considering high in situ stress, high temperature and high osmotic pressure, which is a critical issue in deep rock engineering. This study reviewed existing rock dynamic studies considering such three factors, summarized the influence of these factors to dynamic responses of rocks. Experimental systems, data analytical methods, and experimental results were summarized. In the last, future directions in deep rock dynamics were proposed.