The energy consumption during deformation or shearing process of geomaterials heavily depends on the hysteresis behavior of geomaterials and loading rates. From the point of minimum energy consumption, the optimum loading process is investigated in this paper. In case of consolidation of clays, the optimum time history of loads among various time histories which lead to a prescribed settlement at a prescribed time is calculated from the consolidation theory. It is verified by a set of experimental results. In case of unconfined compression test of soil mortar specimens, the optimum loading rate which shows minimum energy consumption from the initial state to the peak strength is investigated. Parameter sensitivities on the energy consumption are discussed based on the empirical model of a stress strain relationship of soil mortar. The authors conclude that energy consumption during deformation of geomaterials can be reduced by the optimization of loading process. This method is expected to contribute to the improvement of the efficiency of earth works, such as excavation of ground and compaction of soils.

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A new runway called D runway was constructed off the present Tokyo International Airport (Haneda Airport), consisting of pile structures and reclaimed land. In this construction, the Cone Penetration Test (CPT) was extensively employed to observe behavior of the clayey foundation for stability and prediction of the settlement in the future. In this paper, methods for predicting the degree of consolidation were discussed, using results from CPT in the reclaimed parts as well as the sea wall, where the foundation was stabilized by Sand Drain (SD) and Sand Compaction Pile (SCP) methods, respectively. In addition, the variation of the strength from the trend during the reclamation process was studied in comparison of a case study from the Kansai International Airport, where the investigation was conducted using the unconfined compression test (UCT). It is found that the variation from UCT is much larger than that from CPT, suggesting that results from UCT are influenced by the sample disturbance.

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This paper describes the method that measures displacements from the three dimensional coordinate of the radio wave transmitter attached on the slope by the phase differences of received signals that were received by the receivers in the slope surroundings. Concretely, the special low power radio wave emitted by the transmitter on the slope was received by four or more receivers, and then the transmitter coordinates were calculated by an intersection of iso-phase-difference surfaces of each received signal. In the study, we consider the calculation method of the transmitters’ coordinate values and prove by the experiments that we can in real time measure the slope displacement with a high degree of accuracy by using devices with the radio wave of the frequency of 2.4GHz. We show that we can estimate the precision using GDOP that is determined by geometrical arrangement of the transmitters and receivers and verify the applicability of the proposed method in a real slope.

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To develop new biogrout using calcium phosphate compounds (CPC), we monitored the change in the pH and ammonia generation using microorganisms in soil, and conducted unconfined compression test of sand test pieces cemented by CPC with soil extract including microorganisms and each of four ammonia sources. The pH of supernatant of soil solution with ammonia source temporally increased. Ammonia ion was detected in the supernatant of each of soil solution. Microorganisms which could utilize ammonia source were isolated from the soil extract. Unconfined compression strengths of test piece cemented by calcium acetate as a calcium solution were increased by the addition of ammonia source from average 42.9 kPa to 57.6 kPa compared with the case of non-addition. These results indicate calcium phosphate compound is utilized as a novel biogrout with ammonia source and in situ soil microorganisms.

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