Path loading method used in determination of rock triaxial strength after failure

A loading path and strength technology, applied in the direction of applying stable tension/compression to test the strength of materials, preparation of test samples, etc., can solve the problem that the impact mechanism is not very clear, and achieve the loading method is simple, easy, and widely practicable , good simulation effect

Inactive Publication Date: 2011-10-19
CHINA UNIV OF MINING & TECH
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Problems solved by technology

However, in 1986, Xu Dongjun and Geng Naiguang analyzed the influence of loading paths on the strength and deformation and failure characteristics of hard and weak rocks, and the results showed that the strength of rocks affected by conventional triaxial and confining pressure stress paths is related to the test lithology: The strength of hard rock under the path of unloading confining pressure is slightly lower than that under conventional triaxial compression; the opposite is true for weak rock; in 2008, Wang Bin et al. analyzed the impact of conventional triaxial compression and The influence of rock strength parameters, the analysis shows that the strength of marble under the path of unloading confining pressure is lower than that of marble under conventional triaxial compression
To sum up, how the loading path affects the rock strength characteristics is still controversial, and its influencing mechanism is still not very clear

Method used

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  • Path loading method used in determination of rock triaxial strength after failure
  • Path loading method used in determination of rock triaxial strength after failure
  • Path loading method used in determination of rock triaxial strength after failure

Examples

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Embodiment 1

[0021] Example 1: figure 2 Shown is the initial confining pressure σ in the loading path experiment 31 =5MPa and final confining pressure σ 32 = 2 times the initial confining pressure σ 31 time experimental curve. First, place the Φ50×100mm marble cylindrical sample in the three-axis airtight pressure cylinder of the servo testing machine. Fill the interior with hydraulic oil until it is completely filled, and apply hydrostatic pressure to the marble cylindrical sample at a loading rate of 0.5MPa / s, so that the confining pressure of the cylindrical sample is loaded to the design initial confining pressure σ 31 =5MPa, keep the initial confining pressure σ 31 = 5MPa remains unchanged, apply an axial bias (σ 1 -σ 31 ), so that the sample is loaded to the control point after the peak strength h ( h The axial strain corresponding to the point is 9.8 ×10 -3 ), to form a rock sample after cracking, apply a hydrostatic pressure of 0.5MPa / s to the rock sample after cracking...

Embodiment 2

[0022] Example 2: image 3 Shown is the initial confining pressure σ in the loading path experiment 31 =5MPa and final confining pressure σ 32 = 4 times the initial confining pressure σ 31 time experimental curve. First, place the cylindrical marble sample (Φ50×100mm) in the triaxial airtight pressure cylinder of the servo testing machine. The pressure cylinder is filled with hydraulic oil until it is completely full, and the hydrostatic pressure is applied to the marble sample at a loading rate of 0.5MPa / s, so that the confining pressure of the sample is loaded to the design pressure value σ 31 =5MPa, keep the initial confining pressure σ 31 = 5MPa remains unchanged, apply an axial bias to the marble sample according to the displacement loading rate of 0.002mm / s (σ 1 -σ 31 ), so that the sample is loaded to the control point after the peak strength h ( h The axial strain corresponding to the point is 9.8 ×10 -3 ), to form a rock sample after fracture, apply a hydro...

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Abstract

The invention discloses a path loading method used in the determination of rock triaxial strength after rock failure. The method comprises the following steps that: first, samples of engineering rock mass requiring testing are collected; the collected samples are prepared into cylindrical samples; upper and lower rigid loading terminals of the samples closely contact a pressure head of a testing machine; hydrostatic pressure is applied to the cylindrical sample, such that an initial confining pressure to the sample is loaded to a designed value; with the initial confining pressure maintained, axial load is then applied to the cylindrical sample, and the pressure to the sample is loaded to a control point after a peak value intensity, such that a rock failure sample is formed; hydrostatic pressure is then applied to the rock failure sample, such that final confining pressure to the sample is loaded to a higher value; with the final confining pressure maintained, axial load is then applied to the rock failure sample, such that a yielding failure is occurred to the rock sample. With the testing method, mechanical characteristics of rock re-failure after failure can be researched, triaxial strength characteristics of rocks after failures can be acquired, and corresponding technical measures can be provided for the problems in failed surrounding rock reinforcing in the field of deep underground engineering.

Description

technical field [0001] The invention relates to a loading path method for measuring the triaxial strength of rocks after cracking, and is especially suitable for simulating the experimental process in which the supporting object of deep underground engineering is the strength of cracked rock mass. Background technique [0002] All kinds of rock engineering, such as underground engineering, dam foundation engineering, joint slope engineering, nuclear waste disposal engineering, etc., are usually in a three-dimensional stress state, so the strength characteristics of rocks in a three-dimensional stress state are important for rock engineering stability evaluation. important mechanical parameters. At present, the triaxial strength of rock is usually obtained by gradually increasing the axial load under constant confining pressure to induce yield failure of the rock sample (conventional triaxial compression path), or loading the rock sample to a certain level under high confinin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/10G01N1/28
Inventor 杨圣奇靖洪文
Owner CHINA UNIV OF MINING & TECH
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