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3/26/2021 Articles | International Journal of GEOMATE

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163

MODIFICATION OF ROCK MASS CLASSIFICATION IN THE ROCK SLOPE PLATY JOINTED ANDESITE AT SELOHARJO AREA

*Arie Noor Rakhman^1,3, Zufialdi Zakaria¹, Dicky Muslim², Iyan Haryanto², Sri Mulyaningsih³

1Post Graduate Programme of Geological Engineering, Universitas Padjadjaran, Indonesia; ²Geological Engineering, Universitas Padjadjaran, Indonesia; ³Mineral Technology, Institut Sains & Teknologi

AKPRIND, Indonesia

*Corresponding Author, Received: 25 Oct. 2018, Revised: 05 Dec. 2018, Accepted: 20 Dec. 2018 ABSTRACT: The research area is located in the Seloharjo Area, the southern hills of Opak River, Bantul Regency, Yogyakarta Special Region, Indonesia. This study explores the application of rock mass classification assessment by modifying the Q system (SQR) for rock slope stability (SMR) where the constituent lithology is platy jointed andesite. Andesite in the research area is lava haze, where currently the rock slopes are prone to rockfall since the earthquake in 2006. Correction of Q system parameters in the research area is controlled by oriented slopes and joints that were weathered into clay minerals filling the joints. Slope between 74° and 78° with strikes of the slope face between N 110° E and N 228° E. Strike direction of the planar joint plane is between N 136° E and N 238° E with an angle of dip is 20° and 26°. The presence of secondary minerals dominated by smectite and illite clay minerals. Based on the value of the RMR between 43 and 72 with the SMR value between 59.99 and 87.03, the Q value between 7.47 and 299.35, the SQR value between 84.58 and 2,564.10, the equation in the form of SMR = 7LnSQR + 30 is obtained.

Keywords: Modification, Q-system, Lava, Platy joint, SMR

1. INTRODUCTION

The research area is located at a cliff along the Imogiri-Kretek, Seloharjo area, Bantul Regency or 21 km from Yogyakarta to the south, Indonesia.

The UTM coordinates of the research area is in 425,208.944 to 425,397.893 mE and from 9,116,652.795 to 9,116,892.772 mN. The location was composed of cracked volcanic rocks, where it was prone to rock mass movement. Cliffs that have the same direction as the fault line of the Middle Miocene tectonic in the Southern Mountains where the direction of the northeast generally has the potential of mass movement of rocks collapsed after the 2006 earthquake, especially on the cliff side of Opak River [1, 2]. Rockfall is potentially caused by vibrations of the earthquake waves that propagate through the weakening zones such as joints and fault [3]. Opak River is a fault line or known as Fault Opak is a major fault with the orientation of the movement of the fault block is directed northeast-southwest direction. The fault is formed from the reactivation of the normal fault during the formation of graben in the Paleogenic Period [1, 4].

Regional geological mapping shows the lithology of the hill consists of andesite lava rocks, some intrusions, and andesite breccia as part of the Nglanggran Formation. Volcanic rocks were part of the Nglanggran Formation where the rocks were Miocene-aged [5]. The outcrop of lava in the field has been intruded by andesite dike, as it was the

existence of a typical group of ancient volcanoes Parangtritis – Sudimoro [6]. The Pattern of tectonic structure of tectonic product Early Miocene in the form of fault which have the direction of fracture south-southwest – north- northeast. The structure was a controller for the formation of volcanoes. The visible volcanic landscape was currently the product of tectonic lifting during the Middle Pleistocene. The Tertiary volcanic activity was polygenetic [6-8].

The behavior of rock mass to rock slope stability can be identified through the rock mass classification system by determining the classification of rock data [9]. Classification of rock data includes rock strength, rock quality designation, joint orientation and groundwater condition [9-12]. Barton, et al. in 1974 added the assessment of the joint system of rock blocks as a parameter of rock mass structure. There is also an assessment of joint roughness, type of mineral in the joint filing and active stress condition as part of rock block strength parameters [13]. Assessment of rock mass classification is influenced by the geological condition of an area [14, 15].

Rakhman and Triheriyadi [16] suggested that rock slopes in the research area were composed by platy jointed lava. Based on the RMR rock mass classification, the lava is estimated as a poor quality rock. One important factor that determines the stability of rock slopes is the style of the rock slope [17-20]. The relationship between the typical rock mass classification of lava igneous rocks is International Journal of GEOMATE, Dec., 2018 Vol.16, Issue 53, pp.163 - 170

Geotec., Const. Mat. & Env., DOI: https://doi.org/10.21660/2018.53.32848 ISSN: 2186-2982 (Print), 2186-2990 (Online), Japan

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International Journal of GEOMATE, Dec., 2018 Vol.16, Issue 53, pp.163 - 170

164 the result of comparison between the values of Rock Mass Rating system or RMR [10], Rock Mass Quality System or Q [13] and Slope Mass Rating system or SMR [11] for rock slopes. The purpose of this study was to obtain the relationship between the classifications of rock mass from the volcanic rock slopes of andesite lava.

2. METHOD

Primary data has been collected in the field at seven rock slope locations. The seven locations and coordinates of the location of rock slopes are presented in the table as follows (Table 1).

Table 1 Location coordinates for the seven rock slopes in the research area

Rock slope mE mN

IM-1 425,270.189 9,116,888.078 IM-2 425,284.927 9,116,861.998 IM-3

IM-4 IM-5 IM-6 IM-7

425,277.919 425,323.450 425,397.893 425,208.944 425,247.310

9,116,842.024 9,116,892.772 9,116,860.599 9,116,712.925 9,116,652.795 Field data collected from the seven rock slopes consists of morphological slope conditions, petrology, and rock structure. Slope conditions consist of slope height, dip slope and strike slope.

Petrographic and X-ray diffraction analysis used to study the structure, texture, and mineral composition of the rock. The data of joint structure consists of a joint set, joint geometry, the frequency of joints per meter length (Rock Quality Designation), the spacing distance between joints, joint wall surface, continuous joint, joint thickness, weathering conditions on rock-wall contacts, type of mineral in joint filling material and water inflow.

Physical and mechanical properties of rocks identified in the laboratory include uniaxial compressive strength, weight unit, moisture, the degree of saturation, porosity, and void ratio. Data collected on rock slopes at IM-3 is additional data as a complement to previous research by the authors [16].

Assessment of rock mass classification begins by estimating the value of RMR. The RMR value was derived from the equation calculation as follows [10].

6 5 4 3 2

1 R R R R R

R

RMR= + + + + + (1)

where R1 = rating of strength of intact rock R2 = rating of Rock Quality Designation R3 = rating of discontinuities spacing

R4 = rating of discontinuities condition R5 = rating of groundwater condition R6 = rating of discontinuities orientation

The Q value was calculated by using the formula as follows [13].

SRF J J J J

Q RQD ^w

a r n

×

= (2)

where RQD = value of Rock Quality Designation Jn = rating of joint set number

Jr = rating of joint roughness number Ja = rating of joint alteration number Jw = rating of joint reduction factor

SRF = rating of joint stress reduction factor The Q assessment was then referred to as Qori. As an adjustment of the Q value of the surface conditions, the Q value was calculated by the SRF value modification approach by Ajoodani-Namin in 1999 [21]. The SRF value modification is determined from the rating as a condition of the calculation results of the formula as follows.

35 . 0

160→ =

× < SRF H

JCS

γ (3) 11

. 0

160→ =

× ≥ SRF

H JCS

γ (4)

where JCS = joint compressive strength γ = unit weight of rock slope materials H = height of rock slope

In this research, the Q value modified by Ajoodani-Namin was then referred to as Qmod. The equation of the RMR to Q relationship from Qori

and Qmod values uses the approach to the RMR valuation relationship equation with the results of the predecessor research [22,23].

44

9 +

= LnQ

RMR (5)

Furthermore, the RMR value was used for the determination of SMR and Q relationship equations. Based on the Romana equation of 1985, the SMR value can be estimated by using the formula as follows [11].

4 3 2

1 )

(F F F F RMR

SMR= + × × + (6)

Where RMR was value of Rock Mass Rating, computed according to Bieniawski’s 1979 proposal; F1 was depended on parallelism between joints and slope face strikes, F1 = (1 - sin A)², where A was denoted the angle between the strikes of the slope face (αs) and the joint (αj); F2

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165 referred to joint dip angle, F2 = tg² βj, where βj

denoted the joint dip angle; F3 was rating of difference between the slope face (βs) and joint dip (βj); F4 was rating of method of excavation.

Corrected Q values and geometry calculations of rock slopes and discontinuities become the basis for assessment of Slope Quality Rating (SQR).

The value of SQR from each rock slope is used to calculate the SMR [21].

According to predecessor researchers such as Hall in 1985 and Orr in 1992 mentioned that the relationship between SMR and RMR by following the linear regression equation [24-27]. The SMR assessment of the original RMR value was then referred to as SMRori. The RMR value from the relationship approach with the Qmod value was then used to calculate the SMR. The estimated SMR value was then referred to as SMRmod. From the relationship between the values of SMRori and SMR_mod using linear regression relationships obtained correlation coefficient values (r). The value of r was used to indicate the tendency of validating the relationship between the SMR values. The constant value of the SMR equation to Q becomes the unique value of the modified Q system for rock slope of the volcanic rock, especially the rock formations of Nglanggran.

3. RESULT AND DISCUSSION

The morphology of andesite lava hills in the study area has an elevation of 12.5 to 105 meters from sea level. The hills have a very steep slope between 74° and 78° with strikes of the slope face between N 110° E and N 228° E (Fig. 1). The andesite lava outcrop at the bottom is slightly decayed and the more upward the weather becomes stronger. Especially on joint wall surfaces, the physical appearance of rocks tends to be dark gray (fresh) on the inside and reddish brown on the surface. The small holes of scoria are common in platy jointed andesite lava.

The presence of secondary minerals dominated by smectite and illite clay minerals in XRD clay- oriented analysis shows that the structure of scoria and joint in rocks contributes to the weathering process. The existence of weathering minerals is also identified through specific gravity physical properties (2.65 – 2.80) and uniaxial compressive strength (18.71 MPa – 61.69 Mpa). Clay minerals are abundant, especially present as fracture fill minerals in fault line scarp (an example of observation location at IM-1). Bronto [6], Mulyaningsih and Sanyoto [28] suggested that andesite lava with these characteristics was part of the Nglanggran Formation as a product of ancient volcanoes where lava formed entered the marine zone. Based on field observations and references

from previous researchers on the physical characteristics of the rock, it was interpreted that these properties were influenced by the process of rock formation as a lava haze or “laze”.

The joint system encountered in the form of 2 joint sets where the joint is commonly held N46°E / 57° and N160°E / 59°. The position of the planar joint plane is strike direction between N 136° E and N 238° E with an angle of dip is 20° and 26°.

Joints have joint spacing between 4 and 18 cm.

General discontinuities condition is slightly rough surfaces, separation < 1 mm, irregular, undulating and highly weathered walls, sandy-clay coatings, small clay-fraction. Some of the others are slightly weathered joint walls, non-softening mineral coatings, sandy particles, clay-free disintegrated rock. A few of the others are slickenside surfaces, undulating with separation 1-5 mm, continuous, medium over-consolidation, softening clay mineral fillings (at the location of IM-1 observation). In a minor inflow of groundwater conditions with increasingly weathered discontinuities, it tends to affect the decrease in RQD values ranging from 87.81% to 43.37%. At IM-1, mylonite was found as a joint filler with a position equal to the fault plane of the normal fault, N53°E / 75° (Fig.2).

This fault and its minor structure joint are interpreted as part of the fault that was formed from the reactivation of the volcanic structure during the formation of structure in the Paleogene Period.

Fig.1 Rock slope of IM-1, IM-2, and IM-3 from hill morphology in the research area (top). Rock slope of IM-4 and IM-5 in the eastern hill morphology (bottom left). The western part of the hill morphology for the location of rock slopes IM- 6 and IM-7 (bottom right).

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166

Fig. 2 Joint filled with clay minerals as mylonite at rock slopes of IM-1(left). Joint sets on platy jointed lava haze (right).

Based on field data and laboratory test results, the RMR parameter values for the seven rock slope locations can be summarized in the form of tables (table 2 and 3).

Table 2 The RMR classification and rating of parameters for rock slopes IM-1, IM-2, IM-3, and IM-4

Parameters IM-1 IM-2 IM-3 IM-4

R1 2 7 4 4

R2 13 17 8 13

R3

R4

R5

R6

RMRbasic

RMR Class Description

8 10 10 0 43 43 III Fair

8 25 10 0 67 67 II Good

8 20 10 0 50 50 III Fair

8 20 10 0 55 55 III Good On the rock slope at IM-5, IM-6 and IM-7 can be determined the RMR classification are shown in the table as follows (Table 3).

Table 3 The RMR classification and rating of parameters for rock slopes IM-5, IM-6, and IM-7

Parameters IM-5 IM-6 IM-7

R1 4 4 7

R2 13 13 17

R3

R4

R5

R6

RMRbasic

RMR Class Description

8 20 15 0 60 60 III Fair

8 25 15 0 65 65 II Good

8 25 15 0 72 72 III Fair

Rock mass classification for Q systems and rating of the parameters on rock slopes of IM-1, IM-2, IM-3, and IM-4 are as follows (Table 4).

Table 4 The Q system classification and rating of parameters for rock slopes IM-1, IM-2, IM-3, and IM-4

Parameters IM-1 IM-2 IM-3 IM-4 RQD 55.78 84.42 43.37 52.49

Jn 4 4 4 4

Jr Ja

Jw

SRF Q (Qori)

Class Description

1.5 8 1 2.5 1.05

D Poor

3 2 1 2.5 12.66

B Good

2 3 1 2.5 2.89

D Poor

2 3 1 2.5 3.50

D Poor Assessment of Q system parameters from rock slopes at IM-5, IM-6 and IM-7 are shown in the table as follows (Table 5).

Table 5 The Q system classification and rating of parameters for rock slopes IM-5, IM-6, and IM-7

RQD 55.78 59.18 87.81

Jn 4 4 4

Jr Ja

Jw

SRF Q (Qori)

Class Description

2 3 1 2.5 3.27

D Poor

3 2 1 2.5 8.88

C Fair

3 2 1 2.5 13.17

B Good The correlation between RMR and Q through the values of the parameters on the seven rock slopes can be presented as follows (Fig. 3).

Fig. 3 Correlation relationship between RMR and Q for seven rock slopes in the research area.

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167 According to Fig. 3, the relationship between RMR and Q (Qori) can be estimated by an equation as follows (Eq.7).

42

11 +

= LnQ_ori

RMR (7)

In order for the Q system to be used as a rock mass classification for the application of rock slope, the Q system needs to be modified. Q system modification is done using the SRF factor formula as Ajoodani-Namin criterion (Eq. 3 and Eq.4). The Q (Qmod) value obtained is the result of correction of the adjustment of initial stress conditions on the surface where its use was applied to the rock slopes of IM-1, IM-2, and IM-3 are as follows (Table 6).

Table 6 Calculation of the Qmod by using SRF assessment parameters for rock slopes IM-1, IM-2, IM-3, and IM-4

RMR 43 67 50 55

Qori

JCS (KN/m²)

H (m) γ (KN/m³)

SRF

1.05 18,710

11 25.05

0.35

12.66 56,890

13 25.56

0.11

2.89 36,280

10 24.37

0.35

3.50 29,430

9 25.27

0.35 Qmod 7.47 287.80 20.65 25.00 Rock mass classification for Q system modification (Qmod) on rock slopes of IM-5, IM-5, and IM-6 are as follows (Table 7).

Table 7 Calculation of the Qmod by using SRF assessment parameters for rock slopes IM-5, IM-6, and IM-7

RMR 60 65 72

Qori

JCS (KN/m²) H (m) γ (KN/m³)

SRF

3.27 31,390

7 25.49

0.11

8.88 35,320

8 24.97

0.11

13.17 61,690

10 25.54

0.11 Qmod 84.52 201.76 299.35 The correlation between RMR and Q (Qmod) results of calculations with SRF parameter determination can be presented as follows (Fig. 4).

Fig. 4 Correlation relationship between RMR and Qmod for seven rock slopes in the research area.

According to Fig. 4, the relationship between RMR and Qmod has an R-value (R=0,9809) that is higher than the R-value of the relationship between RMR and Qori (R=0,9691). Ranasooriya and Nikraz [22], Singh and Goel [23] suggested that the high correlation coefficient of the equation (R), the equation has high validity as a Bieniawski criterion (Eq.5). The relationship between RMR and Qmod can be estimated by an equation as follows (Eq. 8).

30 7 _mod+

= LnQ

RMR (8)

The value of the corrected Q (Qmod) with an increased R-value was represented by the influence of the slope height to the strength of the rock composing the rock slope as a determinant of the value of the SRF. There was a tendency that the higher the height (where the H value ranges from 7 to 13 meters) the greater the strength of the rock composing the slope (18.71 to 61.69 MPa).

Modified Q system can be applied to rock slope by approaching Q relationship with SMR through RMR. The following SMR assessment was the SMR value by rating its parameters without involving the modified Q value (SMRori).

The rock mass classification value of the SMR for rock slopes IM-1, IM-2, IM-3, and IM-4 in the research area is shown in Tables 8 and 9.

Table 8 The SMR classification and parameter ratings for rock slopes IM-1, IM-2, IM- 3, and IM-4

RMRbasic 43 67 50 55

αs

βs

αj

βj

F1

212 78 182

20 0.2500

212 74 136

24 0.009

210 76 202

26 0.7410

228 78 232

26 0.8654 Continued to next page

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168 F2

F3

F4

SMRori

Class Description

0.13 60 15 59.99

III Fair

0.20 60 15 82.01

I Very good

0.24 60 15 75.58

II Good

0.24 60 15 82.35

I Very good The SMR parameter assessment for rock slopes IM-5, IM-6, and IM-7 is shown in the table as follows (Table 9).

Table 9 The SMR classification and parameter ratings for rock slopes IM-5, IM-6, and IM-7

RMRbasic 60 65 72

αs

βs

αj

βj

F1

281 78 230

20 0.0497

160 74 238

24 0.005

158 78 230

26 0.0024 F2

F3

F4

SMRori

Class Description

0.13 60 15 75.39

II Good

0.20 60 15 80.01

I Very good

0.24 60 15 87.03

I Very good The SMRmod value is based on the SMR rock mass classification equation and its parameter rating (Eq.6) and the equation of the RMR relation to Qmod (Eq.8) as follows.

4 3 2 1 mod

mod 7LnQ 30 (F F F ) F

SMR = + + × × +



 



 × × +

× + +

= 7

7 ) 30

7 _mod ¹ ² ³ ⁴

mod

F F F LnQ F

SMR

7 30 exp )

7 _mod ¹ ² ³ ⁴

mod +



















 × × +

×

= F F F F

Q Ln

SMR (9)

SQR can be generated from the SMR equation [22], through the SMR equation (Eq. 9) the SQR equation is obtained as follows.







 × × +

×

= 7

exp ¹ ² ³) ⁴

mod

F F F Q F

SQR (10)

The SQR value of each rock slope is used to calculate the SMR with the SMR equation for the SQR value as follows.

30

mod= LnSQR7 +

SMR (11)

The results of the calculation of the SMR on the SQR value of each rock slope are shown in Tables 10 and 11 as follows.

Table 10 The SMRmod and parameter ratings for rock slopes IM-1, IM-2, IM-3, and IM-4

Parameters IM-1 IM-2 IM-3 IM-4 Qmod 7.47 287.80 20.65 25.00

F1 F2

|F3|

F4 SQR

0.2500 0.13

60 15 84.58

0.0009 0.20

60 15 2,456.78

0.7410 0.24

60 15 797.62

0.8654 0.24

60 15 1,243.96 SMRmod

SMRori

61.06 59.99

84.65 82.01

76.77 75.58

79.88 82.35 Table 11 The SMR_mod and parameter ratings for

rock slopes IM-5, IM-6, and IM-7

Parameters IM-5 IM-6 IM-7 Qmod 84.52 201.76 299.35

F1 F2

|F3|

F4 SQR

0.0497 0.13

60 15 762.21

0.0005 0.20

60 15 1,721.16

0.0024 0.24

60 15 2,564.10 SMRmod

SMRori

76.45 75.39

82.16 80.01

84.95 87.03 By using the value of the calculation of SMRmod and SMRori, the equation of the relationship between the two SMRs and the correlation coefficient of the equation (R) is obtained. The relationship between the two SMRs can be presented as follows.

Fig. 5 Correlation relationship between SMRori and SMRmod for seven rock slopes in the research area.

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169 Based on the graph of the relationship between the SMR values in Fig. 5, it is known that the value of the correlation coefficient of the equation (R) is 0.9740. The R-value close to 1 indicates that the SMR equation resulting from SQR calculation is declared valid. This means that the value of the Q parameter modified by the relationship of the equation to the RMR can be applied to rock slope with the SMR rock mass classification assessment approach.

Correction of Q system parameters (SQR) in the research area is controlled by oriented slopes and joints that were weathered into clay minerals filling the joints. Slope between 74° and 78° with strikes of the slope face between N 110° E and N 228° E. Strike direction of the planar joint plane is between N 136° E and N 238° E with an angle of dip is 20° and 26°. The presence of secondary minerals dominated by smectite and illite clay minerals.

4. CONCLUSION

Modification of rock mass classification for rock slopes of platy jointed andesite is done by modifying the Q system (SQR). This classification has been concluded from RMR, SMR, and Q.

Oriented slopes and joints that were weathered into clay minerals filling the joints are controllers of SQR values as correction of system Q parameters in the research area.

Based on the value of the RMR between 43 and 72 with the SMR value between 59.99 and 87.03, the Q value between 7.47 and 299.35, the SQR value between 84.58 and 2,564.10, the equation in the form of SMR = 7LnSQR + 30 is obtained. The application of this formula is recommended for platy jointed andesite rocks, part of the Nglanggaran Formation, especially andesite as lava haze in the research area.

5. ACKNOWLEDGMENTS

This research was supported by a Doctoral Dissertation Research Grant Program from the Indonesian Ministry of Research, Technology, and Higher Education (RISTEK-DIKTI). The authors thank our colleagues from Universitas Padjadjaran and Institut Sains & Teknologi AKPRIND who provided insight and expertise that greatly assisted the research. The first author thanks Nur Widi Astanto Agus Triheriyadi, S.T., M.T. for assistance with a particular technique, and Prof. Dr.

Ir. I Wayan Darmawan, M.Sc, researcher, Bogor Agricultural University, for comments that greatly improved the manuscript.

6. REFERENCES

[1] Astuti B.S., Rahardjo W., Listyani R.A., and Husein S., Morphogenesis of Inlier hills Watuadeg Region - Pengklik, Prambanan, Daerah Istimewa Yogyakarta^*), Proceeding of Southern Mountains Geological Workshop 2007, Special Publications, No.38, Center for Geological Survey of Indonesia, Bandung, 2009, pp. 31-44.^*)in Bahasa

[2] Karnawati D., Mechanism of Rocks Movement due to Earthquakes: Overview and Analysis of Engineering Geology^*), Dinamika Teknik Sipil, Vol.7, No.2, 2007, pp. 179–190. ^*)in Bahasa [3] Novianta M., Achmad M.S.H., Setyaningsih

E., dan Rakhman A.N., Earthquake Datalogger Using Vibration and Local ULF Geomagnetic Field Measurement, Proceeding of 2nd Engineering International Conference (EIC), UNNES, Semarang, 2013, pp. 110-114.

[4] Soehaimi, Marjiyono and Setianegara, R., Seismo-tectonics and Zoning of Disaster Potential and Risk of Earthquakes in Coastal Areas at Krakal Beach, Gunung Kidul Regency, DIY Province^*), Proceeding of Southern Mountains Geological Workshop 2007, Special Publications, No.38, Center for Geological Survey of Indonesia, Bandung, 2009, pp. 63-78.

*)in Bahasa

[5] Sidarto, Geology of the Southern Mountains in Gunungkidul Area and Surroundings Interpreted from ALOS Imagery, Proceeding of Southern Mountains Geological Workshop 2007, Special Publications, No.38, Center for Geological Survey of Indonesia, Bandung, 2009, pp. 1-18. ^*)in Bahasa

[6] Bronto S., Fossil Volcanoes in the Southern Mountains of Central Java, Proceeding of Southern Mountains Geological Workshop 2007, Special Publications, No.38, Center for Geological Survey of Indonesia, Bandung, 2009, pp. 171-194. ^*)in Bahasa

[7] Setiadji D.I., Kaiino S, Imai A., and Watanabe, K., Cenozoic Island Arc Magmatism in Java Island (Sunda Arc. Indonesia): Clues on Relationships between Geodynamics of Volcanic Centers and Ore Mineralization, Journal of Resources Geology, Vol.56, No.3, 2006, pp. 267–292.

[8] Mulyaningsih S., Husadani Y.T., Umboro, P.A., Sanyoto, S., and Purnamawati, D.I., Explosive Volcanism Activity Producing Lower Semilir Formation in Jetis Imogiri Area^*), Jurnal Teknologi Technoscientia, Vol.4, No.1, 2011, pp. 64-78. ^*)in Bahasa [9] Liu Y.C. and Chen C.S., A New Approach for

Application of Rock Mass Classification on Rock Slope Stability Assessment, Journal of Engineering Geology, Vol.89, Issues 1-2,

(14)

170 2007, pp. 129-143.

[10] Bieniawski Z.T., Engineering Rock Mass Classifications, John Wiley & Sons, New York, 1989, pp. 1-251.

[11] Romana M., Seron J.B. and Montalar E., SMR Geomechanics Classification:

Application, Experience, and Validation, International Society for Rock Mechanics (ISRM) 2003 – Technology Roadmap for Rock, South African Institute of Mining and Metallurgy, 2003, pp. 1-4.

[12] Hudson J.A., Comprehensive Rock Engineering, Volume 3, Pergamon Press Ltd, Headington Hill Hall, Oxford, 1993, pp. 9-24.

[13] Anonymous, Using the Q-system: Rock Mass Classification and Support Design, Norwegian Geotechnical Institute (NGI), Oslo, 2015, pp.

1-54.

[14] Djakamihardja A.S. and Soebowo W., Stability Study of Rock Slopes on the Liwa- Krui Highway, West Lampung: An Approach to Empirical Methods^*), in Proceeding of the Indonesian Mining Slope Stability II on Department of Mining Eng., ITB, Bandung, 1996, pp. 153-163.^*)in Bahasa

[15] Larbi G., Abderrahmen B., Ismail N., and Mohammed-Laid B. The Classification Systems as a Tool to Estimate the Stability of Discontinuous Rock Mass—A Numerical Approach: The Iron Mine of Boukhadra (Algeria) as a Case Study, Electronic Journal of Geotechnical Engineering (EJGE), Vol.17, 2012, pp. 419-433.

[16] Rakhman A.N. and Triheriyadi N.W.A.A., The Effect of Discontinuity of Volcanic Rock Mass on Slope Stability in the Jelapan Area and Surroundings, Pundong District, Bantul Regency, Daerah Istimewa Yogyakarta^*), Jurnal Teknologi Technoscientia, Vol.10, No.1, 2017, pp. 71-77. ^*)in Bahasa

[17] Van P.T. and Maegawa, K., Experiments and Numerical Modeling of a Rockfall Protective Wire Rope Fence, International Journal of GEOMATE, Vol. 2, No. 2 (Sl. No. 4), 2012, pp. 219-226.

[18] Alzo’ubi A. K., The Role of Block Ratio and Layer Thickness on Rock Slopes Movement Style, International Journal of GEOMATE, Vol. 8, No. 2 (Sl. No. 16), 2015, pp. 1271- 1277.

[19] Adriansyah Y., Muslim D. and Zakaria Z., Risk Analysis of a Major Pit Slope Failure at the Batu Hijau Open Pit Mine Operation PT Newmont Nusa Tenggara; In Engineering Geology for Society and

Territory – Vol. 5, Springer International Publishing Switzerland, 2015, pp 721-724.

[20] Shokouhi A., Gratchev I. and Kim D.H., Rock slope stability problems in Gold coast area, Australia, International Journal of GEOMATE, Vol. 4, No. 1 (Sl. No. 7), 2013, pp. 501-504.

[21] Fereidooni D., Reza, G. and Heidari M., Assessment of a Modified Rock Mass Classification System for Rock Slope Stability Analysis in the Q-system, Earth Sciences Research Journal, Vol. 19 No, 2, 2015, pp.147-152.

[22] Ranasooriya J. and Nikraz H., Reliability of The Linear Correlation Of Rock Mass Rating (RMR) and Tunnelling Quality Index (Q), Australian Geomechanics, Vol. 44, No 2, 2009, pp. 47-54.

[23] Singh B. and Goel R.K., Engineering Rock Mass Classification, Chapter 9, Elsevier Inc, 2011, pp. 119-123.

[24] Zakaria Z., Geomechanics Analysis of Halang Formation in Regional Geological Structure Around Citaal River, Kuningan, West Java, Bulletin of Scientific Contribution, Vol. 4, No.

1, 2006. pp. 19-28.

[25] Zakaria Z., Muslim D. and Sophien I., SMR Correction on Coal Mining Slope Design at Balikpapan Formation and Kampungbaru Formation, Sangasanga, East Kalimantan, Buletin Sumber Daya Geologi, Vol. 7, No. 3, 2012, pp. 147-157.

[26] Zakaria Z., Muslim D., Jihadi L., and Sabila Z.S., Modification of Slope Mass Rating for Stable Slope Design, in Proc. of 10th Asian Regional Conference of IAEG on Kyoto University, Kyoto, 2015, pp. 1-6.

[27] Zakaria Z., Oscar A.W., Sabila Z.S., and Jihadi, L.H., Modified Slope Mass Rating for Slope Design in Open-pit Mining, in R.

Ulusay, O. Aydan, H. Gercek, M.A. Hindistas,

& E. Tuncay (Eds), Rock Mechanics and Rock Engineering: From the Past to the Future, CRC Press (Taylor & Francis Group), London, 2016, pp. 641-645.

[28] Mulyaningsih S. and Sanyoto S., Geology of Mount Merapi Volcano; As a Reference in Interpretation of Tertiary Composite Volcanoes at Gunung Gede-Imogiri Area, Daerah Istimewa Yogyakarta^*). Proceeding of 3rd Seminar Nasional Aplikasi Sains &

Teknologi (SNAST), 2012, pp. B242-B251.

*)in Bahasa