Characterizing rock mass deformation mechanisms during plate load tests at the Bakhtiary dam project

Agharazi, Alireza; Tannant, Dwayne D.; Martin, C. Derek

doi:10.1016/j.ijrmms.2011.10.002

Cited by 21 publications

(8 citation statements)

References 15 publications

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“…1) was derived from elastic deformations caused by loading an isotropic-linearly elastic infinite half-space with a rigid circular plate. However, in reality, most test excavation geometries are far from this assumption, and the excavation shape can influence the results of plate loading tests (Agharazi et al 2012). In order to minimize geometric effects on test results, the height of the test (loaded) surface should be at least 1.5 times the plate diameter from the floor (Fig.…”

Section: Plate Loading Tests and Theorymentioning

confidence: 99%

Development of a Highly Portable Plate Loading Device and In Situ Modulus Measurements in Weak Rock Masses

et al. 2015

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In recent years, underground mines in Nevada are increasingly exploiting in weak mineralized zones at greater depths that are intensely fractured and highly altered. The mechanical behavior of these rock masses ranges between weak rock and very stiff soil. A common limitation for design of underground mining excavations in these types of rock masses is absence of in situ geotechnical data. This limitation is generally overcome by estimating in situ mechanical behavior from empirical relationships so that the continuum-based numerical methods can be used to evaluate ground support designs. Because of the cost, time, and specialized equipment involved, historically in situ tests have not been performed in these underground mines. Predictive rock mass modulus relationships that are currently available in the literature are derived from field testing of predominantly goodquality rock masses. Consequently, there is limited confidence in using these models for rock masses with Rock Mass Ratings less than 45. In order to overcome some of these limitations, a portable plate loading device (PPLD) was designed and fabricated. The PPLD allows one to perform low cost and relatively quick in situ deformability tests to be performed on weak rock masses in underground mines. Test procedures and data reduction methods were developed to limit potential sources of error associated with the PPLD test. A total of fourteen plate loading tests were performed in weak rock masses at two different active underground mines in Nevada, USA. The resulting the test data were compared to eight published empirical rock mass modulus relationships to determine which, if any, of these relationships are sufficiently accurate for estimating modulus in similar geotechnical conditions. Only two of these relationships were found to be sufficient for first-order estimations of in situ modulus.

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Section: Plate Loading Tests and Theorymentioning

confidence: 99%

Development of a Highly Portable Plate Loading Device and In Situ Modulus Measurements in Weak Rock Masses

et al. 2015

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“…An extensive foundation study included plate loading tests performed in exploration adits excavated into the abutments. Full details on the site geology and field test methods are provided in Agharazi et al and Agharazi [10,11]. Agharazi et al [10] analyzed the results of plate loading tests at the Bakhtiary Dam site and determined that for the intensely fractured rock, in-situ deformation behavior was a combination of both normal closure and shear displacement of joints, which ultimately results in compaction of the rock mass.…”

Section: Bakhtiary Dam Sitementioning

confidence: 99%

“…Full details on the site geology and field test methods are provided in Agharazi et al and Agharazi [10,11]. Agharazi et al [10] analyzed the results of plate loading tests at the Bakhtiary Dam site and determined that for the intensely fractured rock, in-situ deformation behavior was a combination of both normal closure and shear displacement of joints, which ultimately results in compaction of the rock mass. With successive load-unload cycles, the fractured rock stiffened indicating the pieces became more-tightly interlocked after each cycle, and the stress-displacement plots were mainly non-linear with high total and permanent displacements.…”

Section: Bakhtiary Dam Sitementioning

confidence: 99%

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Development of a multivariate empirical model for predicting weak rock mass modulus

Kallu

Keffeler

Watters

et al. 2015

International Journal of Mining Science and Technology

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“…These tests are time-consuming, expensive, and diffi cult to conduct and the reliability of the results is sometimes questionable (Palmstrom & Singh, 2001;Hoek & Diederichs, 2006). Besides, in-situ test results may be very different depending on the test method (Agharazi, Tannant & Derek Martin, 2012;Kavur et al, 2015). This means that relying on just one in-situ method is diffi cult.…”

Section: Introductionmentioning

confidence: 99%

Comparison between deformation modulus of rock mass measured by plate jacking and dilatometer tests

Rezaei

Ajalloeian

Ghafoori

2017

Przegląd Naukowy Inżynieria I Kształtowanie Środowiska

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For determination of the in-situ deformation modulus of rock mass at Bakhtiari Dam site, located in south-west of Iran, plate jacking tests (PJT) and dilatometer tests (DLT) carried out during the geotechnical investigations. In this study, the results of PJTs and DLTs were compared. This comparison involves 89 vertical and horizontal PJTs and 83 DLTs carried out in 6 rock units of Sarvak formation. Although, both PJTs and DLTs in the Bakhtiari Dam site were performed in same geological and geotechnical conditions, but there are not sufficient side by side data to make a paired two samples correlation. Therefore, the mean of in-situ data was compared at each rock unit. Besides Mann–Whitney U tests were performed to compare in-situ test results. The comparison shows that the deformation modulus measured by both methods has no significant differences. However, in low quality rock masses the moduli measured by the use of DLTs were greater than the modulus measured by PJTs. Conversely, in high quality rock masses the results of PJTs were greater than DLT’s.

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Characterizing rock mass deformation mechanisms during plate load tests at the Bakhtiary dam project

Cited by 21 publications

References 15 publications

Development of a Highly Portable Plate Loading Device and In Situ Modulus Measurements in Weak Rock Masses

Development of a Highly Portable Plate Loading Device and In Situ Modulus Measurements in Weak Rock Masses

Development of a multivariate empirical model for predicting weak rock mass modulus

Comparison between deformation modulus of rock mass measured by plate jacking and dilatometer tests

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