Study on the Impact of Cyclic Wetting and Drying on the Shear Strength of Stabilized Expansive Soils

2012 ◽  
Vol 594-597 ◽  
pp. 96-99
Author(s):  
Yun Dong ◽  
Wei Zhong He ◽  
Bao Tian Wang
Keyword(s):  
Shear Strength ◽  
Shear Test ◽  
Expansive Soils ◽  
Test Results ◽  
Strength Index ◽  
Wetting And Drying ◽  
Slope Analysis ◽  
Normal Strength ◽  
The Times ◽  
The Impact

To offer or predict the shear strength of stabilized expansive soils after cyclic wetting and drying for the slope analysis, the paper carried out direct shear test on the stabilized expansive soils after different times of cyclic wetting and drying. The test results show: The first 3-5 times of cyclic wetting and drying will cause the shear strength decreased sharply, and after about 7-9 times of cycle, the shear strength will trend to a stable value, which is about 40-60% of the normal strength before the cycles. Logarithm model can well fitted the variation of the shear strength and the times of cyclic, so the shear strength index can be predicted by using the models which was established according to the test results.

Study on the Impact of Long-Term Immersion on the Shear Strength of Compacted Lime Stabilized Expansive Soils

2012 ◽  
Vol 238 ◽  
pp. 431-434
Author(s):  
Yun Dong ◽  
Wei Zhong He ◽  
Bao Tian Wang
Keyword(s):  
Shear Strength ◽  
Immersion Time ◽  
Direct Shear Test ◽  
Shear Test ◽  
Expansive Soils ◽  
Test Results ◽  
Slope Analysis ◽  
Normal Strength ◽  
The Impact

To offer or predict the shear strength of compacted lime stabilized expansive soils after long-term immersion for the slope analysis, the paper carried out direct shear test on the compacted stabilized expansive soils after different immersion time. The test results show that long-term immersion has significant impact on the shear strength of the lime stabilized expansive soils, the shear strength reduced sharply after soaking, but the shear strength tends to a stable value about 60%~70% normal strength while soaking is longer than 50 days. Logarithm model can well fitted the sketch of φ, c and immersion times within 50 days, which may be used to predict the shear strength of the stabilized expansive soils quickly.

scholarly journals Study on the Influence of Moisture Content and Drying-Wetting Cycles on the Shear Strength Index of Silt in the West Bank of Qinghai Lake

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Lei Zhang ◽  
Jixiang Yan ◽  
Jiake Tan ◽  
Yi Liao
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Shear Test ◽  
West Bank ◽  
Qinghai Lake ◽  
Strength Index ◽  
The West ◽  
Wetting And Drying ◽  
Optimal Moisture Content ◽  
Shearing Strength

In this paper, the expressway engineering case along the west bank of Qinghai Lake is taken as the research background, and the typical “aquatic grassland” silt on the west bank of Qinghai Lake is taken as the research object. Through the geotechnical test, wet-dry cycle test, and direct shear test, the influence of moisture content and wet-dry cycle on the shear strength of silt and its indexes are studied. The results show that the shear strength index c and φ of unmodified silt first increase and then decline with the increase of water content, and the optimal moisture content of the shear strength is about 30%. The values of c, φ, and shear strength of remolded silt decrease with the increase of wetting and drying cycles. When the cycles exceed 5 times, the moisture content does not have much effect on the shearing strength.

Effect of weathering on the compressibility and shear strength of a natural clay

2006 ◽  
Vol 43 (6) ◽  
pp. 618-625 ◽  
Author(s):  
Giovanni Gullà ◽  
Maria Clorinda Mandaglio ◽  
Nicola Moraci
Keyword(s):  
Shear Strength ◽  
Direct Shear Test ◽  
Shear Test ◽  
Direct Shear ◽  
Test Results ◽  
Natural Clay ◽  
Standard Equipment ◽  
Overconsolidated Clays ◽  
Weathering Process

In situ, seasonal changes expose soils to frequent wetting–drying–freezing–thawing cycles. Such processes can favour and trigger shallow instabilities controlled by the weathering process. This paper presents an experimental study carried out to investigate the effects of the weathering process, caused by the wetting–drying–freezing–thawing cycles, on the compressibility and shear strength of a natural clay. Several specimens were trimmed from block samples of overconsolidated clays taken from a slope in south Calabria, Italy. Specimens were subjected to wetting–drying–freezing–thawing cycles of different durations and then tested with standard equipment (oedometer and direct shear). Test results show that the wetting–drying–freezing–thawing cycles caused a change in the initial microstructure that produced a decrease in the compression index and an increase in the swelling index. Moreover, the direct shear test results show a decrease in the peak shear strength and demonstrate that a larger reduction occurs in the first month of weathering cycles. The intense cycles performed in the laboratory produced a decay of compressibility and a shear strength approaching reconstituted values. The conclusions are important when choosing the shear strength parameters required when studying shallow landsliding in clay slopes.Key words: weathered clay, structure, cycle of degradation, shallow instability.

scholarly journals Comparative Study in Method of Compaction by Consolidated Drained and Direct Shear Test

2020 ◽  
Vol 78 (2) ◽  
pp. 143-152
Author(s):  
Abdul Samad Abdul Rahman ◽  
N. Sidek ◽  
Juhaizad Ahmad ◽  
N. Hamzah ◽  
M. I. F. Rosli
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Triaxial Test ◽  
Direct Shear Test ◽  
Shear Test ◽  
Void Ratio ◽  
Direct Shear ◽  
Test Results ◽  
Stress Strain ◽  
Strain Behaviour

Soil compaction has been a common practice in the construction of highways, embankments, earth dams and other related structures where the condition of the soil is high in void ratio and therefore having a very low in bearing capacity. Therefore, the soil needs to be compacted in order to minimize the void ratio and in the same time would results in having a very high bearing capacity to sustain load. Nevertheless, only a few researches have been done to investigate the method of compaction using different energy on the behavior of shear strength by consolidated drained and direct shear test. In this research, the effect of different compaction in energy of 25 number of blows compared to 40 number of blows on the stress-strain behaviour of drained triaxial test has been done and findings of the data are to be compared with direct shear test. Results reveal that there is an increase in soil unit weight by using different energy in compaction with an increase of 5% from 1790 kg/m3 to 1880 kg/m3 for 25 and 40 number of blows respectively. However, the stress-strain behaviour of the specimens shows differently when compared between consolidated drained triaxial and direct shear test. The shear strength for direct shear-stress is at higher value compared to drained triaxial test. For drained triaxial test, results reveal that the effective friction angles are increase only about 1% from 37° to 38°. This is due to the soil particles rearranging itself with the different applied pressures thus eliminating the effects of different energy on the shear strength of the specimens. However, for direct shear test, the shear strength increases drastically from 29° to 32°. The increase of the shear strength is more likely influence by the soil particle arrangement due to the impact of the energy of the no of blows to the desired specimen.

Properties of Hard Rubber. XXI. Influence of Vulcanization Temperature

1947 ◽  
Vol 20 (4) ◽  
pp. 1039-1053
Author(s):  
H. F. Church ◽  
H. A. Daynes
Keyword(s):  
Impact Strength ◽  
Power Factor ◽  
Present Report ◽  
Small Samples ◽  
Test Results ◽  
Plastic Yield ◽  
Different Temperatures ◽  
Similar Materials ◽  
The Times ◽  
The Impact

Abstract In previous reports the properties of hard rubber made from rubber and sulfur were studied with particular reference to the effects of varying the rubber-sulfur ratio and vulcanization time. In the present report, a continuation of this investigation, the influence of temperature of vulcanization of similar materials is studied. Materials having rubber-sulfur ratios of 65/35 and 70/30 were vulcanized in a press at three different temperatures, namely, 165°, 155°, and 135° C, the times of vulcanization employed being estimated to be equivalent to 5 hours at 155° C. As a check on the estimate of the equivalent times, small samples of the same materials were vulcanized for various shorter and longer periods and were tested for plastic yield temperature and percentage of free sulfur. The main materials were tested for the following properties by the methods described in the previous report : Combination of sulfur, density, cross-breaking strength and elongation, impact strength, plastic-yield temperature, permittivity and power factor at audio and radio frequencies, and surface discoloration in sunlight. Certain anomalous figures were obtained in the impact test results which were thought to be due to the necessity of carrying out the longer vulcanization processes in stages. Arrangements were made accordingly to conduct the vulcanization continuously in such cases. This procedure brought about a considerable improvement in the results. These results confirmed the conclusion reached in the previous report that impact strength is very sensitive to untraced variables in manufacture. The results of the permittivity and power factor tests are discussed at some length, since they afford useful information on a number of other variables, principally rubber-sulfur ratio, frequency, and temperature of test. In a general discussion of the results, the choice of the best vulcanization temperature is examined. It is concluded that the selection of the best temperature involves compromise between opposing tendencies in the different properties.

Metallurgical reactions of Sn-3.5Ag solder with various thicknesses of electroplated Ni/Cu under bump metallization

2005 ◽  
Vol 20 (10) ◽  
pp. 2772-2779 ◽  
Author(s):  
Chang Pin Huang ◽  
Chih Chen ◽  
C.Y. Liu ◽  
S.S. Lin ◽  
K.H. Chen
Keyword(s):  
Shear Strength ◽  
Solid State ◽  
Shear Test ◽  
Consumption Rate ◽  
Test Results ◽  
Under Bump Metallization ◽  
Solder Bumps ◽  
Snag Solder ◽  
Microelectronics Industry ◽  
Metallurgical Reactions

Nickel has been widely used as an under-bump metallization (UBM) material in the microelectronics industry. The solid-state reaction between the eutectic SnAg solder bumps and three thicknesses of Ni/Cu UBM was investigated, with 5 μm-Cu/3 μm-Ni, 3 μm-Cu/2 μm-Ni, and 0 μm-Cu/1 μm-Ni. It was found that the shear strength of the solder bumps decreased after the solid-state aging at 150 °C for 200 h, and it did not change much after it was prolonged for 500 and 1000 h. Aging of the Ag3Sn intermetallic compound (IMC) and grain growth of the solder are responsible for the decrease in the shear strength. Furthermore, the shear test results indicated that the fracture mode switched from ductile to brittle for the solder bumps with 1 μm Ni after aging longer than 200 h, causing the strength of the solder to decrease abruptly. This is attributed to the consumption of the peripheral Ni layer after the solid-state aging for 1000 h. The Ni consumption rate was measured to be 0.02 μm/h1/2 at 150 °C.

scholarly journals Analisis Kestabilan Lereng Berdasarkan Kekuatan Geser Massa Batuan Terhadap Perubahan Kandungan Air Pada Tambang Batubara Di Area Blok Menyango

PROMINE ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 71-77
Author(s):  
Novandri Kusuma Wardana
Keyword(s):  
Shear Strength ◽  
Natural Condition ◽  
Shear Failure ◽  
Friction Angle ◽  
Direct Shear ◽  
Test Results ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Wet Condition ◽  
The Impact

Mining activities is commonly to work with the problem of stability of rock mass, then befordesaining mine’s slope should know rock shear strength parameters, such as cohesion (c) andinternal friction angle value ( . Beside those parameters, also needed to know the impact ofwater content to the rocks. The water content will effect rock’s shear strength, proof by the rockcondition which is ductile when it is dry and soft when it is wet. Based on test results was doneusing sandstone with laboratory scale of direct shear test were analyzed using mohr – coulomband patton criteria (1966). It is known that the cohesion (c) of sandstone decreased from 510,35kPa at natural condition down to 133,75 kPa at wet condition. The internal friction angle ( ) alsodecreased from 54,56° at natural condition down to 48,45° at wet condition. The reduction of theshear strength is caused by fragments and clay minerals characteristics which are so reactiveand very easy to absorb water so that the cohesion of the sandstone reduce the active normalstress so that working the shear stress required to cause the shear failure becomeweaker. From the results, it is also known that the shear surface roughness had a lot ofinfluence on the shear strength the normal stresses applied on the direct shear tests werevery low under 20% of UCS.

scholarly journals Enhancement Punching Shear in Flat Slab Using Mortar Infiltrated Fiber Concrete

2020 ◽  
Vol 6 (8) ◽  
pp. 1457-1469
Author(s):  
Ali Sabah Imran Shwalia ◽  
Nabeel Hasan Ali Al-Salim ◽  
Haider M. Al-Baghdadi
Keyword(s):  
Shear Strength ◽  
Punching Shear ◽  
Test Results ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Vertical Loading ◽  
Reinforced Concrete Slabs ◽  
Fiber Concrete ◽  
Effective Depth ◽  
Normal Strength

In this paper, improving the punching shear of slab column connection using mortar infiltrated fiber concrete is studied. Eight specimens of reinforced concrete slabs identical in dimension and reinforcement were tested, six of them were casting with hybrid concrete (normal strength concrete and mortar infiltrated fiber concrete) and two specimens were cast with normal strength concrete as control specimens. All specimens were tested under vertical loading. The mortar infiltrated fiber concrete was cast monolithically with the normal strength concrete at different thickness at one and a half times of the effective depth (1.5d) at the center of the slab, once at all the thickness of cross section of the slab and the others at half thickness either tension or compression face of the slabs all cases cast with two types of fiber. The vertical load was applied upward through a square column with a dimension of (100 mm). In all slabs, no failure in mortar infiltrated fiber concrete was observed. The test results showed that the use of mortar infiltrated fiber concrete improves the punching shear strength for some cases according to the type of fibers and the location of casting mortar infiltrated fiber concrete in slabs. The enhancement in punching shear strength due to using mortar infiltrated fiber concrete at 1.5d square shape (265 mm) ranged from 4% to 46% compared with the control specimens.

Experimental Study on Shear Strength of Expansive Soil Improved by Lime - Weathered Sand

2013 ◽  
Vol 446-447 ◽  
pp. 1441-1447
Author(s):  
Meng Yun Huang ◽  
Jun Lai Xiong ◽  
Ji Bing Tang ◽  
Chi Long
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Direct Shear Test ◽  
Shear Test ◽  
Expansive Soil ◽  
Dry Density ◽  
Direct Shear ◽  
Mass Ratio ◽  
Angle Of Internal Friction ◽  
The Impact

This paper ananlyzes and contrasts the direct shear test of the expansive soil with different weathered sand dosage (mass ratio) and different lime dosage (mass ratio) in the case of the expansive soil with some water content and dry density .And try to analyzes and researches the impact of expansive soil improved by weathered sand and lime shear strength index . The direct shear test by the expansive soil mixed with different proportions of weathered sand and lime can be concluded that: mixing the weathered sand to improve the shear strength of expansive soil is effective, and cohesion gradually decreases with the increase of doped proportion of sand and the angle of internal friction first increases with the increase of doped proportion of sand and then decreases ;mixing of lime is effective to improve the shear strength of expansive soil, and cohesion gradually decreases with the increase of doped proportion of lime and angle of internal friction first increases and then decreases with the increase of doped proportion of lime. The shear strength of improved expansive soil can meet the subgrade filling with soil standards and at the same time the expansive soil improved by weathered sand and lime reduces the amount of lime and reduce project cost when to achieve the same shear strength standards.

Sign in / Sign up

Export Citation Format

Share Document