Elastic wave propagation in saturated soil is investigated in order to grasp the frequency dependent wave propagation property of actual soil. First, a closed form solution of Biot's equation is derived under a one-directional wave propagation condition. Then, the frequency dependent properties of waves in various soils such as clay, silt, sand, gravel and soft rock are computed and discussed. The behavior is shown to be classified into three states : low frequency, high frequency and transient. Properties hardly change in the low and high frequency states. The degree of saturation is shown to hardly affect the shear wave property, but it greatly affects the dilatational wave property, especially in a highly saturated condition. Permeability hardly affects the properties at low and high frequency states, but it does change the frequency range of the transient state. Next, the applicability of Biot's formulation is examined and the high frequency state derived from Biot's equation is shown to be valid when permeability is larger than that of silt. Finally, it is shown that various mechanical properties can be evaluated using the frequency dependent characteristics of the wave, some of which are difficult to measure in situ with conventional tools.

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A series of shaking table tests are made to investigate the uplift behavior of sewer pipes caused by liquefaction of surrounding soil. It is shown that uplift displacement of pipes buried in unliquefiable original soil, which does not allow a dissipation of excess pore water pressure from liquefied backfill soil, increases drastically when they are subjected to extensive shaking. Uplift displacement of pipes buried in liquefiable original soil, on the other hand, accumulates rather gradually even at moderate shaking. A different behavior on residual deformation of the backfill and the original soils is also observed. In relation to the effects of soil condition, damage to sewer pipes in Towada City caused by the December 28, 1994 Sanriku-Haruka-Oki earthquake is reported and discussed. It is estimated that upper backfill soil consisting of sandy gravel may have liquefied because it was under loose and saturated condition and was subjected to earthquake motion under nearly undrained condition due partly to its own low permeability and also to the existence of surrounding original soil with low permeability.

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During past earthquakes, several types of underground structure were damaged by uplift movement, because they were relatively light compared with the buoyancy force resulting from liquefaction of the adjacent subsoil by earthquake. To investigate this uplift behavior, a variety of model tests were conducted. In these tests, the uplift of underground structures was caused by both nearly instantaneous deformation of a surrounding subsoil layer and gradual movement of a pore fluid, while reconsolidation of liquefied soil resulted in settlement of the structure. Several different effects of structure type on uplift behavior were observed, including reduction of excess pore water pressure in a soil layer overlying completely-buried box structures and three dimensional deformation of the backfill soil surrounding a manhole together with deformation of original soils thus "squeezing" the backfill soil into the space occupied by the manhole. Analysis of the test results suggests that a safety factor against uplift, which was defined based on the equilibrium of vertical force acting on the structure, can be used to evaluate the triggering of uplift.

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During the 1993 Kushiro-Oki Earthquake, several sewer manholes in Kushiro Town were ejected up to 1.5m. In order to evaluate their failure mechanism, level and boring surveys, cut-off investigation and laboratory tests were carried out. It was estimated that the backfill soil which liquefied extensively moved laterally toward the bottom of the ejected manholes. Possible influences of the original subsoil on the uplift displacement are discussed together with the applicability of safety factor against uplift.

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A sample of [³H] tobrarnycin (5, 000 Ci/Mole) has been synthetized and incubated with
the bacterial ribosome and its subunits. The results obtained show that this antibiotic has
two types of binding sites. The primary one is probably responsible for the inhibition of
protein synthesis whereas the secondary one is probably related to the misreading and reading
tiirough of the messenger RNA.

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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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Damage to sewer pipes in Kushiro City caused by the January 15, 1993 Kushiro-Oki and the October 4, 1994 Hokkaido-Toho-Oki earthquakes is reported and analyzed. Based on the results of a damage survey for restoration work of the pipes and on those of a boring survey conducted near both the damaged and undamaged sites, analyses are performed on the condition of the backfill and the original soil layers surrounding the pipes. In the wetland and flood-plain region, liquefaction of the backfill soil was considered to be the major cause of the damage, while existence of a peat layer with low permeability and/or a sandy layer that is liquefiable in the original soil was considered to affect the extent of the damage. In the terrace region, instability of the original slope was also considered to have caused the damage.

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This paper presents a method capable of evaluating the seismic stability of a cut slope formed by strain-softening soil; to date, no method appears to be available for this purpose. The method consists of the following steps : (1) the horizontal vibration of a sliding mass subjected to an earthquake loading is converted into an equivalent single-degree-of-freedom (SDF) system with a smooth hysteretic restoring force; (2) a failure criterion and a damage index for the converted SDF system is established; and (3) the safety based on the response statistics obtained through random vibration analysis is evaluated. Reliability against sliding failure is assessed for specified intensity and duration of a seismic loading using results from a nonlinear-hysteretic random vibration analysis.

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