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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Circuit techniques to enhance the linearity of input-voltage-to-current (V/I) conversion and to increase the output impedance of a current source by compensating for the low intrinsic gain of a transistor were introduced to realize a high-frequency operational transconductance amplifier (OTA) for a low supply voltage using sub-100-nm CMOS processes. Applying these techniques, a MOS 7th-order Gm-C linear-phase low-pass filter (LPF) was realized using a 65nm CMOS process. A simplified biquad LPF that can serve as a component of a 7th-order LPF was newly developed by replacing OTAs with resistors. As a result, the -3dB frequency bandwidth, group delay ripple, 3rd-order distortion, and 3rd-order input intercept point (IIP3) were 200MHz, 2.2%, ≤ -55dB with a 100MHz input, and +10.3dBm, respectively, all with a ±0.Vp-p input signal at each input terminal in the pseudodifferential configuration. The LPF including an output buffer dissipated 60mW in the case of a .2V supply. Wide spurious-free dynamic range (SFDR) characteristics were confirmed up to high frequencies.

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The correction factor (η_ie) for the ultimate bearing capacity of a footing placed adjacent to a slope, taking into account the combined effect of horizontal and vertical seismic loads, represented by horizontal and vertical seismic coefficients, k_h and k_v, respectively, was derived using a modified Janbu's slice method. The influence of slope angles ‘α’ on the values of ‘η_ie’ are studied here. It was found that the values of η_ie can be expressed as an exponential function of ‘k_h/(-k_v)’ and ‘α’, with a measurable interdependency between ‘α’ and ‘η_ie’. The influence of ‘α’ on the value of ‘η_ie’ increases as the input value of ‘k_h/(-k_v)’ increases. Equations derived based on the analytical results are proposed to account for this effect. Based on the analyses of 11 near-fault seismographers obtained in the 1999 Chi-Chi earthquake in Taiwan, a ratio between the vertical and the horizontal seismic coefficients, λ, of between ±0.25 is suggested for including the combined effect of vertical and horizontal seismic forces in evaluating the seismic bearing capacity of footings located in near-fault areas.

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At present, analytical or empirical formula for seismic bearing capacity of footings adjacent to slopes is not available. This study uses a pseudo-static-based approach in conjunction with rigorous Janbu's slice method to derive analytical values of seismic bearing capacity factors (N_γ) and correction factors for the effects of inertia of soil mass and load inclinations for a rigid footing adjacent to cohesionless slopes. It is shown that both the bearing capacity factors (N_γ) and the correction factors for the seismic bearing capacity of footings placed on level ground derived herein are comparable with those reported in the literature. Empirical equations regarding the effects of slope angles and load inclinations, expressed using generalized forms of those proposed in the literature, are also derived. It is also found that the empirical equations derived in the present study provide values of correction factors in good agreements with the analytical ones, indicating the validity of using these empirical equations for assessing the bearing capacity of rigid footings situated on the slope subjected to pseudo-static seismic loading.

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In this study the field feasibility of an innovative thermal technique to improve the performance of prefabricated vertical drains (PVD) used in conjunction with the preloading ground improvement method is investigated. For this purpose, two identical .0 m high full-scale test embankments for preloading were constructed over the soft Bangkok clay where a conventional PVD system was installed underneath one embankment and a novel prefabricated vertical thermo-drain (PVTD) system was utilized for the other. The PVTD unit consists of a U-tube made of cross-linked polyethylene plastic (PEX) that is attached to a conventional PVD unit. Preheated water at about °C is circulated through the attached U-tube to raise the soil temperature underneath the PVTD embankment. The behavior of the two test embankments were compared in terms of excess pore water pressure and consolidation results. The comparison shows the advantage of a PVTD system over a conventional PVD system. The rate of consolidation increases significantly in the PVTD system due to the temperature effect on the hydraulic conductivity. Moreover, the embankment with the PVTD system generates more settlement due to the thermally induced irreversible contraction of saturated normally consolidated soft Bangkok clay.

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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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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 stability of

‒tetrahydrocannabinol acetate (‒THC‒OAc) and ‒tetrahydrocannabinol acetate (‒THC‒OAc) in -liquid during storage was investigated. ‒THC‒OAc liquids in cartridges were stored at 80℃ or 30℃ for 28 days. The relative concentrations of cannabinoids in the liquids were measured by gas chromatography with flame ionization detection. ‒THC‒OAc decreased during storage at either temperature. ‒THC, a minor impurity, also decreased. ‒THC‒OAc liquid in a cartridge was stored at 80℃ for 57 days. The concentration of ‒THC‒OAc and ‒THC, a minor impurity, did not change during that time. Cannabinol acetate increased in all liquids, and unknown products were also detected by gas chromatography/mass spectrometry (GC/MS). The ‒THC‒OAc and ‒THC‒OAc liquids were subjected to GC/MS to detect representative diluents, glycerol, propylene glycol, and polyethylene glycol 400, but none of these were detected.

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Repetitive liquefactions in angular and subangular gravels from an alluvial fan, in the case of two earthquakes with accelerations lower than that of a former which had caused liquefaction some months before, are described. The liquefaction took place from the surface, down to a depth of approximately 10 m. Water laden with sediments spouted out for some tens of minutes after the strong motion ceased. Knowledge of the grain size distribution of the sediments inside the body of the alluvial fan roughly defines the areas of the fan prone to future liquefaction. Non-repetitive liquefaction in overconsolidated fine fluvio-lacustrine sand of glacial origin at the unusual depth of 14 m to 16 m is also described. From the observation of sand lifted up for 10 m inside a large diameter well, and of that which spouted out from several microvents, it was estimated that extra-pore pressure was close to lithostatic conditions. Nevertheless, modeling of intrinsic pore pressure buildup on the DESRA2 programme gives lower values than the experimental one. Geotechnical characteristics of the 12 m-thick sandy stratum indicate that the upper part is unusually soft, either due to water circulation or past repetitive liquefactions which prevented reconsolidation. It is suggested that excess pore pressure generated by the earthquake was also due to redistribution of pressure from adjacent sediments.

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Some existing analytical methods which have been used in geotechnical engineering are modified to handle the shear strength reduction with time due to softening in fissured, over-consolidated clays and mudstones. These are limit equilibrium analysis of slope stability, calculation of earth pressure and calculation of stress and displacement around a tunnel. The softening effect is incorporated in these analyses using the failure criterion and the time-dependent strength parameters proposed previously by the authors. Examples are presented which emphasize the importance of appreciating the softening effect in analyses and further illustrate that the effect of shear strength reduction with time due to softening could easily be captured with existing analytical methods.

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　コンクリート舗装はアスファルト舗装よりもわだち掘れやひび割れに対する耐久性が高く，舗装の長寿命化が期待される．しかしながら，寒冷地では凍上対策を確実に実施されない場合，早期に破損が生じることが知られている．本研究では，既設アスファルト舗装をコンクリート舗装へ打ち換える場合の凍上対策として，XPS（押出法ポリスチレンフォーム断熱材）を用いた断熱工法の適用性を試験施工により検討した．断熱材の保護および路盤の品質確保のため必要となる路盤厚さの検討，断熱材の耐力照査，および熱伝導解析による断熱効果のシュミレーション結果に基づいて試験施工を実施した結果，良好な施工が可能であること，路床の支持力低下が懸念される融解期においても通常期と同等の支持力が得られること，期待される断熱効果が得られることが明らかとなった．

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　ある道路トンネル内に使われているプレストレストコンクリート舗装（以下，PC舗装）において，縦断方向及び横断方向のひび割れが確認された．現地調査の結果，大きなひび割れが発生している箇所では，PC鋼材の破断や，たわみが大きな箇所では，PC舗装版と路盤の間に空洞の確認もされた．

　そこで，それら2つの要因が，PC舗装のたわみにどのように影響を及ぼしているかを把握するために3次元非線形FEMによる解析的検証を実施した．解析の結果，空洞の大きさの方が，プレストレス減少よりも，たわみに与える影響が大きいことが分かった．加えて，空洞が生じると，PC舗装のみで荷重に抵抗する梁形式に近い耐荷機構に変化すること，さらに，舗装表面に負曲げが生じる可能性があることが分かった．

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　近年，空港，高速道路ならびに国道の開削調査等により，舗装の損傷における水の影響が明らかになってきた．舗装の長寿命化を実現するには，水が介在することで生じる損傷の過程を正しく理解することが大きな意味を持つ．そのためには，室内評価において，供用中の道路で実際に観測されるような損傷を再現でき，加えて耐水性能の異なるアスファルト混合物に対して，その性能差を有意に比較検討できる評価方法を獲得することが重要と考える．本検討では，既往研究で究明したアスファルトの骨材からの剥離メカニズムを踏まえ，国内・海外の試験法を参考に新たに開発した，改質アスファルト混合物の新たな耐水性評価法を提案し，さらに試験精度を高める手法も検討した．

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