With the development of the country's large-scale infrastructure, the demand for underwater tunnel construction is increasing; however, regarding the construction, operation and maintenance of underwater tunnel are more difficult, the tunnel durability needs to be concerned as well as the life-cycle design. This paper investigated the waterproof and durability measures of the Tokyo Bay Transverse Highway Tunnel, and proposed a comprehensive durability strategy of “multiple waterproof, multi-anticorrosion, and life-cycle design” for the construction of large diameter underwater tunnel. In addition, a life-cycle design method was established with the performance and cost as indicators, and was applied to evaluating of a submarine tunnel under four construction and maintenance plans. As the result, it was clarified that the plan of the high durable tunnel in the initial stage was the most beneficial, and the life-cycle design method was effective. Conclusively, the rational planning and design, scientific construction and maintenance of underwater tunnels could be foundationally supported by development of a life-cycle design system accounting for the economy, safety and environment.

The Yellow River Tunnel located on Jiluo Road in Jinan is one of the largest road-rail joint tunnels which are currently constructed in China. It is the first super-large-diameter shield tunnel to cross over the river suspended above ground in the world. The project had some characteristics, such as large shield excavation section, long excavation distance, shallow overburden, high water pressure, deep working shaft foundation pit, and high protection requirements for surrounding structures. Based on engineering construction environment and construction risks, the overall design plan of the Yellow River Tunnel was analyzed, which included engineering horizontal and vertical section design, cross section layout, environmental risk controlling, tunnel structure and construction organization. The design schemes of super-large-diameter shield tunnel suitable for the middle and lower reaches of the Yellow River were determined. The design ideas and engineering features of the tunnel across the Yellow River on Jiluo Road in Jinan city was introduced, which provided reference for similar engineering design.

In many cases of shield tunnel collapse accidents occurred both domestically and internationally, the development process of the collapse showed the characteristics of progressive collapse, leading to serious economic losses and casualties. However, the research is still in its primary stage. The lack of understanding of the triggering conditions, development process, and effective prevention measures of the progressive collapse of shield tunnels restricted the high-quality development of urban rail transit in China. Based on the statistical analysis of nearly one hundred cases of tunnels accidents all over the world and focused investigation into 23 typical cases of progressive collapse from 2003 to 2020, the characteristics of progressive collapse of shield tunnels was analyzed. Using statistical methods, the initial damaged location, stratum, damage degree and other factors of shield tunnel progressive collapse accidents and their relationships were categorized and evaluated. The main characteristics were clarified. Based on the comprehensive analysis of multiple cases, the development process of the shield tunnel lining structure damage in the accident was generalized, and it corresponded to the damage degree of the tunnel structure. Finally, considering the interaction between the tunnel structure and the surrounding stratum, the response of the surrounding water and soil during the collapse was analyzed, and it was pointed out that the progressive collapse of the shield tunnels was a fluid-solid coupling dynamic problem. The research results are helpful to improve the relevant understanding of the progressive collapse of shield tunnels, and provide guidance for the prevention and control of the progressive collapse of shield tunnels.

With the development and utilization of urban underground space, deep buried shield tunnels get more and more popular. How to determine the vertical earth pressure above deep buried shield tunnel is the key issue for reasonable segment design. With the increase of tunnel depth, the soil arch effect is increased and the disturbed zone will be formed above the tunnel. Numerical investigation of the excavation of deep buried tunnel in sand was carried out using PFC2D to observe the shape of the disturbed zone above the tunnel. Based on it, a modified failure mechanism of TERZAGHI was improved and a new computing method of vertical earth pressure above deep buried tunnel in sand was proposed. The results showed that the disturbed zone was triangular, the sliding surface was not vertical which was assumed by TERZAGHI. The lateral pressure coefficient of the sliding surface was larger than the suggested value of TERZAGHI. Finally, the results of the proposed method was verified using the field observed data. The proposed method can be used to analyze the vertical earth pressure above deep buried tunnel.

Based on the analysis of the tunnel TBM construction process and technology, using the three-dimensional geological modeling technology and engineering simulation technology, a construction cycle network simulation model was established, which could achieve the prediction and visual analysis of TBM tunnel construction process. Taking the DXL tunnel project in Tibet as the research object, coupled with the three-dimensional geological model of the DXL tunnel, an optimized analysis of the TBM construction schedule of the DXL tunnel was performed through simulation calculations. The relationship between the completion probability and the construction time was fitted, and the expected completion probability was determined. The construction process was visualized and suggestions to guarantee the construction progress were proposed.

When encountering strong earthquake, geological conditions or structural stiffness mutation, serious earthquake damage may occur to shield tunnel, and the earthquake damage mainly concentrates on the joints. Through shaking table test and indoor static test, a series of studies were carried out for the weak seismic parts or conditions such as the shield tunnel passing through the soft and hard interface stratum, the joint of cross passage and the longitudinal. The results showed that the seismic response of the shield tunnel in the hard-soft interface stratum still had followability, but showed a “double peak” phenomenon, and the larger internal force response values were distributed in the range of 2.5 times the tunnel diameter on both sides of the stratigraphic interface. The connection stiffness of shield tunnel and transverse passage had an effect on mechanical response of tunnel, and the influence range of rigid connection on the main tunnel was about 3 times of the width of a cross passage, and it was reduced to 1.5 ~ 2 times in the case of flexible connection. The longitudinal joints of shield tunnel mainly bear axial tension or pressure under the seismic. The segments on the bolt hole side and sleeve side were dominated by compressive strain and tensile strain, respectively. The failure test showed that the sleeve and the segment constitute a destructive chain. The sleeve and the segment exhibit slip failure and tension crack failure, respectively. The research can provide a reference for seismic design of shield tunnel.

When shield machine goes through the stable rock stratum, the backfilled grouting behind the segmental linings will inevitably escape along the gap between the shield shell and the stratum to the cutter plate and the excavation surface. Based on Bingham fluid, the theoretical calculation formula of the loss amount for the shield tail grouting escaping was established, and the relationship between the loss amount of grouting, the properties of grouting, gap thickness and grouting pressure was analyzed. The experimental models with different properties of grouting, gap thickness and grouting pressure for escaping of shield tail grouting were established and tested, and their results verified the rationality of the theoretical calculation formula proposed. Based on the formula for calculating the amount of escaping grouting of shield tunnel, the critical condition of the escaping grouting commonly occurred in subway tunnel construction was obtained, i.e. the relationship between the viscosity resistance of grouting and the thickness of gap between the shield shell and surrounding stratum. The findings can be expected to guide the preparation of grouting of shield tunnelling in stable rock stratum.

With the rapid development of underwater shield tunnel construction in China, the waterproof problem of segment joints is becoming more and more prominent, and the hydraulic pressure on shield tunnel is also increasing, which poses a severe challenge to the waterproof safety of the tunnel. The waterproofing of shield tunnel with high hydraulic pressure has gradually become a hot topic at home and abroad. Aiming at the possible problems in the design stage, construction stage and long-term operation stage of segment joint waterproofing of shield tunnel with high hydraulic pressure, the relevant important research at home and abroad were summarized, mainly including: material selection, section design, corner processing, arrangement of multi-channel sealing gasket, waterproof of bolt hole, numerical simulation and test analysis of sealing gasket, waterproof performance of sealing gasket under earthquake action and long-term durability evaluation of aging sealing gasket material. The existing problems and the research trend of related waterproof problems were discussed.

In the process of earth pressure balance(EPB)shield tunneling at silty clay stratum, it is easy to occur shield clogging with cutterhead and poor plasticity characteristics of the muck, so it is necessary to carry out soil conditioning to ensure the safe and efficient tunnel-construction of the shield. Taking one construction section of Hangzhou Metro Line 10 as an example, this study conducted liquid and plastic limit tests for soil conditioner selection, and then applied for the improvement of silty clay. The validity of selected conditioner and its parameters was verified through the slump test and compressive strength test of conditioned soil, and field soil conditioning test on the basis of the laboratory test. It was found that foam could significantly reduce the plastic limit of silty clay. Silty clay stratum was more sensitive to the increase of water content(w)and foam injection ratio(FIR). The slump value of conditioned soil increased with the increase of water content and foam injection ratio, and its compressibility also improved with the increase of foam injection. After optimizing the improvement parameters of conditioned soil, the torque of the shield cutter plate was significantly reduced, and the driving parameters of the shield remained stable,which indicated that the optimization and improvement parameters of the stratum were set reasonably, and that the improvement effect of the silty clay stratum using foam agent was significant.

Based on the slurry shield circulation system of Wangjiang Road Tunnel Project in Hangzhou, a model of drainage pipe was built in three parts. The effects of mud velocity and mud weight on pipeline pressure loss and slag-carrying characteristics of slurry shield circulation system were studied. According to the pressure loss and distribution under the actual construction parameters obtained by the simulation model, the installation position of the drainage pump was calculated. The results showed that the pressure loss could be reduced with the increased of pipe diameter, and the effect was gradually reduced with the increase of pipe diameter. The pressure loss was almost proportional to the mud density and increases with the increase of inlet velocity, and the growth trend increased with the increase of velocity. Mud inlet velocity was an important factor affecting the conveying capacity of pipeline. With the increase of mud flow rate, the influence of mud weight on the accumulation quality would be weakened.

With development of railway transportation, shield tunneling technology has been widely used. As a key component of shield tunneling, the working efficiency and failure form of hob were directly related to the geological conditions and had an important influence on construction schedule and safety. Based on a subway tunneling project, its geology related was analyzed firstly, then the failure types and corresponding causes of the disc cutters were also explained. Finally, a brief discussion was given about the material properties of disc cutters. The results showed that the failure forms were mainly partial grinding, edge curl, fracture of disc cutter ring, cutter ring off, fracture of cutter shaft.