A lot of infrastructures were built in the advanced economic growth period, they are used for about 40 years and need repair. Therefore, the establishment of the reasonable maintenance management technique is demanded. A technique for establishing the maintenance database of road tunnels is proposed by using GIS (Graphic Information System). Based on the database and numerical simulations of time-depended behaviour of a tunnel, the tunnel performance and maintenance cost are quantitatively evaluated. In addition, the AM (Asset Management) technique for road tunnels is also proposed and applied to a real case for verifying its practicability.

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Rock bolts have become a common measure for providing ground support. However, the effect of rock bolts in sandy ground is not verified theoretically and it is presumed that rock bolts in sandy ground exert the ability on the ground stability if its length and arrangements are designed appropriately and rock bolts are installed at the proper timing. In this paper, to clarify the mechanism of rock bolts effect in sandy ground, trapdoor model tests with various bolt length, inclination of rock bolts and time for installing rock bolts were carried out. It was found that in deep tunnel the longer bolts than loosened zone have the effect of integrating ground around a tunnel and rock bolts installed after the occurrence of loosened zone have the similar effect as the rock bolts installed before the occurrence of loosened zone.

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It is important to consider the relation of a excavation speed and a hardening velocity of shotcrete when it evaluates supporting effects of shotcrete to get stability after excavation. Therefore, in this study, it was analyzed by using sequential excavations and supports with an axisymmetrical model for new type shotcrete which developed rigidity by a short time and ordinary shotcrete. These types of shotcrete were compared with each other in terms of effectiveness for supporting the ground.
As a result, the former type of shotcrete was found to be more effective for ensuring the stability of the ground around the tunnel because it provides great reaction forces near the face.

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Excavation of a cavern results in formation of excavation disturbed zone (EDZ) in surrounding rock. The EDZ is defined as the area where properties have been changed due to changes in the stress state and the distribution of porewater pressure. In this paper, we have proposed crack tensor model and virtual fracture model in consideration of excavation damaged zone due to blasting. These models have been applied to analyze the excavation of a shaft and drift using limited information obtained from ground surface investigations on the Mizunami Underground Research Laboratory project. As compared to the result without the excavation damaged zone, the hydraulic conductivity has increased in the surrounding rock remarkably.

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In urban area, constructions of soft ground tunnels are usually important in terms of prediction and control of surface settlement and gradient. Several approaches are readily used for prediction of the ground deformations associated with tunneling. This paper discusses the subsidence prediction using FEM analysis and Artificial Neural Network (ANN) with FEM database. This paper, firstly, investigates the application of FEM simulation using a proposed model to predict ground movement caused by tunneling of a shallow NATM tunnel in unconsolidated soil. The proposed model used here incorporates reduction of shear stiffness, as well as strain softening effects of given material strength parameters. Numerical simulation is performed with material property values, E, v, c, and φ, obtained from laboratory. Some additional parametric studies are performed. FEM results shows as agree well with compare of field data. Secondly, ANN modeling is performed for subsidence prediction. ANN studies database to provide an FEM analysis result. A learned (trained) ANN model has the potential to provide accurate desired output (true output) from input data. However, once the network is trained, its running speed is very high, thereby reducing the total time consumed in the analysis. The trained ANN model is further validated by carrying out parametric studies to assess whether the model gives logical and consistent trends and a case study to verify the application to the actual NATM tunnel in prediction problem. The two methods, FEM and ANN, offer a practical way for predicting final displacement of shallow NATM tunnel, enabling rational safety management scheme to be employed.

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High-quality-shotcrete (HQSC) began to be applied on the site of New Bullet Train Projects in fiscal year 1997 about ten years ago. A viscous characteristic when it is fresh, the use realities of the fine aggregate, the strength characteristic, and the strength characteristic of hardened materiales have been examined for HQSC. Authors have examined the water retention characteristic of powders and the fine aggregate from the result of the fine aggregate data and the test mixing on 119 sites. This report describes the result of the examination about the influence of the water retention characteristic on the fresh properties of HQSC.

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Rock mass for disposing of radioactive waste are required to be durable for a long time. Grouting with clay-type materials is therefore desirable for improving the impermeability of the rock mass. Mixing ethanol solution with bentonite produces slurry that is more dense and less cohesive than the one made by mixing water with bentonite.
This paper presents the results of a laboratory test of injection into model cracks and of an in-situ test.
The tests were conducted to assess the applicability of ethanol bentonite slurry as an impermeable grout to control the occurrence of seepage-causing cracking detected during tunnel excavation.
It was suggested that ethanol bentonite slurry is effective as an impermeable grout material because not only of lower cohesiveness but also of higher density of slurry provided by using ethanol instead of water.

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From the experience with tunneling, it has been suggested how to mobilize groundarch in surrounding rock. It can be obtained by controlling a loosening zone, which is considered as the post-peak behavior of rock. Focused on the elastic and non-elastic behaviors of rock in tunneling, the authors investigated over 500 convergence curves observed in six tunnel projects through shale and sandstone, granodiorite and slate layers. In conclusion, the allowable limit of deformation should not exceed beyond the range of strain-softening, and should be smaller than 0.5-0.8 % in tunnel diameter so as to mobilize a potential bearing capacity ofsurrounding rock.

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It's hard to obtain enough data by the prior geological investigation for construction of mountain tunnels. Usually, standard support patterns are used, and then they are modified to the optimized support patterns based on geological condition of face or the measurement data. Recently, it is possible to construct the tunnel upon the hard condition (unconsolidated rock and fracture zone, etc) by development of auxiliary method. However, forward investigation method of face is not established. In this paper, tunnel estimation system based on geologic prediction ahead of face by mechanical data is presented, and the evaluation applied to construction site is described.

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To establish a more precise inspection method on backfill grouting thickness distribution especially at a sharp curve, the calculation method on tail void thickness distribution was developed, based on the examination on the characteristicsof in-situ measured data concerning with tail void. Furthermore, its performancewas validated by applying this method to the in-situ data. As a result, the followings were made clear: 1) even if copy cutter range is same, overcutting area and tail void thickness distribution depend on the cutter face rotation directionand its speed; 2) tail void distribution can be calculated by using deviation from cutter face center to segment center.

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Long term field measurement has been conducted on the shield tunnel deformation over 20 years, which has been planned to be employed for the Tokyo Bay area rapid transit train system. The measurement results have been quite different from the predicted. Three dimensional finite element analysis has been performed, which takes account of actual geological conditions and the variation of drainage condition along the shield tunnel lining due to the severe longitudinal deformation of the tunne

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This analytical proposal was investigated by a series of model tests on the behavior of shield tunnel including shaft in the longitudinal direction. In the experimental study, firstly, seismic motion was applied to the test models to confirm the effectiveness of analytical model. Secondly, the interaction between tunnelincluding shaft and the ground was investigated by the test in the model ground.

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As well known, the water pipeline is one of the most important lifelines, any accident of the water pipe will seriously affect our urban life. When the water pipelines constructed in deep underground, the buckling of water pipes under external pressure is considered for existing high ground water pressure. To prevent such buckling, it is necessary to study the buckling behavior, buckling design method and the enhancement measures of water pipe.
In this paper, the bucklingbehavior of the steel pipe with ring-stiffeners is studied by numerical analysisusing FEM codes. The results of the conventional analytical method is compared with that of numerical analysis and the more rational buckling design method and the reinforcement of steel water pipe is discussed.

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This paper describes a method of reflecting the three-dimensional effects in a two-dimensional structural analysis for the design of a circular deep shaft of a shield tunnel entrance. The method is based on the result of three-dimensional FEM for different structural conditions whether there is any ring beam or inside wall for a body of the shaft. We conclude that in the design of the entrance with the shaft using two-dimensional structural analysis, the analysis requires an effect of a restraint of a convergence movement of the diaphragm wall. The effect is conducted by spring elements and the using of it is expected to leads to reasonable specifications for diaphragm wall and inside wall for a body of the shaft.

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A method of numerical simulation of the ground deformation due to tunneling accompanied by the sinking of the pneumatic caisson is proposed through a series of parametric studies. The normalized data of vertical and horizontal distributionsof ground displacements obtained at three of the construction sites are examined. It is found through the present study that all of 1) the depth-dependent Young modulus, 2) the friction force on side wall and 3) the forced displacement into the cavity of frictioncut and scraped ground are indispensable to explain those data by the elastic finite element analysis.

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In this paper, the optimal design of tunnel lining is considered from the mechanical point of view and an optimal design method is proposed. The object of the optimal design method is minimizing the cost of tunnel lining under the conditionthat the tunnel will not collapse plastically due to the external forces. To show the effectiveness of this proposed optimization method, we solve three types of tunnel examples; circular tunnel, horseshoe-shaped tunnel, and rectangular-shaped tunnel.

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