Development of Lateral Displacement Meter and its Applications in Triaxial Test
The soil deformation characteristic in small strain region (less than 1%) has become important especially in soil deformation prediction during the tunnel construction and dynamic analysis. There is much research, which has been done regarding the measurement of small strain by using proximeter on triaxial test apparatus. A study on shear modulus at very small strain (<0.001%) has been done using the dynamic test as the simplest method.
The most recommended test on studying about the small strain is triaxial tests employing the proximeter to measure local deformation of soil specimen. To fix elastic constants, not only the Youngfs modulus E but also the Poissonfs ratio Ë are important. Therefore, in this study, triaxial tests were conducted under CU and CD conditions in saturated Yoneyama sandy silt to determine the accurate measuring equipment. Three types of lateral displacement meters (LDM) were suggested to measure the lateral displacement and the ability of each LDM was compared. It was proved that the LDM type 3 showed the most reliable results comparing other types with less error during saturated isotropic consolidation. Using LDM type 3, further experiments were carried out in determining the Poissonfs ratio Ë of saturated Yoneyama sandy silt during CD conditions with different consolidation time. As a result, it was shown that the effect of consolidation time on soil stiffness should be considered.