The report gives a brief overview of the history and development of Soils and Foundations from its founding in 1960 to the golden jubilee year 2010. The statistics concerning the journal's distribution and the academic contents of the published papers are presented, updated from those first published by Takemura et al. (1999). Major events are chronicled and their impacts the assessed on the readers, contributors and the course of the journal's later development. Such events include online publishing and adopting the impact factor, among others. The long-term trends in the research topics, employed approaches (experimental, analytical, etc.), authors' identity, etc. are discussed based on the statistics considering all the papers published in the past. The report also offers a complementary perspective to the journal's contributions to the geotechnical society by reviewing the award-winning papers.

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To look back at the traces of the development of “Soils and Foundations” and write up a synthesized story of evolution is, needless to say, beyond the capacity of the author. It is rather easy to retrospectively describe the achievements of old times, but it becomes increasingly difficult to deal with more recent advances because of the vast majority of events taking place—too many to digest— and also because it is all but impossible to simply explain such complex work. Yet, in the course of time, while less important events are put gradually out of our memories, only the noteworthy and most significant achievements remain. It is the telling of these memories that survive the passage of time that establishes them as of commonly recognized milestones. As such, it would be wise to rely upon the natural screening process as just described and not dare to touch on the most recent development in details. In this context, the intention of this article is mainly to unveil the progress in the early period of the Japanese Geotechnical Society (JGS) and to clarify the situations culminating in the birth and subsequent evolution of the English journal, “Soils and Foundations”. Regarding the events related to more recent developments, only a bird's eye view will be presented herein.

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The focus of this paper is on the significant role of several soil-cement-mixing technologies employed in Trans-Tokyo Bay Highway project. The two major issues are the large scale improvement of existing soft clay deposits by cement-mixing in place controlling the strength, and the construction of large offshore embankments by the underwater placing of slurry type cement-mixed sand at the ramp sections controlling the strength and density, and dry type cement-mixed sand at flat places of one of the man-made islands. These issues are described in relation to the construction of the world's largest diameter shield tunnels and a huge offshore diaphragm wall. A new method to determine the design strength of cement-mixed soil for limit equilibrium stability analysis was developed based on CD and CU triaxial test results. Advanced laboratory stress-strain tests contributed greatly to the geotechnical design and construction control. The importance of accurate measurements of small strain in triaxial tests to obtain relevant design parameters is emphasized. The strength and deformation characteristics of cement-mixed soil encountered in this project are summarized. It is shown that they are comparable with those of natural sedimentary soft rocks which support a number of important heavy infra-structures allowing a limited amount of ground deformation.

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Kansai International Airport was planned to provide a fundamental solution to the aircraft noise pollution problem in the area surrounding Osaka International Airport (Itami Airport) and to the increasing demand for air transportation This man-made island was constructed 5 km offshore in Osaka bay to minimize noise pollution in residential areas. The airport commenced operations in September 1994. The second phase of construction work involved building an island further offshore than the island built in the first phase. Since the sea water is deep at the Kansai International Airport construction site and the layers below the seabed consist of a very soft layer of Holocene clay (immediately below the seabed surface) followed by alternate layers of Pleistocene clay and sand/gravel, the construction of an airport island was expected to produce a considerable amount of ground settlement. The amount of settlement during and after construction needed to be predicted in the design of the airport islands, and the results needed to be considered in the details of the land development work. This report outlines the second phase construction work at Kansai International Airport and describes the related geotechnical issues, with a particular emphasis on settlement.

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The paper describes the technical transition of earth structures for the super express known as the Shinkansen. To ensure the safe running of Shinkansen, the earth structures needed to be adequately designed and constructed with consideration of cost effectiveness and high stability. These earth structures include embankments for the slab tracks, reinforced retaining walls, reinforced cut slopes, aseismic abutments, soil improvement and performance-based design. New construction techniques and design methods, model tests, field construction tests and evaluations of these designs were carried out to construct the best possible earth structures. The actual applications of the earth structures listed above to secure the safe running of the Shinkansen are introduced.

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The Akashi Kaikyo (Strait) Bridge, one of the major bridges of the Honshu-Shikoku bridge network connecting the main island and the Shikoku island, is the world's longest suspension bridge with a center span of about 2,000 m. The bridge was constructed over the Akashi Strait and opened to traffic in 1998 after a construction period of about 10 years. The granite stratum in the Akashi Strait was very deep, while the granite stratum provides the foundations for the other long span bridges which have been constructed in Japan. Three of the four foundations had to be constructed on either a weakly cemented gravelly soil deposit or a sedimentary soft rock layer. The geological structure was carefully investigated and the geotechnical properties, in particular the strength and deformation characteristics of these geomaterial types, were carefully evaluated. To this end, a comprehensive series of advanced triaxial compression (TC) tests were performed on rotary core tube samples of sedimentary soft rock after it was found that the due design was not possible based on unconfined compression tests. Both CD and CU TC tests and cyclic undrained triaxial tests were performed on rotary core tube samples (30 cm in dia.) of the gravelly soil. Based on the data, the long-term and seismic stabilities of the foundations were evaluated. The importance of strain- and pressure-dependent nonlinear stress-strain behaviour at small strains, as well as accurate strain measurements in the laboratory stress-strain tests, was confirmed by analyzing the full-scale behaviour of the foundation during and after construction and comparing the back-calculated stiffness values with those obtained from laboratory stress-strain tests, pressure-meter tests, plate loading tests and field shear wave velocity measurements.

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By focusing on the mechanical behavior of geomaterials observed by means of laboratory tests, we have attempted to survey the 50 year history of relevant studies presented in Soils and Foundations and to introduce some of the recent research outcomes. First, the developments of a variety of testing apparatuses and procedures are summarized, with a particular focus on the effects of boundary conditions and sample disturbance, local and microscopic measurements, and the observation of small strain behavior as well as large strain behavior. Second, studies on the properties of sandy soils, clayey soils, other problematic soils and cemented soils including aged soils and soft rocks, respectively, are reviewed briefly. Third, because it is a research topic that has had the attention of so many researchers for so long, and some remarkable progress has been achieved recently, studies on viscous behavior, including the dependency on the loading rate and creep deformation, are overviewed.

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The review of 50 years of papers published in Soils and Foundations demonstrates that significant effort has been made by many researchers to develop soil models. The contributions of Soils and Foundations in the area of soil modeling are subdivided into two topics: (a) “macro”-mechanics and (b) “micro”-mechanics. The attention to macro-mechanics is focused on continuum-based models, whereas that to micro-mechanics is focused on discrete based models. Soils are examples of complex systems, made up of basic units that interact to generate an emergent response that is more complex than the response of the units themselves. Despite the challenges posed by the complexity of the systems, our understanding of the link between the particles, their interactions and the overall “macro-scale” soil response has significantly been improved over the life of Soils and Foundations. In this review of contributions to soil modeling, many examples of macro-scale soil models developed with a real consideration of the mechanical response of the individual particles were found.

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This paper provides a comprehensive survey of the numerical methods related to geotechnical problems, most of which were reported in papers appearing in Soils and Foundations. The reason why most of the reviewed papers are concentrated in Soils and Foundations is that if we were to include papers appearing in other journals in the field of geotechnical engineering, closely related to numerical methods, e.g., Computers and Geotechnics, Int. J. Numer. Anal. Meth. Geomech., etc., we would have to deal with almost all the papers in those journals. Firstly, we present a description of the current status of the numerical methods, and then give a brief review of the literature covering several topics in geotechnical applications. The scope of the review is limited, and thus, the authors do not profess to cover the entire range of literature.

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Due to the increasing world population growth and competition for space, especially in bigger cities, the construction of subsurface civil engineering structures has become unavoidable. Safety, both during and after the construction of such structures, is of paramount importance to civil engineers. One of the main challenges in securing this safety is presented in the form of groundwater flow and its control. In this paper, the state of the art techniques for controlling groundwater flow during underground excavation are outlined with case studies from some construction sites in Japan. It needs to be pointed out that no single technique is adequate for controlling groundwater flow at an excavation site. Also, not so much attention has been paid to the designed groundwater level, which plays a major role in the stability of the structure after construction. In addition, groundwater conservation has yet to be considered in the designs of such structures. It is necessary for by-passes for groundwater flow to be constructed and monitored over the long term to assess their performances.

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Foundation engineering emerged as a discipline of modern engineering science in 1940s. Design and analysis as well as practice of foundation engineering have made a significant progress up to the present time. This paper gives an overview of the development of foundation engineering, mainly referring to papers published in Soils and Foundations. The paper describes the theoretical development of foundation analysis and a recent increasing trend of foundation practice of adopting various hybrid foundations. The paper points out the importance of environmental considerations in foundation design and practice, including low noise and vibration reduction, reuse of existing foundations and use of natural energy through foundation elements. The paper then provides authors’ views of future directions in foundation studies and practice.

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Tunnels serve various functions such as in subway systems, underground electric power lines, gas pipes, telecommunication lines, water supplies and sewer lines and many other pipelines. The trend of tunnel construction is toward deeper and longer tunnels. In addition, the excavation of tunnels in difficult ground conditions is now not uncommon, though the tunnels themselves are still difficult to construct. Advanced studying methods have been developed for the prediction, monitoring and evaluation of the performance of tunnels and ground. Today, experimental methods and analytical methods are the main approaches used in tunnel studies. In this paper, the present state of tunnel construction and the main study methods are discussed, and the various experimental and analysis methods and their usage are compared. Tunnel excavation is very complex because it involves soils, structure and interaction problems. There is no one perfect studying method, though there are good combinations of numerical analyses and experimental methods which provide the optimum approach for solving tunnel related problems.

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This paper first reviews the earthquakes that occurred since 1995 and then outlines the significant lessons learnt from disasters. The discussion then goes into the induced development of engineering practices that were triggered by those disasters. It is clear that major development occurred in design philosophies, soil improvement, and facilities for research. The last section of this paper addresses the compound effects of earthquakes and rainfall that may make the extent of the disasters worse.

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This paper provides an overview of the modern understanding of the behavior of soils and foundations during an earthquake based on the papers published in Soils and Foundations over the last fifty years. The most fundamental issues in geotechnical earthquake engineering are the non-linearity of soil under cyclic loading and its implications on the seismic performance of geotechnical structures. The non-linearity of granular materials is essentially anisotropic, whereas the linear or equivalent linear model often used in conventional practices is isotropic. The non-linearity of dry soil is characterized by the difference between the peak and residual strengths, and the increased awareness of the implications of this difference over time has allowed for the development of a generalized methodology for evaluating active earth pressures. The non-linearity of saturated soil under undrained cyclic shear differs fundamentally from that of dry soil, with saturated soil capable of mobilizing 100% of the shear strain in the double amplitude. The cyclic behavior of saturated soil under initial shear is typical of most seismic behaviors of geotechnical structures, including embankments, caisson quay walls, and underground structures. The liquefaction-induced flow failure of geotechnical structures is associated with the steady state of sand in the order of 10 kPa. However, the challenge in the coming decades will be to evaluate the combined effects due to cyclic loading and the steady state. Moreover, the effects of pore water migration are significant in the case of highly permeable geotechnical materials when evaluating settlement of the ground or addressing inter-layered structures of clay and sand. Although current research is elucidating the mechanics of partially saturated sands, the new challenge is to understand combined hazards, such as a combination of earthquake motions and tsunamis. Thus, new approaches and technologies need to be developed.

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The many recent slope failures due to heavy rainfall have been accompanied by significant loss of life, and massive damage to infrastructures and heritage. Many studies have been done to investigate the mechanism of rainfall-induced slope failures and establish a prevention system for slope disasters. In this paper, the state-of-the-art research works on slope failures due to rainfall published in the journal of Soils and Foundations (S&F) during the latest 50 years are reviewed and summarized. This report is written with the perspective that knowledge of unsaturated soil mechanics is necessary to elucidate the mechanism of rainfall-induced slope failure.

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To date, numerous ground improvement techniques have been developed and applied to various types of ground for various improvement purposes. However, they were not developed at the same time, but were developed and applied one by one according to social demands and the development of society. As the development ground improvement techniques improved and such techniques came to used more widely, a great deal of research effort was devoted to their design, execution, quality control and quality assurance, with the results published in many journals and conference proceedings. Soils and Foundations has published a large number of papers related to ground improvement. This article introduces a brief historical review of the development of ground improvement techniques, and then highlights the major papers published in Soils and Foundations over the last 50 years.

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This paper is an overview of the status in geo-environment research in the past, the present and the future in Japan as witnessed by the publications in “Soils and Foundations” over the years. The authors have paid special attention to the geotechnical researches concerning technologies of waste disposal, including radioactive waste disposal, the reuse and recycle of by-product and waste, the evaluation of the environmental impact of waste and by-product, and countermeasures and adaptations to the contamination of ground/groundwater. Some representative papers on the geo-environment published in “Soils and Foundations” have been drawn on heavily in this paper. The commentary provided by the authors is largely from a geo-environmental perspective. In addition, the authors have also paid attention to geotechnical issues in the research.

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This paper traces the recent introduction of performance-based design (PBD) into Japanese design codes (especially geotechnical design codes) and describes the distinguishing characteristics of PBD codes. An overview is provided for source documents that initiated the concept of performance-based design, and consideration is given to the impact of the WTO/TBT Agreement and Japanese government policies on this issue. Three design codes are introduced to explain the development of PBD codes in Japan: JGS4001-2004 ‘Principles for Foundation Design Grounded on a Performance-Based Design Concept’ (Geocode 21); Technical Standards for Port and Harbor Facilities (TSPHF); and Specifications for Highway Bridges (SHB). The first one is a model code established by JGS, whereas the latter two are regulatory design codes used in practice. Performance-based design is now recognized as the most important concept in code drafting and the majority of design codes will introduce this concept at least partially. Thus, PBD is a key concept for understanding the current Japanese design codes.

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