scholarly journals Geotechnical Engineering

2019 ◽  
Author(s):  
Abd Rahim
Keyword(s):  
Safety Factor ◽  
Hydropower Plant ◽  
Q Value ◽  
Supporting System ◽  
Total Displacement ◽  
Rock Quality ◽  
Headrace Tunnel ◽  
Q System ◽  
Geomechanical Classification

Geotechnical analysis below the surface of hydropower plant is one way to determine the stability of the opening holes in determining the supporting system. A discussion about supporting systems cannot be separated from the analysis of the construction of recommended supporting system based on the weighting value of the geomechanical classification of the RMR and Q-System. The aims of this study are: 1) understanding the quality and class types of rock, 2) determining the supporting of RMR and Q-system, 3) understanding the safety factor of opening hole using Phase2. This study was carried out by recording data directly in the field, which later were used to determine the number of rock bolt needed in the installation of the supporting. Based on geomechanical classification, the rock mass in headrace tunnel adit 1 up stream has an average RMR value of 58 (moderate rock quality) and Q-system value of 4.06 (moderate rock quality), while adit 2 up stream has an average RMR value of 47 (moderate rock quality) and Q-system value of 2.30 (poor rock quality). Based on these geomechanical classification data, each type of supporting types is obtained. Supporting headrace tunnel adit 1 and 2 type, RMR value of type 1 can be applied to the RMR (60-80). RMR value of type 2 can be applied to the RMR (40-60). Supporting headrace tunnel adit 1 and 2 type, Q-system value of type 1 can be applied to Q-value (4-10). Q-system value can be applied to Q-value (1-4). Based on the modeling results using phase2, the total displacement of headrace tunnel adit 1 up stream is 0.92 cm with safety factor value of 1.20 and the total displacement of headrace tunnel adit 2 up stream is 1.17 cm with safety factor value of 1.04.

scholarly journals Rancangan Geometri Rencana Lereng Akhir Waste Dump terhadap Displacment Batuan Dasar Area Waste Dump PT X Kecamatan Palimanan, Kabupaten Cirebon, Provinsi Jawa Barat

2021 ◽  
Vol 1 (1) ◽  
pp. 22-29
Author(s):  
Rana Antariksa D ◽  
Yuliadi ◽  
Zaenal
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Slope Stability ◽  
Safety Factor ◽  
Open Pit ◽  
Open Pit Mining ◽  
Waste Dump ◽  
Value Analysis ◽  
Total Displacement ◽  
Element Method

Abstract. PT X is a company engaged in the cement factory industry in West Java that uses an open-pit mining system with limestone mining. X is planning the location of waste dump placement using the in-pit dump method, so a safe and efficient final slope design is needed. For optimal stockpiling activities, slope geometry planning on the waste material dump needs to be carried out slope stability analysis. Slope stability is influenced by slope height, slope angle, rock mass strength, rock type, and groundwater level. The purpose of this research is to find out whether or not a slope is stably displayed in the Safety Factor (FK) value. Analysis process is carried out using the Finite Element Method and the Boundary Equilibrium Method. The analysis was carried out on bedrock and pile material. Analysis of bedrock using Finite Element Method in the Goa area in Sections A - B and C - D obtained SRF values ​​of 4.6 and 16 with a total displacement of 13,771 m and 6 m. In the area of ​​Mount Bindis Section E - F and G - H obtained SRF values ​​of 2.5 and 4.75 with a total displacement of 11.8 m and 3 m. Analysis of the embankment material in the Goa In areas with Sections A - B and C - D FK values ​​obtained = 2.11 and 1.56 and for Section C - D FK 2.62 and 1.94. In the Mount Bindis Area with sections E - F and G - H FK values ​​= 1.59 and for Section G - H FK values ​​= 2.31 and 1.57. The disposal obtained the amount of volume that will be accommodated in each area of ​​11,175,191.19 LCM and 74,749,919.45 LCM. Abstrak. PT X adalah perusahaan yang bergerak di industri pabrik semen di Jawa Barat yang menggunakan sistem penambangan terbuka dengan penambangan batu kapur. X sedang merencanakan lokasi penempatan pembuangan limbah dengan menggunakan metode pembuangan di dalam pit, sehingga diperlukan desain lereng akhir yang aman dan efisien. Untuk kegiatan penimbunan yang optimal, perencanaan geometri lereng pada tempat pembuangan bahan limbah perlu dilakukan analisis stabilitas lereng. Stabilitas lereng dipengaruhi oleh ketinggian lereng, sudut lereng, kekuatan massa batuan, jenis batuan, dan tingkat air tanah. Tujuan dari penelitian ini adalah untuk mengetahui apakah kemiringan secara stabil ditampilkan dalam nilai Safety Factor (FK). Proses analisis dilakukan dengan menggunakan Metode Elemen Hingga dan Metode Kesetaraan Batas. Analisis dilakukan pada material batuan dasar dan tiang pancang. Analisis batuan dasar menggunakan Metode Elemen Hingga di daerah Goa di Bagian A - B dan C - D memperoleh nilai SRF 4,6 dan 16 dengan total perpindahan 13,771 m dan 6 m. Di daerah Gunung Bindis Bagian E - F dan G - H diperoleh nilai SRF 2,5 dan 4,75 dengan total perpindahan 11,8 m dan 3 m. Analisis bahan timbunan di Goa Di daerah dengan Bagian A - B dan C - D nilai FK diperoleh = 2.11 dan 1.56 dan untuk Bagian C - D FK 2.62 dan 1.94. Di Wilayah Gunung Bindis dengan bagian E - F dan G - H nilai FK = 1,59 dan untuk Bagian G - H nilai FK = 2,31 dan 1,57. Pembuangan memperoleh jumlah volume yang akan ditampung di masing-masing area 11.175.191 LCM dan 74.749.919,45 LCM.

scholarly journals KUAT TARIK ANGKER KANTILEVER DENGAN METODE PENDEKATAN JRC (STUDI KASUS JALAN KANTILEVER KM. 461+480 TAPAKTUAN)

2018 ◽  
Vol 1 (3) ◽  
pp. 647-656
Author(s):  
Jumaidi Jumaidi ◽  
Munirwansyah Munirwansyah ◽  
Sofyan M. Saleh
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Safety Factor ◽  
Standard Penetration Test ◽  
Rock Quality Designation ◽  
Penetration Test ◽  
Loading Test ◽  
Rock Quality ◽  
Ground Anchor ◽  
Cut And Fill

Abstract: The Tapaktuan-Bakongan is the national road access to the South-West part of Aceh. Topographically shows that the road consist of canyon and a very steep cliff, which will be impossible to build more infracstructure using either blasting or cut and fill method with heavy equipment. Referring to the situation, the study about anchor tensile strength, which is used in construction of road access expansion using cantilever method is conducted. The research methode is begin by collecting the real data which are Standard Penetration Test data (SPT) SNI 4153-2018 and tensile graund anchor proving test (Bristish Satndard 8081:1981) and geological data taken from SPT drilling data. Furthermore, the data involved N-SPT, Joint Roughness Coefficient (JRC), shear stress will be analyzed and yield loading test value. Finally, from the loading test value, the reseacher will evaluate the stability of tensile capacity and safety factor (SF) of ground anchor. From the data analysis obtained that rock mass of STA 1+ 280 or KM. 461 +480 geologically contain unrigid and very strong limestone with N-SPT value greater than 50 where the rock condition is solid concrete and could be crushed using blasting method. Five samples are taken from the 10 meters driling for the laboratory test and obtain the minimum compressive strength is 51,10 MPa and maximum is 103,89 MPa with JRC from 2 to 20. In addition, the rock quality designation (RQD) calculation yield the average stone quality is 60,8% which means the rock has medium quality. Ground anchor failure if the proving test over 80% UTS(ultimate tensile strength)   i.e. the load increment reaches 92,55% UTS or 54 MPa. Therefore, the proving test maximum capacity for ground anchor is 54 Mpa and safety factor is 1,85 which are suitable to geological condition research area.Abstrak: Ruas jalan Tapaktuan – Bakongan merupakan ruas jalan nasional lintas Barat – Selatan Aceh. Kondisi topografi ruas jalan terdiri dari tebing yang terjal dan lereng yang curam sehingga tidak memungkinkan dilaksanakan pelaksanaan kontruksi pembangunan/peningkatan dengan metode blasting (penggunaan bahan peledak) maupun metode cut and fill yang menggunakan alat-alat berat. Dari permasalahan tersebut dilakukan sebuah kajian mengenai kuat tarik angker yang digunakan pada pelaksanaan pembangunan pelebaran badan jalan dengan menggunakan metode kantilever untuk daerah dengan kondisi topograsi tebing yang terjal dan lereng yang curam. Metode yang diterapkan pada penelitian ini diawali dengan pengumpulan data riil yang meliputi data Standard Penetration Test (SPT) SNI 4153-2008 dan uji tarik proving test ground anchor (British Standard 8081:1981) dan data geologi yang dihasilkan dari data pengeboran SPT. Selanjutnya dari data-data yang diperoleh dilakukan analisis data yang meliputi analisis nilai N-SPT, Joint Roughnes Coefficient (JRC), gaya geser, yang menghasilkan angka loading test. Dari data hasil loading test dapat dievaluasi stabilitas kapasitas tarik dan safety factor (SF). Dari data analisis didapatkan bahwasanya kondisi geologi batuan di STA 1+ 280 atau KM. 461 + 480 terdiri dari batu gamping tidak lapuk dan sangat keras dan dapat dipecahkan dengan peledakan dengan nilai N-SPT lebih besar dari 50 dimana kondisi batuan sangat padat. Dari hasil pengeboran sepanjang 10 meter diambil lima sampel untuk di uji laboratorium dan diperoleh nilai compressive strength minimal 51,10 MPa dan maksimum 103,89 MPa dengan nilai JRC 2-20. Selain daripada itu hasil perhitungan rock quality designation (RQD) menunjukkan kualitas batuan pada lokasi kajian rata-rata 60,8% yang berarti kualitas batuannya adalah sedang. Ground anchor putus pada saat uji tarik proving test diatas pembebanan 80% UTS yaitu pembebanan sampai 92,55% UTS (ultimate tensile strength) atau sebesar 54 MPa. Dengan demikian kapasitas maksimum hasil uji tarik proving test ground anchor yaitu sebesar 54 MPa dengan faktor keamanan 1,85 sesuai dengan kondisi geologi daerah kajian.

scholarly journals Peningkatan Kestabilan Pilar Tambang Bawah Tanah Marmer di PT Gunung Marmer Raya

2020 ◽  
Vol 3 (1) ◽  
pp. 27-38
Author(s):  
Purwanto Purwanto
Keyword(s):  
Rock Mass ◽  
Safety Factor ◽  
Underground Mining ◽  
Underground Mine ◽  
Joint Movement ◽  
Pillar Stability ◽  
The North ◽  
Joint Monitoring ◽  
The Stability ◽  
Q System

PT Gunung Marmer Raya  (PT GMR), a room and pillar underground marble mining is located about  73 km to the north from Makassar, in Desa Tabo-Tabo, Kecamatan Bungoro, Kabupaten Pangkep. In the mining location, discontinuities are found as joint structure across the production area. The purpose of this service is to make pillar redesign that can improve the stability of underground mine. These activities start with field observation, determining the rock characteristic through sample testing in the laboratory, classifying the rock mass using Q-system method, up to redesigning a form of implementation to increase the stability of the marble underground mine. According to calculation of rock mass classification using Q-System, the recommended buffering is systematic bolting and fiber reinforced sprayed concrete as thick as 5-6 cm with spacing between bolts of 2.2 meters, or systematic bolting without concrete layering with spacing between-bolt 1.8 meter. Joint monitoring, especially on pillars, need to be done routinely so joint movement could be anticipated for progressive movement. The existing dimensions of pillar 5 m x 5 m in length and width is not recommended due to the safety factor is under 1,0  (unstable condition). Based on observation and analytic calculation, for each pillar height of up to 11 meters the pillar is recommended to redesign with length and width 5 m x 9 m for the chain pillar (safety factor around 1.35-1.49); and 5 m x 12 m for barrier pillars (safety factor around 1.58-1.74). Key Words: Underground mining; room and pillar method; Q-system classification system; pillar stability; marble mining.

scholarly journals Structural geological methods in the geotechnical practice – rock mass rating. Advantages and problems of the rating methods

2020 ◽  
Vol 81 (1) ◽  
pp. 35-54
Author(s):  
Ivan Dimitrov
Keyword(s):  
Rock Mass ◽  
Jointed Rock ◽  
Statistical Weight ◽  
Classification Systems ◽  
Metamorphic Rocks ◽  
Rock Mass Rating ◽  
Empirical Relationships ◽  
Rock Quality ◽  
Field Criterion ◽  
Q System

This paper presents a review of the most common geotechnical rock rating methods. The directional properties of the rock’s anisotropies are exemplified, by a case of resolution of stresses in folded and foliated metamorphic rocks. In such rocks, depending on the geometry of the folds, the ambient stress field can generate varying shear potential along the foliation planes in different parts of the excavation. The commonly used rating schemes, with accent on the geological feasibility of the classifications, are discussed – Protodiakonov’s rock scale, Terzaghi’s grading for construction of tunnels, then the rock quality designation of Deere, the Bieniawski’s rock mass rating (RMR), the Hoek, and Brown’s GSI and the Barton’s Q-system. It is emphasized that in spite of its broad use, the RQD is distorting the statistical weight of the joint groups as some steeply dipping joints may be completely neglected. It is recognized that the RMR is the simplest to use but underestimates the directional properties of the rock anisotropies, which require better definition and has no provision for lithologically varying rock packages, although it has the advantage of using the uniaxial compressive strength, which other systems do not employ. The Hoek and Brown’s criterion went too far with complex empirical relationships, which rely on extensive laboratory testing, so it is no more field criterion. Besides, its geological descriptive powers are rather poor and now, new form of GSI classification is offered for nearly every lithological type. Barton’s Q-system, being best suited to case studies of actual underground constructions, suffers from the fact that is centered nearly exclusively on joints, which may be justified in Norway, where mainly magmatic and high grade metamorphic rocks are present but should be applied cautiously in areas, where sedimentary, volcanic and strongly foliated rocks are exposed. In general, for all the discussed geomechanical classification systems (RMR, GSI, Q) the rule is valid, that they work better in an isotropic, strong but jointed rock masses and do not work well in week layered and foliated rocks.

scholarly journals TUNNEL SUPPORT BY ROCK QUALITY INDEX (Q) SYSTEM FOR ULTRABASIC ROCK: A CASE STUDY IN TELUPID, SABAH, MALAYSIA

2020 ◽  
Vol 4 (1) ◽  
pp. 22-25
Author(s):  
Ismail Abd Rahim ◽  
Mohamad Saiful Nizam Mohamad
Keyword(s):  
Ultrabasic Rock ◽  
Geological Mapping ◽  
Q Value ◽  
Surface Mapping ◽  
Tunnel Support ◽  
Thick Fiber ◽  
Class D ◽  
Support Estimation ◽  
Q System ◽  
Fiber Reinforce

The study area is underlain by the ultrabasic rock of partly Sabah Ophiolite Complex of Cretaceous ages. The objectives of this study are to determine the Q-value and to estimate the permanent support measures for 20m span, 10m high and eastern direction of the proposed tunnel in the study area. Engineering geological mapping (lithological and surface mapping and discontinuity survey), laboratory study (petrographical study) and testing (Uniaxial Compressive Strength testing) and data analysis (stereographic plots, Q system parameters evaluation and support estimation) was used in this study. The results show that the rock mass is classified as lherzolite, strong, excellent quality, more than four joint sets, slightly altered discontinuity wall, dry excavation and favourable stress condition. The equivalence dimension (De) are 15.4 for the permanent roof. The Q-value for permanent roof and wall of the proposed tunnel are 1.4 (Class D or poor and type 5) and 3.5 (Class D or poor and type 3), respectively. The permanent and temporary supports for the roof and wall are systematic bolting, 700J energy absorption of fiber reinforce sprayed concrete, 9-12 and 5- 6 cm thick fiber reinforce shotcrete, respectively.

scholarly journals Submerged Wall Instead of a Penstock Shutoff Valve—Alternative Protection as Part of a Refurbishment

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2247 ◽  
Author(s):  
Roman Gabl ◽  
Markus Wippersberger ◽  
Jakob Seibl ◽  
Christian Kröner ◽  
Bernhard Gems
Keyword(s):  
Renewable Energy ◽  
Hydropower Plant ◽  
Life Extension ◽  
Design Parameters ◽  
High Point ◽  
Hydropower Plants ◽  
Headrace Tunnel ◽  
Attractive Option ◽  
Overall Performance

Hydropower is an important source of renewable energy. Due to ageing infrastructure, more and more existing hydropower plants have to be refurbished and modernised. This includes a complete review of the design parameters as well as the change of specific parts. Investments should be targeted to improve the overall performance of hydropower plants and ensure a long lasting life extension. This paper presents the concept of the submerged wall as a local high point in the headrace tunnel, which can—in combination with the intake gates—replace existing penstock shutoff valves. Such a replacement was conducted for the hydropower plant Schneiderau in Austria, which also allowed us to prove the concept based on measurements including a simulated break of the penstock. The presented solution can help to reduce investment costs and also minimise maintenance efforts and therefore is an attractive option for classic penstock shutoff valves for comparable projects.

scholarly journals ANALISIS LERENG TERASERING DALAM UPAYA PENANGGULANGAN LONGSOR METODE FELLENIUS DENGAN PROGRAM GEOSTUDIO SLOPE

2019 ◽  
Vol 10 (2) ◽  
pp. 53-60
Author(s):  
Dimas Haryadi ◽  
Mawardi Mawardi ◽  
Makmun R. Razali
Keyword(s):  
Power Plant ◽  
Slope Stability ◽  
Safety Factor ◽  
Hydroelectric Power Plant ◽  
Hydroelectric Power ◽  
Type Safety ◽  
Plant Area ◽  
Steep Slopes

The Musi Hydroelectric Power Plant area in Kepahiang Regency is a hilly area that has steep slopes that are prone to landslides. One of the landslides that occurred at October 2017 precisely occurred on a highway between Susup Village, Bengkulu Tengah Regency and Ujan Mas District, Kepahiang Regency. This study aims to analyze the slope stability of the terraces using the Fellenius Method. The results of testing the physical properties of the soil indicate that the soil on the slopes of the area of the Musi Hydroelectric Power Plant is clay. The slopes studied in the Musi hydropower area are all prone to landslides because safety factor, FK <1,5. Based on the results of the research on the slopes of the safest type 1 slope the value of the safety factor is the type of slope of the slope trap 3,19o,FK = 1,61 greater than the safety factor value of slope type 2 slope trap 19o, FK = 1,57 and safe slope type safety factor value slope of 19o, FK = 1.519 and the value of the safety factor of the original slope type of slope 30o, FK =0,88.

scholarly journals Enhanced Operational Flexibility of a Small Run-of-River Hydropower Plant

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1897
Author(s):  
Jean Decaix ◽  
Anthony Gaspoz ◽  
Vlad Hasmatuchi ◽  
Matthieu Dreyer ◽  
Christophe Nicolet ◽  
...  
Keyword(s):  
Power Plants ◽  
Renewable Energies ◽  
Operating Conditions ◽  
Hydropower Plant ◽  
Electricity Production ◽  
Operational Flexibility ◽  
Settling Basin ◽  
The Public ◽  
Headrace Tunnel ◽  
Run Of River

Over the last two decades, the public policies for promoting new renewable energies allowed the growth of such energies around the world. Due to their success, the policies are changing, forcing the producers to adapt their strategy. For instance, in Switzerland, the feed-in tariff system has been modified in 2018 to promote an electricity production from renewable energies that matches the demand. For small hydraulic power plants owners, such a change requires to increase the flexibility of their fleet. The SmallFLEX project, led by HES-SO Valais, aims at demonstrating on the pilot site of Gletsch-Oberwald owned by Forces Motrices Valaisannes SA, the possibilities to increase the flexibility of the power plant and to provide new services. The paper focuses on the methodology followed to warranty the use of the settling basin, the forebay tank, and the third upper part of the headrace tunnel as a new smart storage volume. By combining laboratory tests, numerical simulations, and on-site measurements, the new range of operating conditions has been defined. These data can be used to foresee economic gains. The methodology and the outputs of the project can be useful for performing such a study on other power plants.

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