Table 2 presents the coefficient of volume change values under different vertical pressures for silty sand with clay soil and silty-clay soil tested by 1D oedometer
. Horizontal and vertical permeability values under different vertical pressures are evaluated using the developed horizontal and vertical permeability apparatus and are shown in Figure 4.
where [lambda] denotes the slope of the normal compression line in e-ln [[sigma]'.sub.v] space; [tau] is the reference time, and it equals to the duration of each load increment in the oedometer
test; and [[sigma]'.sup.r.sub.v] is the reference stress corresponding to the incremental time [tau] and increases with the development of the viscoplastic strain according to
In order to achieve the aim of the study, the soil was investigated with a triaxial pressure apparatus, direct shear apparatus and oedometer
Special teflon oedometer
rings were made, which were entirely non-reactive to acid.
Those tests include traditional tests to determine basic physical properties, oedometer
tests, and consolidated-drained triaxial compression tests.
Standard laboratory equipment based on the axis translation technique, such as the pressure plate, volume extractor, suction-controlled oedometer
, modified triaxial apparatuses, and standard tensiometers, are the most common devices used to control or measure matric suction.
Evolution of the (a) liquid limit ([w.sub.L]), plastic limit ([w.sub.P]) and initial water content as a function of the smectite percentage and (h) the void ratio as a function of the vertical stress in oedometer
Investigation of the sand porosity via oedometer
testing, The Baltic Journal of Road and Bridge Engineering 5(3): 139-147.
(a) According to results of oedometer
tests, the stress-strain relation curve is fitted with a hyperbolic model [16, 17]:
The test method consists of placing a compacted soil specimen at the desired water content in an oedometer
, applying a predetermined applied vertical stress to the specimen and inundating the specimen with distilled deionized water to induce the potential collapse in the soil specimen.
The material parameters include for example the slope of normal compression line X and the slope of swelling line k which directly relate to the slopes of the loading and unloading curves observed in oedometer
, or the critical angle of internal friction [[phi].sub.ef].
There is a linear relationship in e-lg p' for normally consolidated soft soils according to the oedometer