Calculation of comprehensive internal friction angle by natural

1.

Cohesion, also called cohesion. The calculation method is: in the case of effective stress, the cohesion is obtained by decting the total shear strength from the friction strength. On the other hand, cohesion is the shear strength of the failure surface without any normal stress

The classical expression of internal friction angle is Coulomb's law τ=σ tan φ+ C

for cohesive soil, C is not 0, for sandy soil, C is 0, φ、 C can be obtained by triaxial test (or direct shear). Under different confining pressures, the maximum principal stress and minimum principal stress can be obtained, and the stress circle can be made. Under at least three different confining pressures, three stress circles can be made, and the common tangent of the three circles can be made. The inclination angle is the internal friction angle

The relationship between repose angle and internal friction angle:

1, repose angle and internal friction angle all reflect the internal friction characteristics of granular materials

The concepts of angle of repose and internal friction angle are different. The internal friction angle reflects the friction characteristics between layers of granular materials, and the angle of repose represents the rolling ability of a single granular material on the pile, which is the appearance of the internal friction characteristics

3. For similar materials with similar mass and moisture content, the angle of repose is always greater than the internal friction angle, and is greater than the sliding friction angle. The angle of repose is equal to the angle of internal friction for loose materials such as sand which lack cohesion

extended data

determination method of internal friction angle

in order to determine the internal friction angle of granular materials, the Mohr envelope of this material must be determined by experiment. Two methods can be used to determine the Mohr envelope of granular materials

Triaxial compression test the triaxial compression test device is developed by using the device to study the shear characteristics of soil. When the device is used for shearing test of bulk materials such as grain, the pre compacted grain is sealed in the rubber film and put into the compression chamber. The pressure in the compression chamber is graally increased to a predetermined pressure. The axial cutting load is applied to the grain column by universal testing machine or other loading device

In this way, the grain column is subjected to air pressure in the radial direction σ Under the combined action of compressed air pressure and axial load in the circumferential direction, the failure time is less than 3 σ The value of 1 can be measured by recorder. Repeat the above procere to get different results σ Principal stress of grain column failure at
3 σ The Mohr envelope of bulk material in a certain compaction state is obtained

Direct shear test

direct shear test can be carried out on the shear apparatus shown in the figure. The shearing instrument consists of three basic parts: shearing groove, loading device and recorder. The shearing groove comprises a base, a shearing ring and a top cover. The normal pressure is applied to the shear ring by the vertical compaction load, and the shear force is applied to the shear ring by the electric or mechanical transmission device. The transmission device is equipped with a force sensor or dynamometer to measure the shear stress acting on the contact plane between the base and the shear ring

reference source : network cohesion

reference source : network internal friction angle

2. 1. Shear strength of cement soil: the shear strength of cement soil increases with the increase of compressive strength. When FCU = 0.30 ~ 4.0Mpa, its cohesion c = 0.10 ~ 1.0MPa, which is generally about (20 ~ 30)%, and its internal friction angle changes between 20 ~ 30 degrees. &# 39; S/g  mn
uoh  7Sz5!^
in triaxial shear test, the specimen has a clear and flat shear plane, and the angle between the shear plane and the maximum principal stress plane is about 60 degrees.  AFwdJte9e
{ 2f - 8Z&>
according to the regression analysis of the test results, the relationship between the cohesion c and the unconfined compressive strength FCU of cement soil is approximately a power function, and the formula is as follows: C = 0.2813 * (FCU ^ 0.7078). The condition of the equation is: FCU = 0.3 ~ 1.3mpa& gt; w< &# 39; 0
 u  W %#
compressive molus of cement soil: when the vertical stress reaches 50% unconfined compressive strength, the ratio of stress to strain of cement soil is called deformation molus E50 of cement soil. When FCU = 0.1 ~ 3.5Mpa, E50 = 10 ~ 550MPa. According to the linear regression analysis of the test results, it is obtained that E50 = 126fcu] 3sp w {= ^ (
8zw2zkv2 |
the same explanation is also given in the book of highway foundation treatment manual Foundation treatment and underpinning technology - the third edition has calculation examples for foundation pit slope treatment with mixing piles.

3. It seems to calculate the effective stress. That is to subtract the pore water pressure!

4.

Internal friction angle of silt φ Generally 18-25 °， The cohesion is generally 5-10kpa

Internal friction angle of

round soil φ Generally 18-22 °， The cohesion is very small, which can be regarded as 0

The value of internal friction angle depends on the frictional resistance and interlocking action between soil particles, and the internal friction angle reflects the frictional resistance property of soil. Cohesion is the characteristic index of cohesive soil, which includes the original cohesion formed by the molecular gravity between soil particles and the solidified cohesion formed by the cementation of compounds in soil

Therefore, internal friction angle and cohesion are two mechanical indexes of soil shear strength. The shear strength of soil refers to the ultimate resistance of soil to shear failure. The essence of the strength of soil is the shear capacity of soil

Shear strength index of

soil internal friction angle φ、 Cohesion c φ—— Internal friction angle of soil ° C -- cohesion of soil (kPa)

φ、 C is related to the properties of soil, the experimental methods and conditions. Therefore, when we talk about the strength index, we should indicate its test conditions Extended data:

the shear strength of soil can be considered to be composed of internal friction between particles and cohesion caused by molecular gravity of cement and bound water film, Among them, the interaction among clay particles, water and electricity system is the most common. The interaction between particles may be attractive force or repulsive force

The cohesive force of

soil is e to the combined action of attraction and repulsion between soil particles. Gravity in clay mainly includes the following types:

1, electrostatic gravity

it includes Coulomb force and ion electrostatic force. Because the clay mineral particles are flaky, they have negative charges in the plane part and positive charges in the corners of both sides, and they will attract each other when they contact each other

The van der Waals force is the intermolecular attraction. The opposite dipole attraction between the polarizing molecule and the adjacent polarizing molecule may be inced. When the polarizing molecule approaches the nonpolarizing molecule, it may also ince the latter to attract the opposite dipole

The cementation between particles is a kind of chemical bond. Intergranular cementation includes oxides of carbon, silicon, lead and iron and organic mixtures. These cementitious materials may come from the soil itself, i.e. formed in the process of mineral dissolution and reabsorption, and may also come from the water solution in the soil

When the normally consolidated soil is unloaded after consolidation and becomes overconsolidated soil, its shear strength does not decrease proportionally with the decrease of effective normal stress, but retains most of the strength

The cohesion does not come from the cementation and chemical bonding between clay particles, but from the friction strength as cohesion. It includes the strength caused by suction in unsaturated soil and the strength of occlusal performance in coarse-grained soil

5. 1. Cook the noodles in a pan, remove the water and mix with 1 tbsp sesame oil
2. Add chopped celery, peanut, soy sauce, chili oil and sugar to mix well.

6. Those who haven't been there don't know. Ask the rehab center

7.

City: Nanning

property name: Nanning Baoneng global financial center

bus line: take No.10 bus and get off at the district CPPCC station; Take No.212, No.26, and get off at Xinmin Taoyuan intersection; Take No.97 bus and get off at the east station of Taoyuan intersection in Jiangbei City.

other modes of transportation: Route 1: drive 250 meters along Gonghe road and turn left into Minsheng Road after passing 168 building on the left for about 200 meters; Drive 200 meters along Minsheng Road, turn right towards the South Ring Road and enter the South Ring Road; Drive 620 meters along the South Ring Road, turn left and enter Zhongshan Road; Drive along Zhongshan Road for 610 meters, turn left for 210 meters and go straight to Taoyuan road; Drive along Taoyuan road for 130 meters, turn around and continue to drive along Taoyuan road for 220 meters to reach the destination

(the information is for reference only, and the information of the sales office shall prevail.)

Click to view more real estate information

8. It used to be at the intersection of Deshi, but now it seems to be in Bajiao. It's just the intersection of shiting River Bridge and Deyang. It's a little bit closer to Deyang.

9. Unknown_Error