Centrifugal model tests are conducted to clarify the effects of an invert on the lining stability of a tunnel. The pressure which is provided by compressed air within a rubber bag is given in the ground surface under the centrifugal acceleration state. Displacements of the lining and the ground are recorded on digital video tape, and the displacements and shear strains are analyzed by a picture analysis system. The stability of the lining and the development of shear strain of the ground are compared between the cases with and without the invert. Quantitative effects of the invert on the lining stability is made clear.

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 To clarify the stability of tunnel face and tunnel convergence excavated in squeezing rock, the numrical analysis was conducted. And the Nanao Tunnel was analyzed, which constructed tunnel in squeezing rock. As a result, tunnel face stability can be improve by using face bolts. And tunnel cross deformation can restrict by tunnel ring closure immediately. AIso, from analysis result of the Nanao tunnel, it is possibletocontrole the cross deformation and stabilize tunnel cross when closure stage is properly to rock state. And also, measurement result and numerical analysis are analogously.

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 It is reported that the amount of the seepage water measured in an undersea tunnel has been decreasing. The decrease of the seepage water is preferable in the view of tunnel maintenance. However, it can change the pore water pressure in the surrounding ground and reduce the safety of the lining. Therefore, we evaluate numerically soundness of the undersea tunnel by the soil-water coupled finite element analysis. We assume that the permeability decrease in surrounding ground is the reason for the decrease of seepage water and consider three cases. It is concluded that there is possibility that the permeability leads change of pore water pressure or expansion of plastic zone.

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 lt is necessary to predict the influence of the surrounding ground and tunnel during the excavation of twin tunnel. Usually, the influence of the excavation patterns and the efftct of the interaction between the ground and existing structures are not taken into account. In this research, using a new tunnel device in which a hybrid type boundary condition is applied at the excavation face to determine inner displacement and stress at the tunnel periphery, model tests on tunnel excavation are carried out. Non-linear finite element analyses are also conducted with the same scale of the model tests. It is revealed that building loads, the earth pressure distribution and ground movements during tunnel excavation depends on the distance between the twin tunnels.

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 It is essential to employ the observational design and construCtion method to manage tunnel projects efficiently. The original tunnel design is immediately verified or modified based on the in-situ data sequentially obtained in the construction stage. This study proposes an integrated prediction system for geological conditions ahead of tunnel faces, which is composed of long-interval, middle-interval, and short-interval prediction subsystems. The applicability of those subsystems is verified with actual field data.

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 The behavior of the ground during tunnel excavation is usually being investigated conducting experiment where displacement is applied in the boundary of the tunnel periphery and stress around the excavation face is being evaluated with the experiment where stress boundary is applied. In this research, for more realistic model tunnel excavation, a new device has been developed in which a hybrid type boundary condition is applied at the excavation face to determine both inner displacement and stress at the tunnel periphery. Model tests on tunnel excavation are carried out with the new device and a comparison has been made with the results of the previous model tests conducted with the apparatuses applying either displacement boundary or stress boundary. Non-linear finite element analyses are also conducted using elastoplastic subloading tij model with the same scale of the model tests. It is revealed that displacement significantly occurs near the crown of the tunnel whereas it is almost zero at the tunnel invert. The displacement mode is close to that of the test of stress controlled excavation. On the other hand, the earth pressure distribution is in between the displacement controlled and stress controlled excavations. The new apparatus can reproduce the phenomenon of real tunnel excavation problem.

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 Facebolts are frequently used in order to reinforce the ground ahead of the cutting face. They are especially effective for tunnelling in poor conditions due to ground squeezlng. According to our centrifuge model tests and parametric studies with numeric alanalysis method, it demonstrated that bond strength was influential on failure pattern and ground movement. We subsequently developed new facebolts with checkered steel surface which can present much larger bond strength. Furthermore, this paper describes an actual employment of these new bolts to several site.

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 The noise reduction effect of a sound insulation door installed in a tunnel under construction can be analyzed practically by the numerical analysis using the SEA method. However there was a problem that the prediction analysis is quite difficult at the planning stage because there was not the predictive technique of the sound pressure spectrum level(SPSL) of blast noise to be necessary as input data. In this Study, We analyzed relationship between gunpowder quantity and frequency domain damping characteristic of the sound pressure level in the tunnel based on field measurement results. And based on this analysis, we propose a predictive equation for the SPSL of the blast noise in the tunnel, and discuss its applicability.

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 We observed upheavals of the earth's surface during excavating the tunnel at shallow overburden ground with the cast-in-place lining method. But remarkable upheavals have not been generally observed on the same situation with the shield tunneling method. The present paper examined the difference between two tunneling methods by keeping our eyes to the consolidating time of grout materials.
 We definited the influence range and considered that shear stresses don't work only on 2 side walls but also on 4 walls in the Terzaghi's earth pressure and calculated subsidence and upheaval limit pressure. Furthermore, We studied the correlation between the ground deformation and the influence range.

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 The design method of diaphragm walls for circular shafts of great-depth follows the design method for small-to medium-depth shafts. Design loads are currently determined without reasonable or scientific foundations.
 It is reported that, in some cases, the results of measurements with earth pressure gauges placed in the circular shaft of great-depth showed that the axisymmetric lateral pressures are smaller than the design values, but non-axisymmetric lateral pressures are larger than the design values.
 We should however note that the readings of earth pressure gauges are significantly affected by the initial value set at their placement. Therefore, it is not certain that the readings can be relied upon to determine pressures acting on the diaphragm walls correctly.
 This paper discusses comparison of lateral pressures inversely calculated from sectional forces in the horizontal direction measured in the diaphragm walls of five circular shafts of great-depth, with the design lateral pressures.

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 Long-term consolidation of surrounding ground may cause deformation, cracks of segment, opening of joints and other faults in shield tunnels located in soft clayey soil. To distinguish the cracks and opening caused by consolidation from those caused by another reason, such as construction method, it is required to develop the calculation method considering the progress of cracks and opening in accordance with the time-history stress and strain experienced by the shield tunnels. This paper proposes the calculation method, coupling the ground-tunnel interaction analysis and the sophisticated tunnel deformation analysis.

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 Cracks due to thermal stresses that occur in the side walls of large cut-and-cover tunnels adversely affect tunnel durability. In many cases, therefore, thermal stress is analyzed to control thermal stress cracking. However, the analytical accuracy is not good enough for estimation.
 This paper discusses methods for improvmg the accuracy of thermal stress analyses, taking as an example a side wall about 1.0 m thick of a large cut-and-cover tunnel. The methods involve the following three points: consideration of drying shrinkage, utilization of the diagrams in the Standard Specifications for Concrete Structures-Design(JSCE), and three dimensional thermal stress analysis considering drying shrinkage induced by humidity migration.

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