Experimental study on shear strength parameters of municipal solid waste employing a large direct shear apparatus

Author(s):  
Vahid Dehdari ◽  
Mohsen Ajdari ◽  
Ali Rostami
2011 ◽  
Vol 295-297 ◽  
pp. 454-459 ◽  
Author(s):  
Zhen Ying Zhang ◽  
Da Zhi Wu

Basing on the new developed direct shear testing instrument and the tri-axial test instrument with large scale specimen, the shear strength parameters of municipal solid waste has been studied. The municipal solid waste is divided into three parts: the material that is easy to be biodegraded, reinforced material that is difficult to be biodegraded and the incompressible solid waste material. The proportions of these three parts are selected as 80%, 5% and 15%, respectively. A series of laboratory tests have been performed for different initial void ratios, different vertical pressures and different confining pressures applied on the test specimen. Testing results show that the initial void ratio is the main influence factor for the shear strength parameters of the municipal solid waste, the relationship between the shear stress and the shear strain is a strain hardening curve, the shear stress increases gradually with the shear strain. Besides, the principle effective stress increases with the axial strain and the confining pressure in a hardening increasing trend, and the principle effective stress decreases with the increase of the initial void ratio of the municipal solid waste. The shear strength shows a linear relationship to the vertical pressure applied on the test specimen, and it is in accordance with the law of coulomb. According to the testing results of the direct shear test and the tri-axial test, the shear strength parameters are obtained. The cohesion varies from 4.7 to 12.2kPa, and the internal friction angle varies from 14.5 to 28.2 degree.


2013 ◽  
Vol 438-439 ◽  
pp. 1176-1180 ◽  
Author(s):  
Gao Feng Chen ◽  
Ying Fa Lv ◽  
Zhi Huai Huang ◽  
Yan Chang

The unconsolidated-undrained fast shear tests of saturated-unsaturated remolded soil samples under different moisture content which is 1.1%, 10.1%, 14.9%, 19.9%, 24.2%, 29.9%, 37.7% respectively, and normal stress which is 50kPa, 100kPa, 200kPa, 300kPa, 400kPa respectively, were studied by the modified SDJ-1-type strain direct shear apparatus and U.S. Lab VIEW data acquisition system. The shear strength parameters of unsaturated soil samples, i.e. general cohesion and general internal friction angle were obtained based on Mohr-Coulomb strength theory. The test results showed that the general cohesion firstly increased and then reduced with the moisture content increasing, and the general internal friction angle increased with the moisture content decreasing. The function between the general shear strength parameters and the moisture content was studied. The concept of general shear strength parameters was proposed in the paper, and would provide a simple and practical method to obtain the strength parameters for engineering practice.


2011 ◽  
Vol 71-78 ◽  
pp. 918-922
Author(s):  
Zhen Ying Zhang ◽  
Da Zhi Wu

Basing on the new developed direct shear testing instrument, the biodegradation strength properties and strength parameters of municipal solid waste with higher content of organic matter have been studied. The municipal solid waste is divided into three parts: the material that is easy to be biodegraded, reinforced material that is difficult to be biodegraded and the incompressible solid waste material. The proportions of these three parts are 80%, 5% and 15%, respectively. A series of laboratory tests have been performed for different initial void ratios and different vertical pressures applied on the test specimen. Testing results show that the initial void ratio is the main influence factor for the biodegradation strength of the municipal solid waste, the relationship between the biodegradation shear stress and the shear strain is a strain hardening curve, the biodegradation shear stress gradually increases with the shear strain. Besides, the biodegradation shear strength shows a linear relationship to the vertical pressure applied on the test specimen, and it is in accordance with the law of coulomb. According to the testing results, the biodegradation shear strength parameters of municipal solid waste are obtained. The cohesion varies from 11.5 to 24.0kPa, and the internal friction angle varies from 8.3 to 29.0 degree.


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