What is the physical difference between the strength index c value of rock and soil? 5

1. c is the cohesive force and the internal friction angle.

2. The ultimate stress of the soil when it reaches yield or fail under the action of external force. Due to shear stress.

It plays a controlling role in the destruction of soil, so the strength of soil usually refers to its shear strength.

3. The principle of determining strength: the strength of soil is generally determined by some characteristic stresses on its stress-strain relationship curve, such as yield stress.

Failure stresses (or peak stresses), etc., these characteristic stress values are related to the type of soil and physical conditions (such as loading time, loading rate, drainage conditions, etc.). In the conventional test that does not consider the influence of loading time or loading rate on soil strength, three typical stress-strain relationship curves can be obtained for different soils, one is when the stress increases with the strain until the peak, the soil cracks, and with the further increase of the strain, the stress gradually decreases from the peak value, and finally reaches the stable stress value. In this regard, people take the peak stress as the failure intensity, and the last stable stress value as the strength after failure.

The second is that when the stress reaches the maximum value, although the stress does not increase, the strain continues to increase, and the maximum stress value can also be taken as the failure strength. The third is that under the larger strain, the stress does not reach the maximum value, but continues to increase with the strain, for which the boundary value of the linear and nonlinear segments is generally taken as the yield strength.

The stress-strain curves described above are obtained from short-term (tens of minutes or hours) tests, and therefore various eigenvalues on the curves.

are considered short-term strength. However, since the life of the project is several decades or even longer, the long-term strength of the actual project needs to be determined.

c is cohesiveness.

for the internal friction angle.

Check for yourself.

Answer]: c The internal friction angle of soil and the cohesion c are the two mechanical indicators of soil shear strength. The failure of the foundation is mainly due to the insufficient shear strength of the bearing layer under the foundation, and the shear failure of the soil, so the theory of shear strength of the soil is the theoretical basis for studying and determining the bearing capacity of the foundation.

In practical engineering, there are three main types of engineering problems related to the shear strength of soil: the bearing capacity of the building foundation, the earth pressure, and the stability of the structure. Item A, consolidation theory is a theory to study the relationship between pore water pressure and effective stress in soil and the deformation of soil to reach the final stable value, and the relevant parameters are permeability coefficient, compressibility coefficient, etc.; B, seepage in the soil refers to the flow of seepage or other fluids in the soil pores in the mountains, and its relevant parameters include water head, flow velocity, pore water pressure, hydraulic slope, permeability, seepage flow, etc.; D, the degree of compactness is generally used to characterize the degree of compactness, and the degree of compactness is related to the porosity.

Water permeability (permeability coefficient), solubility (solubility, relative melting speed), softening (softening coefficient), disintegration.

Answer]: The main mechanical properties of a rock include: uniaxial compressive strength; and the deformation parameters of the rock; Shear resistance and strong appeal. Among them, the base belt and compressive strength are the most basic and commonly used indicators to represent the mechanical properties of rocks.

Rock Physics.

Properties refer to the mechanical, thermal, electrical, acoustic, radiological and other characteristic parameters and physical quantities of rocks.

The physical properties of Zhi rocks include: color, streaks, luster, transparency, hardness, cleavage, fracture, brittleness and ductility, elasticity and flexibility, relative density, magnetism, luminescence, electricity, and other properties. Among the mechanical characteristics are seepage properties and mechanical properties.

The engineering physical performance indexes of rock and soil are as follows:

Physical and mechanical properties such as soil shear strength, elastic modulus, deformation modulus, compressive modulus, cohesion, internal friction angle, etc., should be determined by test according to standard test methods.