Shear strength analysis of grouted coal waste materials to improve mine outslope stability: a laboratory analysis

1990 ◽  
Vol 8 (3) ◽  
pp. 227-240
Author(s):  
J. R. Jones ◽  
T. E. Ackman
2019 ◽  
Vol 10 (1) ◽  
pp. 250 ◽  
Author(s):  
Andrzej Gruchot ◽  
Tymoteusz Zydroń

The paper presents the results of research on the influence of compaction on the shear strength of fly ash, unburnt and burnt coal wastes, and a composite (a mixture of unburnt coal waste and 30% of fly ash). The tests were carried out in a triaxial compression apparatus on samples with a diameter and height of 10 and 20 cm, respectively. In order to verify usability of the tested waste materials for earthworks, stability calculations of the road embankment made of these materials were carried out. It was shown that the tested materials were characterized by high values of shear strength parameters, which significantly depended on compaction. The most favorable values of the angle of internal friction and cohesion were obtained for the burnt coal waste, slightly lower for the composite, and the lowest for the fly ash. Stability calculations for the road embankment model showed that the slope inclination and the load on the embankment have a significant influence on the factor of safety. It was also shown that a decrease in cohesion causes significant decrease in the factor of safety. The tests and the stability calculations showed that the tested waste materials are useful for earth construction purposes.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chenkai Zhu ◽  
Lei Nie ◽  
Xiaofei Yan ◽  
Jiawei Li ◽  
Dongming Qi

Abstract In this work, the structure of composite was designed as Core Stack and Surface Stack, which was treated with the expandable graphite (EG) and metal oxides such as iron oxide (IO), hydroxyapatite (HA), and aluminum tri-hydroxide (ATH). The mechanical performance of composites was characterized via flexural performance and interlaminar shear strength analysis. The flame retardance and smoke suppression of composite was explored in detail by LOI, UL-94, and cone calorimeter test. The findings presented that flexural properties of composites were observed to decrease due to delamination of surface stack, whilst no significant effect on interlaminar shear strength. In comparison with control composite, the loading of metal oxide into composite Surface Stack led to the reduction of peak heat release rate, total heat release, and fire growth index effectively. Moreover, the remarkable decrease in total smoke production could be observed due to the addition of iron oxide and the flame retardant mechanism was discussed. This study was the preliminary exploration of composite with flame retardant design which could be potential solution to improve flame retardancy and smoke suppression of composite with better mechanical structure preservation.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Pan Chen ◽  
Changfu Wei ◽  
Jie Liu ◽  
Tiantian Ma

A theoretical model is developed for describing the strength property of unsaturated soils. The model is able to predict conveniently the strength changes of unsaturated soils undergoing repeated changes of water content. Suction stress is adopted in the new model in order to get the sound form of effective stress for unsaturated soils. The shear strength of unsaturated soils is dependent on its soil-moisture state based on the results of shear experiments. Hence, the parameters of this model are related tightly to hydraulic properties of unsaturated soils and the strength parameters of saturated soils. The predictive curves by the new model are coincident with experimental data that underwent single drying and drying/wetting cycle paths. Hence, hysteretic effect in the strength analysis is necessary to be considered to predict the change of shear strength of unsaturated soils that underwent drying/wetting cycles. Once the new model is used to predict the change of shear strength, lots of time could be saved due to avoiding heavy and complicated strength tests of unsaturated soils. Especially, the model can be suitable to evaluate the shear strength change of unsaturated soils and the stability of slopes experienced the drying/wetting cycles.


Author(s):  
Shubham Bansal ◽  
Anil Kumar Misra ◽  
Tanuj Chopra ◽  
Purnima Bajpai

2019 ◽  
Vol 12 (3) ◽  
pp. 658-693
Author(s):  
A. M. D. SOUSA ◽  
M. K. EL DEBS

Abstract Concentrated loads in slabs without transverse reinforcement, usual in highway bridges, result in the horizontal spreading of the shear force towards the supports, situation in which not all the slab width contributes in the shear strength. Based on this, the analytical models of shear strength and punching capacity in slabs may not be suitable to deal with this loading. Since this topic is not widely discussed in the national technical literature, the paper aims to present contributions to these analyses with a focus on the accuracy level of the shear strength analytical models recommended by ABNT NBR 6118:2014. Therefore, the models available in the Brazilian code were applied to an experimental database with 118 test results and the results obtained by the Brazilian and European codes were compared. The results demonstrated that, as presented in the Brazilian code, shear strength model in one-way slabs can lead to unsafe resistance predictions while the punching capacity model can lead to very conservative predictions. From the analysis, it is concluded that considering the reduction of the shear force, in the case of loads distributed in small areas close to the support in slabs, and the use of more suitable procedures to define the effective width, it is possible to improve the level of accuracy of relations between experimental and theoretical values, but this still leads to high percentages of unsafe predictions of resistance (> 40%).


Author(s):  
Tanuj Chopra ◽  
Purnima Bajpai ◽  
Anil Kumar Misra ◽  
Shubham Bansal

1982 ◽  
Vol 3 (12) ◽  
pp. 529-540 ◽  
Author(s):  
M. G. Heaton ◽  
J. S. Buyer ◽  
J. P. Hershey ◽  
I. W. Duedall ◽  
R. D. Giauque

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