Cyclic triaxial tests

Laboratory testing methods are presently used on almost an exclusive basis to establish the requisite information for seafloor soils. These testing methods typically include the cyclic triaxial test (ASTM D5311), the cyclic simple shear, and the resonant column (ASTM D4015) techniques. The range of strain levels produced by these test apparatus are... 

Results of cyclic triaxial test on Gulf of Mexico clay. 

Variation of cyclic stress ratio with number of cycles of loading, N, in reversed displacement-controlled tests of remolded clay, (a) Constant frequency and (b) constant strain. (After Procter, D.C., and Khaffaf, J.H., Cyclic triaxial tests on remoulded clay, /. Geotech. Eng., 10,1431-1445,1984. Reprinted with permission of ASCE.)... 

Degradation cfSoil Modulus Model pile tests suggest that an expression similar to that developed by Idriss et al. (1978) from cyclic triaxial tests on clay may be applied to describe the degradation phenomena of soil modulus due to cycling. Therefore, for the cyclic displacement model of degradation, the modulus degradation factor Dg may be approximated by the expression... 

Procter, D.C., and Khaffaf, J.H. 1984. Cyclic triaxial tests on remoulded clay. Journal of Geotechnical Engineering, ASCE, 110, No. 10, pp. 1431-1445. 

This article presents results from an experimental study of pre- and post-liquefaction characteristics of non-plastic sand-silt mixes at silt contents from 0% to 100% by weight, and three natural non-plastic silts. Undrained cyclic triaxial tests followed by dissipation of cyclic-induced pore pressures were carried out in order... 

Undrained cyclic triaxial tests were conducted using an automated apparatus (GEOCOMP Inc., MA) at a constant cyclic stress ratio (CSR=Ao,/2a ) of 0.2 at a fi-equency of 0.2 Hz. For safety purposes, die maximum axial strain allowable was set at 8%. All specimens had an initial effective isotropic confining stress of 100 kPa. The axial displacement, cell pressure, and sample pore water pressure were monitored using a built-in data acquisition system. Once the specimen liquefied, cyclic loading phase was terminated. 

The stiffness of soil at cyclic loading conditions is even more specific and very often a hysteresis loop can be found during cyclic testing (e.g. cyclic triaxial testing). Multiple loading cycles can cause degradation of the soil strength. This has... 

Cyclic triaxial testing determination of liquefaction and breaching potential. 

Finally, laboratory tests able to measure the dynamic soil properties at high strain levels have been derived from conventional tests by adding cyclic loading capabilities to the testing apparatus. Examples are represented by cyclic triaxial tests with local strain measurements and cyclic simple shear tests. 

Laboratory tests can be classified into two groups (1) shipboard testing including Torvane, laboratory miniature vane shear (ASTM D4648), pocket penetrometer, and fall cone penetrometer and (2) shore-based tests, which includes the above as well as triaxial tests (ASTM D4767) direct simple shear, dynamic, and cyclic tests, consolidation tests (ASTM D4186, ASTM D2435) and the usual array of index property tests, and special tests appropriate... 

ASTM. D5311. Standard Test Method for Load Controlled Cyclic Triaxial Strength of Soil. American Society for Testing and Materials, Philadelphia, PA, p. 11. 

Laboratory investigations Comparison between results of cyclical tests (cyclical triaxial) with stresses calculated by numerical methods which simulate the propagation of the seismic waves in the medium. Drawbacks difficulty of sampling. Advantages gives an estimate when correlations are not avaUable. 

The repeated triaxial test applies a repeated axial cyclic stress of fixed magnitude, load duration and cycle duration to a cylindrical specimen. While the specimen is subjected to the dynamic cyclic stress, it is also subjected to a static confining stress provided by a pressure chamber. The cyclic load application, though, is to better simulate the actual traffic loading. 

Permanent deformation behaviour can also be determined by using the triaxial cyclic compression test (see Section 7.6.2). Figure 3.13 shows results obtained when asphalt concrete mixtures were used (AC 20 mm) with and without polymer-modified bitumen. 

In addition to the above, the maximum permissible bitumen content is determined by executing the triaxial cyclic compression test according to CEN EN 12697 (2012), Method B, or the unconfined static creep test (see Section 7.6.3). This ensures sufficient resistance of the CAM to permanent deformation. 

The creep coefficient, 6, is the slope from the least square linear fit on the log e versus log M-values (n = load applications) determined from the triaxial cyclic compression test in... 

Two specimens per bitumen content (use five levels of bitumen content), after curing for Marshall testing, are subjected to either the triaxial cyclic compression test or the static creep test at 40°C 0.5 C. 

According to EN test methods, the total number of pulses applied is 3600 (approximately 2 h), for the uniaxial cyclic compression test with confinement, or 10,000 pulses (approximately 6 h), for the triaxial cyclic compression test (vacuum induced). 

Test method B determines the creep characteristics of bituminous mixtures by means of the triaxial cyclic compression test. In this test, the confining stress is induced by vacuum and the cylindrical specimen is subjected to a cyclic axial stress. This test is most often used for the purpose of evaluation and development of new types of mixtures. 

In the triaxial cyclic compression test, the cylindrical specimen is subjected to a confining pressure, c, on which a cyclic axial pressure is superposed. 

Figure 7.21 presents creep results from the triaxial cyclic compression test, using asphalt concrete mixtures with nominal maximum size aggregate 20 mm (AC 20 mm) with varied... 

In a study to compare the permanent deformation behaviour of asphalt concrete (AC 20 mm) when gradation and binder content were varied but within the tolerance limits using different testing procedures, it was found that the ranking of the mixtures was the same regardless of the procedure used, with the triaxial cyclic compression test included... 

The layer modulus may also be determined in the laboratory by using the triaxial test with repeated axial cyclic stress, if in situ moisture and stress state conditions determined are simulated and applied in the laboratory. However, AASHTO (1993) provides a method... 

CEN EN 13286-7. 2004. Unbound and hydraulically bound mixtures - Part 7 Cyclic load triaxial test for unbound mixtures. Brussels CEN. 

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