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

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.

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
A. Hemalatha ◽  
N. Mahendran ◽  
G. Ganesh Prabhu

The experimental investigation on the effects of granular fill and geogrid reinforced granular fill on the behaviour of the static liquefaction potential of the subsoil is reported in this study. A series of plate load test were carried out with different thickness of the granular fill, number of geogrid layers, and size/dimension of the footing. The test results were presented in terms of bearing capacity and subgrade modulus for the settlement ofδ10,δ15, andδ20. The experimental results revealed that the introduction of granular fill significantly increases the bearing capacity and effectively control the settlement behaviour of the footing. The introduction of geogrid in granular fill enhanced the Percentage of Control in Settlement and Bearing Capacity Ratio by a maximum of 328.54% and 203.41%, respectively. The introduction of geogrid in granular fill interrupts the failure zone of the granular fill and enhances the subgrade modulus of the footing by a maximum of 255.55%; in addition subgrade modulus of the footing was increased with an increase in the number of geogrid layers. Based on the test results it is suggested that the footing with large size has beneficial improvement on the reinforced granular fill.


2008 ◽  
Vol 33-37 ◽  
pp. 617-622
Author(s):  
Wei Shen Zhu ◽  
Bin Sui ◽  
Wen Tao Wang ◽  
Shu Cai Li

Two-phase modelling testing was performed to study the shear strength of rock bridges of jointed rock mass in this paper. The failure process of rock sample containing multiple collinear cracks was observed. Based on theory of fracture mechanics and analytical method, a rock-bridge failure model was proposed and the expression of shear strength was derived. Comparison of calculated shear strength and the model test results was made and they agree well.


2011 ◽  
Vol 230-232 ◽  
pp. 367-371
Author(s):  
Xiao Yong Li ◽  
Kang Xu ◽  
Si Yuan Wang

There are three normal sizes of loading plate as 30 cm, 50 cm, 75 cm in roadbed compaction quality detection. The size effect rule for coefficient of foundation is obtained from the investigation on plate load test results by the experiment in lab. The laboratory test may control well the conditions by building the test section modeling the roadbed. The test section is 15 m by 5m. The diameters of loading plate used is 30cm, 35cm, 40cm, 45cm, 50cm, 55cm, 60cm, 65cm, 70cm and 75cm in the test. The regression equation between coefficients of foundation measured by different size of loading plate has been concluded. It is obtained that the ratio of coefficients of foundation between the plate of 50 cm and 30cm is 1.6 for granule filler, 1.65 for grind filler, and the one between the plate of 70 cm and 30cm is 2.17 for granule filler, 2.3 for grind filler.


2016 ◽  
Vol 8 (2) ◽  
pp. 79-84 ◽  
Author(s):  
Mindaugas Mikolainis ◽  
Marijus Ustinovičius ◽  
Danutė Sližytė ◽  
Tatyana Zhilkina

This article summarises dynamic deformation modulus correlation with second reload of static plate load test results for an even thickness soil strata layer. An analysis of execution and result interpretation of both static deformation modulus and dynamic deformation modulus is provided also. Different correlations between the two modulus according to different authors are provided. Since dynamic plate load test is not regulated in Lithuania as a soil compaction contron method, a few dynamic plate load tests and static plate load tests were executed in order to compare compaction results. The additional experiments for dynamic plate load tests in different depths were executed which showed that deformation modulus is dependant on depth of test execution, thus it is worthwile to mention to be cautious on compaction results in trenches.


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