| Abstract: | Abstract When artificial islands are constructed, they are subject to surface subsidence, which is the resultant sum of the consolidation strata, many of which seem differ in character. When these strata are soft and thick, or heavily loaded, it becomes very difficult to estimate how much settlement will eventually take place, and over how long a period. For the estimate to be accurate, the settlement characteristics of each layer must first be determined. For this purpose, the authors have investigated a new method of measuring settlement, based on two unique principles. One principle is the application of a permanent magnet as an indicator of settlement, and the other is the exploitation of semiconductor, magneto‐resistance elements for detecting the magnetic fields. In advance of the observation, the magnets are forced into the earth, being pushed out through the bore‐hole casing by the oil jack at suitable depths and intervals. The small‐sized magneto‐resistance element is essential to the practicality and efficiency of this method. In this study, the principles of this method, measuring procedure, the special characteristics and potential of this system, and the results of field trials are described. |
