Leakage of water due to internal erosion through a dam body or foundation is a major problem with fill-type dams. Recent case histories and research suggest that most cases of internal erosion are possibly triggered by hydraulic fracturing. However, the quantitative mechanism of hydraulic fracturing still remains to be solved. Therefore in-situ hydraulic fracture tests were carried out with a cheap, concise apparatus using boreholes dug in the soft clayey volcanic soil foundation of a low earth dam (Oyachi Dam) in Niigata Prefecture. Water was injected into the foundation through a perforated pipe by two methods : one was under a controlled injection pressure and the other was a controlled injection flow rate. In the former method, the relationship between flow rate and injection pressure was observed and it was found that a yield pressure or fracture pressure existed in all the tests. By repeating the injection test it was confirmed that once a crack is developed, it is very easily reopened by a water pressure a little higher than the earth pressure exerted on the crack. In the latter method, the relationship between injection pressure and time was observed and it was found that fracture pressure varied with flow rate. The boreholes were excavated to observe the development of fracture cracks and it was also found that the cracks had developed perpendicular to the borehole periphery, which means that fracture cracks were induced by tensile stress and denies the explanation that fractures are caused by shear failure.

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A comparative study of the static and dynamic response of a slope is carried out, using the large deformation theory of the updated Lagrangian formulation and the conventional infinitesimal theory. In the static analysis, a strength reduction method proposed by one of the authors is used to evaluate the safety factor of the slope. It is found that by the large deformation theory, the safety factor is larger than that calculated by the infinitesimal theory, and this difference becomes large along with the reduction of elastic modulus. In the dynamic analysis, it is observed that the large deformation theory gives smaller sliding displacement and larger response acceleration than the infinitesimal approach. It is concluded that in many cases the large deformation approach gives more adequate solutions.

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Based on the concept "intermediate soil wedge" which is dependent on mobilized frictional resistance, a new theory has been developed for evaluating the seismic earth pressures against retaining walls under any condition between the active and passive states. For this theory, the seismic earth pressure is separated into four components according to their formation. New equations are proposed to determine the distribution, resultant and point of application for each component. An equivalent seismic coefficient is introduced to take into account non-uniform seismic acceleration distribution with depth. The equations place special emphasis on dependence of the seismic earth pressure on mode and level of wall movement. The equations can be reduced to the Mononobe-Okabe equation for the limiting conditions. Their applicability was confirmed by comparing the predictions with a number of previous model test results.

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During earthquakes, saturated loose sandy soils often liquefy, causing serious damage to buildings and underground structures. Various construction methods have been employed to stabilize these soils against liquefaction. The popular methods are those which increase their density. Vibration and impact methods are commonly employed, but these often pose a problem of noise and vibration in urban areas. Results of previous experiments have shown that Quick Lime Consolidated Briquettes (QCB), a soil stabilizer made of quicklime and cement placed to form cylinders, significantly increases resistance to liquefaction by utilizing the effects of water absorption, swelling, and hardening. In the present study, shaking table tests were performed to evaluate the earthquake resistance of soil treated with QCB. Results of these test showed that the response acceleration and excess pore water pressure in QCB-treated soils were scarcely affected by the excitation of 200 Gals. The soil settlement due to shaking was about one tenth of that for the untreated soil, proving the effectiveness of QCB during earthquakes.

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A finite element model capable of taking into account nonlinear hysteretic soil behavior is presented to study earthquake induced retaining wall movement. The model also accounts for increase in lateral stresses and settlement associated with grain slip caused by cyclic loads. The predictive capability of the proposed method is verified by comparing responses given by the model with those computed by another existing finite element model and also with responses recorded at the Cambridge centrifuge facility. The study reveals that the wall displacement can be substantially affected, among other factors, by the increase in lateral stresses due to grain slip and wall-soil friction. Care should be taken when selecting a constant value of wall-soil friction angle for the entire duration of excitation since structural changes can occur in the soil adjacent to the wall.

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The ability of Climacodon septentrionalis to immobilize and kill a mycophagous nematode (Aphelenchoides sp.) in vitro is described for the first time. Two isolates produced droplets (20–45 μm in diameter) that formed at the apices of tall, stalked, and branching secretory cells (700–

,500 μm tall). On 2% modified malt extract agar, nematodes became enveloped in the droplets, which restricted their ability to move and resulted in complete immobilization and death within several hours of contact. The rate of decomposition of the nematodes varied considerably, with most individuals persisting for weeks whereas others were degraded within several days and appeared to be colonized by dense hyphal growth. This study provides the first documentation of a non-agaricoid fungus producing secretory cells that are able to immobilize nematodes.

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The behavior of the soft clay grounds subjected to repeated loading is different from that subjected to sustained loading. The difference in settlement between these two loading patterns should be due to secondary compression over a long period of time. Consequently, soft clay grounds subjected to repeated loading tend to be more compressible than those subjected to sustained loading. Therefore, it is necessary for engineers to predict post-construction settlements under repeated loading. In this respect, the preloading is considered to be promising as a countermeasure to reduce the settlement of clay under repeated loading as well as under sustained loading. The effect of preloading on post-construction consolidation settlement of soft clay subjected to repeated loading after removal of a part of preload is investigated in the present paper. It has become clear that the settlement of a clay sample after preconsolidation is mainly affected by the amount of preload, the degree of consolidation due to the preload, the amount of permanent load and the amount of repeated load after removal of preload. The calculated settlement versus time relations using a method to estimate the amount of consolidation settlement of soft clay grounds subjected to repeated loading after removal of preloading were compared with the observed degree of consolidation as parameters of the intensities of preload and repeated load.

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The paper presents results from an extensive experimental model study of response of dry sand to impact of a rigid tamper. In the laboratory tests a circular steel tamper was repeatedly dropped on sand contained in a large tank. Measurements included tamper acceleration aud soil pressure at impact, tamper settlement, aud soil densities and strains. Effects of tamper drop height, weight and contact area were investigated. A method is presented for the evaluation of global dynamic stiffness of the soil mass affected by the impact by calculating a dynamic settlement modulus (DSM). The DSM values are determined from integration of the impact acceleration record with respect to time using measured integration constants. DSM values show good correlation to soil densities and corresponding elastic moduli obtained from laboratory tests for loose sand. However, for dense sand, results indicate apparent discrepancies between elastic modulus and the higher DSM values. Analyses of normalized impact energy and the resulting densification in the sand in terms of normalized dimensions of volumetric strain (relative density) contours show unique correlations which are used for a proposed rational design method for dynamic compaction in dry sandy soils.

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(³H) Tobramycin was used as a probe to determine the relationship between the structure of aminoglycoside antibiotics and their ability to remove this drug from its higher affinity binding site on the ribosome. The dissacharide moieties (neamine, tobramine, gentamine) appeared to have a common binding site, whereas the kanosamine, garosamine and ribose moieties determined the specificity of this binding. Amikacin and butikacin behaved in an anomalous manner in spite of their close structural relationship to tobramycin.

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Experimental investigation on stress development in sand due to installation and uplifting of helical screw anchors is presented. Five model anchors with different geometry were tested to examine the effect of screw shape on stress development in sand. The sand was placed in layers and mechanically compacted by a hand-held air hammer. The testing tank was equipped with stress transducers located at predetermined positions to allow measuring the stresses in the sand around and in the near vicinity of the installation path. Stress transducers were oriented such that vertical and lateral stresses could be measured. Anchors were installed into layers of dense, medium, and loose sands. Stress measurements indicated that the tested sands were slightly overconsolidated due to the utilized placing technique. Furthermore, measured stresses were used to determine the extent of stress field inside the sand. Deflections of sand surface, during pullout load application, were measured by displacement transducers. The stresses measured within the sand together with the recorded surface deflections were utilized to establish the extent of the mechanism of failure for shallow, transit, and deep anchors.

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　本研究では，空石積みの修復活動のオーガナイザーに半構造化インタビューを行い，参加者がいかにしてオーガナイザーになるのかを把握し，さらに継続的に活動を続ける可能性が高まる場のマネジメントの在り方について考察した．その結果，オーガナイザーに共通する前提として類似する石積みに対する思いと活動を取り巻く環境を有していることなどが分かった．また，活動を実践することによる変化の特徴として様々な役割を果たさざるを得ない実践を経験したこと，即興的なコーディネート，ルールの原則の理解，修復作業のアレンジという4つの特徴が見られた．これらより活動のマネジメントとして，役割分担を固定しない，ルールの優先順位の伝達，雑談を促すの3つを示した．

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　ラオス国のナムニアップ

水力発電プロジェクトに関わる少数民族モン族3,500人の移転に際し，住民の強い反対に直面し，同意取得と移転完了に至るまでに多大な労力と時間を要した．反対の理由として，移転地の土壌の品質と，山間における焼畑と狩猟・採集を主とする循環型から，平地における水田耕作による定住型の農業形態への移行に対する不安が影響した．この対処として，事業者は移転地内にパイロットファーム（実験農場）を開設し，住民を招待して土壌改良や農業技術の指導を試みた．本論文では，パイロットファームにおける移転計画の実証や情報伝達，フィードバックの効果，ライフスタイルの変化に伴う新たな生産活動を創造する場としての可能性について論じるものである．

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　本研究は，公共交通のサブスクリプション型運賃は持続可能なのか，採算が取れるのか，導入の意思決定は如何に行われたのかを明らかにするため，筑波大学と小山市におけるエリア乗り放題格安バス定期券の導入プロセスと効果を分析した．筑波大学は，学内交通環境改善検討の結果，大学がバス事業者から

年間有効の定期券6千枚を一括買取りし，大学構成員に再販することで割引を実現して17年間サービスを継続していた．小山市は，市民のバス利用促進を目的に市内全線定期券の7割引を決断し，販売期間を暫定年として，延長して2年間サービスを継続，減収が無いため恒久サービスに転換していた．両事例には，公的主体による収入保証，モビリティ・マネジメントの継続と定期券購入者増加，地域の協働などの共通点があった．

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　住民主導型交通は，住民によって管理される地域共有資源「コモンズ」としての側面を有する．本研究の目的は，Ostromのコモンズ管理論の視座から住民主導型交通を捉え，住民の協力行動とその持続性についての考察を行うことである．具体的には，住民主導型交通を運営する

つの地域の住民組織へのヒアリング調査を行い，Ostromのコモンズ管理論の視座からその実態を定性的に把握する．そして，把握した実態をコモンズ管理の指針であるコモンズ設計原理から評価し，住民の協力行動とその持続性について考察する．考察として本研究は，住民主導型交通の運営方式により，コモンズ設計原理から適合しない状況が発生することを指摘し，その状況を改善する取り組みを行う環境づくりの重要性を指摘した．

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　ラオスでは，都市と農村部にかかわらずごみが散乱しており，特にビニール袋やペットボトルなど「土に還らないごみ」が目立つ．住民たちには「ごみの分別」という概念が無いようにみえる．関西電力が関わったラオスの水力発電プロジェクトでは，貯水池に住む少数民族モン族520世帯3,500人に対して，移転村を建設するとともに固形廃棄物埋立て処理場を建設，運用を開始した．住民らは，山間部で焼畑や狩猟・採集を主とする自給自足の生活から，町に近い平地への都市的な生活へ転換することになり，新たに発生するごみ問題をどう解決したのか，さらに住民の意識は変わったのかの観点から水力発電プロジェクトが果たした役割を検証する．

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