| 摘要 |
PROBLEM TO BE SOLVED: To provide a ground improvement method for liquefaction countermeasures that can suitably and securely improve liquefaction strength at a low cost.SOLUTION: A ground improvement method includes the steps of: inserting an air injection pipe 21 into the ground to be improved and injecting air bubbles; installing a transmitter 31 which transmits a sound wave into the ground including the sandwiched ground to be improved and a plurality of receivers 32 arrayed in a vertical direction, and receiving the sound wave transmitted by the transmitter 31 by the respective receivers 32 so as to find distributions of elastic wave speeds and energy attenuation on the basis of arrival times and amplitudes of sound waves; and estimating a liquefaction strength distribution of the ground to be improved on the basis of the distributions of elastic wave speeds and energy attenuation. Further, the method includes a step of injecting air bubbles into a part of the ground to be improved that does not reach predetermined liquefaction strength according to the estimated liquefaction strength distribution. |
