Large-strain undrained pressuremeter interpretation based on loading and unloading data

1994 ◽  
Vol 31 (1) ◽  
pp. 71-78 ◽  
Author(s):  
R.S. Ferreira ◽  
P.K. Robertson

Traditionally pressuremeter tests results are interpreted using only the loading pressure–expansion data. An interpretation method has been developed that makes use of both the loading and unloading portions of a pressuremeter test and incorporates nonlinear, undrained soil behaviour. This method has been modified to handle large trains. The proposed interpretation accepts that some level of soil disturbance exists during the early stages of a pressuremeter test, and hence more emphasis is placed on the unloading portion of the test. A methodology is described to allow this interpretation procedure to be applied to self-bored, prebored, and full-displacement undrained pressuremeter tests. The proposed method is evaluated using self-boring and full-displacement pressuremeter test results from various published field projects. The interpretation is accomplished using commercially available microcomputer software that can perform the curve-matching process for both loading and unloading portions of the test. Key words : pressuremeter, loading data, unloading data.

1992 ◽  
Vol 29 (6) ◽  
pp. 918-928 ◽  
Author(s):  
R. S. Ferreira ◽  
P. K. Robertson

An interpretation method has been developed to incorporate nonlinear soil behavior to interpret undrained pressuremeter test results. The method makes use of both the loading and unloading portions of the pressuremeter test. The proposed interpretation method accepts that some level of soil disturbance may exist during the early loading portion of the pressuremeter test. This is accomplished by putting greater emphasis on the unloading portion and the final part of the loading portion of the test. The method is evaluated using self-boring pressuremeter results from Fucino, Italy. Key words : pressuremeter, interpretation, undrained, unloading.


Author(s):  
Shaosen Ma ◽  
Guangping Huang ◽  
Khaled Obaia ◽  
Soon Won Moon ◽  
Wei Victor Liu

The objective of this study is to investigate the hysteresis loss of ultra-large off-the-road (OTR) tire rubber compounds based on typical operating conditions at mine sites. Cyclic tensile tests were conducted on tread and sidewall compounds at six strain levels ranging from 10% to 100%, eight strain rates from 10% to 500% s−1 and 14 rubber temperatures from −30°C to 100°C. The test results showed that a large strain level (e.g. 100%) increased the hysteresis loss of tire rubber compounds considerably. Hysteresis loss of tire rubber compounds increased with a rise of strain rates, and the increasing rates became greater at large strain levels (e.g. 100%). Moreover, a rise of rubber temperatures caused a decrease in hysteresis loss; however, the decrease became less significant when the rubber temperatures were above 10°C. Compared with tread compounds, sidewall compounds showed greater hysteresis loss values and more rapid increases in hysteresis loss with the rising strain rate.


2003 ◽  
Author(s):  
Akihiro Matsuda

This paper proposes a new numerical model of lead material to predict mechanical properties of isolation and vibration control devices using lead as damping material. Shear and tensile loading tests of lead were carried out to make the numerical model. Shear loading test specimen were constructed from a circumferential lead part welded at the top and bottom to steel flanges. Cyclic stress-strain relations in large strain region were obtained from shear loading test results. The elastic constants and the initial yield stress were given from tensile loading test results. Therefore a numerical model was made using both shear loading and tensile loading test results. Mechanical properties of lead dampers and isolated rubber bearings were simulated using the proposed numerical model via finite element method to show applicability of the model.


2009 ◽  
Vol 46 (3) ◽  
pp. 281-295 ◽  
Author(s):  
D. C. Bobei ◽  
S. R. Lo ◽  
D. Wanatowski ◽  
C. T. Gnanendran ◽  
M. M. Rahman

An experimental study was carried out to investigate the static liquefaction behaviour of sand with a small amount of plastic and nonplastic fines. Five series of tests were conducted in drained and undrained conditions. The drained test results indicate not only that the failure line coincides with the critical state, but also that the development of volumetric strain during shearing was not sensitive to the initial confining pressure. In both isotropically and anisotropically consolidated undrained tests, a so-called “reverse behaviour” was consistently observed. The results were also interpreted in the critical state framework. The critical and steady state (CS/SS) data were found to trace along the same curve in e–log( p′) space, irrespective of the stress history and effective stress paths. A comparison between the isotropic consolidation line (ICL) and critical state (CS) curve showed that a small amount of fines can significantly change the shape and position of the ICL relative to the CS curve. Furthermore, the soil behaviour manifested in both drained and undrained shearing led to the development of a modified state parameter.


Author(s):  
Anand J. Puppala ◽  
Yalcin B. Acar ◽  
Mehmet T. Tumay

Low strain dynamic shear modulus property is generally used to subclassify soil strata, determine elastic settlements under geotechnical structures, and characterize the dynamic nature of soils. Several methods to interpret the dynamic shear modulus of sands from in situ friction cone test results have been developed. These methods used calibration chamber test data of clean sands. Therefore, these methods are not valid for interpreting the shear modulus of cemented sands. Introduced here is an interpretation method to estimate the shear modulus of cemented sand. Thirty-seven friction cone penetration tests (CPTs) were conducted on artificially cemented sand specimens of relative densities ranging from 45 percent to 85 percent and confining pressures ranging from 100 to 300 kPa in a laboratory stress-strain-controlled calibration chamber. Cementation levels of 1 and 2 percent were used in preparing cemented specimens. Resonant column tests were also conducted on the same sand with identical cementation levels. The CPT and resonant column test data are used in developing an interpretation method that includes semiempirical correlations. Simple interpretation charts are also provided to directly estimate the low strain shear modulus of cemented sand from tip resistance, unconfined compressive strength, and relative density data. Comparisons between predictions of the proposed interpretation method and the present measured shear modulus test data indicate that the interpretation charts have provided reasonable predictions. The comparisons also indicate that the predicted results on clean sands obtained by different researchers are in agreement with each other.


Géotechnique ◽  
2016 ◽  
Vol 66 (2) ◽  
pp. 137-148 ◽  
Author(s):  
Z. Abchir ◽  
S. Burlon ◽  
R. Frank ◽  
J. Habert ◽  
S. Legrand

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