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The Use Of Lightweight Material At Road Access Construction On Slope Hansen Tananda; Aris Handoko; Paulus Pramono Rahardjo
Indonesian Geotechnical Journal Vol. 2 No. 3 (2023): Vol. 2, No. 3, December 2023
Publisher : Himpunan Ahli Teknik Tanah Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.56144/igj.v2i3.61

Abstract

To achieve the design elevation from the existing ground level, an embankment work with a thickness of 8-10 meters thick on the slope should be conducted considering both the safety aspect as well as the economic aspect. Based on the conceptual drawing by Contractor, the embankment will sit on the slope without any grading works. The drawing shows that the embankment will be constructed directly on the existing slope. Any fill work on the original slope without any proper reinforcement will cause stability issues.  The discussion about the embankment area construction concept has come up with some options such as the use of a slab-on-pile system and the use of a combination sheet pile - bore piles and the use of mini piles under the embankment. Based on further discussion with Contractor and Owner about the technical aspect and construction cost required, it is recommended to construct an embankment with lightweight material (geofoam). The use of lightweight geofoam is a suitable solution to be considered. Another advantage of using geofoam is that the construction period is faster than conventional methods. Geofoam installation work already started on November 2022. On February 2023, the geofoam slope construction finished.
Excess Pore Pressure Migration Analysis Due to High Embankment Construction – Case Study East Kalimantan Lie, Edwin; Rahardjo, Paulus Pramono; Wijaya, Martin
Journal of the Civil Engineering Forum Vol. 10 No. 2 (May 2024)
Publisher : Department of Civil and Environmental Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jcef.9713

Abstract

A 42-inch pipeline traverses a predominantly flat right-of-way (ROW), running from south to north in East Kalimantan. Adjacent to the ROW, a coal mine concession was located on the western side, while the Mahakam River lies a further 3 km to the east. A mining waste dump has been constructed since 2010, situated in an area underlain by soft alluvium soil (Qa). The waste was stacked, reaching heights of up to 75 meters, with its toe approximately 200 m from the edge of the ROW. In 2016, a failure occurred in the ROW, causing the 42-inch pipeline to shift a maximum of 6.8 m horizontally, and rise by 2.0 m within a 300 m span. A geotechnical investigation was then conducted, consisting of 7 CPTu with dissipation testing. The CPTu results indicated high pore pressure, with a layer of soft clay ranging from 15 to 32 m thickness found in the ROW area. A hypothesis was formulated suggesting that the soft clay was not fully consolidated. Hence, the failure of the pipeline was possibly caused by the migration of excess pore water pressure accumulated during the construction of the waste dump. Results of the investigation indicated that the permeability coefficient was 2.5 times greater in the horizontal direction compared to the vertical ones (kh/kv = 2.5), allowing the pore water pressure to migrate more easily in the horizontal direction. This study aims to elucidate how the migration of excess pore water pressure in the horizontal direction influences ground stability. The analysis was conducted using finite element software MIDAS GTS NX, with the kh/kv varying from 2.5 to 100 times to explore excess pore pressure movement behaviors. The results of this study confirm that excess pore pressure migration can occur horizontally if the horizontal permeability coefficient is larger than its vertical counterpart. Thus, this study highlights that the greater the permeability coefficient and the larger the ratio, the further the excess pore pressure travels. Moreover, the horizontal displacement increases with the permeability coefficient ratio.
Karakterisasi Tanah Vulkanik di Kabupaten Kediri, Jawa Timur, Indonesia Berdasarkan Uji CPT, SPT, dan PMT: Site Characterization of Volcanic Soil in Kediri Regency, East Java, Indonesia Based On CPT, SPT, and PMT Wiwarsono, Fransisko; Rahardjo, Paulus Pramono; Sadisun, Imam Achmad
Cantilever: Jurnal Penelitian dan Kajian Bidang Teknik Sipil Vol. 12 No. 2 (2023): Cantilever
Publisher : Department of Civil Engineering and Planning, Faculty of Engineering, Sriwijaya University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35139/cantilever.v12i2.205

Abstract

Indonesia is a country surrounded by the Pacific Ring of Fire so that various areas are dominated by volcanic soil. Volcanic soils have unique and unusual characteristics, different structures and properties from soil in general, and are strongly influenced by geological processes. Volcanic soils were also found to be problematic and caused a lot of geotechnical damage. Research on volcanic soils from a geotechnical perspective in Indonesia is still very limited. This study aims to characterize volcanic materials in Kediri Regency, East Java, Indonesia, based on in situ testing using CPT (Cone Penetration Test), Standard Penetration Test (SPT), and Pressuremeter Test (PMT). CPT and SPT are the most common and frequently used field tests, while PMT is used to obtain horizontal stresses. Some data from the X-Ray Diffraction Analysis (XRD) test and corebox drilling results will also be used in this study. Field test results will display soil classification and parameters, which will then be combined, and empirical correlations will be obtained for site characterization as well as comparisons with other volcanic soil literature studies. The results showed that the volcanic soil in Kediri Regency consists of non-lateritic to lateritic soil. Based on the CPT and SPT correlations, it was found that the qc/N value was greater than in general soils for both cohesive and non-cohesive soils. The authors also found a relationship between parameters and interpretation of PMT data against NSPT for cohesive volcanic soils in the study area.
KAJIAN KARAKTERISTIK DAN KECEPATAN KONSOLIDASI PADA TANAH LAKUSTRIN BANDUNG Georgeshua, Cornelius; Rahardjo, Paulus Pramono; Desiani, Asriwiyanti
JMTS: Jurnal Mitra Teknik Sipil Volume 8, Nomor 1, Februari 2025
Publisher : Prodi Sarjana Teknik Sipil, FT, Universitas Tarumanagara

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24912/jmts.v8i1.31953

Abstract

Bandung is an ancient lake area formed by years of sedimentation. The result of the sedimentation is then called the Bandung lacustrine soil where the soil has very soft characteristics, is water saturated, has relatively high voids, low shear strength and is very compressible. This study aims to determine the consolidation characteristics of Bandung Lacustrine soil in the Gedebage area using CPTu Test, Drill Test, SPT Test, Laboratory Test and settlement plate instrumentation. CPTu Test, Drill Test and SPT Test are intended to determine the layering and depth of the Bandung Lakustrine soil where the Bandung Lakustrine soil is at a depth of 5 - 30 m. Laboratory and Settlement Plate tests were conducted to determine the physical characteristics and consolidation of the Bandung Lakustrine soil. From this research, it is known that Bandung Lakustrin soil has high moisture content (Wn > 200%), high pore number value (e > 4), relatively high primary and secondary strain value (Cc = 2 - 4 & Ca = 0.005 - 0.09), and relatively high strain (12 - 54%), coefficient of consolidation (Cv) ranges from 2.49 - 16.18 x10-3 cm2/s based on CPTu dissipation data. ABSTRAK   Bandung merupakan daerah danau purba yang terbentuk akibat sedimentasi bertahun-tahun. Hasil sedimentasi tersebut yang kemudian disebut dengan tanah lakustrin bandung dimana tanah memiliki karakteristik yang sangat lunak, jenuh air, memiliki void yang relatif tinggi, kuat geser yang rendah dan sangat kompresible. Penelitian ini ditujukan untuk mengetahui karakteristik konsolidasi pada tanah Lakustrin Bandung pada kawasan Gedebage menggunakan Uji CPTu, Uji Bor, Uji SPT, Uji Laboratorium dan instrumentasi settlement plate. Uji CPTu, Uji Bor dan Uji SPT ditujukan untuk mengetahui pelapisan dan kedalaman dari tanah Lakustrin Bandung dimana tanah Lakustrin Bandung berada pada kedalaman 5 – 30 m. Uji Laboratorium dan Settlement Plate ditujukan untuk mengetahui karakteristik fisik dan konsolidasi tanah Lakustrin Bandung. Dari penelitian ini diketahui bahwa Tanah Lakustrin Bandung memiliki kadar air yang tinggi (Wn > 200%), nilai angka pori yang tinggi (e > 4),  nilai regangan primer dan sekunder yang relatif tinggi (Cc = 2 – 4 & Ca = 0.005 – 0.09), dan reganan yang relatif tinggai (12 – 54%), koefisien konsolidasi (Cv) berkisar 2.49 – 16.18 x10-3 cm2/dt berdasarkan data disipasi CPTu.
Evaluasi Perilaku dan Viskositas Material Pasir Kelanauan pada Kondisi Terlikuifaksi dengan Menggunakan Piezocone Johan, Albert; Rahardjo, Paulus Pramono; Widjaja, Budijanto
Jurnal Teknik Sipil Vol 31 No 3 (2024): Jurnal Teknik Sipil - Edisi Desember
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jts.2024.31.3.7

Abstract

Abstract Liquefaction is phenomenon of the loss of shear strength of saturated sandy soil. Liquefaction has become one of the primary concerns for Indonesia and the world, especially after the occurrence of liquefaction in Palu due to Palu-Donggala earthquake. Learning from the liquefaction phenomena after the Palu-Donggala earthquake event on 28 September 2018, many researchers have conducted liquefaction and flow slide study. In order to complete the study of the liquefaction phenomenon, an experimental study using shake table, chamber, and piezocone is conducted to evaluate the behaviour and viscosity of liquefied silty sand material. Based on the observation during liquefied condition, the silty sand material will experience an increase in excess pore pressure and a decrease in tip resistance. In addition, it is also known that sleeve resistance, speed of penetration of the piezocone, and zone of influence due to piezocone penetration are the main keys in determining the viscosity of the silty sand material during liquefied condition Keywords: Liquefaction, viscosity, silty sand, piezocone
PERBANDINGAN PERILAKU PERBAIKAN TANAH METODE PRELOADING VAKUM DAN PRELOADING TIMBUNAN DENGAN ELEMEN HINGGA 2D Gusnadi, Zakwan; Rahardjo, Paulus Pramono; Lim, Aswin
Teras Jurnal : Jurnal Teknik Sipil Vol. 11 No. 2 (2021): Volume 11 Nomor 2, September 2021
Publisher : UNIVERSITAS MALIKUSSALEH

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29103/tj.v11i2.513

Abstract

Abstrak Perbaikan tanah lunak dengan pra-beban (preloading) dimaksudkan untuk mereduksi penurunan pada masa operasional dan meningkatkan kekuatan tanah. Preloading dalam perbaikan tanah lunak biasanya dikombinasikan dengan Prefabricated Vertical Drain (PVD) guna mempercepat proses disipasi air pori. Metode preloading dapat dilakukan dengan cara konvensional menggunakan timbunan ataupun dengan tekanan vakum. Untuk mengetahui perilaku preloading dengan tekanan vakum ini digunakan metode elemen hingga 2D menggunakan program bantu ABAQUS (berasal dari nama alat hitung Abacus). Hasil analisis menunjukan pada hari ke 217 perbaikan preloading vakum menghasilkan penurunan sebesar 1,23 m dan preloading timbunan menghasilkan penurunan sebesar 1,18 m, namun pola penurunan yang terjadi dengan preloading vakum terlihat lebih besar pada 35 hari pertama perbaikan. Pada perubahan tekanan air pori preloading vakum menunjukan reduksi tekanan air pori, sedangkan dengan preloading timbunan tekanan air pori meningkat pada masa konstruksi dan tereduksi pada masa perbaikan. Lebih lanjut pada perilaku deformasi lateral di kaki timbunan, metode preloading vakum menunjukan pergerakan lateral ke arah dalam area perbaikan sedangkan dengan preloading konvensional pergerakan lateral tanah terjadi ke arah luar area perbaikan. Kata kunci: ABAQUS, Elemen Hingga 2D, Perbaikan Tanah, Vakum Preloading Abstract Improvement of soft soil by preloading is intended to lower the settlement of operation time and increasing soil strength. Preloading in the improvement of soft soil usually combined with Prefabricated Vertical Drain (PVD) to accelerate the pore water dissipation process. The preloading method can be done in a conventional way using the embankment or vacuum pressure. To find out the behaviour of preloading with this vacuum pressure, we used the finite element method 2D by using the ABAQUS support program. The result of the analysis shows on the 217th day, vacuum preloading improvement produces a settlement by 1.23 m and the embankment preloading produce 1.18 m, but the settlement pattern that occurs with preloading vacuum was seen to be greater in the first 35 days of improvement. In terms of changes in pore water pressure on vacuum preloading shows that the pattern of pore water pressure is reduced, while with pore eater pressure on preloading heap increased during construction and reduced during improvement. Further on the lateral movement behaviour in the toe of the embankment, the vacuum preloading method shows the lateral movement towards the improvement area while embankment preloading shows the lateral movement occurs towards the outside of the improvement area. Keywords: ABAQUS, Finite Element 2D, Soil Improvement, Vacuum Preloading