TA 3111 Mekanika Batuan – Batuan & Mekanika BatuanBATUAN DAN MEKANIKA BATUAN - 1 Suseno Kramadibrata Made Astawa Rai Ridho K Wattimena Laboratorium Geomeknika FIKTM - ITB Pendahuluan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Over the last decade there has been an unprecedented increase in the development of civil and mining works, both for surface and underground in Indonesia. The civil work that concerns to the geomechanics engineers have been mostly associated with tunnelling development. Most of the open pit mining development has been related to the exploitation of low to medium grade gold, coal deposits, and to some extents to the expansion of a nickel mine and limestone quarries for cement factories. On the other hand, underground mining development apparently has been attributed to the expansion of the existing underground coal mines and development of two underground gold mines. It is clear that the geomechanics engineers, who are responsible of designing and implementing the proposed mining method should take account economic considerations as well as safety awareness. Moreover, design of large rock excavations must rely on many geomechanics parameters, which are often determined on laboratory as well as insitu tests. Obviously, the data obtained from laboratory tests are frequently based on relatively small size samples. The insitu tests to determine the direction and magnitude of insitu stress are very rare to be carried out, as they are very expensive. Although insitu underground monitoring has been practiced at a number of mines, roof collapse, wall and floor deformation and support failure still take place. This may relate to inability of the geomechanics engineers to fully understand the behaviour of the real rock mass condition. And this is due a limited information could be obtained, either from laboratory tests, insitu tests or field observation. Problems identified in the open pit mines have apparently been linked to, slope stability of working bench and outside dump, low bearing capacity and rock breaking efficiency. On the other hand, problems encountered in the underground mines may be as follows; determination of input parameters for analysis of an underground opening stability, insitu stress determination, and selection of rock excavation method. This paper therefore describes the parameters controlling the stability of open pit and underground mines. These may be elaborated as follows; the overall geology of Indonesia, tropical weather, the typical slope and underground opening failures, behaviour of geological materials, laboratory test procedures and case studies associated with the geomechanics problems in Indonesian mining are given. TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Magmatic Belts in Indonesia Distribution of Metallic, Non-metallic Minerals and Coal in Indonesia TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan clastic. Second. The earth .90% of Indonesian land is covered by quarter sediment namely. and pyroclastic sediments resulted from volcano activities. sedimentary rock and rock formation formed from volcanic activities are dominant in Indonesia. The young rock formation apparently should have not been well compacted. and as a results the porosity is relatively higher than that of old rock formation. it should be borne in mind that there are three tectonic plates i. intersect each other in Indonesia. Eurasia . and this particular rock formation has a very wide range rock types. As a matter of fact. and soils resulted from rock weathering.Australia . Thus.quakes in the world happens in Indonesia. .quakes normally cause tension zones that ultimately create unstable zones. As far as the rock type is concerned. This rock type is seemingly not quite dense. Regarding the tectonic activities..17% of the active volcanoes in the world are located in the Indonesian archipelago and there are 3 volcanoes magmatic belts. the rock formation in Indonesia is very young. alluvial. First. about one tenth of earth . about 80 . About 13% .Keunikan Geologi Umum Indonesia TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan There are three interesting geology phenomena of Indonesia. and third there are many tectonic activities taking place in Indonesia.Indian Pacific Ocean.e. stretching from Sumatra to Irian Jaya. it is not unusual if strong and many tectonic activities take place in Indonesia. as well as trass alluvial. 17% of the active volcanoes in the world are located in Indonesian archipelago 3 volcano magmatic belts: stretching from Sumatra to West Papua & mineral belts also relatively occupying the same magmatic belts High rainfall 3000 . & has a very wide range rock types. high porosity ± 13% .90% Indonesian land is covered by quarter sediment & the rock formation is very young There are many tectonic activities occurring in Indonesia The young rock formation have not been well compacted.General Geology Of Indonesia TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan ± 80 .4000 mm & mostly in Sumatra. not quite dense. & this turns hard rock formation into so-called soft rock Rapid mining development coupled with soft rock behaviour lead to Geomechanical or rock engineering problems . ambient temperature & intensity of ultraviolet rays over a year period causes chemical weathering occur frequently. Kalimantan & Java A combination of high rainfall. particularly the chemical weathering.4000 mm. These facts of course cause a great contribution toward the weathering process. Laterite and monmorilonite clay is the typical materials resulted from weathering process. it can be noted as well that the ambient temperature and intensity of ultraviolet ray over a year period are relatively high. This weathering process would therefore turn hard rock formation into so called soft rock formation. This happens mostly in the areas of Sumatra. because once it gets wet it will expand very quickly and consequently influence the deformation behaviour. . monmorilonite clay is the most interesting one. Kalimantan. Hence. And. Beside the high rainfall rate. As a result of this unique condition Indonesia has a very high rainfall rate. west Java.Iklim & Cuaca TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Indonesian archipelago is located within the Equator and between Asia and Australia continents and surrounded by Pacific and Indian oceans. it is not surprising when rock changing takes place frequently. and the average annual rainfall rate being 3000 . . Batuan adalah susunan mineral dan bahan organis yang bersatu membentuk kulit bumi. Batuan yang tidak terkonsolidasi (unconsolidated rock). 2. Batuan adalah semua material yang membentuk kulit bumi yang dibagi atas : Batuan yang terkonsolidasi (consolidated rock).Definisi Batuan Menurut Geologiwan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan 1. Klasifikasi Geologi Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Batuan Beku (igneous rocks) Batuan Sedimen (sedimentary rocks) Batuan Malihan atau metamorf (metamorphic rocks) . Proses Pembentukan Berbagai Jenis Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Proses pembentukan batuan beku Proses pembentukan batuan metamorphic Proses pembentukan batuan sediment . Berbagai Jenis Batuan Penting Dalam Rekayasa Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Basalt Gneiss Gneiss . Rocks flow and recrystallize under new tectonic stresses to form weak foliation planes. evaluation of intact rock anisotropy in terms of strength and modulus is inevitable. either dealing with inherent intact rock anisotropy from an exploratory borehole or induced rock anisotropy due to in situ fracturing [1].TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Pengaruh Geologi Batuan Terhadap Rekayasa Batuan-1 Out of the three generic categories of rocks. Irrespective of the size of the engineering projects. . where stability of large rock mass is concerned. is associated with tectonic evolution and development of layers of contrasting mineralogical assemblages.e. Such planes of weakness (i. in response to high pressure and temperature gradients. schistosity) affect the strength and deformational behaviors of rocks with orientation to the applied stresses. Segregation of constituent minerals. metamorphic rocks exhibit highest degree of anisotropy [1]. As a result their engineering properties vary with the direction of loading. β (the angle between the major principal stress direction and the foliation plane).TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Pengaruh Geologi Batuan Terhadap Rekayasa Batuan-2 Prediction of the anisotropic responses of strength and deformation of rocks involves study of specimens at different orientation angles. which is characteristic of metamorphic rocks such as schists. is due to a process of metamorphic differentiation. Preferred orientation of minerals like mica and chlorite in response to tectonic stresses makes schistose rocks foliated. Anisotropy. . TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Jenis Struktur Batuan . misalnya dengan cangkul dan belincong. . 2. Batuan adalah suatu bahan yang keras dan koheren atau yang telah terkonsolidasi dan tidak dapat digali dengan cara biasa.Definisi Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Menurut Teknik Sipil .Geoteknik 1. Istilah batuan hanya untuk formasi yang keras dan padat dari kulit bumi. .Definisi Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Menurut Talobre Menurut Talobre. minyak dan lain-lain). orang yang pertama kali memperkenalkan Mekanika Batuan di Perancis pada tahun 1948. batuan adalah material yang membentuk kulit bumi termasuk fluida yang berada didalamnya (seperti air. Definisi Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Menurut ASTM Batuan adalah suatu bahan yang terdiri dari mineral padat (solid) berupa massa yang berukuran besar ataupun berupa fragmenfragmen. . Tanah dikenal sebagai material yang “mobile”.Definisi Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Menurut Umum Batuan adalah campuran dari satu atau lebih mineral yang berbeda. tidak mempunyai komposisi kimia tetap. rapuh dan letaknya dekat dengan permukaan bumi . Batuan tidak sama dengan tanah. joint. .39 3.Komposisi Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Mineral SiO2 AI2O CaO MgO % 59.9 3.9 4.25 2. dll.02 Batuan terdiri dari batuan padat baik berupa kristal maupun yang tidak mempunyai bentuk tertentu dan bagian kosong seperti pori-pori.7 Mineral Fe Na2O K2O Fe2O3 H2O % 3.98 2. crack.69 2. fissure.8 14. 1994). This approach has been much concerned with the defects within the rock mass rather than the rock material it self. the descriptor soft would appear to be far more appropriate as it applies to the intact rock material. the following term “rocks which are susceptible to physical and chemical weathering resulting in such effects as deterioration in strength. Hence. Accordingly. Fairhurst. 1991. when soft rock have been encountered in an open pit or an underground mines. squeezing and swelling” may be appropriate.Definisi Soft Rock TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan There are many terms used to describe materials being considered as soft rock (Johnston. the technology applied has usually involved the empirical hard rock approached. which are mainly controlled by discontinuities. As mentioned earlier. The intact rock material is supposedly independent of any discontinuities that may or may not influence its engineering behaviour. 1981). Unlike the hard rock properties. The most well known intact rock classification scheme frequently used by geomechanics engineers is the one from the ISRM (Brown. slaking. it is not unusual that rock-engineering problems involving soft rocks have traditionally been solved by extrapolating from the historically separate technologies of either soil mechanics or rock mechanics. a considerably close relationship is observed between the properties. However. it has usually been a specialist of rock mechanics who has sought a solution. Consequently. the behaviour of the ground composed of such soft rock and weak rock largely depends upon the physical and mechanical properties of rock elements. For example. determined for rock and those determined for rock masses. 1993 and Vutukuri & Katsuyama. . There is ample evidence in the rock mechanics literatures to show that the same characteristic is repeated with hard rocks as shown in Figure 6 for Tennessee marble. for low confining pressure. demonstrate a typical of overconsolidated behaviour with relatively brittle stress strain curves and well defined failure planes as well as degree of dilatancy. Again.Definisi Soft Rock TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Considering the intact rock classification. According to Johnston (1991) and Vutukuri and Katsuyama (1994) the UCS of soft rocks is in the range of 0. Francis (1994) claims that weak rock is associated with the UCS (sc). < 1.25 respectively. Thus. yet the different is the order of the stress level. soft rocks and hard rocks are similar. it is therefore of importance to set up a guideline to define the range of soft rock in term of strength. 1999 and Wawersik & Fairhurst. As the confining pressure is increased.5 GPa and > 0. as confining is increased. . within which the brittle ductile transition takes place. ultimately failure is characterised by bulging. Young’s Modulus (E) and Poisson’s Ratio (n) of < 5 MPa. The results of claystone. The Rock Mass Classifications proposed by Bieniawski (1973) and Barton et al (1974) implied that intact rock that is considered as very weak corresponds to the unconfined compressive strength (UCS = sc) of less than 25 MPa and the RQD is less than 25% respectively. it turns to normally consolidate and ductility becomes apparent.25 – 25 MPa and less than 20 MPa respectively. Furthermore. 1970) during triaxial tests is illustrated in Figure 6. This indicates that a transition from brittle to ductile behaviour becomes apparent. The behaviour of Ombilin claystone and Tennessee marble (Kramadibrata. it can be said if any intact rock processing the UCS of less than 25 MPa can be regarded as soft rocks. the strength characteristics of. Soft Rocks TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Soft rocks are rocks that have failed under their in situ stresses. Soft rocks are what they are because of where they are. soft rocks may be described as geomaterials with properties between soils and rocks. Soft rocks are what they are relative to where they are. Generally. . Physical characteristics of Soft Rocks S. Glaser.D.M. Doolin / International Journal of Rock Mechanics and Mining Sciences 37 (2000) 683±698 TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Physical characteristic Associated problems Low ratios of strength to applied Failure through intact portion stress Naturally occurring fractures Volume changes Creep sensitive Sliding on weak interface Change in effective stresses by swelling or slaking Squeezing may occur . D. Doolin / International Journal of Rock Mechanics and Mining Sciences 37 (2000) 683±698 TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Nature of weakness Cause Structurally weak Evaporites Organics Tectonics Fault zones Weathering/chemical reaction Example rocks Shale. gypsum Coal. mudstone. saprolite Naturally Weak Chemically or mechanically altered . Glaser. lignite Melange Clays and gouge Marls. chalk NaCl KCl. D. sandstone. marl.M. diatomite.D.Categories of Soft Rocks S. 1970).9 MPa 0 0 0.5 Axial strain (%) 300 48.6 .0 0. 1999.PTBA Ombilin Dev iatoric Stres s (MPa) 40 15 MPa 10 MPa 30 20 5 MPa 10 0 0.8 MPa 0 0.0 1.0 2.5 2.4 Axial strain (%) 13.3 MPa Axial stress (MPa) 200 27.5 1.6 MPa 100 6.2 0. Wawersik & Fairhurst. 50 Claystone .Kurva Tegangan Regangan Ombilin claystone & Tennessee marble TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan (Kramadibrata. TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan 5 LONDON CLAY Strength measured in laboratory Strength estimated from insitu tests 4 5 LONDON CLAY Strength measured in laboratory Strength estimated from insitu tests 0 1 2 3 Diameter of specimens Spacing of fissures 4 5 4 3 3 2 2 1 1 0 0 0 1 2 3 Diameter of specimens Spacing of fissures 4 5 . Marsland. 1993.Efek Skala UCS Hard Rocks & Soft Rocks (Kramadibrata and Jones. 1971). The rock mechanics has been taught at the DME since mid 60s The development of rock mechanics had not been noteworthy until large U/G power houses & tunnelling in the Hydro Electric Projects were built in Indonesia (1982 in Saguling. West Java) Since then the U/G constructions & development of U/G coal & gold mine as well as the expansion & new development of open pit coal mine. gold mine. copper mine & nickel mine have significant contributions to the geomechanics development in Indonesia .Development Of Engineering Geomechanics In Indonesia TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Up to date: ± 20 Mining Schools & > 50 School of Civil Engineering Of 20 Mining Schools ±15 undergraduate levels & the rest is three year mining degree & < 5 mining departments teach well rock mechanics The DME Institut Teknologi Bandung ITB has been the benchmark of the mining education in Indonesia ever since. Field Surveys & Studies in Open Pit & U/G Mines TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan U/G monitoring: convergence & magnesonic probe extensometer at hydro electric power projects. raise boring ventilation shaft in U/G Pongkor gold mine. open pit copper & coal mines & U/G gold & coal mines Slope stability monitoring: prisms. road header for driving at U/G Ombilin coal mine. ripping and shovel at a number of open pit coal mines . ground vibration monitoring based on scaled distance at a number of civil projects. & Bucket Wheel Excavator. diggability & excavatability: tunnel boring machine for tunnelling at hydro electric project in Singkarak. surface mines & quarries Cuttability. U/G Ombilin coal mine & U/G Pongkor gold mine Insitu deformability: pressure meter & plate loading tests at civil projects Rock mass & geological structure mapping: quarries. counter weight balance. magnesonic probe extensometer at Muara Tiga Besar open pit coal mine Rock blasting performance: fragmentation (Kuz Ram method). Research Development at The Geomechanics Laboratory DME ITB TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan DME ITB possesses the most well equipped geomechanics laboratory & teaching resources in Indonesia The geomechanics research is mostly associated with final year students. rock cutting and safety related to the instability of open pit & U/G excavations Interesting phenomena to be studied: soft rock engineering. rock blasting. time dependent behaviour and the role of scale effect on the extrapolation of laboratory test result into rock mass condition . Doctoral research projects & commercial Main areas of research: rock mechanics related. Hudson / International Journal of Rock Mechanics & Mining Sciences 41 (2004) 255–273 . J.-T. Feng.Blok Diagram Model Mekanika Batuan & Rekayasa Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan X.A. Meskipun penyelesaian ini masih secara empiris dan kualitatif. terowongan.Definisi Mekanika Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Menurut Talobre 1. 4.banyak mengemukakan problem yg paling sering dihadapi oleh para geologiawan di proyek bendungan. Mekanika batuan tidak sama dengan ilmu geologi yg didefinisikan oleh Talobre sebagai sains deskriptif yg mengidentifikasi batuan & mempelajari sejarah batuan. Mekanika batuan tidak sama dengan ilmu geologi terapan . Mekanika batuan . 3. Dengan mencari analogi-analogi. Mekanika Batuan merupakan gabungan dari: Teori + pengalaman + pekerjaan/pengujian di laboratorium + pengujian insitu. terutama dari proyek-proyek yang sudah dikerjakan dapat menyelesaikan kesulitan-kesulitan yang dihadapi pada proyek yang sedang dikerjakan. 2. .teknik & juga sains yg tujuannya mempelajari behaviour batuan di tempat asalnya agar dapat mengendalikan pekerjaan yang dibuat pada batuan tsb seperti penggalian dibawah tanah dan lain-lainnya. aliran atau deformasi dari batuan. kecepatan. yaitu rekahan (fracture). mekanika batuan adalah : Analisis dari beban atau gaya yang dikenakan pada batuan. Analisis dari dampak dalam yang dinyatakan dalam tegangan (stress).Definisi Mekanika Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Menurut Coates (Canada) 1. 3. 2. Analisis akibat dari dampak dalam tersebut. regangan (strain) atau enersi yang disimpan. Efek utama Geofisika aspek dinamis dari perubahan volume & bentuk gelombang seismik.perubahan bentuk. . Mekanika batuan adalah ilmu yang mempelajari efek dari gaya terhadap batuan Efek utama Geologiwan . perpindahan.percepatan. Bagi para insinyur. Mekanika adalah ilmu yang mempelajari efek dari gaya atau tekanan pada sebuah benda . .Definisi Mekanika Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan US National Committee On Rock Mechanics (1984) Mekanika batuan adalah ilmu pengetahuan yang mempelajari perilaku (behaviour) batuan baik secara teoritis maupun terapan. merupakan cabang dari ilmu mekanika yang berkenaan dengan sikap batuan terhadap medan-medan gaya pada lingkungannya. Konsep kontinum adalah fiksi matematik yang tergantung pada struktur molekul material yang digantikan oleh suatu bidang kontinum yang perilaku matematiknya identik denga media aslinya. Hampir semua mekanika perpindahan benda padat didasarkan atas teori kontinum. Material ekivalennya dianggap homogen. mempunyai sifat-sifat mekanik yang sama pada semua titik.Definisi Mekanika Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Menurut Budavari Mekanika batuan adalah ilmu yang mempelajari mekanika perpindahan padatan untuk menentukan distribusi gaya-gaya dalam dan deformasi akibat gaya luar pada suatu benda padat. Penyederhanaannya adalah bahwa semua sifat mekaniknya sama ke semua arah pada suatu titik di dalam suatu batuan . struktur batuan. dan rekahan berkembang begitu tegangan terjadi pada batuan selama proses geologi. ilmu ini berlaku untuk masalah deformasi suatu struktur geologi.Definisi Mekanika Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Menurut Hudson & Harrison Mekanika batuan adalah ilmu yang mempelajari reaksi batuan yang apabila padanya dikenai suatu gangguan. patahan. . Semua kotak lainnya menunjukkan interaksi antara satu dengan lainnya. yang ditulis secara diagonal dari kiri atas ke kanan bawah pada Gambar berikut Garis ini sering disebut sebagai diagonal utama. dan rekayasa. Dalam hal material alam. seperti bagaimana lipatan. aliran air. Topik utama mekanika batuan adalah batuan utuh. tambang dan perminyakan. Beberapa tipe rekayasa yang melibatkan mekanika batuan adalah pekerjaan sipil. tegangan. TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan . 1990).Matriks interaksi mekanika batuan & rekayasa batuan yang menunjukkan subyeksubyek utama & interaksinya (Hudson dan Harrison. Anisotrop Karena sifat batuan heterogen. kontinu dan isotrope . B3. B2. yang mempunyai sifat homogen. anisotrope maka untuk dapat menghitung secara matematis misalnya sebuah lubang bukaan yang disekitarnya terdiri dari batuan B1.Sifat Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan 1. joint. fissure) dimana kekerapan. fault. perluasan dan orientasi dari bidang-bidang lemah tersebut tidak kontinu. 2. Ukuran. bentuk dan penyebaran void berbeda di dalam batuan. Diskontinu Massa batuan di alam tidak kontinu (diskontinu) karena adanya bidang-bidang lemah (crack. diasumsikan batuan ekivalen B’ sebagai pengganti batuan B1. B2. Ukuran dan bentuk partikel/butir berbeda di dalam batuan. B3. Heterogen Jenis mineral pembentuk batuan yang berbeda. 3. diskontinu. Asumsi batuan ekivalen untuk mempermudah perhitungan di dalam mekanika batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan B1 B2 B3 B1 Ekivalen . .. claystone .basalt containing minerals undetectable by the naked eye.fine-grained rock consisting of .Homogeneous Rock TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan fine-grained homogeneous rock .. Untuk kondisi tertentu. Mekanika batuan banyak menggunakan: teori elastisitas plastisitas dan mempelajari batuan. fissure. tetapi ada beberapa yang tumpang tindih. batuan adalah sistem “multiple body “ Analisis mekanika tanah dilakukan pada bidang. sistem struktur batuan secara eksperimen .Beberapa Ciri Dari Mekanika Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Dalam ukuran besar. Mekanika batuan dikembangkan secara terpisah dari meknaika tanah. sedang analisis mekanika batuan dilakukan pada bidang dan ruang. batuan diskontinu karena adanya kekar. solid & massa batuan yang kuat/keras. Karena keadaan alamiah & lingkungan geologi. crack. dapat dikatakan bahwa mekanika batuan adalah mekanika diskontinu atau mekanika dari struktur batuan. maka batuan dapat dianggap kontinu. schistosity. cavities dan diskontinuitas lainnya. Secara mekanika. multiple-body rock system c) Very fissured poly-body rock system Multiple –body rock system d) Articulate rock system .TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan a) single-body sound rock system Mono-system rock b) Fissured. TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Tambang Dangkal Kuari Tunnel Lubang bukaan besar Tambang Dalam Bendungan . even though engineers design in fractured materials as a matter of course.Permasalahan Rekayasa Batuan-1 TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Theoretical questions on fractured media. and parsimoniously represented? Can scale-dependent properties of a rock mass be measured and incorporate into models? Can behavior of fractured media be predicted at an acceptable level? What is the best way to represent rock mass for fluid flow and transport modeling (uncoupled or coupled)? Is the present understanding of coupled phenomena adequate? . Questions posed included: Are data collected for theories that intact actual rock mass behavior. possibly reflecting that engineers do not feel comfortable with the level of theoretical understanding. or is sampling biased by theory? Can the discontinuity system of a rock mass be detected. mapped. However. A key factor in the successful development of the open pits should have been the overall wall slope angles that would hitherto have been considered at best optimistic and worst rarely achievable. The regulations have been employed since 1995. . the open pit mines are more concerned with slope stability. According to one of the regulations from the Department of Mines of Indonesia. These are gathered from a number of mine sites that would have been relevant to be exposed. wall and floor of underground openings is one of the important geomechanical properties to be understood. including failures controlled by geological structures and failures independent of geological structure The following rock engineering or geomechanical problems and resolutions occurring in the open pit and underground mines are explained. In general. whereas deformation behaviour of back. the instability or failure that occur both in open pit and underground mines obviously involves two major mechanisms.Permasalahan Rekayasa Batuan-2 TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan Rock engineering problems in the open pit and underground mines are not much different. and these regulations are enforced with the intention of reaching a high safety standard. a study of slope stability analysis must be conducted prior to the bench development with height is greater than 15 m. Berapa dan bagaimana besarnya daya dukung (bearing capacity) dari batuan dipermukaan dan pada berbagai kedalaman untuk menerima berbagai beban ? 3. schistosity. Bagaimana sikap batuan di bawah beban dinamis ? 5. Metode pengujian laboratorium apa saja yang paling mendekati kenyataan untuk mengetahui kekutan fondasi atau sifat batuan dalam mendukung massa batuan ? 9. Bagaimana pengaruh dari bidang-bidang lemah (kekar. rongga dan diskontinuitas lainnya) pada batuan terhadap kekuatannya ? 8. bidang perlapisan. retakan. Bagaimana reaksi dari batuan ketika diambil untuk dipergunakan ? 2.Permasalahan Rekayasa Batuan-3 TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan 1. Bagaimana nilai modulus elastisitas dan Poisson’s ratio dari batuan ? 7. Bagaimana kekuatan geser batuan ? 4. Bagaimana pengaruh gempa pada sistem fondasi di dalam batuan? 6. Bagaimana memperhitungkan kekar dan sesar dalam perencanaan pekerjaan di dalam batuan ? . atau bahkan dapat diukur ? 8. Bagaimana menanggulangi deformasi yang diakibatkan oleh perbedaan yang bersifat perlahan-lahan (creep) pada batuan. 2. Bagaimana pengaruh “anisotrope” terhadap distribusi tegangan dalam 4. Dapatkah keadaan tegangan di dalam massa batuan dihitung secara tepat. Bagaimana mekanisme keruntuhan/kehancuran dari batuan (failure of rock)? 7. Bagaimana korelasi dari hasil-hasil pengujian kekuatan batuan yang telah dilakukan di lapangan dan di laboratorium dalam menyiapkan percontoh batuan ? 5. Apakah roof bolting pada atap sebuah lubang bukaan di bawah tanah sudah aman sehingga lubang tersebut dapat digunakan sebagai instalasi yang permanen ? .Permasalahan Rekayasa Batuan-4 TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan 1. 6. Bagaimana metode pengujian yang akan dilaksanakan yang sesuai dengan kondisi lapangan terhadap sifat-sifat batuannya. Hukum apa saja yang menyangkut aliran plastik (plastik flow) dari batuan ? batuan ? 3. Faktor-faktor apa saja yang menyangkut perencanaan kemiringan lereng dari suatu massa batuan ? 9. teknik fondasi dan teknik bangunan air. perilaku batuan. Menyelenggarakan penyelidikan yang bersifat teknik pada batuan. seismik dan tektonik. dapat dipelajari sifat fisik. 5. Berdasarkan hasil-hasil pengujian yang dilakukan pada batuan. . 9. 2. Menyangkut struktur statik dan dinamik dari batuan. plastisitas. sifat mekanik (statik dan dinamik). 8. elastisitas. Mengembangkan peralatan uji batuan yang baik dan metode standar pengujian untuk kuat tekan serta kuat geser batuan. Mempelajari sifat batuan di bawah kondisi thermal dan sistem keairan (water regimen). “leaching”. 7. Mengumpulkan dan mengklasifikasikan informasi batuan dan sifat-sifat fisiknya dalam dasar ilmu mekanika batuan. 3.Ruang Lingkup Mekanika Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan 1. 6. Menyelenggarakan penelitian terhadap mekanisme kerusakan/kehancuran batuan. 4. Mengembangkan cara pengambilan percontoh batuan secara rasionil dan metode identifikasi serta klasifikasi batuan. dan bentuk kerusakan (failure) di bawah beban statik dan dinamik dari batuan tersebut. Mengembangkan metode pengukuran di lapangan (in-situ) dari sifat deformasi statik dan dinamik batuan serta tegangan sisa di dalam batuan di bawah kondisi lingkungan yang bermacam-macam seperti pelapukan. atau deformasi batuan. analisis dari efek dalam. 8. Mempelajari beban atau gaya yang bekerja pada batuan.Ruang Lingkup Mekanika Batuan TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan 1. peledakan. Mempelajari pengaruh gaya-gaya pada batuan dan yang utama adalah berkaitan dengan fenomena yang mempengaruhi pendugaan rekahan dan deformasi. 7. energi dalam. Menyangkut struktur statik batuan dan kestabilan batuan sangat penting ditinjau dari sudut keamanan (safety) dan ekonomi. Mengganti dengan metode ilmiah dari perencanaan teknik pada batuan yang banyak menggunakan media empiris sebelumnya. 3. 10. maksudnya tegangan dan regangan. Mempelajari sikap massa batuan asli dibawah kondisi beban dan kondisi lingkungannya 6. Mengorganisir penelitian tentang perkuatan batuan dan pengukuran tegangan in-situ. 9. pemotongan dan pengasahan. Mempelajari stabilitas struktur rekayasa yang material utamanya adalah batuan. dan akhirnya analisis dari gaya-gaya dalam seperti rekahan. Merangsang dan menyebarkan ilmu pengetahuan tentang batuan dan mekanika batuan. . 5. Mempergunakan mekanika batuan untuk memecahkan persolan-persoalan teknik secara praktis. 4. Mempelajari proses pengurangan ukuran batuan dengan menggunakan gaya-gaya luar seperti pemboran. 2. aliran. sehingga turut memberikan konstribusi terhadap kemajuan disiplin ilmu mekanika batuan. TA 3111 Mekanika Batuan – Batuan & Mekanika Batuan .