scholarly journals Research of the Behavior of Clay Materials with Double Porosity

2021 ◽  
Vol 13 (6) ◽  
pp. 3219
Author(s):  
Hynek Lahuta ◽  
Luis Andrade Pais
Keyword(s):  
Double Porosity ◽  
Strength Properties ◽  
Triaxial Tests ◽  
Building Structures ◽  
Foundation Soil ◽  
Problematic Use ◽  
The North ◽  
Static Liquefaction ◽  
Confinement Stress ◽  
Clay Materials

This contribution presents results from a series of compression and undrained triaxial tests to study the mechanical behavior of dump clay from the north of Bohemia. The use of these materials as a foundation for construction can’t be achieved without the adoption of some precautions. This comes from embankment, formed by digging the ground (altered claystone), up to the level of coal mining which is in a sub horizontal stratigraphic layer. A potential static liquefaction behavior was observed in undrained tests for high confinement stress. A structural collapse was noticed with the results obtained in the triaxial test. This collapse is characterized by an unexpected large decrease in deviator and mean effective stress. The soils formed have strength properties that are potentially dangerous. These concepts can improve the use of these kinds of soils in geotechnical engineering work. It continues and expands the results obtained in previous research, especially the future problematic use of these materials as the foundation soil for line or building structures.

scholarly journals Anisotropy of the Strength Properties of Clays of the North of Belarus

2016 ◽  
Author(s):  
Aliaksander Kremniou ◽  
Nikolai Vishniakov
Keyword(s):  
Uniaxial Compression ◽  
Strength Properties ◽  
Strength Characteristics ◽  
Triaxial Tests ◽  
Experimental Investigations ◽  
Test Results ◽  
Glacial Origin ◽  
The North

This paper describes the results of experimental investigations anisotropic clay at triaxial tests and uniaxial compression. A band clay of glacial origin has been selected for the study widespread in the north of Belarus. Clays have layered texture due to the conditions of formation. Tests were carried out at different angles to the plane of soil stratification. Test results show significant differences in the values of strength characteristics of soils.

scholarly journals Mitigating natural events to avoid disaster in public school buildings: seismic retrofitting of SDN 42 Korong Gadang

2018 ◽  
Vol 229 ◽  
pp. 02021
Author(s):  
James Mwangi ◽  
Laura Putri ◽  
Listhbeth Collins
Keyword(s):  
School Facilities ◽  
Seismic Retrofitting ◽  
Building Structures ◽  
National Agency ◽  
Electrical Grid ◽  
The North ◽  
Australian Plate ◽  
West Sumatra

With over 50 million students, Indonesia has the fourth largest education system in the world. The first twelve years of education are compulsory for all citizens. The students, together with over 3 million teachers spend six (or five in some cases) days a week at over 300,000 schools, typically from 6:30 AM to 2 (or 3) PM. Geographically, Indonesia is traversed by the infamous “ring of fire” and prone to natural events resulting from the tectonic plate movements of the Australian Plate from the South, the Eurasian and Sunda Plates from the North and the Philippine Plate from the East. Left unmitigated, these natural events would lead to natural disasters emanating from resulting earthquakes and leading to tsunamis, landslides, the collapse of building structures and failure of lifelines (roads, pipelines, electrical grid, etc.). In an effort to provide disaster-safe schools, the National Agency for Disaster Management has required that school facilities be a community center in case of disasters and serve as emergency shelters. Retrofit of existing buildings will be needed to comply with government guidelines. This paper presents a case study of the determination of structural deficiencies of an existing school building in SDN 42 Korong Gadang, Padang, West Sumatra and implementation of a seismic retrofit (design and construction) at the same building to mitigate potential earthquake disaster.

Anisotropic shear strength of a residual soil of sandstone

2008 ◽  
Vol 45 (3) ◽  
pp. 367-376 ◽  
Author(s):  
Adriano Virgilio Damiani Bica ◽  
Luiz Antônio Bressani ◽  
Diego Vendramin ◽  
Flávia Burmeister Martins ◽  
Pedro Miguel Vaz Ferreira ◽  
...  
Keyword(s):  
Shear Strength ◽  
Effective Stress ◽  
Yield Surface ◽  
Triaxial Compression ◽  
Strength Properties ◽  
Triaxial Tests ◽  
Residual Soil ◽  
Compression Tests ◽  
Soil Stiffness ◽  
Particle Bonding

This paper discusses results of laboratory tests carried out with a residual soil originated from the weathering of eolian sandstone from southern Brazil. Parent rock features, like microfabric and particle bonding, are remarkably well preserved within this residual soil. Stiffness and shear strength properties were evaluated with consolidated drained (CID) and consolidated undrained (CIU) triaxial compression tests. Undisturbed specimens were tested with two different orientations between the specimen axis and bedding surfaces (i.e., parallel (δ = 0°) or perpendicular (δ = 90°)) to investigate the effect of anisotropy. When CID triaxial tests were performed with δ = 0°, the yield surface associated with the structure was much larger than when tests were performed with δ = 90°. Coincidently, CIU tests with δ = 0° showed peak shear strengths much greater than for δ = 90° at comparable test conditions. Once the peak shear strength was surpassed, CIU tests followed collapse-type effective stress paths not shown by corresponding tests with remolded specimens. A near coincidence was observed between the yield surface determined with CID tests and the envelope of collapse-type effective stress paths for δ = 0° and δ = 90°.

Strength Performance of T-Headed Rebar in Concrete

2013 ◽  
Vol 284-287 ◽  
pp. 1401-1408
Author(s):  
Chien Kuo Chiu ◽  
Kai Ning Chi ◽  
Ker Chun Lin
Keyword(s):  
Strength Properties ◽  
Normal Weight ◽  
Concrete Cover ◽  
Building Structures ◽  
Test Results ◽  
Sectional Area ◽  
Cross Sectional ◽  
Strength Performance ◽  
Practical Engineering ◽  
Cover Thickness

In recent years, the T-Headed bar has been gradually applied to bridge and building structures. However, until Year 2008, a debut of the headed bar in the ACI 318 Design Code was found. There were six limitations on materials’ strength properties, bearing area of head and concrete-cover thickness and spacing of the reinforcement with the head to be made in the Section 12.6 of the ACI 318-08 Code. This paper concerns some issues that were difficult application for the practical engineering or had potential to be improved. They include the clear spacing of the headed bars not less than 4 times the diameter of the bars, the bearing area of head of the headed bar not less than 4 times cross-sectional area of the bars and concrete limit on normal-weight and its effective compression strength not more than 42 MPa. In this study, a total of 43 specimens with a CCT node (Compression-Compression-Tension Node) experimental model were conducted to evaluate anchored performance of the headed bars. Study parameters in this work included strength of concrete, size of reinforcement, bearing area of T head, spacing of bars and confinement condition provided by horizontal reinforcement. Additionally, some benchmark specimens those placed straight bars, and standard 90º and 180º hook bars were carried out for comparison. Test results showed that for anchorage performance, the T-headed bars could provide better than the standard 90º and 180º hook bars. Test results also indicated that the headed bars with head bearing area of three times sectional area of the bar were able to perform as well anchored behavior as their head bearing area with four times sectional area of the bar. In addition, comparing the test results of specimens their spacing having 1.5 and 4 times diameter of the bar, it was found that their anchored strength capacities were similar.

Effects of Complex Initial Stress State Parameters on Dynamic Shear Modulus of Loess

2011 ◽  
Vol 243-249 ◽  
pp. 2601-2606 ◽  
Author(s):  
Zhi Jie Wang ◽  
Ya Sheng Luo ◽  
Hong Guo
Keyword(s):  
Stress State ◽  
Shear Modulus ◽  
Principal Stress ◽  
Initial Stress ◽  
Triaxial Tests ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Initial Stress State ◽  
Foundation Soil ◽  
Stress States

The foundation soil of the buildings and structures is often in complex initial stress states. The dynamic torsional shear triaxial tests are carried out on undisturbed and remodeling loess under different complex initial stress states by using the remolded DTC-199 torsional cyclic load triaxial apparatus, and the effects of each complex initial stress state parameter on dynamic shear modulus of loess are discussed. Results show that, other conditions being the same, the influence of angles of initial principal stressα0on dynamic shear modulusGdof loess show a trend of the biggerα0is, the smallerGdis. The effect laws of efficient of initial intermediate principal stressb0onGdof loess are not obvious. When the dynamic shear strain is larger, the bigger initial deviator stress ratioη0is, the smallerGdof loess is. The influence of initial average principal stresspm0on loess is significant. The biggerpm0is, the biggerGdof loess is.Gdof undisturbed loess is greater than that of remodeling loess under the complex initial stress states.

SOME OBSERVATIONS ON THE UNDRAINED SHEARING STRENGTH USED TO ANALYZE A FAILURE

1969 ◽  
Vol 6 (2) ◽  
pp. 97-110 ◽  
Author(s):  
F. A. De Lory ◽  
R. J. Salvas
Keyword(s):  
Clay Soils ◽  
Triaxial Tests ◽  
Silty Clay ◽  
Compression Tests ◽  
Foundation Soil ◽  
Shearing Strength

The undrained shearing strength of the foundation soil at the site of a failure of a low embankment was investigated by several methods. It was found that both field vane and laboratory compression tests tended to underestimate the strength required for stability. Further consideration of the test specimens from sample tubes showed the undrained shearing strength varied considerably with the position of the sample in the tube. Specimens from tubes from another site yield the same type of results. The two silty clay soils involved were studied in more detail using CIU and CAU triaxial tests and comparing cu/p′ ratios. It was found that in general they yielded the values usually obtained for lacustrine clays.

Dynamic Triaxial Test Research of Stage Change of Cohesive Soil

2013 ◽  
Vol 353-356 ◽  
pp. 937-940
Author(s):  
Xiao Yang Rong ◽  
Tian Hong Yang ◽  
Pei Tao Wang ◽  
Hong Wang ◽  
Yang Li
Keyword(s):  
Dynamic Load ◽  
Dynamic Strength ◽  
Cohesive Soil ◽  
Strength Properties ◽  
Triaxial Tests ◽  
Soil Deformation ◽  
Backbone Curve ◽  
Quantitative Basis ◽  
Stage Change ◽  
Soil Dynamic

With the STX-50 pneumatic-typed dynamic triaxial system, the undrained dynamic triaxial tests on the saturated cohesive soil are performed to study the dynamic strength properties. The changing process of the dynamic strength, backbone curve and the soil deformation of the cohesive soil under dynamic load are zoom analysis by stages to get their regularity. It is found that the stage change of the dynamic strength, backbone curve and the soil deformation all exist, which the stage I of the soil deformation has little damage, the stage III is not allowed, the stage II is determined by the importance of the concrete and the sensitive degree to the deformation. In order to analysis the deformation stability and stress stability of the formation in the effect of the dynamic load, provide qualitative and quantitative basis for the soil dynamic study.

scholarly journals Study on some fundamental factors affecting the static liquefaction of sand

2020 ◽  
Vol 61 (HTCS6) ◽  
pp. 40-47
Author(s):  
Kien Trung Nguyen ◽  
Thang Kim Nguyen ◽  
Ha Quang Ta ◽  
Huy Quang Dang ◽  
Keyword(s):  
Significant Influence ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Liquefaction Resistance ◽  
Factors Affecting ◽  
Static Liquefaction ◽  
The World ◽  
Long Time ◽  
Confining Pressures ◽  
Undrained Conditions

Static liquefaction of soil is a hazard that has caused a lot of damage to humans. Therefore, this phenomenon has been studied for a long time over the world, nevertheless, research on this issue in Vietnam is still limited. This paper presents the results of several triaxial tests under undrained conditions to evaluate the influence of some fundamental factors on the static liquefaction of Fontainebleau sand. The results show that the relative density and the confining pressure have a significant influence on the static liquefaction of the sand. When the density of the sand increases, the liquefaction resistance of the sand increases, until a certain limit, the sand changes from liquefaction behavior to dilatancybehavior with a decrease in pore pressure and an increase in mean effective stress. When the test is carried out at different confining pressures, the greater the confining pressure, the higher the liquefaction resistance.

scholarly journals Soil and rock strength parameters of the Shiraidake Landslide, Japan

2001 ◽  
Vol 23 ◽  
Author(s):  
Robert Jelinek ◽  
Prem Prasad Paudel ◽  
Hiroshi Omura
Keyword(s):  
Rock Strength ◽  
Sedimentary Rocks ◽  
Strength Properties ◽  
Triaxial Tests ◽  
Dry Density ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Strength Parameters ◽  
Consolidation Pressure ◽  
Early Tertiary

The Shiraidake area of northwest Kyushu has an extensive distribution of landslides. A series of undrained triaxial tests and unconfined compression tests were carried out to investigate the variation of strength properties in a selected borehole from the Shiraidake Landslide. It is a translational landslide (called the Hokusho-type in Japan) and is composed of the Early Tertiary and Quaternary sedimentary rocks that are prone to rapid weathering. Core rock samples and recompacted soil samples were used for the study. The results provided the fundamental characteristics of soil and rock under the triaxial and uniaxial tests, and indicated that the undrained behaviour of tested soils generally depends on the pre-shear consolidation pressure and dry density. In addition, the type of material used and the tests performed are important factors that influence the soil and rock strength.

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