scholarly journals An Investigation of the Mechanisms Involved in Plate Load Testing in Rock

2021 ◽  
Vol 11 (6) ◽  
pp. 2720
Author(s):  
Ali Mortazavi
Keyword(s):  
Rock Mass ◽  
Construction Projects ◽  
Accurate Determination ◽  
Deformation Modulus ◽  
Load Testing ◽  
Test Results ◽  
Loading Test ◽  
Dam Site ◽  
Rock Mass Modulus ◽  
Measurement Depth

Accurate determination of rock mass deformation modulus is very important in rock engineering projects. The plate loading test (PLT) is a method that is generally used in dam construction projects to determine rock mass modulus. Numerical simulation was used to investigate the mechanisms involved in this test. The first objective of the paper was to employ 3D modeling in the interpretation of plate load tests conducted at the Bazoft dam site in Iran. Additionally, a parametric study of the effects of key parameters such as displacement measuring depth and loading plate diameter on the test results was another objective of the study. The moduli values determined numerically were compared against actual filed testing data determined from in-situ test data conducted at the Bazoft dam site, and the values determined from the ISRM suggested formula. The analysis showed that the optimum measurement depth for rock mass modulus calculation is approximately equal to the loading plate diameter and the data determined from measurement depths beyond one plate diameter can be unrealistic. Moreover, the plate diameter can have a significant effect on test results. As the measurement depth increases, the determined modulus values increase at a much more rapid pace when employing smaller size loading plates.

scholarly journals Mechanical Properties of Sandstones under Initial Unloading Damage

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Hengbin Zhang ◽  
Lehua Wang ◽  
Jianlin Li ◽  
Huafeng Deng ◽  
Xiaoliang Xu
Keyword(s):  
Mechanical Properties ◽  
Rock Mass ◽  
Shear Failure ◽  
Rock Sample ◽  
Triaxial Compression ◽  
Deformation Modulus ◽  
Peak Strength ◽  
Repeated Loading ◽  
Adjustment Process ◽  
Loading Test

To study the influence of initial unloading damage on the mechanical properties of sandstone, the repeated loading test of unloading damaged sandstone was carried out considering 8 initial unloading quantities of 100%, 93.33%, 86.67%, 80%, 73.33%, 66.67%, 40%, and 0%. The results were compared with those of the triaxial compression test of intact samples. The results show that the peak strength of intact samples is higher than that of unloading damaged samples, and the difference is more obvious when the unloading quantity is more than 80%. During the unloading process, the strain increasing rate of rock samples is obvious, and the lateral dilatation is significant, and the deformation modulus and compressive strength of the rock sample deteriorate obviously. From the energy point of view, the greater the unloading damage, the smaller the stored elastic strain energy, which leads to the decrease of peak strength. At present, the unloading fracture inside the rock sample has developed, and the failure mode of the sample gradually changes from compression shear failure to tensile shear failure. In the process of engineering rock mass excavation, the unloading area and unloading damage amount of the rock mass is a dynamic adjustment process. To ensure the safety of the engineering rock mass, it is suggested to determine reasonable reinforcement time, reinforcement area, and reinforcement measures.

Study about Mechanic Parameter of Slope Rock Mass' Structure Plane

2013 ◽  
Vol 368-370 ◽  
pp. 1551-1555
Author(s):  
Si Yu Wu ◽  
Bo Huang ◽  
Rui Jun Liu
Keyword(s):  
Rock Mass ◽  
Deformation Modulus ◽  
Friction Angle ◽  
Mechanical Parameters ◽  
Test Results ◽  
Rock Mass Structure ◽  
Stability Of Slope ◽  
Slope Rock ◽  
The Stability ◽  
Structure Plane

Firstly, the stability of the slope need to determine mechanical parameters of slope rock mass such as deformation modulus, Poissons ratio, cohesion and internal friction angle, etc. For intact rocks, the mechanical parameters mentioned before are easy to determined. While the stability of slope rock mass is controlled by the deformation and intensity. Therefore, how to determine the mechanical parameters of the structure is the key to analyze the stability of slope rock mass. This paper intends to set the slope rock mass below some extra-large bridge as the research object and use numerical calculation to determine the mechanics parameters of rock mass structure plane on the basis of rock sample mechanics test results.

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

2017 ◽  
Vol 26 (3) ◽  
pp. 317-325
Author(s):  
Mohsen Rezaei ◽  
Rasoul Ajalloeian ◽  
Mohammad Ghafoori
Keyword(s):  
Rock Mass ◽  
Deformation Modulus ◽  
Rock Masses ◽  
Sarvak Formation ◽  
In Situ Data ◽  
Geotechnical Investigations ◽  
Two Samples ◽  
Dam Site

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.

The determination of rock mass modulus variation with depth for weathered or jointed rock

1982 ◽  
Vol 19 (1) ◽  
pp. 29-43 ◽  
Author(s):  
R. K. Rowe
Keyword(s):  
Rock Mass ◽  
Jointed Rock ◽  
Load Test ◽  
Test Results ◽  
Plate Load Test ◽  
Worked Example ◽  
Single Plate ◽  
Rock Mass Modulus ◽  
Second Procedure

Weathering or the variation in frequency and tightness of joints may result in an increase in mass modulus with depth for some rocks. This increase in modulus will continue until a depth is reached at which the rock behaves as a sound intact unit and the modulus will be relatively constant with depth below this point. In this paper, elastic solutions are presented for the deformation of such a rock mass due to a uniform or approximately rigid circular loading.Two procedures are described for determining the rock mass modulus profile from plate load test results. The first procedure uses the results from three plate tests to infer the variation in modulus with depth. The second procedure uses the measured variation in displacement with depth below a single plate to infer the mass modulus variation. The application of the two procedures is illustrated by a worked example and by consideration of a field case where the inferred modulus is shown to be in good agreement with alternative modulus variation data.

DEFORMATION MODULUS AND STRENGTH PARAMETERS OF SABALOKA IGNEOUS ROCK MASS

2010 ◽  
Vol 33 (2) ◽  
pp. 153-158
Author(s):  
Mohamed Hassan Aboud ◽  
Mohamed Ahmad Osman
Keyword(s):  
Rock Mass ◽  
Igneous Rock ◽  
Deformation Modulus ◽  
Strength Parameters

Evaluation of rock mass improvement due to cement grouting by Q-system at Bakhtiary dam site

2015 ◽  
Vol 74 ◽  
pp. 38-44 ◽  
Author(s):  
A. Zolfaghari ◽  
A. Sohrabi Bidar ◽  
M.R. Maleki Javan ◽  
M. Haftani ◽  
A. Mehinrad
Keyword(s):  
Rock Mass ◽  
Cement Grouting ◽  
Dam Site ◽  
Q System ◽  
Bakhtiary Dam
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