This year, the Tunnelling Technology Committee established in the JSCE, has its 30th anniversary. The author, having been taking part in the Committee since the beginning, deals with a retrospect of transition of tunnelling technology from steel-arch support to the NATM, and remarked that these developments are indebted to reciprocal stimulations between demands for tunnel constraction and tunnelling technologies. The author suggests in the latter half, that the improvements on the analytical approach to design and on construction method are useful for future tunnelling, and that these improvements should be contributional towards the global environment.

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This report presents the outline of the MONOBEC machine experimentally made for an assumed single-track tunnel as well as the results of cutting and filling tests made on a mock ground. The MONOBEC (Mono-Bent-Cutter) method is being developed as a pre-lining method to prevent surface settlements and maintain the stability of the working face when a tunnel is driven by NATM through urban unsolidified grounds in Japan.
The features of this method are as follows: 1) A solt is pre-cut ahead of the face and exactly along the tunnel profile using an S-shaped bend-type chainsaw cutter; and 2) Shooting concrete into the slot, a continuous concrete lining is formed.

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Single track double and triple tunnel, where the access to the 12 earth coverring station area have been performed by NATM.
At first, we have started to excavate by three sections. We excavate from the middle part of the section and after that, performed both side of sections.
We have applied upper half vertical subdivision method, ringcut method, or grauting method in obedience to their condicions of cutting face or quantity of surface settlements.
The surface settlement have taken place 50 or 60 percents while excavate the middle section, and we have been able to comfirmed that the tendency of the upper part tunnel have caved in at the same time.

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Japan Railway Construction Public Corporation is now constructing Kitanarashino Station in Narashinodai Tunnel on the Toyo Transit Railway Line, a new railway line directly connecting to center of Tokyo.
For the construction of this tunnel and large underground station, CRD (Cross Diaphragm)- NATM is developed and adopted to minimize influences on road traffic and activities in and around the shopping mall. Because it is excavated in unsolidified sand stratum formed in the Diluvium and the earth covering is only about 10m.
As the result, the ground surface settlement could be restrained and minimized.

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We have developed the pre-lining method (PASS method) that can make the thin lining of arch-shell shape on the face, stabilizing the face and decreasing the surface settlement before the excavation. We applied this method to a shallow tunnel in diluvial sandy layer.Ground surface settlement, steel surport stress and shotcrete stress were measured in order to evaluate the ground behavior. This paper presents the comparison between those field measurements and the numerical analysis.The results show that the ground behaves as elastic body by the pre-lining.

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One of the most important items to prevent the accidents caused by the cutting face collapse, such as ground surface depression, is an estimation of the cutting face stability during NATM excavation. Observation point of the cutting face stability is it's deformation. However, excavating operations are done on the tunnel cutting face all day long, it is very difficult to install the observational equipments on theface without interruption. Therefore, we tried to predict the cutting face stability using the observation of the tunnel crown deformation instead of the cutting face deformation.
As a result, the strain velocity of the crown et was effective to estimate the cutting face stability.

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For the construction of the Akima Tunnel, the longest tunnel between Takasaki and Karuizawa of Hokuriku Shinkansen, as first trial on construction of a Shinkansen type tunnel, we adopted the Extruded Concrete Lining Method, for the sake of rapid construction, lavor saving and cost reduction. For transportation of concrete materials as well as muck produced in the course of the rapid excavation, we applied the pneumatic capsule transportation system. Under this system, the transport carriers (capsules) are sent out through the box route with a low pressured air current.

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The upper half vertical subdivision method is one method of excavating flat and large diameter tunnels in the unstable ground. This method has the advantages; the upper half is divided into two faces right and left to improve the stability of the tunnel face by reducing the one cycle excavation width, and the tunnel crown can be stabilized by removing the center deaphragm after the upper half arch is formed.
In this paper, the roles of center deaphragm are considered from the view point of the tunnel stability, based on the results of FEM analysis and field measurements.

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This construction, which execute the tunnel just under the pharmaceutical company about 23 meters in depth, was planed to use the controled blasting method together with mechanical excavation in order to protect the vibration pollution. However, this method might cause the blasting vibration which influence badly on the pharmaceutical company, and the other methods such as mechanical excavation without blasting can not be used by the period and the cost problems of construction. This report introduces an example of the controled blasting method which extend low vibration area than usual by the prediction and the suitable control of blasting vibration.

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Recently the number of tunnel project in rock formation at urban areas is steadily increasing. One of widely accepted tunnelling methods suitable for soft soil to hard rock is TBM (Tunnel Boring Machine) method. In this paper a case study of an inprovement of a slurry treatment plant for TBM with slurry transportation system is presented. Also computer aided allignment control and excavation control method with on line basis as a part of TBM automatic opration performe at our project is shown below.

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This paper describes the results of excavation of Midonogawa Headrace Tunnel using a tunnel boring machine (TBM).
During the excavation, several fractured zones were encountered, and one of them caused the collapse of a tunnel wall with much spring water, completely burying the TBM.
From then on, certain TBM control parameters were adopted for prediction of geology before heading. As another method, Rayleigh wave scanning was carried out experimentally.

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In recent years, artificial intelligence and expert systems have drawn much attention. The authors thought that the expert system would be suited to civil engineering problems such as tunnelling, and have been developing an expert system for tunnel support.
This paper discribes the expert system developed for determination of tunnel support used from tunnel face observation, and this system was applied at tunnel job sites. This system consists of taking a tunnel face picture by the still video camera, image processing of a tunnel face picture and evaluating of tunnel support.

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In tunnelling, we often face the emergency case that we have to take effectable countermeasures against the unkown abnormal situations of support members. We study several basic theories concerned with database system and fuzzy set to develop a tunnel expert system which assists us to solve such difficult problems instead of engineers of experience. This paper presents the system and available basic schemes to verify adaptation of the system to select countermeasures in construction site.

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To comply with social needs for better urban functions, the utilization of deep underground space is now given attention. In the field of planning the network of railways at metropolitan area the deep underground railway for a-few-station-line is very important, urgent proposed project to solve the urban problems, such as congestion of traffic.
This paper mentions the possibility of subway construction to the greater depth with explanation about the design and construction method, studying the technical problems to take shape into the new railway.

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Tunneling work in urban areas requires not only the safety of the tunnel itself against stress, but also sufficient safety of the ground influenced by excavation. There is a growing demand, therefore, for highly reliable prediction of influences on the ground around the tunnel prior to excavation.
By using both field measurement and theoretical approaches, Teito Rapid Transit Authority developed a method for estimating the deformation of the ground around the tunnel during slurry shield excavation in hard ground, and now uses that almost established method in actual tunneling work (Proceedings of the Japan Society of Civil Engineers, No.397/Vl-9, September 1988). However, for soft ground where deformation is greater, there is not yet any established method for estimating groundeformation.
In view of these circumstances, this paper proposes a method for estimating the deformation of soft ground during shield tunneling.

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Presented is an analytical method to predict the behavior of the lining of the existing tunnel when a new tunnel is constructed parallel and close to it. In the analysis, driving forces in the longitudinal and the lateral direction and the change of the earth pressure due to the construction of the new tunnel are evaluated separately. The behavior of the lining of the existing tunnel is computed and compared with the result of the measurement. The analysis shows good agreement with the measurement, hence the proposed method is effective for the design of the construction of closed parallel shield tunnels.

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The purpose of this study is to investigate interaction between the ground surrounding shield tunnel and the segments especially, ring-joint portion. When we regard the shield tunnel as a mechanically continuous tubular structure with equivalent regidity in the axial direction, for practical use. In this paper, numerical simulation of the relation between mechanical properties of the ground and equivalent rigidities is described. The numerical simulation shows that the equivalent rigidity increase with increase of the stiffness of soil material, tunnel-diameter and earth covering.

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Prediction of the vibration level of subway-induced vibration is one of important items in the environment assessment report that has to be made prior to subway construction.
For the purpose of improving the prediction method, an investigation has been made on wave transmitting behavior in the subway shield-tunnel and poor alluvial soil. Distribution of the vibration levels, spectra of the several tracks ana the phase velocity and wavelength of the predominant wave are determined in this study.

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In recent shield tunnels the projects is expected to be constructed at greater depths and with larger cross sectional areas. But the lining is generally constructed by bolting reinforced concreet or steel segments to each other.
A new boltless segments in which concrete are placed in special H-shaped frames, called NM lining, has been developed. The lining is automatically assembled with steel-concret segments mechanicaly conected each other, and is integrated by filling mortur into the space between adjacent steel frames. The applicability of automatic welding to its joint so as to maintain waterproofing at geater depth was also studied.
In this paper, several loading tests of the lining using full-sized segments and its workability and waterproofing are presented.

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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 structual weakness, The operation is a bottle-neck for automation of segment erection.
For eliminating such problems, we have studied and developed a creative “Cotter Jointing Method ”that can achieve an excellent segment jointing effect.
We carried out this Cotter Jointing Method, so report the mechanism and the results.

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When applying a steel fiber reinforced concrete (SFRC) to the Extruted Concretelining (ECL) method, it is essential to understand the load bearing mechanisms of SFRC lining. Then, loading experiment of SFRC ring was carried out to prove the efficacy of SFRC and to obtain the fundamentals datum for design. Biaxial loading method were employed for loading on SFRC ring and load, reaction force, strain, displacement of SFRC ring were measured precisely.
In consideration of experiment result, the behavior of SFRC ring can be understand in detail. Further, bending moment of SFRC ring evaluated by means of curved beam theory and FEM using an effective rigidity is verified in this paper. Also, this paper make reference to the ultimate bending strength of SFRC in comparison with reinforced concrete.

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In recent years, so many plans are proposed to develop unused underground spaces about 50m to 70m deep for public use in urbun areas such as Tokyo in Japan. We have been studying a construction method of deep underground railways in such space. This paper describes on applicability of the conventional design method in Japan for deep underground tunneled station constructed with triple-circuler face shield and the result of the 3-dimensional analysis of the tunneled station structure.

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Two shield machines were used for tunnel excavation to construct about 4km-long submarine tunnel, and they were connected each other at the approximate middle point of the tunnel. A newly developed relative position measuring system is applied to that project. This system is able to pick up the accurate location of two shield machines, using the sensor which are attached on the tip of horizontal pilot-boring rod. Applying this system, the docking of two shield machines was Performed accurately within a few millimeters relative distance deviation.

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Due to the rapid increase of the demand for the underground developments, shield method has been widely used as one of the most important and practical method for the tunnel construction in the cities. However, construction industry recently retains the problems of the shortage and advanced ages of the skilled workers.
Consequently, the automatization has been introduced into the construction industry and its successful effects have been observed in the several cases.
This paper introduces the current automatized shield technologies in Japan and reports their applicabilities and efficiencies on the actual construction project sites.

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Pumping transport of excavated soil in mud pressurized shield method makes the tunnel driving work force less and possible under high water pressurized unnderground conditions. This report describes a study of automatic driving for mud pressurized shield method apply -ing pumping transport. Main elements of this study are 1. Face control system by plunger pump, 2. Measurement system of excavated soil volume, 3. automatic pump driving system, 4. Central supervising system of overall tunnel driving. Effectiveness of such system were proved by field experiment in three construction project.

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The durability characteristic of cutter bits has not yet been explicated fully. This report explains the result of the research which examine and analyze the actual data obtained during excavation by mechanical shield so as to clarify abrasion feature of cutter bits and also improve its durability under long distance excavation.

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A method for the stability analysis of the underground cavern considering the effect of the ground water is proposed. Firstly, pore water pressure is calculated the steady-state seepage analysis. Secondly, the pore water pressure is applied the ground as external force. Computing time by the present method is shorter the one by the coupled stress-flow analysis, because the number of unknowns is fewer in the computation by the present method, and unsteady analysis is not necessary. Therefore, it is a practical method to estimate the stability of the underground structure in the steady-state condition.

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It is well known that the analyzed area has an influence on the result of analysis when we use F. E. M. to simulate the tunnel excavation. In this study, we analyzed how the surface settlement varied depending on the change of the analyzed area, and we proposed the optimum analyzed area for F. E. M. analysis. We also did some trial calc--ulations to examine the influence of the modulus of elasticity of the ground on the simulation of the surface settlement.

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In this paper, an extensive survey of tunnels in squeezing rocks in Japan is firstly presented and the results of this survey is summarised. Then, a new method is proposed to predict the squeezing potential and deformations of tunnels in squeezing rock. The method has been applied to actual tunnelling projects, where squeezing problems encountered, to check its validity and applicability. As an concrete example, an application of the method to predict the squeezing potential and deformations of the rock along a 300 m long section of an actual tunnel was made. It is found that the predictions by the proposed method well agree with observations and it is a very promising tool for tunnelling engineers.

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Taking advantage of the opportunity of excavation of Nabetachiyama Tunnel driven through techtonically disturbed mountain consisting of Tertiary mudstone of Shiiya formation, samples of severely faulted mudstone (fault clay) were taken and tested mainly from the viewpoint of critical state soil mechanics. The conclusions are;(1) The water contents of fault clay in the sections suffered from very heavy squeezing pressure were in the range of critical state corresponding to the effective confining pressure at their depths.(2) The competence factor Fc. decreases as the depth of tunnel η(m) increases obeying the formulae fc=0.79^-0.13-1.13η-^0.13.

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In connection to the analysis of tunnels, one of the important points is to understand the three dimensional effects of excavations. But almost all the existing numerical methods in FEM assume plane strain conditions along the tunnel axis and hence they are 2D methods. Thereby, for engineers it is quite difficult to understand the 3D effects of excavations.
The present study simulates the actual NATM procedure by performing 3D FEM analysis and examines the 3D effects of an excavation.

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For the purpose of establishing the estimation standard of tunnel lining soundness, experiments on lining behaviors and simulation analyses are performed. The experimental setup is a 1/30 scale model of a double track railway tunnel, and the surrounding ground is simulated using hard rubbers, thereby investigating the interaction between lining and ground.
In this paper, we describe a few results of the 2-dimensional experiments and the simulation analyses using a beam-spring model.

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For more efficient use of underground space in urban areas, tunnels close to existing important structures are increasingly constructed. This demands more accurate estimation of ground movement due to tunneling works and its unfavourable effect on the adjacent structures. In order to analyze the behaviour of sand ground due to tunneling in a more realistic manner, an analytical method was developed which takes into account the pressure-dependency, anisotropy and non-linearity of stiffness of sand. It is demonstrated that this method can simulate laboratory model test results substantially better than the conventional linear elastic analysis method.

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Face stability is one of most important factors to excavate safely a shallow tunnel by NATM in a sandy ground. In this study, a series of model tests simulated the cuttinl face of tunnel was performed on unsaturated sand to investigate the failure mechanism of tunnel face in plane strain condition.
It was found the following from the test results.
1) The slip surface generated by face failure is straight plane in the vertical face, but a curved slip or circular arc in the inclined face. Hence, it is necesarry to consider this failure modes to apply to the stability analysis.
2) Stability analysis using the limit equilibrium concept is more usefull to evaluate the face stability of cutting face.

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The system which explores geological structures in front of the cutting face on mountain tunneling is developed. This system has explored the geological structure by means of Rayleigh wave. The following points have been examined in case of loading Tunnel Boring Machine (TBM) with this system.
1. The method of setting the exciter to the cutting face.
2. The method of arranging the exploring equipments to the cutting face.
It is possible to prevent in advance the troubles caused by the geological struc tures, for exeample fault fracture zone in applicating this system to the tunneling. Therefore, safety and rapid construction will be possible.

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Information on fracture distribution in a rock mass is important for stability analysis as well as for prediction of groundwater inflow during tunnel excavation. To investigate the applicability of tomography technique for the use of fracture detection, a series of in-situ tests were conducted in a granitic rock. The velocity profiles obtained from cross-hole radar and seis mic tomography reveals anormalities along fractured zones in the measurement area. From cross-hole injection test, it was shown that these fracture zones can be majour water flow paths.

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Our company possesses 730km water conduits, about 70% of which aged more than 50 years. It has been cited that instead of conventional way such as boring, development of new investigation method is necessary to maintain the conduits more properly. Primary system using ground penetrating radar was developed and proved effective for this use in terms of maximum surveyable depth and accuracy. GPR system would non-destructively and continuously report the conditions behind lining concrete in a short period. Furthermore, by studying electric permittivity of concrete and getting more analytical knowledge through investigations, the system has been practically improved.

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In the present practice, a general inspection of railway tunnels relies on walking patrol or simple measurements, but these methods are not efficient nor accurate. To solve these problems, we take continuous pictures of tunnel lining surface by slit camera system, and examine its applicability and utility for railway tunnels. As a result of related experiments, we found that the slit camera system is more efficient for inspecting a railway tunnel aboard a running car, and the pictures obtained provide more exact records of deformation phenomena of the tunnel lining.

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The old tunnel has various cracks on it's lining. These cracks have been written on the deformation record etc., but it is hard to say that these crack's data have been utilized effectively. This time, we got the chance to investigate the lining's defor-mation of tunnel which length was about 1000m, and as the result of cracks patterns classification, we found many inclined cracks on the lining except traverse and cross cracks, and presumed that the causes of crack are the fall of soils and rocks, water-pressure, difference of squeezing ground pressure and the condition of tunnel const-ruction (such as grouting or drying shrinkage or slope of tunnel).

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The Shibuya-Tunnel of The Keio-Inokashira-Line, L=270m, was constructed about 60 years ago, and because it has been deerepit remarkably, recently we carried out the reform of it for about three years.
This report explains the illustration of the active railroadtunnel reform, especialy in respect to safety and labor saving in spite of it was depended on human power. First main point we want to say is that the mechanization of the mortar chipping down work at the upper part of the tunnel, and second main point we want to say is that the automatization of the assembling arch support work.

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Recently, the use of shotcrete is increasing in the tunnel lining and the repair of structures. Therefore, it is requested to improve the performance of shotcrete for decreasing rebound and dust, and increasing strength and durability.In Europe, silica fume has been widely mixed in shotcrete for solving above problems.This report deals with the performance and quality of wet mix silica fume shotcrete.
According to the results of the experiment, it is comfirmed that the compressive strength and the bond strength of the shotcrete are improved by mixing silica fume.

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Our newly developed System (Novel Material Shield-Cuttable Tunnel-Wall System); the departure-arrival part of the shield tunnel wall is to be constructed by using CFRP for main reinforcement, and precast concrete members with limestone for coarse aggreate.The general idea of our system the structure of the wall, tests undertaken to proove its practical value (cutting test, flexural strength test of concrete, verification test) are given in this report.

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This paper describes the Multiple-Duct-Pipe Jacking Method for Small-Bore Power Conduits which has been developed to rationalize the conduit tunneling work in urban areas.
This new method can reduce the construction period by 20% and the cost by 10%, because it may largely cut the process of the work comparing with the conventional methods.
The overall performance of the method has been verified by field tests carried out in 1989 and 1990.
This method is expected to be applied to the actual works in the near future.

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In the H & V Tunnelling Method, a special rolling control function is used in sprial tunnnelling with multi-face shields. This method allows construction of tunnels that have multi-circular cross-sections with the arrangement of the circles varying continuously from vertical to diagonal and to horizontal or vice versa, as well as ramification from a multi-circular tunnel into separate single-circle tunnels. Authors has implemented verification test construction of a tunnel and has established the techniques relating to the construction procedure. Discussions are made in the present paper on this Method and verification test implemented.

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A tunnel construction method has been developed in which both a shaft and a underground tube are continuously excavated using a hermetically sealed shield machine which is launched from the surface. The pressure-resisting part of the machine was confirmed through tests at a water pressure of 980 kPa.
Theoretical examinations of a shaft segment and the shaft base using the Finite Element Method were carried out assuming a soft ground stratum. This showed the designed structures to be safe.

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This paper aims to, make clear the face stability and the acting load on face in deep inclined shield method by comparing those characteristics of inclined shield model tests with those of horizontal shield model tests relatively. In this model test, X-ray radiography method is in use to investigate the behavior of ground around face. As conclusions, the followings are made clear: 1) the concept of existing method to prevent face failure can be applied to the inclined shield method because the shape of three dimensional loosen area in inclined shield method agrees well with that based on Murayama theory, and 2) the capacity which should be equipped on inclined shield can be designed based on the concept of existing method.

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Now, in Japan, Earth pressure balanced shield's share in shield method is about 70%. Large dimension earth pressure balanced shield will be more as middle and small dimension as.
Recently, High density slurry shield adopt more in earth pressure balanced shield method.
This report describes how to employ shield machines equipped cutter face and long screwconveyer and additives for the excavation of a large dimension tunnel by chemical form and high density slurry injection shield, sets forth the results of the successfully completed excavation works.

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The jet grouting technique is often used to improve soft soil around starting area of shield machine. Thickness of the improving area is usually determined by a rather simple design method based on beam theory, slip circle theory and punching shear theory. However, it is necessary to consider behavior as deep beam of the improving area when its thickness is larger than tunnel diameter.
In this study, the deep beam behavior of the improving area is examined by 3-D FEM analysis, and a new design method based on the deep beam theory is proposed.

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A rockmass is changed in state of mechanical, hydrogeological and thermal proper-ties according to the excavation of a drift or shaft, and these changes are already reported by some researchers. The excavation also influences on hydrocircumstances and causes the change of underground water flow. In order to understand the changes of rock mass properties by shaft excavation quantitatively, the author performed in-situ experiments and investigations.
In this paper, the methods and measuring devices to investigate such changes are mainly reported.

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The Keage station is planned to construct with partition into 120 m long platform section and 66 m long main section for passenger facilities.
The work of main section is being carried out underneath a heavy traffic 3-forked road junction with frequent tramway service at location of narrow valley. Due to these situations, adoption of temporarily roadway supporting method with pipe-roof is indespensable for excavation beneath the roadway with cut and cover method.
Selection of method, analysis of effect of pipe-roof and construction procedure are reported.

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