Aspects of the behaviour of compacted clayey soils on drying and wetting paths

2002 ◽  
Vol 39 (6) ◽  
pp. 1341-1357 ◽  
Author(s):  
Jean-Marie Fleureau ◽  
Jean-Claude Verbrugge ◽  
Pedro J Huergo ◽  
António Gomes Correia ◽  
Siba Kheirbek-Saoud

A relatively large number of drying and wetting tests have been performed on clayey soils compacted at the standard or modified Proctor optimum water content and maximum density and compared with tests on normally consolidated or overconsolidated soils. The results show that drying and wetting paths on compacted soils are fairly linear and reversible in the void ratio or water content versus negative pore-water pressure planes. On the wet side of the optimum, the wetting paths are independent of the compaction water content and can be approached by compaction tests with measurement of the negative pore-water pressure. Correlations have been established between the liquid limit of the soils and such properties as the optimum water content and negative pore-water pressure, the maximum dry density, and the swelling or drying index. Although based on a limited number of tests, these correlations provide a fairly good basis to model the drying–wetting paths when all the necessary data are not available.Key words: compaction, unsaturated soils, clays, drying, wetting, Proctor conditions.

1995 ◽  
Vol 32 (5) ◽  
pp. 749-766 ◽  
Author(s):  
Harianto Rahardjo ◽  
Delwyn G. Fredlund

An experimental program was designed to study the behavior of unsaturated soils during undrained loading and consolidation. A Ko cylinder was designed and built for the testing program. Simultaneous measurements of pore-air and pore-water pressures could be made throughout a soil specimen using this Ko cylinder. Four types of tests were performed on a silty sand. These are (1) undrained loading tests where both the air and water are not allowed to drain, (2) constant water content tests where only the water phase is not allowed to drain, (3) consolidation tests where both the air and water phases are allowed to drain, and (4) increasing matric suction tests. Undrained loading tests or constant water content loading tests were conducted for measuring the pore pressure parameters for the unsaturated soil. Drained tests consisting of either consolidation tests or increasing matric suction tests were conducted to study the pore pressure distribution and volume change behavior throughout an unsaturated soil during a transient process. The experimental pore pressure parameters obtained from the undrained loadings and constant water content leadings agreed reasonably well with theory. The pore-air pressure was found to dissipate instantaneously when the air phase is continuous. The pore-water pressure dissipation during the consolidation test was found to be faster than the pore-water pressure decrease during the increasing matric suction test. The differing rates of dissipation were attributed to the different coefficients of water volume change for each of the tests. The water volume changes during the consolidation test were considerably smaller than the water volume changes during the increasing matric suction tests for the same increment of pressure change. Key words : consolidation, Ko loading, matric suction, pore-air pressures, pore-water pressures, unsaturated soils


2012 ◽  
Vol 535-537 ◽  
pp. 1807-1810 ◽  
Author(s):  
Chao Hui Wang ◽  
Juan Juan Zhao ◽  
Xiao Hua Wang ◽  
Xin Qi Wang ◽  
Sheng Guan Di

The compacting curves of mud solidified by some curing agents, including cements, HSC301, CVC and CDK, were studied by heavy compaction tests. Based on this, prediction formulas for optimum water content and maximum dry density of solidified mud were regressed. Experimental results showed that the optimum water content of mud was increased and the maximum dry density reduced with the increasing amount of curing agent. Regression formulas were offered as a basis for the selection of mud curing agents.


2017 ◽  
Vol 3 (11) ◽  
pp. 1008 ◽  
Author(s):  
Yuyu Zhang ◽  
Wanjun Ye ◽  
Zuoren Wang

This paper presents a study to investigate the effects of water content, lime content and compaction energy on the compaction characteristics of lime-treated loess highway embankments. Laboratory compaction tests were conducted to determine the maximum dry density  and optimum water content  of loess with different lime Contents (0, 3, 5 and 8%), and to examine the effects of water content, lime content and compaction energy on the value of  and . In situ compaction tests were performed to obtain the in situ dry density  and the degree of compaction  of different lime-treated loess. Experimental embankments with different fill materials (0, 3, 5 and 8% lime treated loess) were compacted by different rollers during in situ tests. The results indicate that  increases due to the increase of water content . Once water content exceeds , dry density  decreases dramatically. The addition of lime induced the increase of  and the decrease of . A higher compaction energy results in a higher value of  and a lower value of . The value of  achieves it’s maximum value when in situ water content  was larger than the value of  (+1-2%). The degree of compaction  can hardly be achieved to 100% in the field construction of embankments. Higher water content and compaction energy is needed for optimum compaction.


2020 ◽  
Vol 1 (1) ◽  
pp. 32
Author(s):  
Amit Kumar ◽  
Kiran Devi ◽  
Maninder Singh ◽  
Dharmender Kumar Soni

The evolution of industries is essential for the economic growth of any country; however, this growth often comes with exploitation of natural resources and generation of wastes. The safe disposal and utilisation of industrial wastes has become essential for sustainable development. A possible approach would be to utilize these wastes in construction industries. The stone industry is one such flawed industries that generates waste in dust or slurry form; this leads harmful impacts on human beings, animals, and surrounding areas which, in turn, can lead to soil infertility. In the present study, stone waste was examined for its influence on maximum dry density (MDD), optimum water content (OMC) and unconfined compressive strength (UCS) of soil experimentally. Stone waste was used at 0%, 4%, 8%, 12%, 16% and 20% by weight of soil and UCS tests were conducted at maturing periods of 7, 14 and 21 days. Test results reported that the incorporation of stone waste improved the compressive strength value significantly. Maximum dry density was enhanced; however, optimum water content was reduced with the use of stone waste in soil due to its fine particles. Linear regression equations were also derived for various properties.


2020 ◽  
Vol 1 (1) ◽  
pp. 32
Author(s):  
Amit Kumar ◽  
Kiran Devi ◽  
Maninder Singh ◽  
Dharmender Kumar Soni

The evolution of industries is essential for the economic growth of any country; however, this growth often comes with exploitation of natural resources and generation of wastes. The safe disposal and utilisation of industrial wastes has become essential for sustainable development. A possible approach would be to utilize these wastes in construction industries. The stone industry is one such flawed industries that generates waste in dust or slurry form; this leads harmful impacts on human beings, animals, and surrounding areas which, in turn, can lead to soil infertility. In the present study, stone waste was examined for its influence on maximum dry density (MDD), optimum water content (OMC) and unconfined compressive strength (UCS) of soil experimentally. Stone waste was used at 0%, 4%, 8%, 12%, 16% and 20% by weight of soil and UCS tests were conducted at maturing periods of 7, 14 and 21 days. Test results reported that the incorporation of stone waste improved the compressive strength value significantly. Maximum dry density was enhanced; however, optimum water content was reduced with the use of stone waste in soil due to its fine particles. Linear regression equations were also derived for various properties.


1978 ◽  
Vol 15 (3) ◽  
pp. 391-401 ◽  
Author(s):  
P. J. Rivard ◽  
T. E. Goodwin

The geotechnical characteristics of compacted soils used by the Prairie Farm Rehabilitation Administration in earth embankments were correlated with easily obtained soil properties.Relationships were established between Standard Proctor maximum density and optimum water content versus liquid limit for clay soils. In addition, a relationship was established to determine the Standard Proctor maximum dry density and optimum water content using the results from the one-point Proctor test for clay, and sand and silt soils.Effective shear strength parameters and consolidation characteristics of compacted samples were related to liquid limit, water content, and dry density. The results of field and laboratory measurements of pore pressure were used to relate the pore pressure coefficients U/σ3 and U/σ1 to the deviation of water content from optimum water content and applied stress. A relationship was established between embankment compression and embankment height using field measurements of embankment settlement.The data suggest that similar geotechnical characteristics will be obtained for laboratory and field compacted alluvial and glacial soils when they are placed with Standard Proctor compactive effort at similar water contents, densities, and liquid limit. In this paper 'alluvial clay' is used to describe clays deposited in lacustrine or fluvial environments and 'glacial clay' is used to describe clays deposited by a glacier.


Author(s):  
Trần Thanh Nhàn

In order to observe the end of primary consolidation (EOP) of cohesive soils with and without subjecting to cyclic loading, reconstituted specimens of clayey soils at various Atterberg’s limits were used for oedometer test at different loading increments and undrained cyclic shear test followed by drainage with various cyclic shear directions and a wide range of shear strain amplitudes. The pore water pressure and settlement of the soils were measured with time and the time to EOP was then determined by different methods. It is shown from observed results that the time to EOP determined by 3-t method agrees well with the time required for full dissipation of the pore water pressure and being considerably larger than those determined by Log Time method. These observations were then further evaluated in connection with effects of the Atterberg’s limit and the cyclic loading history.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Kaisheng Chen

By embedding water content sensors and pore water pressure sensors inside the red clay slope on-site in Guiyang, Guizhou, shear tests were performed on soil samples at different depths of the slope under different weather. The changes of water content, pore water pressure, and shear strength index of the slope inside the slope under the influence of the atmosphere were tracked and tested, and the failure characteristics and evolution of the red clay slope were analyzed. It is believed that the depth of influence of the atmosphere on red clay slopes is about 0.7 m, rainfall is the most direct climatic factor leading to the instability of red clay slopes, and the evaporation effect is an important prerequisite for the catastrophe of red clay slopes. The cohesion and internal friction angle of the slope soil have a good binary quadratic function relationship with the water content and density. The water content and density can be used to calculate the cohesion and internal friction angle. Failure characteristics of red clay slopes: the overall instability failure is less, mainly surface failure represented by gullies and weathering and spalling, and then gradually evolved into shallow instability failure represented by collapse and slump. The damage evolution law is as follows: splash corrosion and surface corrosion stage⟶ fracture development stage⟶ gully formation stage⟶ gully development through stage⟶ local collapse stage⟶ slope foot collapse stage.


2002 ◽  
Vol 39 (6) ◽  
pp. 1427-1432 ◽  
Author(s):  
Inge Meilani ◽  
Harianto Rahardjo ◽  
Eng-Choon Leong ◽  
Delwyn G Fredlund

A modified triaxial apparatus with mini suction probes was fabricated to study the matric suction along the specimen height during unsaturated triaxial testing. Three mini suction probes were placed at 3/4, 1/2, and 1/4 height of the specimen, each at 120° apart in the lateral direction. This paper presents the development of the mini probe for matric suction measurements. Evaluation of the performance shows that the fabricated mini probe provides a rapid response and accurate reading under negative and positive pore-water pressure changes. Matric suctions as high as 400 kPa were successfully measured on soil specimens over a time span of 15 h. On the other hand, the mini suction probes were also found to be able to measure a matric suction of 200 kPa for a longer period of 155 h.Key words: matric suction, mini suction probe, triaxial, unsaturated soils, mid-height pore-water pressure measurement.


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