Reduction of Axial Resistance due to Membrane and Side Drains in the Triaxial Test

Author(s):  
Gert Greeuw ◽  
Henk den Adel ◽  
Aad L. Schapers ◽  
Evert J. den Haan
2018 ◽  
Vol 7 (4.36) ◽  
pp. 424 ◽  
Author(s):  
Maxwel Joseph Henri Nainggolan ◽  
Wiwik Rahayu ◽  
Puspita Lisdiyanti

In recent years, utilization of biotechnology in geotechnical field has rapidly grown. One of the biotechnologies being utilized is urease enzyme, a stabilization material by bio-cementation method studied in this research.  Urease enzyme is manually mixed with additional 10% of clay soil to clay shale. The objective of mixing it is to increase the bearing capacity of the clay shale. Consolidated undrained triaxial test was performed for testing the soil strength performance for samples that had undergone curing for 2, 4, and 6 weeks. The results indicated that the sample stiffens, proved by the increase of shear strength from consolidated undrained triaxial test. The shear strength value produced by the variation of the urease enzyme mixture + 10% the clay is higher than that of without the original clay shale.  


Author(s):  
John Barrett ◽  
Ryan Phillips

Abstract Interdependence between pipe-soil interaction springs in a pipe stress analysis should be considered. This example focused on a single pipe configuration “wished” in place in a clay soil. A conventional pipe stress analyses often idealizes the pipe soil interaction with a beam-spring finite element model where independence is assumed between reactions in axial, lateral and vertical directions. There is however interdependence between these springs as recognized in recent Pipeline Research Council International (PRCI) guidelines. For a frictional interface, axial resistance can be much higher than indicated by PRCI guidelines when accounting for increased lateral and vertical bearing pressure. At the same time, lateral and vertical capacities are shown to be reduced in comparison to pure vertical and lateral loading directions. This paper highlights the development of a 3D soil-spring interaction model based on a continuum finite element analysis approach. By developing a soil capacity envelope based on 3D continuum modeling, updated soil springs can reflect modified capacities depending on the direction of pipe movement. For the landslide scenarios considered in application of the model, the directional dependency is shown to change the accumulated plastic strain profile in the pipe.


2021 ◽  
Vol 8 ◽  
Author(s):  
Zhou Chen ◽  
Haocheng Xu ◽  
Mayao Cheng ◽  
Hanwen Lu ◽  
Zhijian Wang ◽  
...  

Aiming to explore the optimal mixture ratio and curing age of solidified muddy soil under dynamic load, the paper intends to investigate whether the solidified muddy soil can be used as filling of high-speed railway subgrade. Based on the dynamic triaxial test, the investigation measured the dynamic strain and dynamic elastic modulus of solidified muddy soil under different mix ratios and curing ages, and also observed the microscopic morphology of solidified muddy soil samples by using scanning electron microscope. The results show that the addition of cement and curing agent significantly increases the dynamic strength and elastic modulus of muddy soil, which effectively improve the dynamic characteristics of muddy soil. The curing effect of the curing agent is more obvious with the increase of the dosage of cement and curing agent under different mix ratio. The content of curing agent plays a leading role in the hydration reaction between cement, curing agent and soil particles. Additionally, in case of the same test conditions, when the ratio of cement mass to dry silt mass is 1:20, the ratio of diluent volume to dry silt mass is 1:20, with 28 days of curing age, its curing effect will reach the best.


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