Tunnel is a underground space that is supported by both original strength of bedrock itself and support of tunnel. The load acting on tunnel depends on bedrock movement accompanying tunnel excavation. Therefore, it is necessary to utilize deformation characteristics for design and execution so that the tunnel support become rational and economical. This relationship is shown in Fig.l. But this relationship has not been known quantitatively yet. Therefore, Two different centrifugal model tests were examined under field of 80G (gravity) centrifugal force so that the authors can obtain basic informations of the characteristic curve (Fenner-Pacher curve).

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This paper presents an analysis of two-dimensional elastic medium containing an elliptical tunnel with elastic lining under the uniform stresses, τ^∞_xz and τ^∞_yz at, infinity. This analysis is based on the complex variable method using a conformal mapping technique, and contains new sliding boundary conditions. Using this solution, we consider the effect of thickness on distributions of stress and displacement.

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When tunnels are excavated in squeezing rock masses, the surrounding rock masses of tunnels sometimes exhibit large deformations to break tunnel supports. This paper presents an analytical method to predict the deformational behavior and evaluate the development of plastic zone, which be considered as the main cause of squeezing phenomenon.The method is based on the assumptions that the ground around tunnel behaves as an elastoplastic dilatant material and exhibits strain-softening behavior.With regard to the support design of squeezing rock tunnels, a method for estimating the optimum support pressure is proposed.Finally, the proposed standard judgment is applied to an actual tunnel to proof its validity.

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The Distinct Element Method (DEM) proposed by Candall (1971) has been attracting attention from engineers, because of its effectiveness in the study on the deformation of granular substances such as sand. One of the merits of this analytical technique is its capability to offer useful data which are difficult to obain through experiments. Displacement of each particle and reaction due to contact between particles are example of such data. The authors et al. have been investigating arch action by means of the trap door test using sandy soil. If the method is proved to be a powerful analytical strategy, the microscopic behavior of soil particles forming an arch can be revealed with a satisfactory accuracy.
This paper discusses the applicability of the DEM, comparing experimetal and analytical results.

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The objective of this paper is to present a new limit state design method for a concrete tunnel lining reinforced by steel fiber under the condition acting both bending moment and compressive force at the cross section. The basic concept of this method is similar to that for a reinforced concrete. However, the current definition of limit state is not available for such a structure due to the difference of loading condition and material. Three limit states characterized by serviceability, strength considering toughness and the deformation around the failure respectively were difined. Note that these limit state doesn't specify the whole failure of the lining but the failure of the member. The opening width of crack is appropriate to specify each limit state. The value for each limit state is proposed based upon the results obtained by flexural loading test for the specimen.

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In order to establish a railway tunnel lining soundness evaluation standard, we developed tunnel lining model test units and carried out three-dimensional loading tests of single and double track tunnel lining models. The ground surrounding tunnel is modeled by springs and lining-ground interaction is able to express. In this paper, we discuss about the three-dimensional behavior of the lining tes ts and the three-dimensional FEM simulation analyses on the tests. The analyses of tunnel lining models were constructed by shell and solid elements. We used FEM program “NASTRAN” and “ABAQUS” for the simulation.

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In this paper, the longitudinal ventilation model for two-way tunnel was examined. Taking the variations of time headway and exhaust emission into consideration, the fluctuations of the concentrations of exhaust emission in two-way tunnel can be evaluated by the computer simulation model illustrated in this study. The sufficient ventilation air flow for acceptable condition can be also evaluated by means of the simulation.

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Tension tests and bending tests using shield tunnel models simulating flat type concrete segments with secondary linings were carried out. Analytical method which can properly explain the test results was proposed. The analytical model is composed of beams and springs which simulate the primary and secondary linings and joints. The interaction between the linings was modeled as spring. One of features of this study is that the spring constant of the interaction between linings was analytically estimated.

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Research has never been made on the effect of the secondary lining of a shield tunnel as to the reduction of subway-induced vibration.
To analyze the effect, study was made by the use of the two methods sa follows:
1) Observations were made at two point, with and without a secondary lining, on the acceleration of tunnel and ground vibration. As a result, no noteworthy difference was found in the diminishing tendency between the two points.
2) Numerical analysis were made by the use of two vibration models, the mass and the FEM. The result was that the secondary lining had little effect on tunnel and ground vibration.

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The required condition for an excavated soil in a pressurized slurry shield tunnelling method to stabilize the excavated face can be expressed as its plastic flowability. However, its quantitative appraisal methodology has not been established. For the time being, it is not easy to sustain the excavated face in case of the excavation into a saturated gravel layer which gives a difficulty to obtain a proper plastic flowability.
This research describes the quantitative appraisals of the plastic flowability in a saturated gravel layer through studying the interaction between the results of penetration resistance tests for the excavated soil from earth controlled tunnels, and the past accomplishments of the controlled pressures in the excavated faces and the excavating speeds.

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The number of shield tunnels with large cross-sections built deep underground has been increasing in recent years. In order to design shields safely and precisely, there are unclarified factors to be studied in detail.
The authors measured actual strain on the shield being in operation, and estimated the earth pressure acting on the shield by means of reverse analysis with FEM.
This paper deals with the studies concerning reverse analysis technique to assume earth pressure, evaluation of the calculated earth pressure, applicability of analytical models and their boundary conditions.

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In this paper, the authors studied design methods of four subway shield tunnels very closely located.
Two different methods of analysis are conducted: One is a conventional tunnel analysis considering total overburden loads and the other is an interactive analysis method where firstly an elast-plastic FEM analysis is conducted stepwisely for 11 step construction of four tunnels and then a frame structure analysis with springs is conducted considering the loads calculated in the FEM analysis.
Both results are compared and evaluated so as to get proper results.

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Model tests have been carried out using an apparatus with several trap doors, to examine an earth pressure distribution patterns during shield driving execution and the redistribution by the succeeding chang of load conditions. The present paper describes the load distribution on lowering trap doors measured by the apparatus with more load cells than before, to get more detailed distribution pattern on one door and the load distribution by surface loading after lowering a trap door. The typical arching pattern of load and the load concentration on the area adjacent to the lowered trap door have been obtained. The analytical results by FEM may explain the test results qualitatively.

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In recent years, the application of multi-circular face shield method to a tunneled station is studied in case of construction of underground railways. It is expected that the form of tunnel lining is complicated. Therefore, it is necessary to investigate the method of analysis in case of the design of tunnel lining.
In this paper, we introduce an example of tunneled station with multi-circular face shield, and describe the structural analysis using FEM and an elementary experiment.

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Recent technical developments in shield method have been remarkable. Teito Rapid Transit Authority has developed a slurry type three-centered shield method which employs a double-track running shield machine to achieve the three-centered circular construction for the station section (with separate platform) only. This method is planned to be put into practical use at the Nanboku Subway Line Shiroganedai Station. The structual characteristics of a three-centerd circular configuration for the station were examined three design methods. These are “beam-spring model”, “commonlyused calculation model” and “FEM analysis”.

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The areas around the Kamisunagawa tunnel were dotted with many cavities from of old coal mines. Furthermore, as this tunnel was planned to pass Gm beneath a very decrepit existing tunnel, there was a fear that the two would interfere with each other.
The main results obtained through this construction method are as follows.
(a) Under complex ground conditions, as in the case of this tunnel, “urethane-injected rock-bolts” are an effective reinforcing measure, as they do not require special equipment.
(b) When excavating the new tunnel beneath the existing one, a distorted settlement phenomenon occurred in the existing tunnel, due to weak strata. When weak strata exist, natural ground reinforcement is required in wide areas.

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Bench blasting operations were carried out above a lined tunnel in a land reclamation site. The 400m long, 5.5m wide tunnel was temporarily constructed for muck transportation. The ground was excavated by 3m-step bench blasting and the excavation ended at 1m above the tunnel crown. Various parameters were monitored during excavation. In this paper, the results of field monitoring are presented. It was observed that no cracks appeared in concrete lining at particle velocities of less than 40kines (cm/sec) and the lining was damaged in the velocity range 40 to 100 kines. It was confirmed that the tunnel deformed elliptically towards the ground surface under the unloading conditions.

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Recently, some tunnels have been deteriorating in Japan. Rockbolting is a useful method of ground reinforcement around deteriorated tunnels. Conventional bolts (Mortar and resin grouted bolts) have been used with some success in such cases, but there may be large variations in installation quality. However, it is considered that the anchoring mechanism of Swellex rockbolts enables them to be used with success. In this paper, the authors discuss applicability of Swellex rockbolts to the reinforcement of deteriorated tunnels from both design and installation points of view.

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Recently Tunneling Methods have been greatly developed giving good results. On the one hand, the tunnels in use are suffering from water leakage reportedly at the section longer than a half of the total length. The maintenance work for the leakage requires a great labour and cost expenses because of serious work in the closed narrow space. The reduction of leak itself is expected in the nature of things.
Here are reported the effective tunnel waterproof methods by use of the lately progressed Sheet Waterproof Technology for construction of the reliable tunnel of the extremely less leakage.

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The authors numerically investigated the behaviors of tunnels during the excavation by the umbrella (RJFP; Rodin Jet Fore Pile) method. The stresses and the deformation in the longitudinal direction should be analyzed by three dimensional (=3D) model. The authors conducted 3D analysis of the tunnel behavior during the construction of the SHYORYO Tunnel of Tomei Expressway, where the umbrella method was applied, and examined the effectiveness of the numerical method by comparing the such results with the observed ones. From the analysis, it was shown that the umbrella method is useful to design a large tunnels.

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It is expected to develop the reliable reinforced method to decrease the surface settlement on the shallow tunnel in urban resion. A new pre-lining method which can make the continuous arched body on the top of the face has been developed. It makes a reverse T type body by using the high pressure grouting with three direction nozzle. The reverse T type body is not only economical shape but also effective function in a complex with the ground.
The grouting test was carried out in the imitation ground to see the shape of improved body and the effect. The model test chaging the shape of the reinforcement was carried out to investigate the effect of this pre-lining method. This paper describes the result of fullsized test and the model test.

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The object of the study was to develop the admixture, which reduce the rebound and gain the high strength of the wet-mix shotcrete, and to develop the accelerating agent for the shotcrete applying to not only dry but also wet surface of rock. As results, following conclusions were obtained.
1. A viscosity agent was very effective to reduce the shotcrete rebound.
2. High strength shotcrete could be obtained to use silica fume and high fineness blast furnace slag.

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Nearly 300mm of displacements occured on the tunnel wall during exca vation over the limit of inner section, although rocks of the tunnel has high strength with respect to the overburden height. Concerning to the large deformation, we attempted to characterize mechanical properties by laboratory tests and microscopic observations of the rock specimen. The results of tests are following, (1) Continuous failure state triaxial test provided remarkably lower shear strength under the suction of water than naturally dry circumstances.(2) Rocks surrounding tunnel has lots of microcracks due to geostructural developments.(3) Drilling for rock bolts produced rapid increase of displacement.
In this case study, the large displacement on the tunnel wall is caused by some development of the squeezing and plastic, even though the overburden hight is low with respect to the uniaxial strength of rocks.

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The 4, 350m long tunnel is now under construction through the volcanic zone, in the center of which Mt.Yakedake as the active volcanic mountain in the North Japan Alps. We measured the vertical and horizontal displacement of volcanic deposit between some interval including the point of pilot tunnel face using inclinometer and sliding-micrometer which was installed borehole drilled crossing to tunnel.
Displacement at anypoint of volcanic deposit begins to occur befor tunnnel face do not arrived at the measurement line, and it increases gradually according to approarch of tunnel face.

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Concerning the displacement behaviors of rocks in front of tunnel face, we attempted to predict overall displacements prior to excavation of tunnel face by means of inclinomater measurement, based on empirical method that OKABE and KONDOH (1987) proposed. The result indicates that overall displacement predicted by this method might be a good agreement with actual displacement for practical use.
We reconsidered to improve the method being more accurate with respect to the method proposed by us. The results provide following equation.
R (%)= 26.70log K+60.55, K=l/A
R: pre-displacements ratio to overall displacements, A; area of tunnel section.
l; critical distance from tunnel face to the point where displacement is nearly equal to zero in front of tunnel face.

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The Konan Tunnel, under construction in a densly populated area of Yokohama City, is a twin tunnels designed to carry three lanes and a sidewalk in each direction. Its specfications are a 16.2m width, a separation of 8.7m between the tunnels, a cross-sectional area of 143m² and an overburden of 5 to 24m.
When excavating a tunnel with a thin overburden, it is important to ensure stability of tunnel itself and to obtain the earliest possible indications of ground subsidence. This paper reports on how total ground subsidence was measured and predicted the behavior of the bedrock ahead of the face.

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A tunnel adjacent to an existing tunnel is being constructed under the supervision of the Japan Highway Public Corporation. The tunnel is 3-lane cross section and constructed in the urban area. The overburden is very shallow and on the surface a few houses and a road exist.
The report describes the behavior of the large tunnel adjacent to the existing tunnel, as well as the effect and the behavior of the RJFP (Rodin Jet Fore Pile) method in order to avoid subsidence of the ground surface and unpreferable effect to the existing tunnel caused by the new tunnel excavation.

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Geological data are quite fundamental to construct a tunnel in safety and low cost. Therefore, observation of a tunnel face during excavation is a regal obligation issue, and selection of a tunnel support system based on the observation results is a essential work for tunnel construction. Geological observation of a tunnel facein the present level, however, have several problems in its recording method. The mainpurpose of the newly developed system described in this paper is to record precise and objective data of a tunnel face. In this system, use of a digital still camera and a personal computer could make tunnel face recording easy and rapid, and reduce labor and work. Recorded observation results by this system are also practical data base of tunnel excavation.

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Satomi Tunnel is one of the long tunnels with the 2, 484m length for the Hokuriku Shin-kansen peoject under construction by Japan Railway Construction Pubric Corporation. The convergence shrank by 400mm because of weakend tuff and mud stone with fracture zone at the 120m-length tunnel support which is 140m below the ground level. Under these geological conditions, the tunnel was safely constructed by choosing the mini-bench method using the conbination of multi-functional gantry-jumbo and the roadheader for the full-face excavation, choosing adequate support systems based on geological conditions and monitoring results, and selecting secondary support systems.

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This tunnel is provided for double track railways for SHINKANSEN.
Total length of GORIGAIIINE TUNNEL is 15.2km. Construction work site has been divided into four sections. TOGURA work section is planned to exacavate approximately 5km, after exacavation of the 620m horizontal shaft, the exacavation work is carried out rapidly by means of the total section blasting method by NATN, by full use of the large motordriven loading shovel and 6-boom gantry jambo crane.

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This work is to construct one of Maglev test line tunnels, Hatsukari tunnel, which is under construction in Yamanashi prefecture.
The special points to mention on the work is the control of the blasting vibration which affects the old quarring site called “OOKUZURE” located at the middle of the tunnel, the precision machine factory and the housing development near the tunnel exit.
This report is the outline of the SD (slot drilling) method with blasting and the effect of the method on a reduction of vibration.

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Cross section of tunnel is in general determined by ordinary load case and rarely affected by seismic load in the tunnel with rectangular section. However a shield tunnel with circular section is influenced strongly of a unilateral load applied in earthquake motion.
This study is conducted for the project of Trans-Tokyo Bay Highway.
This paper shows an evaluation method of soil spring and the necessity of inertia force of the lining and shear force following of ground displacement for the seismic deformation method. Such modified method is possible to obtain almost the same level of sectional force as that of dynamic analysis using FEM model.

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When tunnel is deformed by earthquake ground motion, cracks appear on the reinforcsed concrete lining. Strain of tunnel lining during earthquake is depend on stiffness of cracked section. The relationship between stiffness and strain is nonlinear based on bond characteristics. An axial tension test is carried out. The stiffness of cracked section was mesured directly, and calculated from the strain distribution of reinforcement bar. The calculated stiffness well agrees with the experimental results. And earthquake resistant design of tunnel lining considering the stiffness of cracked section is applied to a test model.

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This study was under planning of a new tunnelling machine having tri-face which consists of one main shield and two sub-shield machines to be conbined with both sides of it when excavating for station space. Cutter head of the sub-shield machine rotates alternately within a limitted rotating angle. The experiment was carried out by the test machine to investigate the fundamental matters for alternate rotation method of cutter head for sub-shield machine such as driving cycle, torque, thrusting power, driving mechanism and the control method, etc.

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Since underground utilization in urban area is becoming deeper and deeper, both precise linear control and high accuracy of erected segments are indispensable to construct deep underground tunnels. In this point, automatic tunneling system with capability of sensitive posture control and quick response to swerves from the target points are being developed nowadays. However, to meet with severer specifications in the future, continuous efforts to renovate new systems, reacting relative position between the shield machine and segments, are highly required as mentioned in this paper.

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This paper investigates the backfill grouts included flyash, and the result of backfill grouting in the construction of shield-tunnel. The quality of this flyash, utilized for this grouts, was below to JIS. Putting stress on bleeding ratio and flow value in workability of the grouts, the mix proportion of the grouts was settled by design of experiments. As a result, the grouting pressure went up and was over the capacity of the grout pump, but it was possible to convey the grouts 530m from the plant. And the ratio of the grouts to the tail void was 130% in diluvial ground.

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Back-fill grouting of shield driven tunnel is significant for not only surrounding media but also acting load on tunnel. Insufficient back-fill grouting may lead enormous amount settlement of ground surface and concentrated load may act on the tunnel. A back-fill grouting model tests have been carried out and a discussion about the behavior of back-fill grouting of shield driven tunnel in this paper. Some elementary tests for grout material have also been done. The differences of the material, pressure of injection and stiffness of surrounding ground varied the behavior of back-fill grout shape.

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To avoid excessive settlements caused by shield tunnelling, a systematic instrumentation is planned to monitor ground behavior during the excavation by slurry shield and to analyze the influence of construction factors on the ground movements. It is found that the ground settlements are as follows, (1) Settlement before cuttng face pass through, (2) Settlement when the shield machine passing through, (3) Settlement after the tail passed away. This paper presents settlement when the shield machine passing through is found to be related to the pose of the shield machine.

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We constructed double-track railway tunnel under operating tracks by pressed muddy water shield method. This tunnel crossed under the tracks obliquely and the overburden of the tunnel was 0.5-1.5 as diameter of it. Under construction, we made protection for the tracks according to overburden, change of soil, and distance between the tracks and the tunnel. We made some observations and measurments paying attension to mechanics of ground behavior as tunnelling.
This paper describe estimation of ground behavior according to overburden and soil quality.

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Enlargement of shield tunnel for the connecting section, has been executed by NATM. In order to establish a safe and economical enlargement method, it is necessary to clarify the behavior of various supporting measures, such as shield segment, shotcrete and of course ground itself. However, it is very difficult to estimate their behavior during enlargement, because the supporting system changes along with the complicated enlargement process. Detailed field measurement and numerical analysis were carried out, and the behavior of supportings is discussed. Obtained informations are useful for the planning of further enlargement of shield tunnel.

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At present, subway construction work is going on for about 3.9 km on the JR Senseki Line. This open-cut tunnel section in the subway construction work of the Senseki Line will cross right above the existing NTT Telephone-line Shield tunnel with an overburden of 2.0 m. For this purpose, we have already executed an estimate of the influence of excavating this new tunnel on the existing shield tunnel, and confirmed that there would be no trouble. Further, in actual construction, we are supervising the construction work, while measuring the behaviors of the existing shield tunnel.

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Recently there are a lot of subterranean construction works such as sluly or earth pressure balanced shield tunnelling in the urban area. Design methods of the shield tunnel linings have been studied in domestic and foreign countries. This paper describes the estimations of compatibility of the prior design models and methods which consist of flame models, flame models with ground-spring reacting with proportional to lining displacement and finite element models based on comparison with field measurements.

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The joint bolt method seem to be most common for jointing shield segments. However this method has two major defects;the bolt fixing and screwing operation requires boxing-out that causes structural weakness. The operation is a bottle-neck for automation of segment erection.
For eliminating such problems, we have studied and developed a creative “Cotter and Quick-joint Method” that can achieve an excellent segment jointing effect.
We carried out this Cotter and Quick-joint Method for constructing power supply tunnel. This paper gives the mechanism and the result of this method.

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The Multi-circular Face Shield Tunnelling Method (MFS) has been developed to mitigate over-excavation of ordinary methods, which construct two or three circular tunnnels and join them. In this study, We have conducted model test to consider interaction between the ground and the tunnel linings of MFS in different conditions and we have analyzed the model test by FEM analysis and flame analysis. On the test, We have got deformations and stresses of the linings as loading. We have not observed the ground reaction clearly, however on the simulations it appears that the calculated results by previous described analysises are relatively good agreement with this model test.

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Construction method for departure or arrival shaft of shield driven tunnel without soil improvement work was first adopted and executed at the project for an electric-supplying tunnel. In this method, a part of tunnel section in the shaft wall was constructed using novel materials of CFRP and lime stone, so as to cut the wall with rotating cutters of shield machines. In this case, a mud-pressurized shield machine (φ2, 930 mm) was employed. The ground is mainly composed of gravel.
While cutting the wall, pressure inside the chamber was controlled at 0.5 kgf/cm² to stabilize facing. Driving speed was 2 mm/min, and it took only 4 hours to cut through the wall. Ground settlements were less than 2 mm, and the execution was considered quite successful.

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Direct underground docking of two shield machines was performed in the Narita sand layer. Since these two shield machines have different required diameters as electric power transmission tunnels, six independent docking hoods, which protrude to overlap to the smaller shield machine, were equipped on the periphery of the larger one. These hoods were also used as retaining walls so as to minimize the chemical grouting area. Stringent coontrol, as well as precise position of the relative location between these two machines, was most critical. However, there were also several other important technical considerations in order to complete the full length slid of the docking hoods as mentioned in this paper.

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This report is made on the counterplan and result to technical problem for the constraction of sharp curved shield tunnel.It is, generally speaking, very difficult to carry out continuous driving, by closed type mechanical machine, of shield tunnel with sharp curve of less than 15 meters radius. The continuous mechanical driving for this shield tunnel with sharp curve of 12 meters radius was planned, by earth pressure balance shield tunneling method with bubble injection, and actually done with good results. It is noted that this shield machine was equiped with bending jack of 13.5 degrees bending angle, which is seldom in the world.

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This paper describes the outline and technical features of Osaka Nannkou Tunnel (ONT). ONT is an immersed tube type undersea tunnel, comprised of three tubes.One includes two tracks of railroad, while the remaining two tubes are for motor vehicles, two lanes each. Steel-concrete composite type structure is adopted as a structure of tunnel elements. this is the first time that this type of structure has been adopted in Japan.

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