Attenuation properties of subway-induced ground vibration propagated from cut-and-cover tunnels were experimentally investigated to improve the accuracy of empirical prediction methods for the Vibration Level and ground-borne noise level in buildings. Vibration accelerations both in the tunnels and on the ground were measured in and around the Tokyo area. This paper presents distributed levels of measured acceleration in the tunnels and ground. Dependency of attenuation properties on frequency is examined, and internal damping in every 1/3 octave band are calculated based on the Bornitz formula. Damping factors with ground conditions are also discussed.

There were the following typos in the article, "Journal of Japan Society of Civil Engineers, Ser. C (Geosphere Engineering) Vol. 69 (2013) , No. 2 pp. 162-173"

The effects of earth pressure balanced (EPB) tunneling on the soil stress path and piezometric head of the soil during tunnel advancement are considered in this study. First, the 3D stress distributions of the area near the crown and spring line of the tunnel are investigated, after which the tunnel stress path with respect to the Mohr-Coulomb yielding surface is presented. Next, by taking into account the three significant factors of a) advance rate of the tunnel face, b) consolidation coefficient of the soil, and c) overburden depth of the tunnel, a parametric study is conducted and the effect of EPB tunneling on the piezometric head field of the soil is examined.

In order to predict the long-term deformation of shield tunnels located in soft clayey ground and conduct their long-term management, this paper investigates the calculation method of long term tunnel deformation due to the consolidation settlement of surrounding ground. Although it is required to take into account of the non-linear behavior caused by the generation of cracks within the tunnel lining and their enlargement, it is difficult to employ the sophisticated segment-ring model for tunnel lining because of calculation time and memory. Therefore, this paper proposes the empirical modeling method of the reduction of stiffness due to the generation and the enlargement of cracks and combines it with the soil-water-coupling analysis of tunnel deformation. The proposed method was verified and validated by the comparison between the calculation results and the field measurement results.

In order to predict the long-term deformation of shield tunnels located in soft clayey ground and conduct their long-term management, this paper investigates the calculation method of long term tunnel deformation due to the consolidation settlement of surrounding ground. Although it is required to take into account of the non-linear behavior caused by the generation of cracks within the tunnel lining and their enlargement, it is difficult to employ the sophisticated segment-ring model for tunnel lining because of calculation time and memory. Therefore, this paper proposes the empirical modeling method of the reduction of stiffness due to the generation and the enlargement of cracks and combines it with the soil-water-coupling analysis of tunnel deformation. The proposed method was verified and validated by the comparison between the calculation results and the field measurement results.

Chemical grouting method can be used in order to improve the loose sand against the earthquake induced liquefaction. Long term stability of chemically stabilized sand is required for the chemical grouting method to be used to prevent the earthquake induced liquefaction. However, it is quite difficult to obtain and predict the long term performance of chemically stabilized sand.<br> Experimental investigation of long term stability of chemically stabilized sand has been carried out by using the promotion of the silica diffusion and leaching within the chemically stabilized sand under the water flow. It is demonstrated that the time dependent variation of the physical properties of chemical stabilized sand is closely related to the silica movement and leaching from the chemically stabilized sand. Silica movement and leaching of the chemically stabilized sand are obtained by the finite element analysis based on the silica diffusion equation.<br> It is concluded that the long term stability of chemically stabilized sand can be quantitatively evaluated using the combination of the flow water promotion test of chemically stabilized sand and the finite element analysis based on the silica diffusion equation.

The chemical grouting has the advantages that equipments are small and the direction of boring has flexibility. Therefore, in Japan, it is frequently used for a soil-improvement method in the railway construction site where workspace or working hours is limited. However, it has the possibility to cause a ground displacement around the site. Because there is no method that estimates it quantitatively, the design based on old cases is still used mainly and focuses on safety overly.
In this Study, the simplified numerical analysis for ground behavior due to the osmotic pressure during injection is proposed.

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.

A hydrogen gas is expected to be a clean, environmentally-friendly future energy source. In order to supply a hydrogen gas with a fuel cell station, the employment of buried pipeline is being studied in Japan and foreign countries. To implement this idea, the most important thing is to ensure the safety against the hydrogen gas leakage from the buried pipeline. Specifically, the understanding of a hydrogen gas movement charactersitics within the compacted soil is extremely important as well as the reliability assessment of pipeline materials. Aiming to establish a safety basis for buried hydrogen gas pipeline system, the full-scale experiment on underground hydrogen gas leakage and the numerical simulation were carried out. The movement characteristics of a hydrogen gas within the soil was investigated and the leaked hydrogen gas was detected at the road surface by the portable gas detector, following the procedure specified by the legal requirement.

A hydrogen gas is expected to be a clean, environmentally-friendly future energy source. In order to supply a hydrogen gas with a fuel cell station, the employment of buried pipeline is being studied in Japan and foreign countries. To implement this idea, the most important thing is to ensure the safety against the hydrogen gas leakage from the buried pipeline. Specifically, the understanding of a hydrogen gas movement charactersitics within the compacted soil is extremely important as well as the reliability assessment of pipeline materials. Aiming to establish a safety basis for buried hydrogen gas pipeline system, the full-scale experiment on underground hydrogen gas leakage and the numerical simulation were carried out. The movement characteristics of a hydrogen gas within the soil was investigated and the leaked hydrogen gas was detected at the road surface by the portable gas detector, following the procedure specified by the legal requirement.

Chemical grouting method is employed frequently within on urban area to improve the strength and permeability characteristics of soft ground. In order to ensure the long term performance of chemically stabilized sand with grouting, the systematic field measurement of the mechanical characteristics of the chemical grouted sandy soil has been carried out by the Japanese Grouting Association for the period of five years, from 2000 to 2005. The test field soil condition consisted mainly of comparatively dense sand with gravel and the ground water table was around 6 m below the ground surface. Four types of silicate grouting materials were employed. Standard penetration tests (SPT), lateral loading tests (LLT), in-situ permeability tests and flow meter tests within a bored hole were conducted to obtain the strength and permeability characteristics of the grouted sand. The SPT-N value and LLT deformation modulus of the grouted sand with a silicate material of an organic hardener has increased for the initial two years and then decreased for the next year. However, its N-value was still the triple times the initial one. It has been concluded that silicate grouted materials have demonstrated the satisfactory performance during the period of three years.

During road excavations for laying gas distribution pipelines, the reuse of the excavated soil for the subgrade backfill significantly reduces the environmental impact. However, when Kanto loam soil, which is a local soil that is widely distributed in the Kanto region, Japan, is employed for the backfill material, the relationship between the amount of the subsidence of the subgrade soil and the cyclic traffic loading must be investigated. In this study, cyclic loading tests on compacted Kanto loam soils are conducted to investigate the subsidence characteristics by using a confined compression apparatus. The subsidence prediction method for subgrade soil (Kanto loam soil) under cyclic traffic loading is proposed on the basis of the cyclic loading test results. Full-scale traffic loading experiments are performed on roadbeds backfilled with Kanto loam soil. Consequently, good correlation is obtained between the amount of the predicted subsidence and the measurement results.

Soil washing is physical-chemical separation for removing the portion of the soil that is most polluted mainly by screen, hydrocyclone, and flotation. This reduces the amount of soil needing further cleanup. In most cases, the contaminants, such as fuels and heavy metals, reside and concentrated in fine-grained soils. The overflow from the hydrocyclone, consisting of fines and water, is treated and converted to a 45%-55% dry solids sludge cake by flocculants addition, sedimentation, thickening, and dewatering. This sludge cake contains the target contaminants and therefore must be managed by disposal at a properly permitted off-site disposal facility. The fines treatment is very important for the recovery of water and for making the sludge cake as dry as possible, in order to create an economical and efficient soil washing system. The proper selection of type and dosage of flocculants is crucial to the success of the fine treatment. This paper describes and proposes a new theory to determine the optimum dosage of flocculants (polymers) based on the soil plasticity index and the pH value. This theory concerning the optimum dosage was verified by subsequent data in the soil washing plant.

This paper focuses on a large settlement behaviour of a shield tunnel, which is constructed in soft alluvial clay strata beneath fresh reclaimed land. The total settlement of the tunnel is more than 0.73 metres and the deformation takes place over more than twenty years after the completion of the tunnel construction. Three dimensional finite element analyses have been carried out to estimate a long-term behaviour of soil and tunnel structure observed in this field. The computed vertical settlement of tunnel structure is compared with the measured data.

A novel stabilizing liquid using air foam rather than bentonite clay slurry, i.e. air foam suspension, is employed in order to stabilize the trench wall surface during a diaphragm wall excavation. Air foam suspension is used to reduce the construction costs of working on an underground diaphragm wall. Air foam suspension is created by mixing the excavated soil with air foam made from a surface-active chemical agent. The performance of air foam suspension depends on its density and consistency, that is, its table flow value (TF). By comparing the trench stabilization capacity of air foam suspension with that of bentonite clay slurry in model tests, the appropriate performance of air foam suspension was confirmed. The cost evaluation of using an air foam suspension for a diaphragm wall excavation is presented.

A novel stabilizing liquid using air foam rather than bentonite clay slurry, i.e. air foam suspension, is employed in order to stabilize the trench wall surface during a diaphragm wall excavation. Air foam suspension is used to reduce the construction costs of working on an underground diaphragm wall. Air foam suspension is created by mixing the excavated soil with air foam made from a surface-active chemical agent. The performance of air foam suspension depends on its density and consistency, that is, its table flow value (TF). By comparing the trench stabilization capacity of air foam suspension with that of bentonite clay slurry in model tests, the appropriate performance of air foam suspension was confirmed. The cost evaluation of using an air foam suspension for a diaphragm wall excavation is presented.

A novel stabilizing liquid using air foam rather than bentonite clay slurry, i.e. air foam suspension, is employed in order to stabilize the trench wall surface during a diaphragm wall excavation. Air foam suspension is used to reduce the construction costs of working on an underground diaphragm wall. Air foam suspension is created by mixing the excavated soil with air foam made from a surface-active chemical agent. The performance of air foam suspension depends on its density and consistency, that is, its table flow value (TF). By comparing the trench stabilization capacity of air foam suspension with that of bentonite clay slurry in model tests, the appropriate performance of air foam suspension was confirmed. The cost evaluation of using an air foam suspension for a diaphragm wall excavation is presented.

The Japanese National Committee for TC28 has produced a committee report on current underground construction activities in Japan, including the technologies of braced excavation and tunneling.
This report is based on technical papers and available construction records from the past decade. In the field of braced excavation, the topics of proximity construction, excavation machines for braced walls, deep shaft excavation, and groundwater flow preservation measures have been selected and introduced, along with some case records. In the field of tunneling, statistical data on tunneling in Japan has been assembled from published data and questionnaires. Several case records using current shield tunneling and urban NATM methods are described. Finally, damages to underground structures due to the 1995 Hyogoken-Nanbu (Kobe) Earthquake are summarized, and new earthquake-resistant designs for shield tunneling and other technologies are introduced.

The Japanese National Committee for TC28 has produced a committee report on current underground construction activities in Japan, including the technologies of braced excavation and tunneling. This report is based on technical papers and available construction records from the past decade. In the field of braced excavation, the topics of proximity construction, excavation machines for braced walls, deep shaft excavation, and groundwater flow preservation measures have been selected and introduced, along with some case records. In the field of tunneling, statistical data on tunneling in Japan has been assembled from published data and questionnaires. Several case records using current shield tunneling and urban NATM methods are described. Finally, damages to underground structures due to the 1995 Hyogoken-Nanbu (Kobe) Earthquake are summarized, and new earthquake-resistant designs for shield tunneling and other technologies are introduced.

The effectiveness of grouting to reduce surface settlements during underground construction in clayey ground was investigated by a field trial and laboratory tests. The field trial was carried out during shield tunnelling work conducted in alluvial clay deposits in Koto-ku, Tokyo. Grout was injected at some distance away from the tunnel, and both surface and subsurface settlements above the tunnel were monitored. Although the initial heave was achieved immediately after the grout injection, the ground continued to settle with time, owing to soil consolidation and grout shrinkage. A laboratory investigation was conducted to investigate the parameters that control the long-term behaviour of grouting in clay. It was found that better long-term grout efficiency can be achieved in overconsolidated clay than in normally consolidated clay, and the efficiency increased with increasing injection volume. Finite element analysis of the laboratory experiments confirmed that the amount and extent of excess pore pressures generated during injection govern the longterm grout efficiency. Finite element analysis of the field trial was also performed to simulate the long-term ground deformation after grout injection.

The aim of this study is to develop a laboratory ground movement measuring device and apply it to a model test of shield tunneling. The thin flexible metal plate was used for measuring ground displacement, to which the strain gauges were affixed. The calibrations of soil displacement obtained from this measuring device were carried out by the trap door tests. The potential of the laboratory ground movement measuring device was demonstrated for the use to measure the ground displacement during shield driving. Furthermore, a series of model tests were carried out to investigate the ground displacement behaviour during shield machine driving.

This general report reviews and examines 27 papers submitted to the session on TBM (tunnel boring machine) and Shield Tunnelling, as a risk management system.

During shield tunnelling operation, a shield machine is driven forward by applying mechanical jack forces behind the machine tail and excavating the soil in front of the machine with its cutting face. In this study, the advancement and excavation processes of the shield tunnelling operation are modelled using the finite element method in order to investigate the effect of these construction processes on the ground response. A new excavating finite element, which models the disturbed soil in front of the cutting face, is introduced. The operation of shield advancement and of soil excavation is simulated using the finite element remeshing technique at each time step of the analysis. The accuracy of the finite element remeshing technique is discussed by analysing one-dimensional consolidation of an isotropic elastic medium. The proposed modelling techniques of shield tunnelling construction are applied to simulate a tunnelling project in Tokyo and the numerical results are compared with the field measurements. The soil deformation mechanism associated with the shield tunnelling operation is examined in detail.

In closed water environments such as lakes or marshes, soil and organic materials deposit at the bottom. In order to solve problems of land smells or water pollution, bottom deposits have been dredged or stabilized with cement. Recently, the reuse of lake-bottom deposits for agricultural compost has been planned, but an efficient flocculation and dewatering method for high water content lake deposits is necessary for this to be implemented. In this study, a series of sedimentation experiments and consolidation tests on lake-bottom deposits dredged from a closed water environment lake were carried out using an organic flocculant. It is shown from the experimental results that an optimum volume of flocculant does exist for efficient sedimentation and that the addition of flocculant improves the dewatering characteristics of lake-bottom deposits.

This paper introduces a numerical simulation procedure for use with the shield tunnelling problems and compares the simulation results with field measurements for soft clay ground. The shield machine advance is simulated numerically by adopting excavation elements and repetitively rearranging the three-dimensional finite element mesh used in the simulation. Deformation of soft clay ground and the effective stress behaviour as the shield machine advances under actual hydraulic jacking forces are modelled successfully by the new procedure. As an example, the application of this procedure to the twin shield tunnelling problem is described.

This paper introduces a numerical simulation procedure for use with the shield tunnelling problems and compares the simulation results with field measurements for soft clay ground. The shield machine advance is simulated numerically by adopting excavation elements and repetitively rearranging the three-dimensional finite element mesh used in the simulation. Deformation of soft clay ground and the effective stress behaviour as the shield machine advances under actual hydraulic jacking forces are modelled successfully by the new procedure. As an example, the application of this procedure to the twin shield tunnelling problem is described.

Drained torsion shear tests of anisotropically consolidated undisturbed clay were carried out using hollow cylindrical specimens, in order to investigate the effects of principal axes rotation particularly on the dilatancy characteristics of undisturbed clay. The magnitude of dilatancy is considered to represent the microstructural change of undisturbed clay during the drained torsion shear process. The plastic volumetric strain of clay was experimentally observed to occur just due to the principal axes rotation under constant mean principal stress p' and principal stress difference q drained shear conditions. The plastic Volumetric strain increment of undisturbed clay under a magnitude of principal axes rotation was found to be greater than that of reconstituted clay.

This paper introduces a numerical simulation procedure for use with the shield tunnelling problems and compares the simulation results with field measurements for soft clay ground. Shield machine advance is simulated numerically by adopting excavation elements and repetitively rearranging the three-dimensional finite element mesh used in the simulation. Deformation of soft clay ground and the pore water pressure behaviour as the shield machine advances under actual hydraulic jacking forces are modelled successfully by the new procedure. As an example; the application of this procedure to tile twin shield tunnelling problem is described.

Soil-cement mixtures were prepared using three types of materials sandy soil excavated from a shield tunnelling construction site in Tokyo, clay slurry used for stabilizing the shield tunnel cutting face, and cement. These soil-cement mixtures were planned to be used for the filling of the lower part (invert section) of the circular shield tunnel cross-section in place of cement mortar. A number of unconfined compression tests were carried out to investigate the time-dependent variation of compressive strength of soil-cement mixtures. The strength of soil-cement mixture was found to be satisfactory as the new invert material and to be influenced by the contents of the clay slurry. It could be seen that the density of soil-cement mixtures measured immediately after mixing and compaction was directly related to the compressive strength.