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    Journal of Geological Resource and Engineering 2 (2014) 55-67

    Empirical Development of the Rock Mass Deformation

    Modulus

    Manouchehr Sanei and Lohrasb Faramarzi

    Department of Mining Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran

    Abstract: Rock mass deformation modulus is a fundamental factor for a safe and economical design of rock structures like large

    underground openings, tunneling, and open pit mine as well as foundations in both the initial state of stresses act on rock mass and its

    strength characteristics. The rock mass deformation modulus recently has been measured by in-situ loading tests and has been

    estimated by use of empirical equation based on classification systems and data of laboratory tests. In-situ tests to measure modulus

    directly are so expensive, times consuming and the reliability of the results of these tests is sometimes doubtful; subsequently, many

    researches have been carried out to estimate this parameter based on classification systems. In this study, a new empirical equation wasproposed by use of statistical analyses based on a database of more than 142 in-situ tests, like plate load tests, dilatometer tests, flat jack

    tests, and classification systems; in addition, properties of the intact rock.

    Key words:Rock mass deformation modulus, in-situ tests, classification systems, empirical equation.

    1. Introduction

    The deformation modulus is the most representative

    parameter describing the pre-failure mechanical

    behavior of any engineering material. Also,

    deformation modulus is an important parameter used inorder to estimate various rock mass properties in a rock

    engineering projects. Many methods are available to

    estimate the rock mass deformation modulus such as

    in-situ tests, empirical equations between deformation

    modulus and rock mass classification system, and

    geophysical (usually seismic) methods as well as

    estimating from laboratory test results [1]. In rock mass,

    the existence of discontinuities makes the mechanical

    properties of rock mass differ greatly from that of intact

    rocks. Although the laboratory tests have existed for

    estimating deformation modulus; however, the results

    are not very suitable for this purpose since the

    specimen is too small. Thus, the in-situ tests are

    presently employed in major rock engineering projects,

    to provide more rational data for the design of rock

    Corresponding author: Manouchehr Sanei, M.Sc. in rockmechanic, research fields: rock mechanics, rock engineering

    and geomechanics. E-mail: [email protected].

    structures which are available for the prediction of rock

    mass behavior under different loading conditions [2, 3].

    Furthermore, the rock mass deformation modulus is

    currently evaluated by means of different types of

    in-situ loading tests such as the plate loading test, the

    flat jack test, the borehole loading tests, and the radial

    jacking test as well as the water chamber test and so on [4].

    In-situ tests to measure modulus directly are so

    expensive, times consuming and the reliability of the

    results of these tests is sometimes doubtful;

    consequently, many authors have proposed empirical

    relations for estimating deformation modulus

    indirectly by using various rock mass classification

    systems such as the RMR (rock mass rating), the GSI

    (geological strength index), the Q (tunneling qualityindex), the RMI (rock mass index) and the RQD (rock

    mass quality designation) like Bieniawski [5], Serafim

    and Pereira [6], Nicholson and Bieniawski [7],

    Mehrotra [8], Grimstad and Barton [9], Mitri et al. [10],

    Hoek and Brown [11], Read et al. [12], Palmstrom and

    Singh [13], Barton [14-16], Galera et al. [17], Shen

    et al. [18], and Sanei et al. [19].

    Moreover, Zhang and Einstein [20] estimated the

    DAVID PUBLISHING

    D

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    Empirical Development of the Rock Mass Deformation Modulus56

    deformation modulus of rock masses by using of RQD.

    Sonmez et al. [21] developed an empirical model to

    determine the deformation modulus of rack masses

    indirectly based on the GSI system. Also, Hoek and

    Diederichs [22] proposed an empirical equation to

    estimate rock mass modulus by use of a sigmoid

    function. On the other hand, Chun et al. [23] presented

    a model in order to predict deformation modulus based

    on multiple and polynomial regression analyses of the

    RMR systems. Furthermore, Sanei et al. [24]

    developed the second-order polynomial equation for

    estimating of rock mass deformation modulus by use of

    JH (Japan Highway) corporation classification system.

    In this study, the values of RMR, Q, GSI and JHclassification systems were determined and properties

    of the intact rock like modulus of elasticity from

    laboratory tests was calculated; in addition, according

    to ISRM [25] the values of rock mass deformation

    modulus from in-situ tests (plate load, dilatometer, and

    flat jack test) were measured. Then, four new empirical

    equations for estimating the rock mass deformation

    modulus were developed by use of a database of 47

    plate load tests, 86 dilatometer tests, and 9 flat jack test

    at the Bakhtiary Dam site in Iran. All in all, by use of

    the statistical analyses among them, the suitable

    equation was select to estimate the rock mass

    deformation modulus.

    2. Bakhtiary Dam Site

    The site of Bakhtiary Dam and Hydroelectric Power

    plant project include the design and construction of a

    315 m high, double curvature, concrete dam, and an

    underground powerhouse, with a nominal capacity of

    1,500 MW, are located in Lorestan Province, in the

    southwest of Iran, northeast of the Tang-e-Panj railway

    station on the Tehran-Ahwaz railway, with the

    following coordinates: 484650E/3257'41N (Fig. 1).

    2.1 Geological Characterization of the Dam Site

    Limestone layers of Sarvak formation, which areMid-Cretaceous marine sediments, form the

    foundation of the dam, powerhouse and other

    appurtenant structures. These layers are generally

    tightly folded. The bed rock consists of limestone and

    marly limestone that contains nodules of siliceous

    limestone (or Chert). These deposits, which were

    sedimented between the formations of Garau (at the

    bottom) and Gurpi (at the top), are marked as

    Bangestan Group (Kazhdomi, Sarvak, Surgah and Ilam

    formations) of Cretaceous age. The limestone of the

    Bakhtiary Dam reservoir, which is overlying Garau

    formation and underlying Gurpi formation, has been

    Fig. 1 Location of Bakhtiary Dam site.

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    powerhouse

    is complet

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    57

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    ility and the

    dding planes

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    Empirical Development of the Rock Mass Deformation Modulus58

    Table 1 Physical and mechanical properties of intact rock specimens.

    Physical and mechanical properties Index Unit Value

    Density g/cm3 2.61-2.74

    Uniaxial compressive strength c MPa 77-133

    Modulus of elasticity E GPa 55-73Poissons ratio - 0.3

    Tensile strength t MPa 6.3-11.2

    Cohesion C MPa 29-36

    Friction angle 35-45

    Table 2 Estimated RMR, Q, GSI and JH values for different rock mass classifications at Bakhtiary Dam site.

    Lithology RMR89 Q GSI JH

    SV2 + SV3 30-51 0.002-80 35-50 67-83

    SV2 + SV3 + SV4 48-66 0.002-100 45-60 75-89

    SV5 + SV6 41-72 0.01-100 45-65 71-91

    SV7 46-56 0.002-100 45-55 75-85

    Table 3 Characteristics of bedding planes and joint sets.

    Value or descriptionFrequency (%)

    Bedding J1 J2 J3

    Aperture (mm)0.1-1 90 90 95 95

    1-5 10 10 5 5

    Spacing (cm)

    2-6 1.5 25 3 6

    6-20 47 48.5 52 25

    20-60 44.5 45 43.5 62.5

    60-200 3.5 4 1.5 6.5

    200-600 3.5 0 0 0

    Infilling

    Clay 42.5 10 2 0

    Calcite 46 67.5 55 43Bitumen 4.5 1 0 0

    FeO 2 0 0 0

    Tight 5 21.5 43 57

    Roughness

    UndulatingSs 19 2 0 0

    PlanarSs 41 2 1 0

    UndulatingSm 5 1 1 0

    PlanarSm 18 47 54.5 72.5

    UndulatingRo 1 0 0 0

    PlanarRo 16 48 43.5 27.5

    SsSlickensided, SmSmooth, RoRough.

    3. Evaluations of Rock Mass Classification

    Systems at the Bakhtiary Dam

    Rock mass classification systems were used for

    various engineering design and stability analysis;

    therefore, based on empirical relations between rock

    mass parameters and engineering applications, such as

    tunnels, slopes, and foundations, the values of rock

    mass classification systems were calculated that are

    given in Table 2.

    3.1 Rock Mass Classification by JH Method

    Akagi et al. [27] presented a new method for the

    classification of rock masses that the JH rating system

    was obtained from the study of 6,101 tunnel sections

    constructed by the JH Corporation. It should be noted

    that the range of JH system is from 0 to 100. Moreover,

    in JH method rocks are divided into four classes

    according to compressive strength in the fresh state and

    the modes of subsequent weathering and deterioration

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    Empirical Development of the Rock Mass Deformation Modulus 59

    as well as investigated the degrees of contribution of

    observation items in each class. Also, grouping of

    rocks in JH classification method are given in

    Table 4.

    4. In-situ Measurements of Deformation

    Modulus

    In-situ deformation tests are expensive and difficult

    to conduct and they are mostly conducted in special

    works; in addition, initial preparations at each test site

    are particularly time consuming. Today, several types

    of in-situ tests are used to determine the modulus of

    deformation. Therefore, in this study, totally, 47 PLT

    (plate load tests), 86 DLT (dilatometer tests), and 9 FJT(flat jack tests) were performed at Bakhtiary Dam site.

    Also, locations of plate load, dilatometer and flat jack

    tests are shown in Fig. 3.

    4.1 Interpretation of Plate Load Test Results

    PLT were performed in the 6 exploratory galleries at

    Bakhtiary Dam site (Fig. 3). In fact, plate load testing

    using rigid bearing plates, were performed in

    accordance ISRM method for determining of rock

    mass deformability. Also, data of all PLTs at dam site

    were analyzed and the values of deformation modulus

    were measured based on the method proposed by

    ISRM [25]. According to ISRM, for rigid plate tests,

    the basic formula for calculating the rock mass

    deformation modulus is:

    2 2,0

    2 1 cot 12 1

    avm

    z

    q a zE arc an z

    w z

    (1)

    wheremE , avq , a, wz,0, and z are modulus of

    deformation (GPa), average stress on the loaded

    surface (MPa), radius of the loaded circular area (m),

    displacement in the direction of the applied load

    beneath the center of circle (at the depth = 0) (mm),

    Poissons ratio of rock mass (taken as 0.3 that

    measured from petite seismic tests in exploratory

    galleries) and depth from the surface (m), respectively.

    Also, the values of in-situ deformation modulus of all

    performed PLTs are given in Table 5.

    4.2 Interpretation of Dilatometer Test Results

    DLT were performed in 21 boreholes drilled at

    Bakhtiary Dam site that they were performed in

    accordance with ISRM method for measuring

    deformability using a flexible dilatometer with radial

    displacement measurements. Also, data of all DLTs at

    dam site were analyzed and the values of deformation

    modulus were measured based on the method proposed

    by ISRM [25]. The basic formula for calculating the

    rock mass deformation modulus is:

    1 id RP

    E DD

    (2)

    where,d

    E , R , D, Pi and D are modulus of

    deformation (MPa), Poissons ratio of rock mass (taken

    Table 4 Grouping of rocks in JH classification method.

    Strength

    weatheringHard Medium Soft

    Massive

    Group l (1,650 [123] data)[massive hard rocks]

    Group 2 (2,698 [673] data)[massive medium, soft rocks]

    Grani (68),Paleo & Mesozoic,Sandstone (192),

    Quartz porphyry (65),Granodioritc (695),

    etc.

    Tuff (1,201), tuffbreccia (331), phyolite (341),

    andesite (479), sandstone (67), basalt (3), etc.

    Planar

    Group 3[planar medium rocks]

    Group 4[planar soft rocks]

    Paleo & MesozoicShale (1,279), etc.Total (1,279) [111] data

    Green schist (218),

    Black schist (27),Tertiary mudstone (229), etc.Total (474) [105] data

    [] means number of samples.

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    Empirical Development of the Rock Mass Deformation Modulus60

    Fig. 3 Locations of plate load, dilatometer and FJT in the exploratory galleries in Bakhtiary Dam site.

    Table 5 Values of deformation modulus in Bakhtiary Dam site.

    In-situ test PLT DLT FJT

    Deformation modulus (GPa) 1.7-35.5 1-22 3-19

    as 0.3), diameter of borehole (mm), pressure increment

    within the considered segment (MPa) and corresponding

    average change in drill hole diameter D (mm),

    respectively. Also, the values of in-situ deformation

    modulus of all performed DLTs are given in

    Table 5.

    4.3 Interpretation of Flat Jack Test Results

    FJT were performed in 3 exploratory galleries at

    Bakhtiary Dam site that they were performed in

    accordance with ISRM method for deformability

    determination using flat jack technique. Also, data of

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    Empirical Development of the Rock Mass Deformation Modulus 61

    all FJTs at dam site were analyzed and the values of

    deformation modulus were measured based on the

    following formula suggested by ISRM [25]:

    D

    P

    vEd

    )1(K2

    i

    (3)

    where,d

    E , , D, P and Ki are modulus of

    deformation (MPa), Poissons ratio of rock mass (taken

    as 0.3), slot opening (mm), pressure increment within

    the considered segment (Bar) and a constant (related to

    the stiffness, shape, configuration, and number of flat

    jacks), respectively. Also, the values of in-situ

    deformation modulus of all performed FJTs are given

    in Table 5.

    5. Results and Discussion

    In-situ tests are expensive and difficult to conduct,

    therefore, the value of the deformation modulus is

    often estimated indirectly from the empirical

    equations. In this study, by statistical analyses, four

    new empirical equations were developed to estimate

    the rock mass modulus by using a database of 142

    in-situ test results at the Bakhtiary Dam site; then, by

    use of statistical analyses among them, the suitable

    equation would be select to estimate deformation

    modulus.

    5.1 Estimation of Deformation Modulus from RMR

    System

    In the first step, the values of RMR classification

    system at the Bakhtiary Dam were determined and

    properties of the intact rock like modulus of elasticity

    from laboratory tests was calculated; in addition, the

    values of the rock mass deformation modulus weremeasured from more than 142 in-situ tests. Then,

    non-linear regression analysis was used between the

    values of relation Em/Ei and the values of RMR. Eq. (4)

    shows that the second-order polynomial withR2= 0.70

    is optimum. Also, plot of the values of relation

    E /Em i versus RMR classification system is shown in

    Fig. 4.

    )0199.10.0363RMR-(0.0003RMR2

    i EEm (4)

    where, Em, Ei and RMR are rock mass deformation

    modulus, modulus of elasticity and rock mass rating

    classification system, respectively.

    5.2 Estimation of Deformation Modulus from Q System

    In the first step, the values of Qclassification system

    at the Bakhtiary Dam were determined and properties

    of the intact rock like modulus of elasticity from

    laboratory tests was calculated; in addition, the values

    of the rock mass deformation modulus were measured

    from more than 142 in-situ tests. Then, non-linear

    regression analysis was used between the values of

    relation (Em/Ei) and the values of Q. Eq. (5) shows that

    the second-order polynomial with R2

    = 0.69 isoptimum. Also, plot of the values of relation E /Em i

    versus Qclassification system is shown in Fig. 5.

    0.0595)0.0044(0.000022 QQEE

    im (5)

    where, Em, Ei and Q are rock mass deformation

    modulus, modulus of elasticity, and tunneling quality

    index classification system, respectively.

    5.3 Estimation of Deformation Modulus from GSI

    System

    In the first step, the values of GSI classification

    system at the Bakhtiary Dam were determined and

    properties of the intact rock like modulus of elasticity

    from laboratory tests was calculated; in addition, the

    values of the rock mass deformation modulus were

    measured from more than 142 in-situ tests. Then,

    non-linear regression analysis was used between the

    values of relation (Em/Ei) and the values of GSI. Eq. (6)

    shows that the second-order polynomial withR2

    = 0.69is optimum. Also, plot of the values of relation

    (Em/Ei) versus GSI classification system is shown in

    Fig. 6.

    )88890GSI03450GSI00040(2 ..-.EE

    im

    (6)

    where, Em, Ei and GSI are rock mass deformation

    modulus, modulus of elasticity, and geological strength

    index classification system, respectively.

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    Empirical Development of the Rock Mass Deformation Modulus62

    Fig. 4 The values of relation Em/Eivs. RMR classification system.

    Fig. 5 The values of relationEm/Eivs. Qclassification system.

    0

    0.1

    0.2

    0.3

    0.4

    0.5

    0.6

    0 20 40 60 80 100

    Em

    /Ei

    RMR

    Em

    /Ei= 0.0003RMR

    2-0.0363RMR+ 1.0199

    R2= 0.70

    0

    0.1

    0.2

    0.3

    0.4

    0.5

    0.6

    0 20 40 60 80 100

    Em/E

    i= 0.00002Q

    2+0.0044Q+0.0595

    R2= 0.69

    Q

    Em

    /Ei

    RMR

    Em/Ei= 0.00002Q2+ 0.0044Q +

    Q

    Em/Ei= 0.0003RMR - 0.0363RMR + 1.0199R

    2= 0.70

    Em

    /Ei

    Em

    /Ei

    R2= 0.69

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    Empirical Development of the Rock Mass Deformation Modulus 63

    Fig. 6 The values of relation Em/Eivs. GSI classification system.

    5.4 Estimation of Deformation Modulus from JH

    System

    In the first step, the values of JH classification

    system at the Bakhtiary Dam were determined and

    properties of the intact rock like modulus of elasticity

    from laboratory tests was calculated; in addition, the

    values of the rock mass deformation modulus were

    measured from more than 142 in-situ tests. Then,

    non-linear regression analysis was used between the

    values of relation (Em/Ei) and the values of JH. Eq. (7)

    shows that the exponential equation with 2 0.67R is

    optimum. Also, plot of the values of relation E /Em i

    versus JH classification system is shown in Fig. 7.0.1392

    ( 0.000002 )JH

    m iE E e

    (7)

    where, Em, Ei and JH are rock mass deformation

    modulus, modulus of elasticity, and JH corporation

    classification system, respectively.

    5.5 Proposed a New Empirical Equation to Estimate

    the Rock Mass Deformation Modulus

    In this study, the rock mass deformation modulus in

    Bakhtiary Dam site was obtained from in-situ tests and

    four new equations. Moreover, in a similar study, the

    deformation modulus in dam site from different

    empirical equations had been determined and the

    results had compared with measured results;

    subsequently, the results showed that the first equation

    of Hoek and Diederichs [22] had the most coincidence

    with measured results. On the other hand, the results of

    in-situ test were compared with four new equations and

    Hoek and Diederichs empirical equation in order to

    choose the eligible empirical equation to estimate

    deformation modulus. Hoek and Diederichs [22]

    proposed the following empirical equation for

    estimation of rock mass deformation modulus:

    0

    0.1

    0.2

    0.3

    0.4

    0.5

    0.6

    0 20 40 60 80 100

    Em

    /Ei= 0.0004GSI

    2-0.0345GSI+0.8889

    R2= 0.69

    GSI

    Em

    /Ei

    Em/Ei= 0.0004GSI2 0.0345GSI+ 0.8889

    R2= 0.69

    GSI

    Em

    /Ei

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    Empirical Development of the Rock Mass Deformation Modulus64

    Fig. 7 The values of relation (Em/Ei) vs. JH classification system.

    75 25

    11

    12100

    1

    m D GSI

    DE

    e

    (8)

    where, D, GSI andmE are distribution factor, geological

    strength index classification system and rock mass

    deformation modulus, respectively.

    In this study, the standard descriptive measure of

    goodness-of-fit was employed to evaluate the accuracy

    of deformation modulus calculated from empirical

    equations. RMSE (root mean squared error) is:

    n

    imm ii

    EEn 1

    2)(1

    RMSE '

    I = 1, 2, , n

    (9)

    where, n, Em andim

    E are the number of data i,

    measured value of deformation modulus, and estimated

    value of deformation modulus by empirical equations,

    respectively. Also, MARPE (mean absolute relative

    prediction error) is:

    n

    i m

    mm

    i

    ii

    E

    EE

    n 1

    '1MARPE i=1, 2, , n

    (10)

    Furthermore, the ER (error ratio) or MER (meanerror ratio) is:

    i

    i

    m

    m

    E

    E 'ER

    i=1, 2,, n

    (11)

    In this study, based on the above equations, the

    values of RMSE and MARPE equations which are

    close to zero and the value of MER equation which is

    close to one, the suitable empirical equation was

    suggested in order that it can carefully estimate the

    values of deformation modulus. A list of the equations

    for selecting the suitable equation in order to estimate

    the deformation modulus is given in Table 6.

    In Table 6, the validation of four new equation by

    use of statistical analyses were examined; subsequently,

    the results showed that Eq. (7) was highly suitable to

    estimate deformation modulus owing to R2 = 0.67,

    RMSE = 0.07, and MARPE = 0.46 as well as

    MER = 1.28.

    0

    0.1

    0.2

    0.3

    0.4

    0.5

    0.6

    0 20 40 60 80 100

    Em/E

    i= 0.000002e

    (0.1392JH)

    R2= 0.67

    JH

    Em

    /Ei

    JH

    Em/Ei= 0.000002e0.1392JH

    R

    2

    = 0.67

    Em

    /Ei

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    Empirical Development of the Rock Mass Deformation Modulus 65

    Table 6 List of the equations for selecting of the suitable equation in order to estimate the deformation modulus.

    Equations 2R RMSE MARPE MER

    Eq. (4) 0.70 0.20 1.73 -0.73

    Eq. (5) 0.69 0.06 0.53 1.31

    Eq. (6) 0.69 0.17 1.85 2.85

    Eq. (7) 0.67 0.07 0.46 1.28

    Eq. (8) - 6.89 0.76 1.65

    Fig. 8 Comparison between the measured and estimated deformation moduli from eq. (7).

    Moreover, the best results can be considered when

    the values of modulus were predicted by Eq. (7). Also,

    the comparison between the measured and estimated

    deformation modulus from Eq. (7) is shown in Fig. 8.

    6. Conclusions

    In this paper, the rock mass deformation modulus by

    actual data collected from Bakhtiary Dam site was

    measured. Then, four new empirical equations to

    estimate rock mass deformation modulus based on

    modulus of elasticity and the RMR, the Q and the GSI

    as well as the corporation JH classification systems was

    developed.

    Then, through statistical analysis (RMSE, MARPE,

    ER and 2R , the rock mass deformation modulus was

    estimated by empirical equations and the results were

    compared with the results of measured deformation

    modulus. All in all, the results showed that Eq. (7) was

    the suitable equation for estimating the rock mass

    deformation modulus.

    Acknowledgments

    The authors express their thanks to the Iran Water

    and Power Resources Development Committee staff,

    0

    5

    10

    15

    20

    25

    30

    35

    40

    0 5 10 15 20 25 30 35 40

    Estim

    ateddeformationmodulusfrom

    JH

    system,

    GPa

    Measured deformation modulus from in-situ tests, GPa(Gpa)

    (Gpa)

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    Empirical Development of the Rock Mass Deformation Modulus66

    Poyry Cu. Engineering Staff, Moshanir Cu.

    Engineering Staff, Dezab Cu. Engineering Staff,

    Stucky Pars Cu. Engineering Staff for providing data

    support, and Isfahan University Of Technology, where

    the research was carried out.

    References

    [1] E.G. Ravandi, R. Rahmannejad, A.E.F Monfared, E.G.

    Ravandi, Application of numerical modeling and genetic

    programming to estimate rock mass modulus of

    deformation, International Journal of Mining Science and

    Technology 23 (5) (2013) 733-737.

    [2] L. Faramarzi, H. Fatahi, Interpretation of plate loading

    test results on major projects, in: Proceedings of the

    ARMS5 (5th Asian Rock Mechanics Symposium),

    Tehran, Iran, 2008, pp. 255-260.

    [3] X.W. Jiang, L. Wan, X.S. Wang, X. Wu, X. Zhang,

    Estimation of rock mass deformation modulus using

    variations in transmissivity and RQD with depth,

    International Journal of Rock Mechanics & Mining

    Sciences 46 (2009) 1370-1377.

    [4] L. Faramarzi, Evaluation of rock mass deformability by

    means of in situ loading tests, Ph.D. Thesis, Kumamoto

    University, Japan, 2005 (Chapter 1).

    [5] Z.T. Bieniawski, Determining rock mass deformability:

    Experience from case histories, International Journal of

    Rock Mechanics and Mining Sciences & Geomechanics

    Abstracts 15 (1978) 237-247.

    [6] J.L. Serafim, J.P. Pereira, Consideration of the

    geomechanics classification of Bieniawski, in:

    Proceedings of International Symposium on Engineering

    Geology and Underground Constructions, 1983, pp.

    1133-1144.

    [7] G.A. Nicholson, Z.T. Bieniawski, A nonlinear

    deformation modulus based on rock mass classification,

    International Journal of Mining and Geological

    Engineering 8 (1990) 181-202.

    [8] V.K. Mehrotra, Estimation of engineering parameters of

    rock mass, Ph.D. Thesis, University of Roorkee, Roorkee,

    India, 1992.

    [9] E. Grimstad, N. Barton, Updating the Q-System for NMT,

    International Symposium on Sprayed Concrete-Modern

    Use of Wet Mix Sprayed Concrete for Underground

    Support, Oslo, 1993.

    [10] H.S. Mitri, R. Edrissi, J. Henning, Finite element

    modelling of cable-bolted stopes in hard rock

    underground mines, in: Proceedings of the SME Annual

    Meeting Albuquerque, New Mexico, 1994, pp. 94-116.

    [11] E. Hoek, E.T. Brown, Practical estimates of rock mass

    strength, International Journal of Rock Mechanics &

    Mining Sciences 34 (8) (1997) 1165-1186.

    [12] S.A.L. Read, L.R. Richards, N.D. Perrin, Applicability of

    the Hoek-Brown failure criterion to New Zealand

    greywacke rocks, in: Proceedings of The Ninth

    International Congress on Rock Mechanics, Paris, 1999,

    pp. 655-660.

    [13] A. Palmstrom, R. Singh, The deformation modulus of

    rock masses: Comparisons between in situ tests and

    indirect estimates, Tunnelling and Underground Space

    Technology 16 (2001) 115-131.

    [14] N. Barton, Rock mass classification, tunnel

    reinforcement selection using the Q-system, in:

    Proceedings of the ASTM Symposium on Rock

    Classification Systems for Engineering Purposes,

    Cincinnati, Ohio, 1987.

    [15] N. Barton, Estimating rock mass deformation modulus

    for excavation disturbed zone studies, in: International

    Conference on Deep Geological Disposal of Radioactive

    Waste, EDZ Workshop: Canadian Nuclear Society,

    Winnepeg, 1996, pp. 133-144.

    [16] N. Barton, Some new Q value correlations to assist in site

    char-characterisation and tunnel design, International

    Journal of Rock Mechanics and Mining Sciences &

    Geomechanics Abstracts 39 (2002) 185-216.

    [17] J.M. Galera, Z. Alvarez, Z.T. Bieniawski, Evaluation of

    the deformation modulus of rock masses using RMR,

    comparison with dilatometer tests, Workshop:

    Underground Works under Special Conditions:

    Proceedings of the ISRM Workshop W1, Madrid, Spain,

    2007.

    [18] J. Shen, M. Karakus, C. Xu, A comparative study for

    empirical equations in estimating deformation modulus of

    rock masses, Tunnelling and Underground Space

    Technology 32 (2012) 245-250.

    [19] M. Sanei, A. Rahmati, L. Faramarzi, S. Goli, A.

    Mehinrad, Estimation of rock mass deformation modulus

    in Bakhtiary Dam Project in Iran, in: F. Hudson, Tan

    (Eds.), Rock Characterisation, Modelling and

    Engineering Design Methods, Taylor & Francis Group,

    London, 2013, pp.161-164.

    [20] L. Zhang, H. Einstein, Using RQD to estimate the

    deformation modulus of rock masses, International

    Journal of Rock Mechanics & Mining Sciences 41 (2)

    (2004) 337-341.

    [21] H. Sonmez, C. Gokceoglu, R. Ulusay, Indirect

    determination of the modulus of deformation of rock

    masses based on the GSI system, International Journal of

    Rock Mechanics & Mining Sciences 41 (5) (2004)

    849-857.

    [22] E. Hoek, M.S. Diederichs, Empirical estimation of rock

    mass modulus, International Journal of Rock Mechanics

    & Mining Sciences 43 (2) (2006) 203-215.

  • 7/25/2019 Empirical Development of the Rock Mass Deformation

    13/13

    Empirical Development of the Rock Mass Deformation Modulus 67

    [23] B.S. Chun, W.R. Ryu, M. Sagong, J.N. Do, Indirect

    estimation of the rock deformation modulus based on

    polynomial and multiple regression analyses of the RMR

    system, International Journal of Rock Mechanics &

    Mining Sciences 46 (3) (2009) 649-658.

    [24] M. Sanei, A. Rahmati, L. Faramarzi, A. Mehinrad, H.

    Chehreh, Development of new empirical equation for

    estimation of rock mass deformation modulus by using of

    JH classification system, a case study: Bakhtiary Dam

    project, Iran, in: Processings of the ICME2013 (1st

    International Conference on Mining, Mineral,

    Metallurgical and Environmental Engineering),

    University of Zanjan, Iran, 2013, pp. 1243-1248.

    [25] International Society for Rock Mechanics, Suggested

    Methods for Rock Mass Determination of In-stiu

    Deformation Modulus, ISRM (International Society of

    Rock Mechanics), 1979.

    [26] Engineering Geology and Rock Mechanics

    Report on Completion of Site Investigations Phase I&II:

    Revision 1, Stucky Pars Engineering Co., Tehran, Iran,

    2009.

    [27]W. Akagi, T. Ito, H. Shiroma, A. Sano, M. Shinji, T.

    Nishi, et al., A proposal of new rock mass classification

    for tunneling, in: International symposium, Modern

    tunneling science and technology, Kyoto, Japan, 2001, pp.

    371-378.