Geomekanika_RMR
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Transcript of Geomekanika_RMR
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8/8/2019 Geomekanika_RMR
1/9
No.
CoreRecove
ry
UCS(MPa)
RQD(%)
JointSpace(cm/joi
nt)
Joint Condition- Type/shape/dip/surface/i
nfill/opening- Soft gauge 5 mm,
continues- Slicken side, gouge 5
mm, 1-5 mm opening- Rough surface, 1 mm
opening, weatheringstage
Groundwater
Condition
Discontunityorientation
RMR
1. 100Dept
h5,5-10 m
0.3230.4110.662Rating
= 0
100100100
Rating= 20
Noseparation / jointRating =20
No separation / jointRating = 10
WetRating = 7
Noseparation / jointRating =0
57
2. 89Depth 10-12,5
m
0.2700.140Rating
= 0
100100
Rating= 20
Noseparation / jointRating =20
No separation / jointRating = 10
WetRating = 7
Noseparation / jointRating =0
57
3. 100
Depth
12,5-16 m
0.140
0.1400.216Rating
= 0
100
100100
Rating= 20
No
separation / jointRating =20
No separation / joint
Rating = 10
Wet
Rating = 7
No
separation / jointRating =0
57
4. 45Depth 16-17.5
m
0.188Rating
= 0
100Rating= 20
Noseparation / jointRating =20
No separation / jointRating = 10
WetRating = 7
Noseparation / jointRating =0
57
5. 100Dept
h17,5-19 m
0.188Rating
= 0
100Rating= 20
Noseparation / jointRating =20
No separation / jointRating = 10
WetRating = 7
Noseparation / jointRating =0
57
6. 80Depth 19-28 m
0.2950.2950.7330.5680.5680.568Rating
= 0
100Rating= 20
Noseparation / jointRating =20
No separation / jointRating = 10
WetRating = 7 Noseparation / jointRating =0
57
7. 100Depth 28-42 m
0.177
0.177
0.177
0.177
0.177
100Rating= 20
97
Rating= 20
95Rating= 20
87Rating= 17
87
Noseparation / jointRating =20
NotcontinuousRating =20
NotcontinuousRating =20
Notcontinuou
No separation / jointRating = 10
Discontinuities length 5
mm(Rating = 6), separation1-5 mm (Rating = 1),smooth (Rating = 1), infillinggouge 5 mm (Rating = 2)dan moderately weathered(Rating = 3). Total = 13
Rating Total = 13
Rating Total = 13
WetRating = 7
Noseparation / jointRating =0
Jointdipping450,favourable.Rating =-2
Rating =-2
Jointdipping700, very
57
55
55
57
54
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8/8/2019 Geomekanika_RMR
2/9
0.354
0.757
0.757
0.757Rating
= 0
Rating= 17
100Rating= 20
85Rating= 17
85Rating= 17
85Rating
= 17
sRating =20
No
separation / jointRating =20Noseparation / jointRating =20
NotcontinuousRating =
20
Noseparation / jointRating =20
Noseparation / jointRating =
20
No separation / jointRating = 10
No separation / jointRating = 10
Rating Total = 13
No separation / jointRating = 10
No separation / joint
Rating = 10
favourable.Rating =0
Noseparatio
n / jointRating =0Noseparation / jointRating =0
Jointdipping500, veryfavourable.
Rating =0
Noseparation / jointRating =0
Noseparation / jointRating =0
54
57
54
54
Average
= 67,22
8. 87Depth 42-43 m
0.757Rating
= 0
85Rating= 17
Noseparation / jointRating =20
No separation / jointRating = 10
WetRating = 7
Noseparation / jointRating =0
54
9. 100Depth 43-62 m
1.445
1.445
1.445
1.445
1.445
97Rating= 20
95
Rating= 20
95Rating= 20
45Rating
= 8
33
NotcontinuousRating =20
NotcontinuousRating =20
Noseparation / jointRating =20
Notcontinuou
Discontinuities length 5mm(Rating = 2), separation1-5 mm (Rating = 1),smooth (Rating = 1), noinfilling (Rating = 6) danmoderately weathered(Rating = 3). Total = 13
Discontinuities length 5mm(Rating = 2), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
No separation / jointRating = 10
Rating Total = 17
WetRating = 7
Jointdipping350,favourable.Rating =-2
Jointdipping450, fair.Rating =-5
Noseparation / jointRating =0
Jointdipping
59
60
58
48
44
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8/8/2019 Geomekanika_RMR
3/9
1.445
1.085
1.085
1.613
1.6131.613Rating
= 1
0.617
0.617Rating
= 0
Rating= 8
33Rating
= 8
100Rating= 20
100Rating= 20
100Rating= 20
100Rating= 20
100Rating= 20
100Rating= 20
sRating =20
Notcontinuou
sRating =20
NotcontinuousRating =20
Noseparatio
n / jointRating =20
Noseparation / jointRating =20
Noseparation / jointRating =
20
Noseparation / jointRating =20
Noseparation / jointRating =20
NotcontinuousRating =20
Rating Total = 13
Rating Total = 17
No separation / jointRating = 10
No separation / jointRating = 10
No separation / jointRating = 10
No separation / jointRating = 10
No separation / jointRating = 10
Rating Total = 17
200, fair.Rating =-5
Jointdipping100, fair.
Rating =-5
Jointdipping200, fair.Rating =-5
Noseparation / jointRating =0
Noseparation / jointRating =0
Noseparation / jointRating =0
No
separation / jointRating =0
Noseparation / jointRating =0
Jointdipping100, fair.
Rating =-5
48
58
58
58
58
57
59
Average
= 60,38
10. 80Depth 62-63,5
m
0.617Rating
= 0
100Rating= 20
NotcontinuousRating =20
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 21
WetRating = 7
Jointdipping200, fair.Rating =-5
63
11. 100Dept
h63,5-65 m
0.617Rating
= 0
85Rating
= 17
Notcontinuou
sRating =20
Discontinuities length 5mm(Rating = 6), separation
1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderately
WetRating = 7
Jointdipping
41
0
, fair.Rating =-5
60
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4/9
weathered (Rating = 3).Total = 21
12. 63Depth 65-66 m
0.617Rating
= 0
85Rating= 17
NotcontinuousRating =20
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderately
weathered (Rating = 3).Total = 21
WetRating = 7
Jointdipping400, fair.Rating =-5
60
13. 100Depth 66-72 m
0.579
0.579
0.579
0.579Rating
= 0
93Rating= 20
93Rating= 20
93
Rating= 20
93Rating= 20
75 cmRating =
15
Noseparation / jointRating =
20
Noseparation / jointRating =
20
Noseparation / jointRating =
20
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 21
No separation / jointRating = 10
No separation / jointRating = 10
No separation / jointRating = 10
WetRating = 7
Jointdipping400, fair.Rating =-5
Noseparation / jointRating =0
Noseparation / jointRating =0
Noseparation / jointRating =0
58
57
57
57
Average= 50,25
14. 100Dept
h 72-76 m
0.579
0.579
0.579
0.579Rating= 0
93Rating
= 20
93Rating= 20
93Rating= 20
93Rating= 20
Noseparatio
n / jointRating =20
Separated withcoal (50cm)Rating =15
Noseparatio
n / jointRating =20
BeddingtypeRating =20
No separation / jointRating = 10
Discontinuities length 5mm(Rating = 6), separation50 cm (Rating = 0), smooth(Rating = 1), soft filling(Rating = 0) dan moderatelyweathered (Rating = 3).
Total = 10
No separation / jointRating = 10
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
WetRating = 7
Noseparatio
n / jointRating =0
Noseparation / jointRating =0
Noseparation / joint
Rating =0
BeddingtypeRating =0
57
65
57
58
Average
= 68,25
15. 93Depth 76-79 m
0.579Rating
= 0
93Rating= 20
BeddingtypeRating =20
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderately
weathered (Rating = 3).Total = 17
WetRating = 7
BeddingtypeRating =0
58
16. 100 0.579 93 Bedding Discontinuities length 5 Wet Bedding 68
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5/9
Depth 79-81 m
Rating= 0
Rating= 20
typeRating =20
mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
Rating = 7 typeRating =0
17. 100Depth 81- 84m
0.747
Rating= 0
100
Rating= 20
Bedding
typeRating =20
Discontinuities length 5
mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
Wet
Rating = 7
Bedding
typeRating =0
64
18. 100Depth884-100
m
0.228Rating
= 0
82Rating= 17
150 cmRating =15
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
WetRating = 7
Jointdipping500,favourable.Rating =-2
56
19. 93
Depth810
1-103m
0.175
Rating= 0
75
Rating= 17
20 cm
Rating =8
Discontinuities length 5
mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
Wet
Rating = 7
Joint
dipping200, fair.Rating =-7
42
20. 100Depth810
3-109m
0.128Rating
= 0
53Rating= 13
18 cmRating =
8
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
WetRating = 7
Jointdipping100, fair.Rating =-7
38
21. 99
Depth810
9-112m
0.128
Rating= 0
53
Rating= 13
No
separation / jointRating =20
No separation / joint
Rating = 20
Wet
Rating = 7
Joint
dipping100, fair.Rating =-7
53
22. 100Depth811
2-113m
0.128Rating
= 0
97Rating= 20
18 cmRating =
8
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
WetRating = 7
Jointdipping100, fair.Rating =-7
45
23. 85Dept
h8113-115m
0.128Rating
= 0
79Rating
=17
6 cmRating =
8
Discontinuities length 5mm(Rating = 6), separation
1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
WetRating = 7
Jointdipping
100
, fair.Rating =-7
42
24. 76Depth811
3-115m
0.128Rating
= 0
76Rating
=17
33 cmRating =
10
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
WetRating = 7
Jointdipping200, fair.Rating =-7
44
25. 100Depth811
5-119
0.128Rating
= 0
76Rating
=17
Noseparatio
n / jointRating =20
No separation / jointRating = 20
WetRating = 7
Jointdipping
200
, fair.Rating =-7
57
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8/8/2019 Geomekanika_RMR
6/9
m
26. 92Depth811
9-121m
0.189Rating
= 0
100Rating
=20
33 cmRating =
10
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
WetRating = 7
Jointdipping200, fair.Rating =-7
47
27. 95Depth812
1-123m
0.189Rating
= 0
100Rating
=20
Noseparation / jointRating =20
No separation / jointRating = 20
WetRating = 7
Jointdipping200, fair.Rating =-7
60
28. 96Depth812
3-124m
0.189Rating
= 0
100Rating
=20
Noseparation / jointRating =20
No separation / jointRating = 20
WetRating = 7
Jointdipping200, fair.Rating =-7
60
29. 95
Depth8124-126m
0.189
Rating= 0
100
Rating=20
No
separation / jointRating =20
No separation / joint
Rating = 20
Wet
Rating = 7
-2 65
30. 100Depth812
6-132m
1.675Rating
= 1
100Rating
=20
75 cmRating =8
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
WetRating = 7
Jointdipping200, fair.Rating =-7
46
31. 97Dept
h8132-134m
0.201Rating
= 0
82Rating
=17
125 cmRating =
15
10 WetRating = 7
Jointdipping
400, fair.Rating =-7
43
32. 100Depth8134-136m
0.201Rating
= 0
82Rating
=17
Noseparation / jointRating =20
No separation / jointRating = 20
WetRating = 7
Noseparation / jointRating =0
65
33. 90Depth813
6-138
m
0.445Rating
= 0
87Rating
=17
75 cmRating =15
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderately
weathered (Rating = 3).Total = 17
WetRating = 7
Jointdipping400, fair.Rating =-7
50
34. 100Depth813
8-142m
0.111Rating
= 0
90Rating
=20
72 cmRating =
15
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderatelyweathered (Rating = 3).
Total = 17
WetRating = 7
Jointdipping300, fair.Rating =-7
53
35. 100Depth814
2-158
m `
0.770Rating
= 0
81Rating
=17
71Rating =
15
Discontinuities length 5mm(Rating = 6), separation1-5 mm (Rating = 1), rough(Rating = 5), no infilling(Rating = 6) dan moderately
weathered (Rating = 3).Total = 17
WetRating = 7
Jointdipping300, fair.Rating =-7
50
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8/8/2019 Geomekanika_RMR
7/9
Massa batuan dapat diklasifikasikan melalui geomekanik. Klasifikasi
geomekanik dan Bienniawsky menilai beberapa parameter dalam massa
batuan yang kemudian diberi bobot (Setiawan, 1990). Parameter yang
diberi bobot adalah : kekuatan batuan, RQD, spasi rekahan, kondisirekahan, kondisi air tanah, orientasi strike (arah jurus perlapisan batuan).
Hasil pembobotan massa batuan (rock mass rating, RMR) ini dapat
digunakan dalam perencanaan terowongan, pondasi maupun pembobotan
massa lereng (Romano, 1990)
Pada setiap perencanaan bagi perencanaan pengembangan wilayah
dan perencanaan fisik yang berwawasan lingkungan, misalnya peletakan
infrastruktur (bangunan), diperlukan pemantauan (monitoring) lingkungan
juga pengelolaan (manejemen) lingkungan. Manejemen lingkungan
dilakukan sebagai antisipasi untuk menanggulangi terjadinya dampak
negatif (kelemahan geologi) dengan cara memperkecil dampak negatif
tersebut, sekaligus memperbesar dampak positif yang timbul (Zakaria dan
wisyanto, 2000).
Berdasarkan deduksi tinjauan pustaka diatas, muncul hipotesis
sebagai berikut :
a. Struktur geologi dapat diidentifikasi dengan mengukur
discontinuitas batuan berupa kekar-kekar dan strike-dip lapisan
batuan.
b. Penandaan atau penilaian kualitas batuan (rock quality designation)
dapat didekati dengan mengukur kerapatan kekar di lapangan.
c. Massa batuan dapat dinilai melalui pembobotan massa batuan (rock
mass rating) metoda/cara analisis geomekanik Bienieawsky.
d. Perencanaan terowongan, pondasi maupun pembobotan massa
lereng dapat didekati dengan melibatkan pembobotan massa
batuan dan pembobotan massa lereng (slope mass rating) dengan
analisis geomekanik.
e. Monitoring dan manejemen lingkungan dapat diarahkan sebagai
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upaya memperkecil dampak negatif dan memperbersar dampak
positif pada daerah-daerah yang mempunyai kelemahan geologi.
Data perhitungan nilai RMR yang diambil adalah berdasarkan nilai
dari core recovery, hal ini dimaksudkan untuk membagi kelompok litologi
batuan berdasarkan data yang diambil dari core sehingga memberikan
penilaian tersendiri dalam setiap parameter penilaian batuan (RQD, UCS
dan RMR). Untuk bidang antar batuan, kekar yang terbentuk sampai
orientasi dari batuan sendiri memberikan parameter tersendiri dalam
penilaian batuan yang pada akhirnya menentukan nilai RMR dari masing-
masing core recovery. Hal ini pun pada akhirnya akan lebih cermat dalam
memilah kualitas batuan yang padu, terlapukkan, terkekarkan, maupun
batuan yang memiliki perbedaan orientasi dengan lapisan batuan yang
sebelumnya.
Dengan kisaran nilai RMR yang meliputi 42-68, dapat diambil
kesimpulan bahwa kualitas dari batuan yang masuk dalam kelas III hingga
II (Fair Rock - Good Rock). Dengan demikian bisa diambil kesimpulan awal
bahwa litologi batuan yang berada pada wilayah tersebut lebih cocok
untuk digunakan sebagai dasar fondasi bangunan yang sedang, dengan
kata lain tidak cocok untuk bangunan berat karena akan mempengaruhi
pembobotan massa batuan yang dapat mengganggu kestabilan bangunan
yang berada diatasnya. Hal tersebut diakibatkan oleh jenis litologi batuan
yang menyusun wilayah, batuan tersebut didominasi oleh material halus
seperti pasir halus dan lempung dan sebagian adalah batubara yang
berselingan dengan batulempung dan batupasir.
Sebagai contoh, untuk yang memiliki nilai RMR 44 masuk dalam
kategori kelas III atau kelas sedang. Litologi batuan tersebut bisa
dikategorikan tidak cocok apabila diatasnya dibangun bangunan yang
memiliki massa yang cukup siginifikan karena bisa menyebabkan
bangunan menjadi tidak seimbang, amblas, terlebih untuk batulempung
dan batupasir halus.
Data core tersebut menjadi sebuah data awal untuk menentukan
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9/9
proses yang akan dilakukan selanjutnya dalam hal pemanfaatan lahan
hingga pengambilan sumber daya berupa batubara yang ditemukan
dalam core. Kualitas dari batuan tersebut ternyata bergantung dari jenis
kekar, jarak atau bidang ketidakselarasan yang terekam dalam batuansehingga mempengaruhi nilai dari RMR. Beda orientasi pengendapan
(bedding type) yang muncul pada core pun pada akhirnya kembali
membuat nilai RMR semakin berkurang. Karena kekuatan dari tiap batuan
yang berbeda, maka diperlukan data yang akurat guna pemanfaatan
lahan atau wilayah selanjutnya. Dan untuk data diatas, diperlukan
kecermatan ketika membangun gedung bertingkat hingga areal
pertambangan mengingat kualitas dari batuan itu sendiri yang memiliki
kekurangan pada kedalaman tertentu sehingga diperlukan kehati-hatian
ketika memutuskan untuk menentukan posisi atau letak dari tiang
pancang.
Selanjutnya adalah kaitan antara nilai UCS dan RMR, sebagai
sampel adalah pada lajur 7 yang memiliki nilai UCS = 0,177 dan RMR =
55. Setidaknya ada 2 parameter berbeda yang saling terkait. Hal ini
karena besarnya nilai UCS (Unconfined Compressive Strength) atau nilai
kuat tekan batuan akan mempengaruhi kualitas batuan (nilai RMR), dan
kegunaan dari litologi batuan berdasarkan nilai RMR tersebut akan
menentukan jenis orientasi kewilayahan atau bangunan yang akan
didirikan diatasnya.