Use of a tilting table to determine the basic friction angle of hard rock samples. Note

A tilting table can be used to determine the basic friction angle of a rock. Dolostone and quartzite sliders with natural and sanded surfaces move at similar angles on sanded plates of dolostone and quartzite. Friction angles measured from conventional direct shear tests on the same specimen are similar.When the natural or sanded sliders are tilted on polished plates, lower friction angles result: about 12° for quartzite and 16° for dolostone. The dolostone sliders leave a loose powder on the polished plates. If the powder is accumulated over successive slides, tilt angles for sliding increase to 30°. Friction angles on polished plates approach a minimum, the mineral friction angle, [Formula: see text], which represents the friction between the minerals making up the rock surfaces. The basic friction angle, [Formula: see text], is the sum of [Formula: see text] and the surface roughness produced by sanding.Tests of a new tilting table design suggest that basic friction angles should be determined with naturally surfaced sliders on plates wet lapped with No. 80 grit. Vibrations from the electric motor driving the table reduce measured friction angles by about 1°. Sliding angles increase up to 2° in very humid conditions. Key words: friction, rocks, tilting table, roughness, humidity, dolostone, quartzite, limestone.

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The Friction Angle of the Leiyang Marble Surface after Exposure to High Temperature

Advances in Civil Engineering ◽

10.1155/2021/8852686 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Meng Hong Peng ◽

Man Huang

Keyword(s):

Surface Condition ◽

Surface Friction ◽

Friction Angle ◽

Effect Of Temperature ◽

Tilt Test ◽

Rock Surface ◽

Sliding Angle ◽

Normal Loading ◽

Basic Friction Angle ◽

Marble Surface

There is a lack of information about the temperature-dependent nature of the rock surface, which is one of the essential parameters to predict the surface friction. In the present study, we experimentally study the effect of temperature on the basic friction angle of the marble surface through the direct shear test under the low normal loading condition and tilting test (Stimpson/disk tilt test). The basic friction angle gradually decreases with the increase in temperature from 20°C to 600°C for the two kinds of the tilting test. The results indicate that the Stimpson test on samples with the length-to-diameter ratio of 2 can be more reliable to estimate the basic friction angle of the rock surface after exposure to high temperatures. The results illustrate that the sliding angle depends on the surface condition. With the increase in the repetitive measurements, the sliding angle decreases as the marble surface is cleaned, and the parameter increases as the marble surface is not cleaned.

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Inverse distance weighting interpolated soil properties and their related landslide occurrences

MATEC Web of Conferences ◽

10.1051/matecconf/201819503013 ◽

2018 ◽

Vol 195 ◽

pp. 03013 ◽

Cited By ~ 2

Author(s):

Purwanto B. Santoso ◽

Yanto ◽

Arwan Apriyono ◽

Rani Suryani

Keyword(s):

Internal Friction ◽

Slope Stability ◽

Soil Properties ◽

Hard Rock ◽

Friction Angle ◽

Inverse Distance Weighting ◽

Central Java ◽

Soil Cohesion ◽

Distance Weighting ◽

Inverse Distance

The causes of landslides can be categorized into three factors: climate, topographic, and soil properties. In many cases, thematic maps of landslide hazards do not involve slope stability analyses to predict the region of potential landslide risks. Slope stability calculation is required to determine the safety factor of a slope. The calculation of slope stability requires the soil properties, such as soil cohesion, the internal friction angle and the depth of hard-rock. The soil properties obtained from the field and laboratory investigation from the western part of Central Java were interpolated using Inverse Distance Weighting (IDW) to estimate the unknown soil properties in the gridded area. In this research, the IDW optimum parameter was determined by validation toward the percent bias. It was found that the IDW interpolation using higher weighting factor corresponds with a higher percent bias in case of the depth of hard-rock and soil cohesion, while the opposite was found for the internal friction angle. Validation to landslide incidents in western parts of Central Java shows that the majority of landslide incidents occur at depths of hard rock of 6 m-8 m, at soil cohesions of 0.0 kg/cm2-0.2 kg/cm2, and at internal friction angles of 30°-40°.

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