Abstract：Because development and utilization of underground space resources is in the geological body, it is Influent by the nature and structure of the geological body and the state of storing of groundwater. This geological problems are state of storing of groundwater, the changing of groundwater water level. ground subsidence , active fault, covered karst collapse and the underground noxious gas. These issues may have adverse impact on the development and exploitation of underground space. An improper countermeasure might lead to heave losses. Therefore, geological condition should be considered as one of important factors when underground space planning is formulated. It is of great important to ward off risks, protect environment and achieve sustainable development.

The dynamic constitutive model of soil is one of the core issues of soil dynamics research, and it is the basis for carrying out dynamic numerical calculation of important civil engineering. The general dynamic constitutive model has many problems, such as many assumptions, small scope of application, and inable to reasonably reflect the dynamic characteristics of geotechnical materials. Starting from the viscous coefficient, through the big data deep mining of a large number of experimental data under the dynamic load of cohesive soil, the main influence coefficient of the viscous coefficient is determined, and the big data calculation model of the viscous coefficient is established. On the basis of the big data static generalized plastic mechanics constitutive model of the research team, the viscous coefficient calculation model was introduced into the viscoelasto-plastic model with the viscoelasto-plastic theory as the model framework, and the generalized plastic mechanics viscoelasto-plastic constitutive model of the big data cohesive soil was established. It has been proved that the fitting degree of this model is 0.956, which can better simulate the dynamic characteristics of cohesive soils under dynamic load.

The Cross-river Tunnel of the East Fuxing Road in Shanghai is the first double-deck tunnel in China. Horizontal Freezing Method was used to construct the cross- passages monitored with a system of information construction. Analyzing the monitored data in details, it is shown that the layout of freezing pipes and the heat radiation of tunnel lining are two important factors affecting the frozen soil's shape. The frozen soil's shape can be divided into three zones according to the lay out of freezing pipes and the heat radiation of tunnel lining. Through defining the radiating coefficient of the tunnel lining, the influencing degree and dimension affecting the frozen soil behind the tunnel lining due to the heat radiation are discussed. The significant conclusions obtained in this paper provide a good reference in guiding future design and construction in similar conditions.

The rapid development of cities brings problems of “great urban disease”, such as environmental pollution, resource shortages, traffic congestion, ever-rising housing prices and so on. The best choice to solve the “great urban disease” is carrying out the development and utilization of urban underground space. This paper summarizes the characteristics of “great urban disease” in the construction of big cities in our country, puts forward the practical significance of development and utilization of urban underground space for urban sustainable development, then summarizes the development situation of urban underground space at home and abroad, and clarifies the core problems and the directions of development and utilization of urban underground space. Based on the analysis of the status quo at home and abroad, the paper puts forward the future development principles of China's development and utilization of underground urban space, meanwhile, from the perspective of practical thinking of China's development and utilization of urban underground space, puts forward certain development viewpoints of the planning layout of future underground cities: advocating the establishment the concept of the fourth land and underground red line from the perspective of legal construction; valuing ideas including combination design, planning with blank, intelligent construction from the perspective of planning, design, construction; proposing to adopt node TOD space layout concept from the perspective of space; adhering to the people-oriented concept from the perspective of sustainable development. The Research Summary and development viewpoints provide a reference for the future development of underground space planning, aiming at providing a new model for the linkage utilization of three-dimensional space of future large cities.

In consideration of the development and construction of the Shanghai Hongqiao integrated transportation hub, introduced the overall layout and the underground space development program of the world's largest transportation hub - Hongqiao integrated transportation hub. At the same time, relying on the hub building, an analysis of the pivotal conditions of underground space development in the region had been done. The necessity and urgency of underground space development in Hongqiao integrated transportation hub region were studied. The objectives, principles and general ideas of underground space in Hongqiao integrated transportation hub region are proposed. Based on the study of functions and scale of underground space, the control requirements of underground space planning were given, and the suggestions on planning of underground traffic facilities, underground complex settings and underground space planning and implementation were recommended.

Based on the seismic damage rehabilitation project of Daliang tunnel in Lanzhou-Xinjiang high-speed railway crossing seismogenic faults, through field investigation, mapping, exploration and other methods, the deformation and damage characteristics of the railway tunnel crossing the active fault zone under near-field strong-earthquake effect were revealed. Combined with the seismic safety assessment conclusions, the multi-dimensional repair methods of earthquake-damaged tunnel in active fracture zone was proposed, which included protection and reinforcement, structural demolition and reconstruction, reserving deformation space, applying devices for the energy dissipation and shock absorption, structure segment design, and using ballastless track with large adjustment. These repair methods possess the rapid and safe characteristic during the construction, which could solve the related problems caused by the further deformation of active fracture in the subsequent operation stage, so as to achieve the adaptive effect of post-earthquake residual slip and moisture slip deformation structure and rapid repair of stick-slip dislocation damage. According to the feedback of field construction and monitoring results, the relevant repair plans were highly feasible, and the repaired tunnel structure has a good carry capacity. This study can provide practical experiences and useful references for the earthquake disaster recovery and seismic fortification of subsequent similar tunnel engineering.

Based on the statistical results of anchorage forms of 81 suspension bridges in China, the application status and development trend of tunnel-type anchorage were analyzed. Combined with relevant research data at home and abroad, the deformation characteristics, failure modes, and the calculation methods of pull-out forces were summarized. Four in-situ scale model tests carried out by our group in soft rock strata were introduced. The feasibility of constructing tunnel-type anchorage in soft rock strata was verified according to the test results. The key factors affecting the stability of tunnels-type anchorage in soft rock strata are clarified. The future studies are considered to be in the following five directions: (1) Study on the load transmision mechanism of tunnels-type anchorage in soft rock strata, and further research the failure mode and long-term stability of tunnels-type anchorage in soft rock strata. (2) The reinforcement measures to prevent the damage of tunnel-type anchorage are studied; (3) Understanding the stress state on the failure surface is the key to calculate the bearing capacity of the tunnel-type anchorage; (4) Combined with model test and discrete element numerical simulation to study the deformation-fracture-instability evolution process of tunnels-type anchorage.

Accurate evaluation of the geostress state and magnitude of engineering rock mass is an important prerequisite for underground engineering design, stability analysis and risk control. In order to clarify current situation of the theoretical study and engineering practice application of high geostress criteria, the direct or indirect influences of temperature, groundwater, tectonic movement, unfavorable geological condition, buried depth as well as the topography and geomorphology on the magnitude of geostress are detailed summarized. Several existing high geostress criteria are analyzed, combined with the latest research results, 18 kinds of geological markers of high geostress areas are summarized. The corresponding engineering phenomena and typical pictures of 13 geological indicators are further analyzed based on engineering phenomena, occurrence conditions and failure mechanisms. A reasonable evaluation of the universality of various criteria has been made, and it is pointed out that the strength-to-stress ratio criterion is a relatively authoritative criterion. Then, combined with engineering examples, the existing 6 calculation and classification methods of the strength-to-stress ratio method are compared. The most accurate strength-to-stress ratio criterion is dry uniaxial compressive strength ratio to maximum principal stress (UCS_drying/σ₁). Study results can provide references for the theoretical research and engineering practice of high geostress classification.

Underground space resources (USR) are a new type of land resources with the dual attributes of resources and environment. The urban underground space resources (UUSR) are extremely precious, sensitive and irreversible resources which are carriers to the survival and development of modern urban. The development and utilization of UUSR must be scientific, in-order and reasonable. Besides, the assessment of UUSR is the basis and premise of UUSR utilization, unified control of national land space and three dimensional urban planning. In this study, the similarities and differences between land and mineral resources assessment, groundwater resource effect assessment and UUSR assessment are analyzed. The actualities, including progress and deficiency of UUSR assessment are discussed from seven aspects. The importance of strengthening UUSR assessment research and its connotation construction are discussed. Three key scientific issues of UUSR are discussed as the multi-scale effect of UUSR assessment elements, the mutual feedback mechanism between UUSR and its development and utilization, and the corresponding dynamic response of UUSR assessment elements. Meanwhile, the main contents of UUSR assessment are explored, and the future trend in five aspects are presented. Subsequently, the preliminary definition and corresponding concepts of the science of underground space resources (SUSR) are proposed. In addition, the basic framework and research paradigm of SUSR are presented.

Abstract：Combined with rock slope engineering examples, the analysis of the calculation methods for anchors axial force in rock slope was carried out in different ways. The results show that the calculated values of bolt axial force by limit equilibrium method, the strength reduction method, equivalent internal friction angle method, 2-D numerical analysis method are relatively large. The calculated values by 3-D numerical analysis method are reliable. It is consistent with the result from actual slope. The calculated values of anchors axial force by lateral rock pressure calculation method and unbalanced thrust method are almost the same with that by numerical analysis method. When the lateral pressure is close to zero, the calculation design method in technical code for building slope has potential safety problems. In this case, the strength reduction calculation method is proposed in this paper. Through a series of case studies, the applicability of the proposed method was clearly exhibited. Anchors axial force is not uniformly distributed, the anchors should be strengthened on the top and the bottom of the slope. The slope which has a good stability during the construction phase can be treated by direct construction method, because the stability of the slope has been fully used to reduce the anchors axial force, and also can optimize the designs.

In view of some problems in the industrial standard " Technical standard for building engineering against uplift (JGJ 476—2019)", this paper presents understanding and thinking. For projects with anti-uplifting design grade A, this standard adds a lot of work content, among which the prediction of underground water level in the service period is a difficulty. The accumulation of basic data and the establishment of groundwater numerical analysis model are feasible approaches. It is not entirely appropriate for the standard to link the anti-uplifting design grade with the foundation design grade. In addition to the overall anti-uplifting stability checking calculation, the "unit anti-uplift stability checking calculation " for the weak parts of the underground structures should also be carried out, which should be considered in combination with the strength and deformation check of the floor. Under the condition of artesian water, the hydraulic head value of most areas of basement floor is the same as that of artesian water. The concept of cross section calculation formula of anti-uplifting bolt reinforcement is not clear. When adopting the active anti-uplifting method, the adaptability of stratum and environment should be fully considered. The problems of soil retention and clogging performance, seepage calculation of the drainage blind ditch and the durability of cutoff wall should be studied more deeply.

Abstract: According to the current situation of People’s Square underground space: three metro lines can be interchanged here; more than fifty bus lines gather here; many commercial, cultural, underground parking facilities are distributed here. The future requirement analysis of People’s Square shows that the present situation of the square can not meet future development requirement. So the successful experience of San Francisco and Montreal can be used in combination with the practical situation of Shanghai People’s Square. This paper presents some ideas of optimization of people’s square underground space: shortening time of metro interchange; integrating metro and bus interchange; connecting the function buildings in this district.

Abstract：This article analysed the engineering characteristic of soft high embankment in Chongqing, and a comparative analysis was carried out for several common foundation treatment plans—grouting, compaction, drilling and punching into the pile by a project case and discussed their properties respectively. This paper proposed a technology of rotary drilling cast-in-place pile for the special nature of the high embankment, in further, introduced its drilling mode and feature and application status in Chongqing, probed into construction quality by dry and wet drilling methods and the advantages and disadvantages in terms of rock breaking, drilling speed, effect of slurry Wall. In the end, a technical measure is proposed for treatment of hole collapse during the construction by dry drilling. It had a certain reference value for similar project.
 

Shenzhen is China's special economic zone and one of the core cities of Guangdong, Hong Kong and Macao. Significant achievements have been made in Shenzhen's urban construction. With the urban ground space of Shenzhen becoming more and more limited, the development of underground space has become the inevitable trend. This paper first summarized the current status, the future planning and the existing deficiencies of underground space construction engineering in Shenzhen, such as underground transportation system (including underground rail traffic system and underground expressway), utility tunnel, underground commercial street and other underground municipal facilities. Secondly, combined with several typical underground space development projects which have been completed or planned in Shenzhen, the design and construction overview was introduced, and the difficulties and technical innovation in these projects were analyzed. Furthermore, based on the existing deficiencies in overall planning, development level, construction difficulty, policies and laws of the urban underground space utilization in Shenzhen, some thoughts and suggestions on the construction of urban underground space in Shenzhen were put forward.

By comparison of fresh air requirement calculation based on domestic specifications with that on PIARC2004,it is pointed out that there are gaps exist on pollutant design concentration and fresh air requirement calculation of urban road tunnel.Through formulae calculation,it is concluded that there are problems on values of vehicle density factor,as well as the problem on air pressure and air temperature modification for CO fresh air requirement.

The mechanical parameters of rock mass are significant in slope stability analysis of open-pit mines. Hoek-Brown strength criterion can fully reflect the characteristics of nonlinear failure of rock mass and it is widely used in engineering practice. Structural plane is a part of rock mass, and how to estimate the shear strength of structural plane in an exact way is also a worthy question to explore. The GSI index was quantified by the contour curve and pressure-resistance test. Using generalized Hoek-Brown strength criterion to calculate the mechanical parameters of the rock mass in II-B slope of Hexing mine. According to the Barton-Bandis theory, the shear strength of structural plane and the stability of sliding rock mass were figured out. The calculation results showed that the safety factor of the slope is Fs=1.285, and the safety factor of the potential slip plane is Fs=0.911. That means the stability of the overall slope is well, but the partial rock mass has the potential to slip along with the structural plane. The analysis results are in accord with the actual situation. It is demonstrated that the strength parameters of rock mass and the shear strength of the structural plane obtained by this method are reasonable.

In order to research the safety reliability of underwatertunnel subjected to the horizontal and vertical earthquake，Fast Lagrangian Analysis of Continua was used for seismic time history analysis and the large-scale geotechnical software FLAC3D was adopted for a shallow soft clay ground underwatertunnel’s numerical calculation．The results indicate that the tunnel residual horizontal displacement is 15．0 mm，and vertical displacement is 31．0mm，but it generates small relative horizontal and vertical displacement; the whole stress and internal force change a little，and the maximum stress amplitude is 5%; and the natural frequency of tunnel is 0． 65 Hz． Overall，the probability of shear，tensile and resonance failure of tunnel is small，and it is safty and reliability． This conclusion can be used for the design of the same type of tunnel．

Making hole from one side can meet the requirements for construction of connecting aisle in normal subway tunnel． This method is not suitable for the site with complex soils and ultra-long channel aisle． In this paper，an ultra-long connected aisle ( net length 13． 8m) freezing from two sides is surveyed and researched． Through this research，it is pointed out that freezing from two sides to freeze the soil is entirely feasible，and the development of frozen wall in different soil layers through on-site monitoring and analysis can be estimated more accurately to determine the excavation time． In this paper，based on the analysis of monitoring results，the temperature field， development of frozen wall and the tunnel deformation of ultra-long connected aisle frozen from two sides are obtained．The results can be used for reference by similar projects．

The performance of anchors relates to the safe operation of the vessel, the research of movement rules of the anchor in the sediment has been concerned by many scholars. The large deformation and failure of soil happened every moment in the process of dragging anchors, involved many mechanical behavior, such as material nonlinearity, geometric nonlinearity and contact nonlinearity, etc. So it may be difficult to study the dragging anchors through the general analytical research tools. In this paper,the physical model test was carried out used the model Hall anchor, and the movement characteristics and attitude variation of the anchor was measured in the dragging process. Then a numerical calculation model was established to simulated the model test based on the Coupled Eulerian-Lagrangian(CEL). The postural changes of the anchor with the dragged distance were depicted, and the buried depth of the anchor along with the horizontal displacement was plotted. The contrast of the numerical and measured results showed good consistency, which verified the reasonability of the CEL method on analyze the dragging anchors. This method can be used for the research and design of dragging anchors.

Abstract: Shanghai Fuxing east road cross-river tunnel is the first double-deck and double tunnel in our country. There are high construction risks because of large section and unfavourable geological conditions. By using risk analysis method, this paper analyzed possible equipment installation risk before refrigeration, freezing operational risk, freezing temperature maintain risk, equipment withdrawal after thawing risk, the construction risk of excavation in the freezing construction of contact channel. It is shown that the freezing construction risks of adjacent passages can be controlled in the medium risk level as taking reasonable measures in the design and construction, and this paper proposed corresponding preventive measures based on the freezing preparation stage, freezing operation, excavation, freezing equipment removal conditions.

It becomes more and more important to carry out the construction of underground informatization under uniform framework.Different from the aboveground’s uniform data and application model,the underground informatization is more isomerous and complicated in many ways and the design of management platform has to be based on the comprehension of data and application model’character.The paper describes the classes and content of underground informatization at first and then summarizes five characteristics based on the analysis of geologic and underground pipes informatization construction.At last this paper designs the uniform framework of underground informatization and analyzes briefly its characteristic and critical technique support.

Microseismic monitoring technology is a high-tech and informationized dynamic monitoring technology for underground engineering.With the fast development of hardware,signal processing and digitizing technology,the applications of microseismic monitoring technology abroad become more and more.An applying research of this technology is coming up now in China.Combined with the research of the author in recent years,the characteristics of microseismic monitoring technology and its functions on application to underground projects are introduced briefly. Based on its applications abroad and at home, several applying aspects to safety monitoring of underground projects are summarized in this paper. An example of successful application of this technology in China is presented.

Abstract: Urban underground pipelines are the important component of urban underground space. There is a universal pattern of urban underground pipeline informationization in China. In the early stages, the government invested on the general survey of underground pipeline resources, constructed database and information system. After that, due to a lack of specifications and standards for data, departmentalization of information resources and a low level dynamic update of information data, the database became worthless, the information system became invalid and the capital and resources were wasted. Tianjin is one of the quickest developing super cities in China. After four years of efforts, by learning the advanced experiences of underground pipeline information services at home and abroad, Tianjin pattern of underground pipelines information management based on the reality of Tianjin is put forward using top-layer design idea. Urban underground pipeline informationization in Tianjin is constructed using “government + enterprise + society” trinity centered management pattern. Under the situation of government zero investment, multiple projects are developed synchronally, the urban underground pipeline informationization is carried out comprehensively and chronically by collecting and arranging data, constructing database, providing and improving services.

A temporal GIS data model(i.e.TGIS)is built in this paper,which has been successfully applied in the first subsea tunnel in the mainland of China—the Xiamen Xiang an subsea tunnel.Firstly,a temporal database to operate the temporal data is raised,and the change of temporal attribute-level data is expressed.Secondly,we make many temporal-spatial queries using the database.Thirdly,by using the temporal GIS data model,the process of the construction progress data disposal and temporal GIS data modeling is expressed in detail. Finally, an application program of the project using 3D visualization technology validates the practicability of the model. The construction of the temporal GIS data model has significant meaning in the progress of the tunnel engineering and underground engineering.

Data center is an important part of promoting the whole society to be highly digitized and informationized. Its reliability and security are very important to the normal operation of the country or enterprise. Due to the high environmental sensitivity and high energy consumption, the location and energy saving of data center has always been the primary and key problem of the whole industrial chain. With the successful completion of some large tunnel type underground data centers in China, the advantages of underground data centers, such as high concealment, low energy consumption, anti-interference and low pollution, have gradually attracted people's attention. Compared with ordinary underground engineering, large underground data centers involve more complex majors and disciplines, and the operating environment is more severe. In view of the future development of data center in the direction of high standard, low energy consumption and green, this paper comprehensively summarizes the development and research status of underground data center at domestic and abroad, and analyzes the classification and related specifications, from the perspective site selection area and construction process, energy consumption demand and cooling technology, energy consumption demand and cooling technology, green data center, this paper summarizes and analyzes the development trend of data center and the characteristics of underground construction, and puts forward the problems and challenges faced by the construction of underground data center in four aspects: collaborative demand of energy saving and environmental control, suitability transformation of existing underground caverns, new underground caverns, intelligent early warning and prevention and control. The development and utilization of underground space is not only a simple space expansion, but also a functional demand. This paper aims to provide ideas for the construction of large underground data center in the future, and also hope to provide reference direction for the development and utilization of functional underground space.

The threaten acting on the underground is bigger than before as the bombing terrorist attacks raged higher. Features of explosive and standard of TNT equivalent weight can be given by compiling terror bombing attacks in the underground leverage on a global presence, and combining the characteristics of underground and scope out the security. Peak overpressure formula of computation of explosive blast and the air blast curve when the normal TNT surface bursting can be used to calculate the overpressure of explosive, further to estimate its kill capabilities and destructive power. The research results can be regarded as basis for making contingency plan so as to coping terror bombing attacks.

According to the analysis of current transportation status in urban center area of China and the prediction of cont radictions to be faced in the future, the author considers that the underground roads will be a new method to resolve traffic problems in urban center area. In this paper, through the analysis of underground constructions in some urban centers of both China and foreign countries, The authors investigate and summarize the reasons of underground traffic system construction and suggest the development modes of urban underground transportation system in China in the future.

To analyze the relationship between microparameters and macroparameters of the uniaxial compression PFC2D model of rock, and to calibrate the microparameters, the orthogonal design and analysis of variance are adopted in this paper. Flat-jointed contact model is used as the contact constitutive model of particles. The orthogonal design is conducted to the microparameters of PFC2D model. Then analysis of variance and dimensional analysis is utilized to analyze the relationship between microparameters and macroparameters. On this basis, the process of trial-and-error method for calibration of microparameters for rock is proposed and is used to calibrate the microparameters of limestone. Simulation results of macroparameters, stress-strain curves and failure characteristics are closed to the laboratory test results, and this validated the significance of the suggestion for trial-and-error method. If a biaxial compression PFC^2D model need to build, the two microparameters (tan φ_b, μ_b) need further calibration. The research results can provide references for the particle flow simulation of rock mechanics tests.

Underground space is an important part of city space. In recent years,under the guidance of our national policy"Integrating peacetime needs with wartime needs",more and more attentions are paid on the combination of civil air defense engineering and underground space development. This paper focuses on the underground space development of Lishui city.The feature of Lishui city and its current situation of underground space development are analyzed,and the resources of underground space are assessed,then the demand of underground space is forecasted.The development goals and strategies of underground space development are studied.The overall layout of underground space development and civil air defense construction system are formulated.Recent-term and Medium-term building plan and some policies and regulations are proposed.All of these can be referred by others cities when their underground space development is planned.

Choosing an appropriate constitutive model for soil is the key to ensure the quantitative accuracy of modeling geotechnical problems. In recent years, two kinds of models, i.e., the hardening soil model (HS model) and the hardening soil model with a small strain stiffness (HSS model) have shown the good validity and advanced nature in existing studies. There are, however, rare reports on their applications in engineering problems of loess. For this goal, in allusion to the laboratory triaxial compression test of loess and the field plate load test on the loess ground, the HS and HSS models as well as the commonly used Mohr-Coulomb model (M-C model) and Duncan-Chang model (D-C model) in the finite element software Diana were employed to carry out a comparison study of numerical modeling. The results show that the HS and HSS models are better than the M-C and D-C models in fitting the resuts of the two tests, and overall, the fitting results by the HSS model are better than those by the HS model. Therefore, the HS and HSS models are more reliable than the latter two in the aspects of modeling the deformation of loess as well as its mechanism of instability and failure, and are of the value to be popularized.