A New Rock Brittleness Evaluation Index Based on the Internal Friction Angle and Class I Stress–Strain Curve

2018 ◽  
Vol 51 (7) ◽  
pp. 2309-2316 ◽  
Author(s):  
Hui Zhou ◽  
Jun Chen ◽  
Jingjing Lu ◽  
Yue Jiang ◽  
Fanzhen Meng
2011 ◽  
Vol 90-93 ◽  
pp. 41-43
Author(s):  
Hong Liang ◽  
Yan Wang ◽  
Tian Ping Zhou ◽  
Zhen Tao Zhang ◽  
Zhi Gang Li ◽  
...  

Abstract. Silt in some areas of our country is very extensive, its distribution is different from the cohesive soil, or sand soil, has unique engineering characteristic. Silt regional characteristics make it has many unique physic-mechanical performance. This article take the G209 (Inner Mongolia Helin to Qingshuihe section) the roadbed silty soil as the study object, study its basic physics, the mechanical properties as well as the distortion and the intensity change rule under the dry-wet circulation, do a comprehensive and systematic analysis about varieties of basic engineering characteristic of the silt in the region Through the condition of dry-wet circulation of unconsolidated tri-axial tests, this article study the silt sample failure pattern under different degree of compaction, stress-strain relations and the change rule of strength. The test results show that: as cycle index less and confining pressure down, test sample is basically brittle failure, on the contrary case, it is behaved for plastic failure and stress-strain curve is close to sclerosis type; When cycle index increase gradually, the cohesion of silt reduced significantly ,with the increase of dry-wet circulation times internal friction angle is on the trend of the attenuation oscillation ; On this basis, we build the relationship expression of shear strength parameters cohesion internal friction angle and dry-wet circulation times.


2012 ◽  
Vol 594-597 ◽  
pp. 512-515
Author(s):  
Zheng Rong Zhao ◽  
Hong Xia Yang

Combined with the silty soil characteristics of the Yellow River alluvial plain and the subgrade filling of Ji-He expressway, the paper discusses silty soil, stabilized silty soil strength and stress-stain characteristics through the indoor triaxial shear test. The results show that the remodeling silty soil has obvious peak, brittle failure, low residual strength after being destroyed and the stress-strain curve shows a softening type in confining pressure 100kPa lower stress level. In the confining pressure 400kPa higher stress level, soil samples peak is not obvious,mainly plastic failure and the stress-strain curve is close to a hardening type. Compared to mixed with 8% lime, stabilized silty soil of mixed with 4% cement and 4% lime shows that the partial stress peak is more obvious when destroyed and the residual strength is drastically reduced and more incline to brittle failure. In different the age, compared to mixed with 8% lime, stabilized silty soil of mixed with 4% cement and 4% lime shows that internal friction angle becomes larger and cohesion improves gradually whose amplitude is much larger than internal friction angle. Therefore, a more effective way to stabilize the silty soil of the Yellow River alluvial plain is to select silty soil mixed with 4% cement and 4% lime.


1939 ◽  
Vol 12 (2) ◽  
pp. 332-343 ◽  
Author(s):  
W. J. S. Naunton ◽  
J. R. S. Waring

Abstract 1. An apparatus is described for measuring the modulus and resilience of rubber over a wide range of frequencies. 2. These measurements can be made at any point in the stress-strain curve of the sample. 3. By increasing the power input, the same apparatus can be used to induce high frequency fatigue in the sample. 4. The earlier work with the torsion head apparatus has been confirmed, namely, that internal friction is greatest near zero strain. 5. High frequency resilience is more independent of degree of vulcanization than tripsometer resilience. 6. Modulus tends to increase with frequency. The effect is least with a rubber gum stock and is greater with compounds containing gas black. 7. Resilience decreases with frequency both in gum and gas black compounds. The decrease is more rapid in the gum compounds. 8. Viscous resistance decreases with frequency and becomes constant at higher frequencies. 9. The modulus of both rubber and Neoprene carbon black compounds decreases with fatigue. 10. The change in modulus with frequency in fatigued stocks is exactly analogous to the change before fatigue in rubber, but there is a slight divergence in the case of Neoprene.


2019 ◽  
Vol 13 (49) ◽  
pp. 557-567 ◽  
Author(s):  
ChenYang Liu ◽  
Yong Wang ◽  
XiaoPei Zhang ◽  
LiZhi Du

2018 ◽  
Vol 22 (1) ◽  
pp. 65-71
Author(s):  
Junfu Lu ◽  
Di Li ◽  
Xiaoqiang Xue ◽  
Shenlin Ling

Sandy pebble stratum is a typical discrete particle unstable stratum, mainly consisting of sand and pebble. However, the effect of coarse-grained content on the stability of stratum is not clear. This paper defined the sandy pebble soil of different coarse-grained content in Chengdu City, Sichuan Province, China as the research object. Research on macro-mesomechanical properties of sandy pebble soil of different coarse-grained content was carried out using the method combining the indoor large-scale triaxial test of coarse-grained soil with the discrete element numerical triaxial test. The research results showed that the stress-strain curve of sandy pebble soil exhibited strain softening with the increase of coarse-grained content; when the confining pressure was the same, the stress peak increased and the strain when the peak was reached decreased gradually with the increase of coarse-grained content. It revealed the functional relationship between coarse-grained content and mechanical indexes of sandy pebble soil such as internal friction angle and cohesion. The internal friction angle and cohesion of sandy pebble soil linearly increased with the rise of coarse-grained material; it proposed the particle discrete element micro parameters of sandy pebble soil of different coarse-grained content, including contact modulus, friction coefficient, particle stiffness ratio, contact bond strength. The research results provided the theoretical support for the new design and construction of sandy pebble stratum project. 


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yanxi Zhao ◽  
Zhongxian Liu

Soil-rock mixtures are often seen in geological deposits. Mechanical properties of these mixtures are controlled by microstructural characteristics such as rock size distribution, rock shape, locations, and content. The effects of material composition on soil-rock mechanical properties were studied in the laboratory. The soil-rock material was screened into different size categories. Medium-scale shearing and triaxial experiments were used to study the relationships among macrodeformation, strength, content, size, and random location of rocks. The medium-scale triaxial shearing instrument included the computer control system, EDC control system, and sensor response. The stress-strain curve of soil-rock mixtures was found as a hardening curve which is approximately hyperbolic, and there was no obvious peak intensity value. When the Mohr–Coulomb criterion was used to depict the curve under a shear strain of 0.15, cohesion first increased and then decreased, a finding opposite to the internal friction angle with a decrease in particle size. Elastic modulus increased with an increase in rock size, but Poisson’s ratio remained constant. In similar conditions, the random location of rocks can lead to a variation range of 4 degree of the internal friction angle, and cohesion values can change in a large range than the mean value.


2019 ◽  
Vol 275 ◽  
pp. 03002 ◽  
Author(s):  
WU Zhiqiang ◽  
CAI Zhengyin ◽  
XU Kai ◽  
GENG Zhizhou ◽  
HUANG Yinghao ◽  
...  

This paper presents the results of a laboratory study on the stress-strain relationship of solidified clay formed in seawater corrosion condition. An automatic triaxial apparatus was used and the axial stress and strain was monitored continuously. The dry density was 1.0g/cm3, the cement contents were 4, 6, 8 and 10% by weight of dry soil particles, and the curing time was 28, 60 and 90 days respectively. Test results indicate that the stress strain relationship of cemented clay was affected by soil density, cement content and curing period. A behaviour of strain hardening to strain softening occurred with the increase of cement content. Strong structure will form in cemented clay when the admixture content is 10% or more. The increase in strength of the solidified foundation is resulted from the increase in internal friction angle and cohesive force. The cohesive force increases obviously with the increase of the cement content and the curing age, but the change of internal friction angle is not pronounced after reaching a certain value.


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