ORIGINAL PAPER

Electrical resistivity variation in uniaxial rock compression

Qiang Sun & Shuyun Zhu & Lei Xue

Received: 22 November 2013 /Accepted: 17 March 2014# Saudi Society for Geosciences 2014

Abstract This paper reports the relationship between electri-cal resistivity and rock failure during uniaxial compression.Experiments of rock samples on an electro-hydraulic servo-controlled testing machine show that the variation of electricalresistivity is closely related to rock deformation. Near to rockfracture, microcracks appear and change the microstructure ofrock mass, causing the rupture of mineral crystal lattice, andthe electrical resistivity has a rapid variation with the growthof cracks. The experimental result shows that rapid variationof electrical resistivity occurs at the critical point with stresslevel of approximately 7585 % relative to the peak strengthin uniaxial compression. This research may be useful to indi-rectly detecting the critical point of rock fracture.

Keywords Rock failure . Electrical resistivity . Criticalinformation . Identification

Introduction

The behavior of rock failure may be reflected in rock stress-strain curves and other physical parameters (Chen and Lin2004). Under an external load, rock cracking or porosityvaries with the received pressure; consequently, the evolutionof stress-strain state and other physical parameters areaffected.

The variation of electrical resistivity with rock cracking hasbeen studied since the 1960s (Brace et al. 1965, Brace andOrange 1968a, b; Brace 1975, 1981; Morrow and Brace 1981;Xiu and Chen 1987; Chen et al. 1992; Lu et al. 1998; Zhanget al. 2003; An et al. 2008). At low pressure, a partiallysaturated rock becomes less resistive but saturated rock be-comes more resistive as the pressure increases. For a rockcomposed of conductive minerals, the electrical resistivity atfirst decreases sharply with pressure, and then is influenced bypressure. For rocks with pores collapsed under pressure, theirelectrical resistivity may either increase or decrease with pres-sure, depending on the initial connectivity of the pores, and anincrease is more common (Brace and Orange 1968b). Chang-es in rock resistivity are almost solely due to dilatant volumechange (Brace 1975). For most rocks, their resistivity in-creases slightly with pressure up to about half of the fracturestress, and drops when the pressure is greater than 80 % of thefracture stress (Brace and Orange 1968a). Changes of electri-cal resistivity were observed in marble, quartz sandstone,sandstone, mudstone and coal or rock under uniaxial com-pression. The resistivity generally varies in four modes:decreasing-increasing, decreasing, stationary-increasing, andincreasing-decreasing just before failure (Li et al. 1999). Thechange of polarized electrical signal induced by compressivestress was also studied as an omen of rock failure(Hadjicontism and Mavromatou 1994), and the effect of geo-logic structures and anisotropy on resistivity measurementwas preliminarily studied with an experimental model and across-square array of electrodes (Matias and Habberjam1986).

Variations in the resistivity have been considered as a pos-sible precursory phenomenon which has been used to evaluatethe deformation and fracture feature of rocks (e.g., Busby andJackson 2006; Liu et al. 2009a, b; Zhang et al. 2009; Wanget al. 2012; Seokhoon 2013; Brantut et al. 2013). In the past fewdecades, considerable experimental effort has been taken to

Q. Sun (*) : S. ZhuSchool of Resources and Geosciences, China University of Miningand Technology, Xuzhou, Jiangsu Province 221116,Peoples Republic of Chinae-mail: sunqiang04@126.com

Q. Sun : L. XueKey Laboratory of Engineering Geomechanics, Institute of Geologyand Geophysics, Chinese Academy of Sciences, Beijing 100029,Peoples Republic of China

Arab J GeosciDOI 10.1007/s12517-014-1381-3

quantify the relation between resistivity and cracks (or stress) ofrock. Experiments on a variety of rock types have measuredtypical resistivity close to rock dilatancy (e.g., Liu et al. 2009a,b; Xue 2011; Wang 2012; Tu et al. 2013), and the effect ofvolumetric dilatancy on resistivity is sufficiently understood.However, owing to technical difficulty, the point correspondingto volumetric dilatancy is still in debate. In this study, based onfracture mechanics and statistical physics, we introduce a fewkey concepts for understanding resistivity variation at the criti-cal point on the stress-strain curve.

The mechanism of resistivity variation is not clear probablybecause the physical process of rock failure is not preciselyknown and the effect of moisture content is not well understood.

In this study, the variations of stress level, strain level, andelectrical resistance in uniaxial rock compression are studiedexperimentally. Based on fracture mechanics and statisticalphysics, we introduce a key concept for rocks in a uniaxialcompression process, which allow understanding resistivityvariation at the critical point on stress-strain curve. We definec and f as the critical stress and peaking stress respectively,and c as the stress level of c/f. The study results show thec judgment on resistivity-stress level curve has a value rangeof 7585 %, which can be used as an internal variable char-acterizing the information on porosity change and informationsource to indentify the critical point of rock failure.

Experiment preparations and testing methods

Rock samples were collected in a coal mine in Jining, Shan-dong province(the rock type is shown in Table 1)and cut into50100 mm cylinders. Two symmetrically located 9581 mm strip shaped electrodes were made by putting gelatinmixed with copper powder along the axial direction on thesurface of each sample.

Rock samples were uniaxially loaded at 0.06 kN/s on anelectro-hydraulic servo-controlled testing machine shown inFig. 1a. The load was measured by an oil pressure sensorconnected to the hydraulic pressure cylinder, and a cylindricalcapacitor displacement sensor fixed to the upper platen wasused to measure the displacement of rock samples in the test.The electrical resistivity was measured with a digital electricalinstrument (SYSCAL-R2) shown in Fig. 1b. During the trial,a series of uniaxial compression tests are conducted in rockmechanics rigidity servo testing system.

The principle of resistivity measurement is shown in Fig. 2:power both ends of the rock sample and the electrode ismeasured at the upper and lower ends, observe the potentialdifference between MN when the current passes through therock sample, so the resistivity can be calculated with Eq. (1).As the rock resistivity is relatively large, the intensity ofcurrent is too small to be measured directly. It is obtainedindirectly by measuring the voltages at both ends of a 1 k

standard resistor in the power supply circuit with the switch K(Fig. 2).

KUMNI

; K A=L 1

Where, is the rock resistivity; K is a coefficient deter-mined by device; A is the cross-sectional area of rock sample;L is the distance between MN; UMN is the potential differ-ence between MN; and I is current.

Test results and discussions microfracturing, resistivityvariation, and failure

Twelve samples were tests under uniaxial compression load-ing until damage is occurred. The samples can be divided intofour types according to the mode of variation of electricalresistivity with stress level: (1) decrease-increase, (2) contin-uous decline, (3) approximate stationarydecrease, and (4)increase-decrease (as shown by Table 1), consistent with (Liet al. 1999).

The decrease-increase type includes #1, #2, and #3 mud-stone samples. Figure 3 shows their strain and stress levels(normalized relative to their peak values respectively), andalso electrical resistivity levels (normalized with their initialvalue, respectively). As the initial water content is small,compaction, reduction of porosity, changes of rock conduc-tivity and decline of electrical resistivity are found in the earlyphase of loading; in later phases of loading, the electricalresistivity increases quickly with the increase of fractures,and a sharp increase is shown.

The continuous decline type includes #4 sandstone, and #6,#8, and #10 limestone samples. Figure 4 shows that in theearly phase of loading, the electrical resistivity changes slight-ly for #4 and #10, and fluctuates within a narrow range for #6,but steeply declines for #8. In the late phase loading, a jumppoint appears for all four samples.

The approximate stationarydecrease type includes #5, #7,#11, and #12. Figure 5 shows that in the early phase ofloading, the electrical resistivity of limestone changes slightly,so fluctuation within a narrow range is found for #5, while it isrelatively stable for #7, #11, and #12. In the late phase ofloading, a jump point also appears for all four samples.

The increase-decrease type only includes #9 arenaceouslimestone sample. The electrical resistivity presents a risingtrend and then falls steeply. In the late phase of loading, theelectrical resistivity significantly declines (Fig. 6).

Three phases can be identified in the stress-strain curvewith different characteristics of electrical resistivity variationduring the compression process of rock specimens before thepeak strength is reached, as shown in Fig. 7:

Arab J Geosci

1. The compaction and elastic phase O-A (shown in Fig. 1).Initially, rock deformation is mostly compaction, withnegligible level of acoustic emission. The original microfissures and pores are closed, as shown in Figs. 7 and 8a.In general, the rock samples have small water content inthe compaction phase.

2. The elastic-stable cracking phase (AC), with continuouscompaction at the beginning, and microfractures devel-oped later. In this phase, electrical resistivity is relativelystable (Figs.7 and 8b). Crack starts at stress levels ofapproximately 3050 % times the peak uniaxial load(Brace et al. 1966; Bieniawski 1967). Volumetric straindilation (Martin and Chandler 1994) and direct micro-scopic observation of test samples (Wong 1982) alsofound microcracks formed and propagating mainly inthe direction parallel to the maximum compressive stress.

3. The yielding phase CD. In this phase, the electrical resis-tivity signal, or the magnitude of the spectra of the elec-trical resistivity signal, changes abruptly with a jump inthe vicinity of the yield point. Micro cracks grow rapidly,with micro breaking developed spatially in rows along thepotential breaking planes until themicro cracks eventuallybecome connected with each other (Fig. 7), as indicatedby the localization of strain, nonlinear axial deformation,lateral strain, and accelerated increase of volumetric strainat the cracks.

Further crack development leads to coalescence of themicro fractures, which sharply accelerates the concentrateddeformation of rock sample in the narrow fracture zone shownin Figs. 7 and 8c, d. The resistivity-stress curve shows that

Table 1 Summary of crack initi-ation and crack damage stresslevels from laboratory test byelectrical resistivity

No of rocksamples

Rock type Pinot D Pinot C Resistivity variationcharacteristics

Stress/MPa

Strain/%

Stress level/% Strain level/%

1 Mudstone 13.0 4.82 81.3 73.6 Decrease-increase

2 Mudstone 11.4 2.13 84.6 65.6 Decrease-increase

3 Mudstone 13.2 2.25 80.2 90.3 Decrease-increase

4 Sandstone 35.2 4.12 85.4 73.2 Continuous decline

5 Limestone 67.5 1.23 84.5 91.7 Stationarydecrease

6 Limestone 79.2 1.31 86.5 88.2 Continuous decline

7 Limestone 25.2 0.63 85.7 77.2 Stationarydecrease

8 Limestone 62.9 0.92 78.7 76.8 Continuous decline

9 Limestone 60.8 1.32 84.6 71.1 Increase-decrease

10 Limestone 54.4 1.42 87.0 94.2 Continuous decline

11 Limestone 87.3 1.55 82.3 84.6 Stationarydecrease

12 Limestone 60.7 1.27 81.3 78.2 Stationarydecrease

Average 83.5 80.4

Fig. 1 The testing machine and resistivity detector. a Loading apparatus.b Digital electrical instrument (SYSCAL-R2)

Arab J Geosci

Electrode B of power supplying

Digital electrical instrument

Standardresistance R

Switch K

Rock smaple

Electrode A of power supplying

Potential electrode MPotential electrode NInsulation board

Insulation boardPressure board

Pressure board

Fig. 2 Schematic diagram of theexperimental system for stress,strain, and electrical resistance ofrock under uniaxial compression

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

90

100

Res

istiv

ity

/%

Stress level /%

Axi

al st

rain

/%

60

70

80

90

100

110

120

130

Resistivity

Strain level

(a)

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

90

100

Resistivity

Strain level

Res

istiv

ity /%

Stress level /%

75

100

125

150

175

200

225

250

275

300

325

350

Axi

al st

rain

/%

(b)

Fig. 3 Relationship betweenstrain, stress, and resistivity ofmudstone. a No. 1, b No. 2

Arab J Geosci

onset of fracture coalescence starts at stress levels of approx-imately 7585 % of the peak strength. For rock samples withhigh moisture content near the narrow fracture zone andconductivity of water within the fissures, the electrical resis-tivity sharply decrease; in the absence of water, the resistivitysharply increases. Therefore, the steep change of resistivity atthe yield point in this phase is closely related to the develop-ment of fractures and volumetric dilatation.

The resistivity sharply changes near the yield point (steepdown or steep up), and the resistivity-stress curve falls intofour types before the failure. The stress and strain correspond-ing to the yield point C are represented as (c,c) respectively,and the peak stress and strain at the point D are taken asreference values, then we have

c cd

100% ; c cd 100% 2

Table 1, Figs. 3, 4, 5, and 6 show that (1) the c of the 12samples are between 75 and 85 %, with a mean of 83.5 % and

deviation within 5 %; (2) the distribution of c is morescattered than c, and their means are 65 and 95 %, respec-tively, for the 12 samples; (3) at the yield point (thresholdpoint) C, the resistivity has a sharp variation.

Case studies

Case 1: uniaxial compression test of different samples

Rock samples (the rock type is shown in Table 2) were cut into50100 mm cylinders. Two symmetrically located 9581 mm strip-shaped electrodes were made by putting gelatinmixed with copper powder along the axial direction on thesurface of each sample. Rock samples were uniaxially loadedat rock samples that were uniaxially loaded at electro-hydraulic servo-controlled testing machine (MTS815). Theelectrical resistivity was measured with a digital electricalinstrument (SYSCAL-R2) (Liu et al. 2009a, b).

10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

90

100

20

30

40

50

60

70

80

90

100

Stress level /%

Ax

ial s

train

/%

Resistivity

Strain level

Res

istiv

ity

/%

(a) No.40 10 20 30 40 50 60 70 80 90 100

0

10

20

30

40

50

60

70

80

90

100

10

20

30

40

50

60

70

80

90

100

110

Stress level /%

Resistivity

Strain level

Ax

ial s

trai

n /%

Res

istiv

ity /%

(b) No.6

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

90

100

30

40

50

60

70

80

90

100

110

Stress level /%

Resistivity

Strain level

Axi

al st

rain

/%

Res

istiv

ity /%

(c) No.80 10 20 30 40 50 60 70 80 90 100

0

10

20

30

40

50

60

70

80

90

100

10

20

30

40

50

60

70

80

90

100

110

Stress level /%

Resistivity

Strain level

Ax

ial s

trai

n /%

Res

istiv

ity /%

(d) No.10Fig. 4 Relationship between strain, stress, and resistivity of rock a No. 4 (sandstone), b No. 6 (limestone), c No. 8 (limestone), d No. 10 (limestone)

Arab J Geosci

The test result is shown in Figs. 9, 10, 11, 12, 13, and 14.Based on the level of resistivity change vs. stress level (the

stress level is normalized relative to their peak value respec-tively, and the resistivity changing level refers to the value ofresistivity normalized by the initial resistivity) obtained fromexperiments on rock samples, the variation of resistivity withstress level can be divided into four types according to themode of variation of electrical resistivity with stress level: (1)decrease-increase, (2) continuous decline, (3) approximatestationarydecrease, and (4) increase-decrease (as shown byTable 2), consistent with (Li et al. 1999).

Three phases can be identified in the stress-strain curvewith different characteristics of electrical resistivity variationduring the compression process of rock specimens before thepeak strength is reached, as shown in Fig. 7. (1) The compac-tion and elastic phase O-A (shown in Fig. 7). (2) The elastic-stable cracking phase (AC). (3) The yielding phase CD. NearPoint C, plenty of micro cracks initiate and grow rapidly, andmicro breaking is developed spatially in rows along the po-tential breaking planes until the micro cracks eventually be-come connected with each other, as indicated by the localiza-tion of strain, and accelerated increase of volumetric strain atthe cracks. In this phase, the resistivity sharply changes nearthe yield point (steep down or steep up).

From Table 2, we can get the average value of stress levelfor point C of 75.1%. It also suggests that the variation of rockresistivity can reflect the changes of stress state, which mayprovide very useful information on rock stability.

Case 2: uniaxial compression test of sandstone sample

Sample of sandstone is cut to hexahedron specimen withdimensions of 707070mm3 (Lu et al. 1992). The electrodehole was prepared on one side without being confined. Thepower supply wire was prepared by the quadrupole method.

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

90

100

Stress level /%

Resistivity

Strain level

Ax

ial s

train

/%

Res

istiv

ity /%

95

100

105

110

115

120

125

130

135

140

145

150

(a) No.5

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

90

100

120

160

200

240

280

320

360

400

440

Stress level /%

Resistivity

Strain level

Axi

al st

rain

/%

Res

istiv

ity /%

(b) No.12Fig. 5 Relationship between strain, stress, and resistivity of limestone. aNo. 5, b No. 12

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

90

100

96

98

100

102

104

106

108

110

112

Stress level /%

Resistivity

Strain level

Ax

ial s

train

/%

Res

istiv

ity

/%

Fig. 6 Relationship betweenstrain, stress, and resistivity oflimestone (No. 9)

Arab J Geosci

Before pressuring, the nonpolarized electrode was inserted tothe measuring hole, and bound on the stand. The samples werenaturally immersed for 10 h. Before testing, the surface ofsamples was dried. The load was measured by an oil pressuresensor connected to the hydraulic pressure cylinder, and a

cylindrical capacitor displacement sensor fixed to the upperplaten was used to measure the displacement of rock samplesin the test (Fig. 17). The electrical resistivity was measuredwith a digital electrical instrument (ZD-8). The press sectionand sample were separated by PTFE membrane. In the testingprocess, with uniform loading pressure interval, the pressurerate was 2.5 to 3.0 MPa/s.

When the ratio between the loading stress and peak stress is79~85 % (Figs. 15 and 16), the resistivity varies sharply, witha jump in the vicinity of the yield point, indicating acceleratedvariation of the resistivity.

Case 3: uniaxial compression test of granite sample

A sample of Sichuan Baihujian granite is cut to a hexahedronspecimen with dimensions of 404080 mm3 (Chen et al.1987, An et al. 1996). The electrode hole was prepared on oneside without being confined. The power supply wire wasprepared by the quadrupole method for three or four direc-tions. Before pressuring, the nonpolarized electrode wasinserted to the measuring hole, and bound on the stand. Thesamples were vacuum-soaked to saturation, and there was nowater supply in the loading process (Fig. 17).

When the loading stress reaches 30 MPa, two timesunloading was carried out, each time unloading 5 MPa. Whenthe loading stress reaches 60 MPa, two times unloading wascarried out, each time unloading 5 MPa. Three phases can beidentified in the stress-strain curve with different characteris-tics of electrical resistivity variation during the compressionprocess of rock specimens before the peak strength is reached,

yield point

Peak

Dila

tion

Axial strain %

Axi

al st

ress

A

C

D

Crackclosure

Yieldregion

Crack closure

Res

istiv

ity

Stress

Resistivity

(dry)

Elasticregion

Crackclosure

Crackgrowth

Calculated crackvolumetric strain

Total measuredvolumetric strain

Vol

umet

ric st

rain

Cont

ract

ion

Lateral strain %

c

d

Resistivity

(wet)

Fig. 7 Stress-strain-resistivitydiagram showing the stages ofcrack development

(b)(a)

(d)(c)Fig. 8 Diagram of rock deformation mode

Arab J Geosci

as shown in Figs. 18, 19, and 20. (1) The compaction andelastic phase. The resistivity was increasing with the increaseof stress level. (2) The elastic-stable cracking phase. Theresistivity changes slightly with the increase of stress level.(3) The yielding phase. In this phase, the resistivity sharplydecreased with the increase of stress level.

When the ratio between the loading stress and peak stress is70~85 %, the resistivity varies sharply with a jump in thevicinity of the yield point, indicating accelerated variation andaccelerated decrease of the resistivity.

Theoretical analysis

(1) The compaction and elastic phase O-A (shown in Fig. 7).

Change of electrical resistivity at this stage is related toinitial water content and the compaction degree of specimen(Sun 2007), and can be represented by Eq. (3).

awmSn; 3

Where a is the proportional coefficient; is rock electricalresistivity; w is pore water (with certain salinity) electricalresistivity; is rock void ratio; m is rock cementation index;and n is saturation index.m is between 1.3 and 2.5; n is relatedto water content and close to 2 when more than 30 % of thepore space is filled with water (Sun 2007).

(2) The elastic-stable cracking phase (AC), with continuouscompaction at the beginning, and micro fractures devel-oped later. In this phase, electrical resistivity is relativelystable (Fig. 7). The differential expression of Eq. (3) canbe expressed as (Lu et al. 1998)

a m

nSS

mlnnlnS

; 4

Where, =Vp/V is the rock void ratio (Vp is the rock porevolume, V is the rock total volume), S=Vw/Vp is the rocksaturation (Vw is the volume of water).

Table 2 Summary of yield stresslevel from laboratory test byelectrical resistivity

No of rock samples Rock type Stress level (%) of Pinot C Resistivity variation characteristics

1 Mudstone 69.8 Stationarydecrease

2 Sandstone 80.2 Decrease-increase

3 Sandstone 74.8 Increase-decrease

4 Sanding mudstone 72.5 Continuous decline

5 Limestone 71.6 Increase-decrease

6 Limestone 75.4 Increase-decrease

7 Limestone 72.9 Increase-decrease

8 Coal petrography 79.8 Decrease-increase

9 Quartz sandstone 78.9 Continuous decline

Average 75.1

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

90

100

Axi

al st

rain

/%

20

40

60

80

100

120

140

160

180

Stress level /%

Res

istiv

ity /%

Resistivity

Strain levelPoint C

Fig. 9 Relationship between resistivity and stress level (No. 5 limestone)

0 10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

80

90

100

Res

istiv

ity /%

Stress level /%

Axi

al st

rain

/%

Resistivity

Strain level

Point C

0

10

20

30

40

50

60

70

80

90

100

Fig. 10 Relationship between resistivity and stress level (No. 1mudstone)

Arab J Geosci

In this stage, generally, the value of Vw is very small.

Therefore, nm VV

nVwVw , the Eq. (4) can be expressed as

a nm

VV

nVwVw

an

VwVw

5

From Eq. (5), one can get that the influence of pore waterchanges to resistivity is greater than the contribution of vol-ume change. In this stage, the resistivity changes consistentwith moisture content changes.

(3) The yielding phase CD. In this stage, if the influence ofgrowth rate of cracks is greater than the change ofmoisture content, the Eq. (3) is expressed as

a nm

VV

nVwVw

a

nm

VV

; 6

where, V>0. The resistivity increases sharply, with a jumpin the vicinity of the yield point.

a nm

V

VnVwVw

mln

a nVWVW

mln

7

where,

Many current technical problems need to be solved tounderstand rock failure process, such as accurately determin-ing the Poissons ratio and identifying rock yield point. Addi-tionally, the evolution of cracks with macro deformation andfailure is not well understood yet. However, as the variation ofrock resistivity is closely related to rock failure process, thevariation of resistivity may provide information about rockfailure (such as yield point, yield stress level and strain level,etc.), and can be used to predict seismic and geological disas-ters (such as rock burst, collapse, and landslides, etc.).

Conclusions

To assess crack initiation and crack damage stress levels inrockmass, the characteristics of resistivity variation during the

loading process are studied in this paper for detecting crackdamage threshold. It is found that

1. The resistivity variation is related to the develop-ment of cracks in uniaxial compression. In the vi-cinity of the threshold point C (Crack coalescence),the resistivity has a sharp variation with the rapidgeneration and growth of micro cracks inside therocks.

2. The data collected from laboratory samples show thatonset of crack coalescence starts at stress levels of ap-proximately 7585 % of the peak strength, when theresistivity signals change sharply. The relation betweenresistivity and stress-strain in uniaxial rock compression isobserved in laboratory tests. Therefore, these conclusionsneed further validation before their robustness under var-ious conditions can be confirmed and incorporated in

0 10 20 30 40 50 60 70 80 90 10080

82

84

86

88

90

92

94

96

98

100

Stress level /%

Res

istiv

ity

/%

Point C

Fig. 15 Relationship between resistivity and stress level (sandstone #1,Lu et al. 1992)

0 10 20 30 40 50 60 70 80 90 10060

65

70

75

80

85

90

95

100

Res

istiv

ity /%

Stress level /%

Point C

Fig. 16 Relationship between resistivity and stress level (sandstone #2,Lu et al. 1992)

Rock smapleMonitoring sensor

strainindicator

Elctricalinstrument

Oscillograph of 16 ray

Acoustic detector

GalvanometerConstant current source

Pressmachine

Pressmachine

Fig. 17 Block diagram of apparatus and measurement system (Chenet al. 1987)

0 10 20 30 40 50 60 70 80 90 100

100

105

110

115

120

125

130

Stress level /%

Res

istiv

ity /%

R1 R2 R3

Fig. 18 Relationship between resistivity and stress level (granite #19,Chen et al. 1987)

Arab J Geosci

physical predicative methods to recognize the thresholdinformation of rock destruction.

Acknowledgments This research was supported by the State BasicResearch and Development Program of China (No. 2013CB036003),the Project Funded by the Priority Academic Program Development ofJiangsu Higher Education Institutions and the Project supported by theNational Science Youth Foundation of China (Grant No.41102201,No.41302233, No.51309222).

References

An JZ, Xiu JG, Chen F et al (1996) Anisotropy studies of rock resistivitychanges under uniaxial pressure and water replenishment (inChinese). Earthquake Res China 12(3):300306

An JZ, Zhou PG, Ma MN et al (2008) Experiments on exploring andmonitoring landslip-mass using geoelectric resistivity observations(in Chinese). Acta Seismol Sin 30(3):254261

Bieniawski ZT (1967) Mechanism of brittle fracture of rock, parts I, IIand III. Int J Rock Mech Min Sci Geomech Abstr 4(4):395430

BraceWF (1975) Dilatancy-related electrical resistivity changes in rocks.Pure Appl Geophys 113(86):207217

Brace WF (1981) The effect size on mechanics properties of rocks.Geophys Res Lett 8(7):651662

Brace WF, Orange AS (1968a) Further studies of effects of pressure onelectrical resistivity of rocks. J Geophys Res 73(4):14331445

Brace WF, Orange AS (1968b) Electrical resistivity changes in saturatedrocks during fracture and frictional sliding. J Geophys Res 73(16):54075420

Brace WF, Orang AS, Madden TR (1965) The effect of pressure on theelectrical resistivity of water-saturated crystalline rocks. J GeophysRes 70(22):56695678

Brace WF, Paulding B, Scholz C (1966) Dilatancy in the fracture ofcrystalline crocks. J Geophys Res 71(16):39393953

Brantut N, HeapMH,Meredith PG et al (2013) Time-dependent crackingand brittle creep in crustal: a review. J Struct Geol 52:1743

Busby J, Jackson P (2006) The application of time-lapse azimuthalapparent resistivity measurements for the prediction of coastal clifffailure. J Appl Geophys 52:261272

Chen GY, Lin YM (2004) Stress-strain-electrical resistance effects andassociated state equations for uniaxial rock compression. Int J RockMech Min Sci 41:223236

Chen DY, Chen F, He GY (1987) Influences of stress reversal on rockresistivity during loading procedure (in Chinese). Acta Seismol Sin9(3):303311

Chen DY, XuDJ, Lu YQ et al (1992) Experimental research on chance ofgeoresistivity anisotropy of pressed rocks and on the spot observa-tion (in Chinese). Acta Seismol Sin 14(3):356362

Hadjicontism V, Mavromatou C (1994) Transient electric signals prior torock failure under uniaxial compression. Geophys Res Lett 21(16):16871690

Li DC, Ge BT, Shu JS (1999) Experiment of resistivity variation of rocksin failure process (in Chinese). J China Univ Min Tech 28(5):491493

Liu SC, Liu XM, Jiang ZH et al (2009a) Research on electrical predictionfor evaluating water conducting fracture zones in coal seam floor (inChinese). Chin J Rock Mech Eng 28(2):348356

Liu SD, Wu RX, Zhang PS et al (2009b) Three dimensional parallelelectric surveying and its applications in water disaster explo-ration in coal-mines (in Chinese). J China Coal Soc 34(7):927932

Lu YQ, Liu JY, Liang ZB (1998) The resistivity precursor features of thelarge-scale limestone sample under loading condition (in Chinese).South China J Seismol 18(3):2127

Lu YQ, Qian J D, Zhao JL, et al (1992) Preliminary research on inducedpolarization effect before rupture of instable rocks (in Chinese).Earthquake 12(4):2836

Martin CD, Chandler NA (1994) The progressive fracture of Lac duBonnet granite. Int J Rock Mech Min Sci 31:643659

Matias MJS, Habberjam GM (1986) The effect of structure and anisot-ropy on resistivity measurements. Geophys 51(4):964971

Morrow C, Brace WF (1981) Electrical resistivity changes in tuff due tostress. J Geophys Res 86:29292934

Seokhoon O (2013) Geostatistical intergration of seismic velocity andresistivity data for probabilistic evolution of rock quality. EnvironEarth Sci 69:939945

Sun J (2007) Archies formula: historical background and earlier debates(in Chinese). Prog Geophys 22(2):472486

Tu JN, Sun Q, Jiang ZH et al (2013) Critical rock apparent resistivityvariation with stress ration along loading progress (in Chinese). JChina Coal Soc 38(2):221225

0 10 20 30 40 50 60 70 80 90 100100

104

108

112

116

120

124

128

Stress level /%

Res

istiv

ity

/%

R1 R2 R3

Fig. 19 Relationship between resistivity and stress level (granite #21,Chen et al. 1987)

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

120

140

Res

istiv

ity

/%

Stress level /%

R1 R2 R3 R4

Fig. 20 Relationship between resistivity and stress level (An et al. 1996)

Arab J Geosci

Wang JX (2012) Theoretical and experimental research on resistivityproperties of rock under loading (in Chinese). Chongqing: Master.Thesis, Chongqing University

Wang YH, Liu YF, Ma HT (2012) Changing regularity of rock damagevariable and resistivity under loading condition. Safety Sci 50:7187227

Wong TF (1982) Micromechanics of faulting in Westerly granite. Int JRock Mech Min Sci Geomech Abstr 19:4964

Xiu JG, Chen DY (1987) Test of the saturation effect on rock apparentresistivity under uniaxial pressure (in Chinese). Earthquake 7(2):3845

Xue L (2011) Renormalization study of percolation criticalstate in rock failure (in Chinese). Beijing: Ph.D. Thesis,Institute of Geology and Geophysics Chinese Academy ofSciences

Zhang L, Huang JG, Gao P (2003) Influence of water on electric resis-tivity of deforming rock samples (in Chinese). Earthquake 23(1):140148

Zhang PS, Liu SD,WuXR et al (2009) Dynamic detection of overburdendeformation and failure in mining workface by 3D resistivitymethod (in Chinese). Chin J Rock Mech Eng 28(9):18701875

Arab J Geosci

Electrical resistivity variation in uniaxial rock compressionAbstractIntroductionExperiment preparations and testing methodsTest results and discussions microfracturing, resistivity variation, and failureCase studiesCase 1: uniaxial compression test of different samplesCase 2: uniaxial compression test of sandstone sampleCase 3: uniaxial compression test of granite sample

Theoretical analysisConclusionsReferences