KR101503219B1 - Method for the quantitative evaluation of rock cleavage by mechanical properties of rock - Google Patents

Abstract

The present invention relates to a method for quantitatively evaluating a rock cleavage by mechanical properties thereof that can evaluate cleavage strength of the rock through a test and measurement on a volumetric strain of the rock. The method includes the steps of: collecting square rock blocks from granite; cutting the surface of the rock block in a direction parallel to the surface of three cleavages; dividing the rock block into a plurality of rock samples; producing core specimen from the rock sample in a direction perpendicular to three cleavages; applying stress to the core specimens; and measuring mechanical reaction from the stress applied to the core specimens, calculating a volumetric strain (ε_v) for each cleavage from the following equation to evaluate relative strength on the surface of three cleavages.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for evaluating a rock mass using rock mechanics,

The present invention relates to a quantitative evaluation method of a rock using the mechanical properties of rocks, and more particularly, to a quantitative evaluation method of rocks using the mechanical properties of rocks, which can evaluate the strength of the rocks by testing and measuring the volume strain rate .

In the dark body, it has defects such as cleavage, microcracks and the like. Among these defects, cleavage can be divided into cleavage of mineral and cleavage of rock. The cleavage of minerals is broken along the cleavage planes of individual minerals, and the rock cleavage is consistent with the direction of the microcracks distributed within the rocks. The fracture of the rocks, Is governed by the amount of microcracks. Since the characteristics of these minute cracks are ambiguous and unidentified, there is a quantitative volume deformation rate (ε _v ^o , ε _v ^mc ) with volume concept through uniaxial compression test. Quantitative discriminant factors for the identification of three quarries were derived, and quantitative evaluation was performed by formulating the process of vertical grain growth with increasing stress.

In relation to this, granite rocks are quarried in the granite rocks at home and abroad. The relative easiness of the granite body is in the order of rift> 2 grain> 3 hardway, and the three kinds of quarries generally form a mutual vertical relationship. In terms of stone structure in English, the term surface structure corresponding to 1, 2 and 3 is referred to as a rift plane, a grain plane and a hardway plane, Are mutually orthogonal.

On the other hand, the directionality of these quarry facies determines the direction of quarrying and affects the rate of quarrying of quarrying blasting for standard stone. Particularly, the ability to identify vertical grains is particularly important.

In the quarrying area, since the quarry surface of the rock is formed differently by the actual quarry, the direction of the first quarry can not be commonly applied, and since the direction of the first quarry is empirically found in most quarries, have.

SUMMARY OF THE INVENTION The object of the present invention is to solve the above problems and to provide a method and apparatus for controlling the development of granite by testing and measuring the strength, volume deformation rate (ε _v ^o , ε _v ^mc ) And to provide a quantitative evaluation method of the results.

The behavior of the granite in terms of volume strain was analyzed, and the microstructural characteristics of horizontal (ε _v ^o _max ) and vertical (ε _v ^mc ) array were quantified. In particular, the progress of the process was assessed by quantifying the deformation of vertical grains, that is, the process of changing the volume deformation rate according to the increase of the stress increment in the stage III- IV. In this process, the differentiation between the three quarries, that is, the quantitative discriminant factor for identification, is naturally derived. The correlation between these quantitative discriminant factors and the density (ρ) of microcracks derived from the enlarged photographs of existing flakes was examined. The correlation between the two is mutually dependent and highly reliable.

Another object of the present invention is to provide a method and apparatus for determining the segregation strength of a rock in accordance with a change in stress applied to the rock, In order to increase the cost.

That is, for the purpose of providing a method for evaluating three quarries for easy quarrying of rock by deriving the mechanical characteristics of the rock by testing and measuring the strength, strain rate and time (sec) do.

According to the present invention, there is provided a method for recovering granite from a granite; A rock block surface cutting step for cutting the surface of the rock block in a direction parallel to the three pitting surfaces; A rock block dividing step of dividing the rock block into a plurality of square rock samples; A core specimen manufacturing step of fabricating respective core specimens in a direction perpendicular to the three crystal faces of the rock specimen; A stress applying step of applying stress to the core specimens; And a volume quantitative evaluation step of evaluating the relative strength of the three texture surfaces by calculating and analyzing the volume deformation rate (ε _v ) through the following equation by measuring mechanical responses according to the stress applied to the core specimens; The present invention provides a quantitative evaluation method of a texture using the mechanical properties of a rock.

Preferably, in the quantitative evaluation step of the texture, the rock fracture process is divided into four intensity ranges (I, II, III and IV) through a stress-volume strain curve, (Ε _v ^o _max ) is obtained through the volume transformation strain of the texture, and the relative strength of the texture is evaluated as the relative strength of the texture is increased as the porosity (ε _v ^o _max ) of the horizontal joint is increased in stage Ⅰ.

Preferably, in the quantitative evaluation step of the texture, the rock fracture process is divided into four intensity ranges (I, II, III and IV) through a stress-volume strain curve, (N) is obtained through the volume transformation strain of the texture, and the relative strength of the texture is evaluated to be lower as the compression index (n) of the horizontal texture is larger at the I stage in the intensity interval of the 4th stage.

Preferably, in the quantitative evaluation step of the texture, the rock fracture process is divided into four intensity ranges (I, II, III and IV) through a stress-volume strain curve, The volume expansion constant (Q) is obtained through the volume strain rate of the texture, and the relative intensity of the texture is evaluated to be lower as the volume expansion constant (Q) is lowered in the stage III.

Preferably, in the quantitative evaluation step of the texture, the rock fracture process is divided into four intensity ranges (I, II, III and IV) through the stress-volume strain curve, and I and II The volume strain rate according to the stress increment is obtained in step 1, and the relative strength of the texture is evaluated to be lower as the magnitude of the volume strain according to the stress increment is larger in steps I and II.

 The characteristics of volumetric strain rate for the specimens of Geochang and Hacchae granite were derived. These properties represent the quantitative distribution of the volume concept (porosity) for microcracks arranged horizontally and vertically within a rock.

       The volume strain rate characteristics of the 4th step (Ⅰ ~ Ⅳ) and the evaluation result of the micro crack through the enlarged photograph (× 6.5) of the flakes were compared. Through these contrasts, we derived the epidemiological factors that represent the differentiation of the three sides. There are advantages of recognizing three sides in advance through the behavior of the volume strain rate in four steps. In other words, prior to the process of evaluating the flakes with complicated procedures, various evaluation factors are provided for the three aspects. The enlarged photograph of the flake covers a part of the rock, especially the distribution of microcracks is ambiguous and may not be typical. In this case, the quantitative discriminant of three dimensions derived from the large specimen of the international standard is very useful. It is also possible to refer to the data on the overall shape analysis of the volume strain curve. In particular, it is possible to quantitatively evaluate a clear volume concept for six directions (see FIGS. 3 and 4) distributed over three quarries. The preliminary recognition of the quantitative arrangement of these resolutions has an advantage that the anisotropic mechanical behavior can be predicted more clearly.

In addition, quantification of the vertical grain growth process (Ⅲ, Ⅳ) can be used as basic data for setting the conditions of explosive blasting on three sides. There are three types (1-type, 2-type, 3-type) based on the horizontal quarry surface.

In addition, it is possible to deduce the fracture strength of the rock by the mechanical characteristics of the rock due to the change of the stress applied to the rock, so that it is possible to accurately determine the quarry directions of the different rocks according to the rocky mountains, .

Also, it is possible to recognize the distinction between the three quarries beforehand by deriving the mechanical properties of the specimen of larger size prior to the analysis of the micro crack using the flake. Furthermore, it can serve as a basis for classification of granitic rocks in the early stage of development.

The separation of the three quarry facies from the actual granite rocks is in the order of rift plane> grain plane> 3 (hardway plane) , And a jet burner. In other words, it can be used as a reference for the direction setting of the quarry surface in the early stage of the development of granite rocks, and furthermore, the control of the amount of explosive powder in the parallel direction of three sides.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart showing a quantitative evaluation method of the texture developed in granite according to the present invention. FIG.
Fig. 2 is a view showing a three-directional texture developed in granite rocks and a process of sampling rock samples and preparing specimens for an indoor mechanics test.
Figs. 3 (a) and 3 (b) are enlarged photographs of thin flakes fabricated in parallel to the first and second surfaces, respectively, and showing sketch results for microcracks.
Fig. 4 is a schematic view showing various physical quantities of texture (microcracks) in six directions. Fig.
FIG. 5 is a graph showing the fracture process of granite through the axial stress-volume strain curve under uniaxial compression (G-1 specimen).
6 is a view showing a stress-volume strain curve for each of the surfaces according to the present invention.
Fig. 7 is a graph showing the stress-volume strain (ε _v ^o , ε _v ^mc ) of each specimen on each side. Compressive volume (ε _v ^o ) of horizontal array microcracks (ε _v ^o ) (Ε _v ^mc ) of the micro-cracks arranged vertically in FIG.
FIG. 8 is a graph showing the relationship between the stress increment and the volume strain, and showing the behavior of the volume strain rate in four steps according to the stress increment (Geochang granite).
FIG. 9 is a graph showing the relationship between the stress increment and the volume strain rate, and showing the behavior of the volume strain rate in four steps according to the stress increment (Hwacheon granite).
Fig. 10 is a comprehensive relationship diagram of stress increment-volumetric strain rate synthesized in Fig. 8 and Fig. 9, showing the behavior of the volume strain rate in four steps according to the stress increment, and a diagram showing the specific area of the specimen (Geochang and Hapcheon granite).

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for evaluating the ease of seakeeping of a quarry stone using the mechanical properties of rocks according to the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a quantitative evaluation method of the texture developed in rocks, especially granites, and quantitatively characterizes the microstructures of microstructures (microcracks) primarily through enlarged photographs of the flakes. Secondly, the fracture process of the 4th step (Ⅰ ~ Ⅳ) is derived on the volume strain rate (ε _v ) curve. In other words, the strength in four steps (σ ₁ ^c , σ ₁ ⁱ , σ ₁ ⁱⁱ And σ ₁ ^f ), in particular the volume strain (ε _v ^o , ε _v ^mc ), were tested and measured.

In other words, the distribution of microcracks associated with the three quarries forming mutual verticals in the granite quarry and the volume deformation rates indicating the porosity (volume) of the crystals are compared with each other, and the volume concept for horizontal and vertical grains forming these three quarries Of the total.

On the other hand, the volumetric strain rate of the three dimensional volume concept (porosity) of the horizontal and vertical grains was derived using the international standard specification (NX size), and the distribution of the two - dimensional microcracks derived from the enlarged photograph of the flakes was compared. This comprehensive contrast gives a clearer assessment of the three quarries and the results of the six directions presented in the diagram (see Figures 3 and 4).

(Ε _v ) curves obtained by using the deformation rate (ε _a ) and transverse strain (ε _l ) data of three specimens of Geocheong and Hapcheon granite ) Were derived. It is possible to derive the volumetric strain rates (ε _v ^o , ε _v ^mc ) for each step through the classification of these four steps.

The strain-volume strain rate relationship diagram was created and quantified with respect to the horizontal deflection at stage I. In particular, it is possible to quantify the incremental growth process (progressivity) by quantifying the vertical grains as the stress increment increases at Ⅱ → Ⅲ → Ⅳ. In addition, the differentiation between the three specimens was evaluated through the morphological analysis of the stress - strain curves.

The correlation between the distribution of microcracks shown in Figs. 3 and 4, and the mechanical properties of stages I to IV was confirmed. This mutual contrast makes it possible to gain a clear perception of the effects on the mechanical properties of the resolution, as well as the inherent characteristics of the resolution.

On the other hand, quantitative discriminant factors of volume concept for the identification of three quarries were derived. We also quantitatively evaluated the growth process of vertical grain (Ⅲ ~ Ⅳ). It can be used as basic data for setting the condition of explosive blasting. The rocks were granite in Geochang area and Hapcheon area.

1 is a flowchart illustrating a method for evaluating the ease of seakeeping of a quarry stone using the mechanical properties of rocks according to the present invention.

1. Rock block extraction step ( S110 )

The rock blocks to be used for the samples were collected from Jurassic Granite (Gahang granite, G: G) of Sangpuri (Gyeongnam), Gyeongnam Province. Geochang granite is a Jurassic granite with inclusions of Precambrian semi-metamorphic gneiss and biotite gneiss. This rock is greyish white, is a neutral villa of isoplasma, and the size of quartz and feldspar is 2 ~ 6mm. The sampling depth of the rock samples is about 20m. In the schematic diagram showing the three-dimensional relationship, the first plane forms a horizontal plane, the second plane forms a north-east direction, and the third plane forms a vertical plane (see a to c in FIG. 2).

Samples were collected from Jurassic granite (Hwacheon granite, specimen: H) of Ugokgori (Shinhwa statue), Hacchun County, Kyungnam Province. Hapcheon granite is light gray and is composed of coarse-grained granite. The size of quartz and feldspar is 2 ~ 9mm. The sampling depth of the rock samples is about 17m.

A square rock block of about 1.2 m in size is obtained in parallel with the first, second and third surfaces of the two stalagmites (see Fig. 2 (c)). A stone block of about 35 cm in size was obtained from a square block of about 1.2 m in size, which was parallel to the first, second, and third sides of the rocks (see Fig. 2 (d)).

2. Stone block surface cutting step ( S120 )

The sampled rock block is cut by using a large rock cutting saw to cut the rock surface in a direction parallel to the three quarrying surfaces to make it flat (see Fig. 2e).

3. Rock block partitioning step ( S130 )

The rock blocks whose surfaces were cut in a direction parallel to the three quarry surfaces were divided into a plurality of square rock samples (see Fig. 2 f). The rock samples thus divided are easy to produce specimens and slabs in the room.

4. Specification  Production stage ( S140 )

NX - sized cores were obtained by working in the vertical direction on the first, second, and third sides of the divided rock samples, respectively. The dimensions of the NX core specimen for the room mechanics test are 5.4 cm in diameter and 10.8 cm in length. NX-sized specimens for measuring the strength, strain, and elapsed time in four steps were made perpendicular to the first, second, and third faces, respectively, and named as -1, -2, and -3 specimens, respectively .

Here, -1 means 1, 2 means 2, and -3 means an axis perpendicular to the plane 3 (see g in FIG. 2).

Preferably, the square rock samples sampled in the sampling step of the rock sample are taken with their mutually orthogonal lift surfaces, grain surfaces and hardway surfaces on the outer surface, and on the lift surface, grain surfaces and hardway surfaces Thereby producing orthogonal specimens.

5. Observation of microcracks

In granite, two mutually orthogonal structures (microcracks) can be measured on the flakes produced parallel to the three-way quarry. Some of the sketch results for micro-cracks and an enlarged picture of the lamellae of geochang and Hapcheon granite are shown in Figs. 3 (a) and 3 (b), respectively.

As shown in the schematic diagram showing the correlation between the quarry surface and the microcracks shown in FIG. 4, the grain 1 and the hardway 2 in the flakes parallel to the first surface and the hardway 2 in the flakes parallel to the first surface, Microcracks of grain 2 and rift 2 can be measured in rift 1, hardway 1 and lamella parallel to plane 3, respectively. The length, average length and density of the microcracks associated with the six directions presented in the resolution diagram are shown in FIG.

On the other hand, the frequency, average length and density of the microcracks in the quartz and feldspar were calculated by the irradiation method, and the characteristics of the microcracks were determined by mechanically connecting the microcracks in the six directions shown in FIG. Analyze the characteristics. That is, the correlation between the various quantitative discriminating factors and the density of the microcracks discussed above.

6. Stress application, step strength and Strain rate  Measuring step ( S150 )

The compressive strength meter used for the measurement of the strain rate and the required time (sec) according to the continuous stress (strength) applied to the specimen was a servo bulb type automatic capacity measuring device having a compression capacity of 160 tons of MTS (Material Testing System) Control system. The measured value is automatically recorded by the A / D converter attached to the computer. The stroke must be controlled in the destructive test. In this test, the speed of the upward stroke of the stress applied is determined to be 0.1 mm / min. Respectively.

The uniaxial compressive strength and strain rate were measured using a displacement transducer for 20 mm (KYOWA, DF20D), an extensometer (MTS, Model 1632.12c), a dynamic strain amplifier (KYOWA, DMP-G), XY ₁ Y ₂ recorder (WATANABE, WX4302) Respectively. On the other hand, the stress, axial strain, ε _a , lateral strain (ε _l ) and time required in seconds are automatically recorded in the test system. The test was conducted by Korea Institute of Geoscience and Mineral Resources. The volumetric strain (ε _v ) was calculated from the following equation (1), where ε _a is the tensile strain of the NX core and ε _l is the transverse strain of the NX core. have.

The axial strain, transverse strain, and volumetric strain rate of each successive stress stage can be summarized as shown in Table 1 of Hapcheon granite.

Stress
(kg / cm ² ) H-1 H-2 H-3 ε _a (-) ε _l (+) ε _v (-) ε _a (-) ε _l (+) ε _v (-) ε _a (-) ε _l (+) ε _v (-) 50 1501 6 1487 1486 6 1473 66 0 66 100 1907 17 1873 1863 21 1818 696 15 665 200 2460 57 2525 2425 58 2307 1428 47 1332 300 3102 96 2909 2985 109 2765 2004 102 1799 400 3469 141 3186 3412 161 3090 2335 146 2041 500 3793 185 3422 3780 208 3364 2612 192 2213 600 4114 238 3638 4092 258 3576 2912 243 2398 700 4365 284 3796 4321 312 3697 3183 305 2547 800 4608 332 3943 4634 375 3883 3375 352 2670 900 4855 385 4082 4856 429 3995 3610 420 2768 1000 5162 455 4251 5104 499 4105 3866 492 2880 1100 5339 499 4339 5290 553 4183 4073 562 2939 1200 5567 563 4440 5538 629 4279 4321 648 3024 1300 5804 634 4535 5774 712 4348 4509 720 3068 1400 5983 688 4606 5935 784 4366 4678 790 3097 1500 6213 767 4677 6169 893 4381 4838 862 3112 1600 6456 855 4743 6390 1017 4354 5052 973 3106 1700 6693 965 4761 6609 1166 4276 5125 1065 3083 1800 6873 1072 4727 6808 1302 4202 5439 1210 3018 1900 7112 1253 4604 7049 1541 3965 5638 1376 2884 2000 7362 1528 4305 7214 1778 3658 5814 1530 2751 2100 7607 1959 3687 7469 2218 3031 6027 1818 2390 2200 7852 2552 2746 7724 2870 1984 6127 2350 1425 2211 7768 3150 1468 2230 6180 2634 87 2300 8106 3460 1185 2340 8246 4114 18

Table 1 shows the values of axial, transverse and volume strain (x 10 ^-6 ) of Hacchin granite (H) against stress.

6-1 Stress - Volume strain rate  4 steps of curve

The criteria for classifying the rock destruction process through the stress-volume strain curves are as follows. (Ⅱ), which is an almost constant rate of increase (Ⅱ), the inflection point is formed, and the curved line is inverted to cause rapid volumetric expansion. And step 3 is divided into step 3.

Ⅰ step (0 ≤ σ ₁ ^c ): the section where horizontal solidification is sealed by compression, Ⅱ step (σ ₁ ^c ≤σ σ ₁ ⁱ ): section with elastic properties, Ⅲ ₁ (σ ₁ ⁱ ≤ σ ≤σ ₁ ^ii): Although the opening by vertical connection is generated according to the load increase, and a steady-state, the section is broken by the tensile stress occurring, ⅳ step ⁽ⁱⁱ ≤σ≤σ σ ₁ ^f _{1, 1} ^f σ: breaking strength ): An unstable crack propagates due to a further increased load, and shear fracture occurs. The intensity for each step is σ ₁ ^c , σ ₁ ⁱ , σ ₁ ⁱⁱ And? ₁ ^f , respectively (Fig. 5). The stress-strain curves of Geochang and Hapcheon granite thus obtained are shown in Fig.

7. Quantitative evaluation step of resolution ( S160 )

7-1 Volume of horizontal resolution (ε _v ^o )

The porosity (oa, 10 ^-6 ) of the horizontal column in Phase I is the compressive strain (ε _v ^o _max ) and represents the horizontal grain volume developed inside the rock (Fig. 5). The porosity (ε _v ^o , ε _v ^o _max ) of the horizontal grains with increasing stress is summarized in Table I (0 ≤ σ ₁ ^c ) (Table 2, Table 3) - volume deformation rate (ε _v ^o ) (Fig. 7 (a) and (d)).

_One
(kg / cm ² ) The volume strain of microcracks, ε _v ^o ( ^10-3 ) G-1 G-2 G-3 H-1 H-2 H-3 0 (? _V ^o _max ) 4.43 2.05 1.34 2.87 2.58 1.67 50 1.33 1.22 1.32 1.40 0.99 1.55 100 0.74 0.88 1.18 1.11 0.85 1.07 150 0.51 0.62 200 0.40 0.62 0.81 0.55 0.44 0.48 220 250 280 290 0 300 0.22 0.38 0.33 0.25 0.18 320 0 390 0 (? ₁ ^c ) 400 0.18 0.07 0.07 490 0 510 0 590 0

Table 2 shows the volumetric strain (ε _v ^o ) of various microcracks due to stress in stage Ⅰ.

Rock name Sample
No. ε _v ^o _max (? V / V)
(× 10 ^-3 ) Geochang granite
(G) G-1 4.43 G-2 2.05 G-3 1.34 Average 2.60 Hapcheon granite
(H) H-1 2.87 H-2 2.58 H-3 1.67 Average 2.37

Table 3 shows the volume strain (ε _v ^o _max ) of microcracks.

The horizontal grain volume decreases with increasing stress in the compression zone (stage I), and the slope decreases sharply by forming an inflection point at the initial stage of stress. Compared to Geochang granite, the Hwacheon granite has a high overlap between -1, -2 and -3 specimens, and the overall slopes are similar. It is indicated that the porosity of the horizontal textures between the three specimens is not larger than that of Geochang granite.

The stress (σ ₁ ^c ) at which the compression is completed in step I is proportional to the porosity (volume) of the horizontal joint for each specimen, and is expressed in the order of -1>-2> -3 specimens. In Hacchin granite with low grain density and high compressive strength, compressive stress is higher than Geochang granite (Table 2).

      In Geochang and Hapcheon granites, the porosity of horizontal grains is in the order of -1> -2> -3 specimens, showing the relative volume difference between the rift microcrack, grain microcrack and hardway microcrack shown in FIG.

      The average porosity of the horizontal grains from the -1, -2 and -3 specimens of Geochang and Hapcheon granites (Table 3) is Geochang granite (2.60)> Hwacheon granite (2.37) The sum of density of microcracks is coincided with the difference in size of the average porosity between rocks, with Geochang granite (ρ: 0.66)> Hwacheon granite (ρ: 0.54).

7-2 Vertical resolution volume strain (ε _v ^mc )

In step Ⅲ _{^{(σ 1 i ≤σ≤σ 1 ii)}} ~ Ⅳ step (σ ₁ ⁱⁱ ≤σ≤σ ₁ ^f) is a period in which the vertical spread result is less stable and unstable. (Fig. 7 (b), (e) and (c), (f) show the relationship between the vertical void porosity and the volume strain rate (ε _v ^mc ) along with the continuous stress increase (Table 4).

σ ₁
(kg / cm ² ) The volume strain of microcracks, ε _v ^mc (× 10 ^-3 ) G-1 G-2 G-3 H-1 H-2 H-3 800 0.18 900 0.16 0.31 1000 0.13 0.28 0.46 0.05 1100 0.21 0.35 0.72 0.15 1200 0.36 0.47 0.84 0.23 0.10 1300 0.49 0.63 1.11 0.31 0.19 1400 0.67 0.85 3.14 0.13 0.45 0.30 1500 0.90 1.10 7.48 0.18 0.58 0.38 1587 11.94 1600 1.25 1.48 0.26 0.78 0.52 1700 1.65 2.00 0.37 0.99 0.69 1800 2.25 3.09 0.56 1.27 0.85 1887 4.48 1900 3.62 0.76 1.63 1.11 2000 6.32 1.23 2.13 1.37 2048 13.97 (? ₁ ^f ) 2100 1.97 3.02 1.86 2200 3.41 3.00 2211 4.65 2230 3.60 2340 5.70 σ ₁ ⁱ 910 720 610 1190 920 980 σ ₁ ⁱⁱ 1301 1316 1170 1677 1523 1464 Destruction time (sec.) 300 230 202 257 215 156

Table 4 shows the volume strain (ε _v ^mc ) of the stress versus microcracks.

The volumetric deformation rate of the vertical settlement of Geochang and Hapcheon granite increases with the increase of stress in the Ⅲ ~ Ⅳ stage, and the slope increases rapidly by forming the inflection point in the late stage of the unstable propagation period of Ⅳ. This phenomenon is most pronounced in the three specimens of geochang granite where lift 1 and grain 1 are arranged vertically. On the other hand, the overall slopes of -1, -2 and -3 specimens are similar to each other in Geocang granite, indicating that the volume difference of microcracks between the three specimens is relatively small (Fig. 7 B and e).

The fracture time (sec.) Was -3 (202) <-2 (230) <-1 (in terms of the volume of the vertical grains) 300) specimens. Compared to Hacchin granite, the overall microcrack density and the density difference of microcracks between the 1st (lift 1: ρ = 0.28) and 2nd (grain 1: ρ = 0.11) The arrangement between the three specimens in Geocang granite is more clear. Inside the -3 specimen, two sets of microcracks, rift microcrack (lift 1) and grain microcrack (grain 1) develop. The microcracks are arranged in parallel with the compressive stress and indicate a sudden volume expansion, i.e., accompanied by a rupture phenomenon, as compared with the -1 and -2 specimens (Fig. 7B).

However, in Hacchin granite, the difference in density of microcracks between 1st (lift 1: ρ = 0.14) and 2nd (grain 1: ρ = 0.12) The average length is in the order of grain 1 (2.56 mm)> lift 1 (2.37 mm). In Hapcheon granite, where the compressive strength is high and the result of No. 1 result is relatively low, the arrangement between specimens (-2 <-3 <-1) is less than geochang granite (Fig. Comparing the two rocks, they have an ideal arrangement in geochemical granite.

However, the relationship between the three specimens can be seen in the stress - volume strain diagram of Geochang and Hapcheon granites. The specimens occupying the middle area, G-2 specimen of Geochang granite and H-3 specimen of Hacchae granite, can have lower volume strain (ε _v ^mc ) than specimens of the upper and lower left regions (Figs. 7B and 7E).

The slope of the linear exponential function is -2 <-1 <-3 in Geochang granite and -3 <-2 <-1 in Hwacheon granite. . The regularity of the slope between the two rocks is lacking. When the commonality between the two rocks is derived, the -1 specimen occupies the upper right area (c and f in FIG. 7).

7-3 Stress - Volume strain rate  equation

In the stress-volumetric strain curves, we derive equations for each stage and quantify the destruction process of sandstones. This method was extended to analyze the microcracks (horizontal and vertical grain) of Geochang and Hapcheon granites.

The equation of phase Ⅰ: the linear volumetric strain line ab in the stress-volume strain curve (Fig. 5, Fig. 6) connects the ab with the volume strain axis. The length oa is the porosity of the inside- In step I, the following equation (2) is obtained.

Where ε _v ^e is the linear volumetric strain and ε _v ^o is the volumetric compacting strain in which the wire strand crack compresses in proportion to the increase in axial stress (0 σ ₁ ≤σ ₁ ^c ) to be. The linear volumetric strain ε _v ^e is given by the following equation (3).

Where K is the slope of the linear deformation line ab. When called in any axial stress σ Ⅰ step _1, the so-called incremental stress ^{_{(stress increment, (σ 1 c}} -σ 1) / σ 1 c) and ε _v ^o Can be expressed by an exponential function as shown in Equation (4) below.

Here, when σ ₁ = 0, ε _v ^o = a, so a can be used as the porosity of the wire seam crack (horizontal grain) and n as the compaction exponent.

The equations of stages III and IV: The volume strain curves in steps III and IV in the stress-strain curves (FIG. 5 and FIG. 6) are shown in Equation 5 below.

Where ε _v ^mc is the volumetric microcrack strain due to microcracks.

The volume strain rate equation by crack propagation for the stress increment ((? _{1 -} ? ₁ ⁱ ) /? ₁ ⁱ ) in steps III and IV is shown in Equation (6).

Where Q is the microcracking or dilatancy constant, and m is the volumetric microcrack strain hardening exponent of microcracks, respectively.

In Equation (1) (Equation 4) and Equations (III) and (IV) (Equation 6), constants and exponents of a and n, Q and m are respectively present.

The tremendously and Hapcheon of 3 of granite one specimen the stress-strain relationship is a volume of the stress Ⅰ phase through (6) increments and ε _v ^o And the stress increment and ε _v ^mc in Ⅲ-Ⅳ are summarized respectively (Table 5, Table 6).

 Stress increment Volume Deformation Rate of Microcracks (× 10 ^-3 ) ε _v ^o ε _v ^mc Ⅰ Ⅲ IV G-1 G-2 G-3 G-1 G-2 G-3 G-1 G-2 G-3 One 4.43 0.87 1.34 0.74 0.81 0.61 0.51 One 2.05 0.84 1.22 0.68 0.88 0.37 0.62 1.00 1.34 0.83 1.32 0.66 1.18 0.31 0.81 0.04 0.13 0.09 0.16 0.14 0.23 0.24 0.42 0.3 0.6 0.1 0.06 0.15 0.08 0.2 0.09 0.28 0.13 0.4 0.43 0.44 0.48 0.45 0.54 0.12 0.12 0.32 0.43 0.39 0.63 0.47 0.91 0.35 0.83 0.39 One 0.43 1.25 0.49 2.46 0.54 6.33 0.55 11.16 0.48 0.68 0.52 0.86 0.55 1.23 0.57 1.74 0.6 2.82 0.61 3.66 0.49 1.03 0.53 1.32 0.56 2.78 0.59 5.21 0.61 9.52

Table 5 shows the stress increment vs. volume strain of microcracks for geochemical granite. Here, the stress increment is Ⅰ: (σ ₁ ^c -σ ₁ ) / σ ₁ ^c , and Ⅲ, Ⅳ step: (σ ₁ -σ ₁ ⁱ ) / σ ₁ ⁱ .

 Stress increment Volume Deformation Rate of Microcracks ( ^10-3 ) ε _v ^o ε _v ^mc Ⅰ Ⅲ IV H-1 H-2 H-3 H-1 H-2 H-3 H-1 H-2 H-3 One 2.82 0.91 1.45 0.83 1.12 0.66 0.655 0.49 0.33 0.32 0.21 One 2.62 0.9 1.27 0.8 1.05 0.7 0.83 0.6 0.62 0.41 0.28 0.21 0.15 One 1.64 0.89 1.11 0.79 One 0.59 0.55 0.36 0.26 0.28 0.18 0.18 0.1 0.15 0.09 0.2 0.15 0.25 0.24 0.28 0.36 0.23 0.18 0.32 0.35 0.39 0.6 0.18 0.12 0.3 0.28 0.33 0.36 0.33 0.48 0.4 1.18 0.45 3.05 0.49 5.92 0.42 0.64 0.48 1.1 0.54 2 0.581 4.66 0.584 4.74 0.38 0.51 0.45 0.87 0.51 1.39 0.55 3.5 0.56 3.7

Table 6 shows the stress increment vs. volume strain of microcracks for Hwacheon granite. Here, the stress increment is Ⅰ: (σ ₁ ^c -σ ₁ ) / σ ₁ ^c , and Ⅲ, Ⅳ step: (σ ₁ -σ ₁ ⁱ ) / σ ₁ ⁱ .

In the relationship diagrams of the stress increment-volumetric strain rates (ε _v ^o , ε _v ^mc ) (FIGS. 8 and 9), the equation of the linear power function is obtained for each specimen and the values of the constants a and Q and the exponents n and m are derived (Table 7, Table 8), quantification of the growth process of the III-IV stage related to the micro-cracks in the horizontally aligned microstructures, and the microstructures in the vertically aligned microstructures. The deformation characteristics of each specimen were compared with each other.

step Ⅰ Ⅲ IV ε _v ^o = a [(σ ₁ ^c -σ ₁ ) / σ ₁ ^c ] ⁿ ? _v ^mc = Q [(? _{1 -} ? ₁ ⁱ ) /? ₁ ⁱ ] ^m Value a ^*
( ^10-3 ) an R ² Q m R ² Q m R ² ( ^10-3 ) ( ^10-3 ) ( ^10-3 ) G-1
G-2
G-3 4.43
2.05
1.34 3.30 4.15 0.90 1.64 1.08 0.85
1.39 0.45 0.98 1.23 0.76 0.90
1.49 1.53 0.90
2.48 1.44 0.99 182.3 5.46 0.88
101.5 7.08 0.94
1239.7 10.29 0.93 Average 2.61 2.11 1.89 0.94 1.73 1.24 0.93 507.8 7.61 0.92 An (%) 118.5 90.5 195.4 8.5 72.2 61.9 9.7 224.1 63.5 6.5

Table 7 shows the relationship between stress increment and volume strain for Geochang granite. Where An is the anisotropy coefficient (%) and can be calculated as Max-Min / average. R ² is a correlation coefficient.

step Ⅰ Ⅲ IV ε _v ^o = a [(σ ₁ ^c -σ ₁ ) / σ ₁ ^c ] ⁿ ? _v ^mc = Q [(? _{1 -} ? ₁ ⁱ ) /? ₁ ⁱ ] ^m Value a ^*
( ^10-3 ) an R ² Q m R ² Q m R ² ( ^10-3 ) ( ^10-3 ) ( ^10-3 ) H-1
H-2
H-3 2.87
2.58
1.67 1.91 2.14 0.93 1.67 1.70 0.93
1.42 1.60 0.99 5.11 2.15 0.98
4.82 2.25 0.99
2.44 1.76 0.99 492.5 6.35 0.98
120.2 6.20 0.95
62.9 5.15 0.92 Average 2.37 1.67 1.81 0.95 4.12 2.05 0.99 225.2 5.90 0.95 An (%) 50.6 29.4 29.8 6.3 64.8 23.9 1.0 190.8 20.3 6.3

Table 8 shows the stress increment-volume strain rate relationship for Hwacheon granite. Where R ² is the correlation coefficient.

7-4 Compression Index and Porosity in Phase I

The compressive index (n) derived from step I (Figs. 8 and 9) is in the order of -1> -2> -3 specimens in the same order as the porosity of the horizontal joints. (Table 7, Table 8).

The compressive index of geochemical granite is in the order of -1 (4.15)> -2 (1.08)> -3 (0.45), which reflects the relative difference in the horizontal resolution developed inside the specimen. Compression indices ranged from 0.45 to 4.15 (mean 1.89), with an estimated anisotropy factor of 195.4% (Table 7).

The compressive index of Hwacheon granite is in the order of -1 (2.14)> -2 (1.70)> -3 (1.60), which is the same as that of Geochang granite. Compression indices ranged from 1.60 to 2.14 (mean 1.81), with an estimated anisotropy factor of 29.8% (Table 8).

The a ^* (ε _v ^o _max ), which corresponds to the porosity of the horizontal joint, and the constant a, which is derived from the correlation, are in proportion to each other and are in the order of -1>-2> -3 specimens. The anisotropy coefficients of a ^* and a are in the order of Geochang granite (90.5 ~ 118.3%) and Hapcheon granite (29.8 ~ 50.6%) (Table 7, Table 8).

On the other hand, the overall mean value and anisotropy coefficient of the three specimens for compressive index are in the order of Geochang granite> Hapcheon granite, which reflects the relative difference of horizontal grains.

Change in Correlation Coefficient: The relationship between the stress increment and the volume deformation ratio (Fig. 8 and Fig. 9) In the case of Geochang and Hapcheon granites, the correlation coefficient (R ² ) in the ^first stage is -2 and -1 specimens (0.85-0.93) <-3 specimens (R ² = 0.98-0.99). Correlation coefficients in stage Ⅲ are -1 and -2 (0.900 ~ 0.993) <-3 specimen (R ² = 0.991 ~ 0.995). In both rocks, the correlation coefficient of linear power function is high in -3 specimen. This distribution characteristic represents the identification criterion of the -3 specimen (Figs. 8 and 9).

7-5 Step II Volume strain rate

A relationship diagram of the stress increment-volume strain (ε _v ) in step II (low strength region) was prepared (FIGS. 8 and 9). The order of -1 (upper region)>-2> -3 specimens are arranged in order from Geochang and Hapcheon granite. When the slope of the first order function (R ² = 0.98 <) was observed, Geochang granite (mean 0.67) was -3 (0.78)> -1 (0.68)> -2 (0.57) )> -2 (0.73)> -3 (0.67), and Hapcheon granite is more sequential.

7-6 The hardening index in steps III-IV

Ⅲ (Σ ₁ - σ ₁ ⁱ ) / σ is a constant that is conceptually opposite to the compression index (n), as the hardening index increases. ₁ ⁱ ) - This means that the curvilinear gradient of the volume strain (ε _v ^mc ) is large and the volume expansion with respect to the stress increment is relatively large (FIGS. 5 and 6).

The hardening index between three specimens of Geochang granite was compared. In the third stage, the order of -2 (1.53)> -3 (1.44)> -1 (0.76) is shown. However, in stage IV, the final stage of the destruction process, -3 (10.29)> -2 (7.08)> -1 (5.46) is the order of the specimen (Table 7).

In particular, the hardening index of the -3 specimen, which is vertically aligned with the result No. 1, is the highest. These results are summarized as follows: In compression test, the compressive force in each specimen and the arrangement of density (ρ) sum of two microcracks horizontally arranged, ie, -3 (Rift 1 + Grain 2, 0.39)> -2 (Rift 2 + Hadway 2, 0.19) > -1 (Grain 2 + Hadway 1, 0.88) (FIG. 4). On the other hand, the anisotropy coefficient of the hardening index is lower than that of the Ⅰ stage compression index (195.4%), followed by Ⅳ stage (63.5%) and Ⅲ stage (61.9%).

The hardening indices between three specimens of Hapcheon granite were compared. In the third stage, the order is -2 (2.25)> -1 (2.15)> -3 (1.76). However, in the IV stage, it is in the order of -1 (6.35)> -2 (6.20)> -3 (5.15), and is in reverse order with Geochang granite (Table 8). The calculated anisotropy coefficients are in the order of Ⅲ (23.9%) and Ⅳ (20.3%).

7-7 Volumetric expansion constants in stages III-IV

The volumetric expansion constant (Q, x 10 ^-3 ) in steps III to IV is a conceptually contradictory constant to the horizontal cavity porosity of the step (Figs. 8 and 9).

The volumetric expansion constants between three specimens of Geocang granite were compared. In the third stage, the order of -1 (1.23) <-2 (1.49) <-3 (2.48) is shown in the reverse order of the horizontal grain porosity of the first stage (-1> -2> -3 specimen). However, in the IV stage, -2 (101.5), -1 (182.3) <-3 (1239.7) is the order of the specimens. The calculated anisotropy coefficients are in the order of phase Ⅲ (72.2%) <Ⅰ (90.5%) <Ⅳ (224.1%).

The volumetric expansion constants of three specimens of Hacchae granite were compared. There is a difference in the order of the horizontal grain porosity in the first stage (-1> -2> -3 specimen). In the third stage, -3 (2.44) <-2 (4.82) <-1 (5.11), and in the fourth stage, -3 (62.9) <-2 (120.2) <-1 (492.5). There is a lack of commonality among the three specimens of Geochang granite, which has a higher resolution density than Hussain granite. The calculated anisotropy coefficients are in the order of I (29.4%) <III (64.8%) <IV (190.8%). Overall, the anisotropic modulus of Ⅰ, Ⅲ and Ⅳ is lower than that of Geochang granite.

7-8 Volume Expansion Constant, Inversion of Hardening Index

Ⅲ The volume expansion constant (Q, 10 ^-3 ) and the hardening index (m) were compared. The volumetric expansion constants in Phase III are as follows: Hwacheon granite (4.12)> Geochang granite (1.73), hardening index, Hwacheon granite (2.05), and Geochang granite (1.24). In stage Ⅲ, Hapcheon granite with high strength has larger volume expansion constant and hardening index value. However, in the IV stage, the volume expansion coefficients are in the order of geochang granite (507.8)> Hapcheon granite (225.2), and hardening index geochang granite (7.61)> Hapcheon granite (5.90) (Table 7, Table 8). This reversal in step IV is due to the difference in density (rho) between the two rocks. That is, the sum of density for all microcracks having various directions in three planes is the sum of the geomorphic granite (1.47)> Hwacheon granite (1.34) (Fig. 4).

On the other hand, the correlation coefficients (R ² ) between volumetric expansion constant and hardening index Ⅲ ~ Ⅳ were in the order of Hapcheon granite (0.95 ~ 0.99) and Geochang granite (0.92 ~ 0.93) (Table 7, Table 8). It is inversed with the grain density between the two rocks, indicating that the degree of anisotropy between three specimens of Geocang granite, ie, grain density difference, is relatively large compared to Hacchae granite.

7-9 steps Specimen  Changes in slope and intrinsic area

8, and Fig. 9, it is possible to classify the relationships among the rocks, the specimens, and the stresses in four stages, and the stress increment-volumetric strain rate (ε _v ^o , ε _v, ε _v ^mc ) (Fig. 10). The derived distribution characteristics are as follows.

Phase I: In general, it is arranged in the order of -3 <-2 <-1 specimen in Geochang and Hapcheon granite. The larger the porosity of the horizontal joint, the larger the volume deformation rate is due to the effect of the compression amount.

Phase II: Sequentially in the order of -3 <-2 <-1 (upper region) specimen in common in Geochang and Hapcheon granites. It should be noted that the slope and the change of the area between the specimens are seen from Ⅱ → Ⅲ → Ⅳ. That is, the slope of the -2, -3 specimen is relatively increased compared to the -1 specimen, and occupies the upper right area. In particular, the slope of the primary function of phase Ⅱ is the largest at -3 (0.78) of Geochang granite and -1 (0.84) of Hacchae granite. In step IV, there is a common characteristic that maintains the highest slope (m).

In the case of Geocang granite, the slope of stage IV (hardening index m) shows an ideal arrangement of -1 <-2 <-3 specimen. The increase in the slope of the double-3 specimen is most apparent. These results are summarized as follows: (1) Rift 1 + Grain 2, 0.39)> -2 (Rift 2 + Hadway 2, 0.19)> -1 (Grain 2 + Hadway 1, 0.88) (FIG. 4). The key point of this study is the stepwise slope of the specimen and the gradual change of the inherent area, and represents the new generation, growth and progress of the existing vertical resolution as the compressive force increases.

Ⅲ ~ Ⅳ: In case of Geochang and Hapcheon granites, they are arranged in the order of -1 <-3 <-2 specimen. -1 specimen is arranged on the left side, the lower region, the -3 specimen is arranged in the middle region, and the -2 specimen is arranged in the right region to occupy the upper region. In case of Hapcheon granite, -2, -3 specimens in Ⅲ stage tend to overlap each other. However, the volume strain rate (ε _v ^mc ) increases in the order of -3 <-2 specimens as the stress increment increases.

There is a difference in the degree of overlap between the -2 and -3 specimens due to the difference in density of vertical grains between the two rocks. The degree of overlap is higher in Hacchin granite, which has a lower density of micro cracks arranged vertically (Fig. 10).

7-10 Linear Strained  inclination

The slope of the linear deformation line ab between the two rocks (× 10 ⁵ kg / cm ² , K) was compared (FIGS. 5 and 6). The mean values of Hapcheon granite (7.33) and Geochang granite (4.91) are in descending order. The slope of Hapcheon granite with uniaxial compression strength and microcrack density (Fig. 4) is higher.

The slope of the three specimens was -2 (5.71)> -1 (5.47)> -3 (3.55) for Geocang granite and -3 (7.77)> -1 (7.50)> -2 It is in order. The regularity between the specimens of both rocks is lacking. However, the slope of the -3 specimen of Geocang granite is the lowest (Fig. 6A).

7-11 Volume strain rate  The values of? And?

The shape of the stress-strain curve was studied. The intersection angle (α) and the angle (β) between the line cd and the horizontal line of the linear deformation line ab of the stage II and the so-called 'initial linear deformation line' cd of the stage IV were obtained. The derivation of the initial linear strain line is possible in the continuous stress and volume strain data per second (Fig. 5).

The α and β angles between the two rocks are large in Hapcheon granite, which has high uniaxial compressive strength and low microcrack density. The angle α was Hwacheon granite (95.3 ~ 98, average value: 96.6), Geochang granite (67.2 ~ 100.9, average value: 84.9), β angle was Hwacheon granite (21.5 ~ 27.6, average value: 28.9) : 17.9). On the other hand, the anisotropy coefficient (%) of α and β angle is in the order of geochang granite (39.6 ~ 133.2)> Hwacheon granite (2.7 ~ 21.1).

The anisotropy coefficient (%) of α and β angle is in the order of β (21.5 ~ 133.2)> α (2.7 ~ 39.6), and β angle is more sensitive than α angle. The difference between the average values of α and β for the two rocks is 11.7 ° (α)> 11 ° (β).

The three angles of G-2 and Hwacheon granite of Geocang granite form an obtuse angle (α <90) and a gentle turn. On the other hand, the G-3 specimen has a sharp change in acute angle (α = 67.2), and the length of the initial linear deformation line cd is the longest. The beta angle (6.8) is the lowest. This change in the volume strain curve represents the behavior of the -3 specimen (Fig. 6A). The α and β angles obtained from the volume strain curve can be summarized as shown in Table 9 below.

Rock name Sample
No. α (°) β (°) Geochang granite
(G) G-1 86.6 16.3 G-2 100.9 30.7 G-3 67.2 6.8 Mean 84.9 17.9 An (%) 39.6 133.2 Hapcheon granite
(H) H-1 95.3 21.5 H-2 96.6 27.6 H-3 98.0 22.7 Mean 96.6 28.9 An (%) 2.7 21.1

 Table 9 shows the α and β angles obtained from the volume strain curve, and An is the anisotropy coefficient (%), which can be calculated as Max-Min / average.

The critical volumetric microcrack strain (ε _v ^mcf , × 10 ³ ) at the fracture strength (σ ₁ ^f ) of Geocang granite was -2 (4.40) <-3 (11.9) <-1 ) (Figs. 5 and 6A). For a large number of specimens, ε _v ^mc And the value of ε _v ^{m cf} is -1, -2 <-3.

This is in contrast to the results of quantitative evaluation of grains developed in Geochang and Hapcheon granites, and the evaluation results of fine cracks (in particular grain density in six directions). In this process, the quantitative mechanical elements of the grain forming the quarry in three directions and the typical arrangement between the specimens are derived and synthesized as shown in Table 10 below.

No. Mechanical factor Geochang granite Hapcheon granite Remarks One Relationship between stress-volume strain rate Step I Horizontal resolution
Porosity
(ε _v ^o _max ) -1> -2> -3 Table 3
7A and 7B, Steps III to IV Curve slope Geochang granite> Hapcheon granite,
Relative comparisons between rocks and bilayers 7
b, e, and c, f 2 Stress increment - Horizontal and vertical resolution volume strain rate relationship diagram
(Stress-volumetric strain rate equation)
 Step I Horizontal resolution
Compression index (n) -1> -2> -3 Tables 7 and 8
8 and 9 Correlation coefficient
(R ² ) Correlation coefficient of linear power function
-2, -1 <-3  Step II Volume strain rate
(? _v ) -1 > -2 > -3 (sub-region) 8 and 9 Step III Volume Expansion Constant (Q) -1 <-2 <-3 Tables 7 and 8
8 and 9 Correlation coefficient
(R ² ) Correlation coefficient of linear power function
-1, -2 <-3  Step IV Volume strain rate
Hardening index (m) -1 < -2 < -3:
Ideal arrangement Tables 7 and 8
8 and 9 Volume Expansion Constant (Q)  -1, -2 <-3 3 Comprehensive relationship diagram  Step I Specimen
Arrangement -3 < -2 < -1 (upper right area) 10 Steps III to IV -1 <-3 <-2
-1: sub-region on the left side,
-3, -2: upper right area,
As you step
-2, -3 (ideal arrangement of geochang granite) 4 Stress-volume strain
The curve (G-3)  Curve of step IV α, β angle -3 <-1, -2
Representative of -3 specimen reflected Table 9
6

Table 10 shows representative arrays of quantitative mechanical elements and specimens forming the three quarries.

As described above, an optimal embodiment has been disclosed in the drawings and specification. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (5)

A rock block sampling step for obtaining a square block of rock from the granite;
A rock block surface cutting step for cutting the surface of the rock block in a direction parallel to the three pitting surfaces;
A rock block dividing step of dividing the rock block into a plurality of square rock samples;
A core specimen manufacturing step of fabricating respective core specimens in a direction perpendicular to the three crystal faces of the rock specimen;
A stress applying step of applying stress to the core specimens; And
A quantitative evaluation step of evaluating a mechanical reaction according to a stress applied to the core specimens and calculating a volume strain rate (ε _v ) by the _following equation and evaluating a relative strength with respect to three resolved faces; / RTI &gt;
(Equation)
? _v =? _a + 2? _l
In the texture quantitative evaluation step,
The rock fracture process is divided into four strength sections (Ⅰ, Ⅱ, Ⅲ and Ⅳ) through the stress - volume strain curves. The volume deformation of the specimens along the stress increment (x axis) (y-axis), and the relative strength of the texture is evaluated to be lower as the value of the y-intercept (a) is larger in the linear function (y = a + bx) Method of quantitative evaluation of texture using.
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