The dike, a structure used to establish an impounding area, plays important roles for the safety of LNG storage rerigeratded to -162°C, which structure should function even if extreme loading conditions arise. The three large post tensioned cylindrical concrete dike have been built for 80000kl LNG tanks at Himeji, Japan. Each dikes has the dimension of 91m in diameter with 14m in effective storage depth. The post tensioned concrete dike is advantageous on structural strength, liquidtightness and economical construction of cryogenic structure in a highly seismic region. The paper covers the overall aspects of design and construction of the dikes.

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A shield tunneling method has been applied more year by year according to society's demands. NTT requires a long and small diameter tunnel for installation of fiber cables.
To construct a long tunnel with 1200mm inside diameter, new tunneling system different from conventional ones had to be developed. Fully automated tunneling and cast in situ lining system using quick setting resin mortar have been studied since 1975.
New tunneling method controlled by computer was developed in 1984. Field trial results show that constructed tunnels are reliable to install telecommunication cables.

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An inspection system of a steel structure is propsed. This system is devided to two sub-systems. One is a system for measuring members constructing the structure. Utilizing a CCD camera, one can spare much time for surveying. Data obtained are stored in a micro-computer system.
Another is a simulation system. This system simulates shop assembly which is carried out in the shop yard. In case that the products do not fullfill the codes of the specification, an appropriate instruction is output. This simulation system was proved to be practble by applying the actual data which were previously prepared for verification.

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“Injection type rock bolt” has been finally succeeded in actual use after repeating tests and improvements under many kinds of the natural ground at the tunnel construction sites.
The principal components of this rock bolt are the bolt provided with a cloth bag fitted on one end of the bolt, injection tube and ventilation tube.
Advantage of “Injection type rock bolt” (1) Even long size bolt can be used. (2) The grout can be filled into the hole without any void. (3) It can be checked easily. (4) A high pullout resistance can be obtained quickly. This is explanation for the process of the development, component of the rock bolt, injecting material, grout pump units (both in the manual and automatic method), the pullout test, the working procedure and the execution.

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When sand-compaction piles are driven in the ground, the lateral displacement will be induced on the adjacent soil. Therefore it is necessary prior to the driving work to estimate the amount of the effect on the neighboring structures. Especially it has a significant consequence on in-ground structures. In this present study, measurements were taken in a weak silty-sand ground and analized in order to establish a prediction method of the soil displacement. Descriptions are given to the developments of two types of prediction methods: one utilizes a finite element method and the other by multiple ragression analysis.

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