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All Journal IPTEK Journal of Proceedings Series Journal of Engineering and Technological Sciences Jurnal Geoteknik Jurnal Teknik Sipil
Hasbullah Nawir, Hasbullah
Kelompok Keahlian Rekayasa Geoteknik, Program studi Teknik Sipil, Fakultas Teknik Sipil dan Lingkungan Institut Teknologi Bandung, Jl. Ganesa No. 10 Bandung 40132.
Civil Engineering, Building, Construction & Architecture Computer Science & IT Engineering

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Pengaruh Siklus Basah – Kering terhadap Kekuatan Geser dan Ekspansivitas Campuran Kaolin – Montmorillonit - Pasir Hendrikus, Edwin Laurencis; Nawir, Hasbullah
Jurnal Geoteknik Vol 9, No 01 (2014)
Publisher : Himpunan Ahli Teknik Tanah Indonesia (HATTI)

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Sebagian besar daerah Indonesia terdiri dari tanah lempung ekspansif. Tanah ekspansif sering menyebabkan permasalahan geoteknik karena perilakunya yang sensitif terhadap air. Penelitian ini ditujukan untuk mempelajari efek siklus basah-kering terhadap perilaku tanah lempung ekspansif yang distabilisasi pasir. Perilaku yang ditinjau adalah kekuatan geser dan potensi pengembangan. Tanah yang digunakan adalah tanah artifisial yang dibentuk dari bentonit, kaolin, dan pasir. Pasir yang digunakan adalah pasir bergradasi baik. Ada dua variasi yang dilakukan dalam penelitian ini, yakni variasi jumlah siklus basah-kering dan variasi kadar mineral lempung. Kadar pasir ditetapkan sebesar 20% terhadap massa kering tanah. Pembentukan tanah artifisial dilakukan pada kondisi kadar air optimum, kemudian siklus basah-kering dilakukan pada tanah artifisial sebelum diuji. Beberapa pengujian dilakukan pada sampel ini, meliputi pengujian terhadap batas plastisitas, berat jenis, parameter pemadatan, distribusi ukuran butir pasir, dan kandungan mineral tanah. Melalui pengujian diperoleh hasil bahwa penambahan pasir sebesar 20% pada tanah ekspansif tidak mencegah penurunan kekuatan geser tak teralir, namun mereduksi potensi pengembangan. Dapat disimpulkan bahwa penambahan pasir hanya efektif untuk mencegah pengembangan dibandingkan untuk meningkatkan kuat geser tanah lempung ekspansif akibat siklus berulang basah-kering. Kata kunci: tanah ekspansif, stabilisasi tanah, pasir, siklus basah-kering
Prediksi Penurunan Tanah Menggunakan Prosedur Observasi Asaoka Studi Kasus: Timbunan di Bontang, Kalimantan Timur Nawir, Hasbullah; Apoji, Dayu; Fatimatuzahro, Rahmatyar; Pamudji, M. Dwi
Jurnal Teknik Sipil Vol 19, No 2 (2012)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1438.831 KB)

Abstract

Abstrak. Penurunan konsolidasi tanah merupakan masalah geoteknik yang sering ditemukan pada kasus timbunan, terutama pada tanah lunak. Penurunan konsolidasi disebabkan oleh keluarnya air pori dari dalam tanah yang disebabkan oleh peningkatan tegangan pada massa tanah. Untuk memprediksi besar penurunan serta lama waktu konsolidasi umumnya digunakan teori konsolidasi satu dimensi Terzaghi. Prediksi penurunan konsolidasi dengan teori ini, pada banyak kasus, memberikan hasil yang lebih besar dari penurunan aktual. Hal ini, salah satunya, disebabkan adanya pengabaian fenomena perkuatan tanah yang mungkin terjadi akibat proses penimbunan secara bertahap. Selain teori tersebut terdapat pula prediksi penurunan tanah dengan metode elemen hingga yang sudah menganalisis penurunan secara dua dimensi bahkan tiga dimensi. Namun untuk metode ini prediksi penurunan terhadap waktu, terutama untuk kasus perbaikan tanah dengan drainase vertikal, metode ini tidak memberikan hasil yang baik. Observasi Asaoka. Melalui prosedur ini, besarnya penurunan akhir dapat diprediksi dengan menggunakan data observasi penurunan akibat timbunan dengan menggunakan metoda curve fitting. Studi ini juga membahas perbandingan metode perhitungan penurunan dengan menggunakan teori konsolidasi Terzaghi, metode elemen hingga dan metode observasi Asaoka.Abstract. Consolidation settlement is a general geotechnical problem found embankment, particularly those founded on soft soil. Consolidation settlement is caused by the discharge of soil pore water induced by the increas of stress in soil mass. Terzaghi one dimensional theory was used to predict the settlement and time rate of consolidation. In many cases, the settlement prediction from this theory provides results much greater than the observed value due to many factors including the neglection of soil strength gain that may occur during consolidation process. In addition, there is also settlement prediction by using observed settlement data from the site using curve fitting method. This study presents settlement prediction method using Terzaghi consolidation theory, finite element method and Asaoka observational method.
Axial and Lateral Small Strain Measurement of Soils in Compression Test using Local Deformation Transducer Nawir, Hasbullah; Apoji, Dayu; Ekawita, Riska; Khairurrijal, Khairurrijal
Journal of Engineering and Technological Sciences Vol 50, No 1 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (634.837 KB) | DOI: 10.5614/j.eng.technol.sci.2018.50.1.4

Abstract

This paper presents the development of a method using local deformation transducers (LDTs) to locally and sensitively measure small axial and lateral strains in soil in a compression test. A local strain measurement system comprising of axial and lateral LDTs was developed referring to the original LDT system and the cantilever LDT system, respectively. The LDTs were calibrated both in air and under water. Their insensitivity to pressurized water was confirmed. The calibration factors for the axial and lateral LDTs were found to be 1.695 mm/volt and 1.001 mm/volt, respectively. The performance in terms of repeatability and stability of the LDT system was evaluated. The repeatability test showed that the average standard deviation of the lateral LDT was 0.015 volt, while the stability test showed that the average standard error of the axial and lateral LDT were 3.13 × 10-5 volt and 2.65 × 10-5 volt, respectively. Unconfined compression tests were conducted on three reconstituted clay samples to examine the proposed axial and lateral LDT system. The stress-strain relationship indicates a nonlinear relationship between the axial and lateral strain of soil instead of the conventionally assumed constant relationship. The results demonstrate this nonlinear behavior even at small strain levels, which were successfully measured using a domestically built axial and lateral LDT system.
Pengaruh Siklus Basah – Kering terhadap Kekuatan Geser dan Ekspansivitas Campuran Kaolin – Montmorillonit - Pasir Hendrikus, Edwin Laurencis; Nawir, Hasbullah
Jurnal Geoteknik Vol 9 No 01 (2014)
Publisher : Himpunan Ahli Teknik Tanah Indonesia (HATTI)

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Sebagian besar daerah Indonesia terdiri dari tanah lempung ekspansif. Tanah ekspansif sering menyebabkan permasalahan geoteknik karena perilakunya yang sensitif terhadap air. Penelitian ini ditujukan untuk mempelajari efek siklus basah-kering terhadap perilaku tanah lempung ekspansif yang distabilisasi pasir. Perilaku yang ditinjau adalah kekuatan geser dan potensi pengembangan. Tanah yang digunakan adalah tanah artifisial yang dibentuk dari bentonit, kaolin, dan pasir. Pasir yang digunakan adalah pasir bergradasi baik. Ada dua variasi yang dilakukan dalam penelitian ini, yakni variasi jumlah siklus basah-kering dan variasi kadar mineral lempung. Kadar pasir ditetapkan sebesar 20% terhadap massa kering tanah. Pembentukan tanah artifisial dilakukan pada kondisi kadar air optimum, kemudian siklus basah-kering dilakukan pada tanah artifisial sebelum diuji. Beberapa pengujian dilakukan pada sampel ini, meliputi pengujian terhadap batas plastisitas, berat jenis, parameter pemadatan, distribusi ukuran butir pasir, dan kandungan mineral tanah. Melalui pengujian diperoleh hasil bahwa penambahan pasir sebesar 20% pada tanah ekspansif tidak mencegah penurunan kekuatan geser tak teralir, namun mereduksi potensi pengembangan. Dapat disimpulkan bahwa penambahan pasir hanya efektif untuk mencegah pengembangan dibandingkan untuk meningkatkan kuat geser tanah lempung ekspansif akibat siklus berulang basah-kering. Kata kunci: tanah ekspansif, stabilisasi tanah, pasir, siklus basah-kering
Excavation Analysis using Stress Path Dependent Soil Parameters Nawir, Hasbullah; Prasetyo, Bagus Eko; Apoji, Dayu
IPTEK Journal of Proceedings Series No 6 (2017): The 3rd International Conference on Civil Engineering Research (ICCER) 2017
Publisher : Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j23546026.y2017i6.3241

Abstract

This paper presents numerical analyses of an excavation using stress path dependent soil parameters, where soil elements in a region of an excavation are represented by specific soil parameters that correspond to their specific stress paths. The performance of the M1 excavation pit in Berlin sand was selected as the analysed case. This excavation pit was supported by diaphragm-wall with a single row of pre-stressed anchors. The numerical analyses of the excavation were performed using finite element program PLAXIS 3D. Mohr-Coulomb model and Hardening Soil model were used as the soil constitutive models. The analyses were performed using two approaches, which are: (i) analysis using axial compression soil parameters, and (ii) analysis using stress path dependent soil parameters. A set of conversion ratios were employed to convert the general soil parameters (i.e. axial compression stress path) to the soil parameters of the other stress paths. These conversion ratios were obtained from an experimental program of true triaxial tests conducted on Bangka sand. The comparison of the field records and the analysis results were discussed. The results show that the stress path dependent approach produced better prediction of diaphragm-wall deformation compare to the general approach using axial compression soil parameters.
Axial and Lateral Small Strain Measurement of Soils in Compression Test using Local Deformation Transducer Hasbullah Nawir; Dayu Apoji; Riska Ekawita; Khairurrijal Khairurrijal
Journal of Engineering and Technological Sciences Vol. 50 No. 1 (2018)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2018.50.1.4

Abstract

This paper presents the development of a method using local deformation transducers (LDTs) to locally and sensitively measure small axial and lateral strains in soil in a compression test. A local strain measurement system comprising of axial and lateral LDTs was developed referring to the original LDT system and the cantilever LDT system, respectively. The LDTs were calibrated both in air and under water. Their insensitivity to pressurized water was confirmed. The calibration factors for the axial and lateral LDTs were found to be 1.695 mm/volt and 1.001 mm/volt, respectively. The performance in terms of repeatability and stability of the LDT system was evaluated. The repeatability test showed that the average standard deviation of the lateral LDT was 0.015 volt, while the stability test showed that the average standard error of the axial and lateral LDT were 3.13 × 10-5 volt and 2.65 × 10-5 volt, respectively. Unconfined compression tests were conducted on three reconstituted clay samples to examine the proposed axial and lateral LDT system. The stress-strain relationship indicates a nonlinear relationship between the axial and lateral strain of soil instead of the conventionally assumed constant relationship. The results demonstrate this nonlinear behavior even at small strain levels, which were successfully measured using a domestically built axial and lateral LDT system.
Strength and Deformation Characteristics of Reconstituted Sand under Different Stress Paths in True Triaxial Tests Hasbullah Nawir; Bagus Eko Prasetyo; Andhika Sahadewa
Journal of Engineering and Technological Sciences Vol. 52 No. 6 (2020)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2020.52.6.10

Abstract

To improve the geotechnical stress"“strain analysis, the stress"“strain behavior of geomaterial under general three-dimensional stress conditions prevailing in the field need to be captured. The true triaxial apparatus is an enhanced version of the conventional triaxial apparatus, which allows to simulate stresses by applying loadings independently in 3 orthogonal directions. This study evaluated the strength and deformation behavior of Bangka sand under true triaxial test conditions. The test specimens were prepared by means of the multi-sieve sand pluviation method. Various true triaxial test stress paths were applied under axial compression, lateral extension, axial extension, and lateral compression with the objective of understanding and developing the empirical correlation of coarse-grained soil strength parameters in axial compression stress paths related to other stress paths. The test results showed that an increase in the value of b, the parameter used to quantify the relative magnitude of the intermediate principal stress to the other principal stresses, resulted in an increase of the internal friction angle and a decrease of the peak stress ratio. In addition it was observed that the Lade-Duncan failure criterion fitted the results of this study better than other failure criteria, namely the extended von Mises, Mohr-Coulomb, and Matsuoka-Nakai failure criteria.
Prediksi Penurunan Tanah Menggunakan Prosedur Observasi Asaoka Studi Kasus: Timbunan di Bontang, Kalimantan Timur Hasbullah Nawir; Dayu Apoji; Rahmatyar Fatimatuzahro; M. Dwi Pamudji
Jurnal Teknik Sipil Vol 19 No 2 (2012)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jts.2012.19.2.5

Abstract

Abstrak. Penurunan konsolidasi tanah merupakan masalah geoteknik yang sering ditemukan pada kasus timbunan, terutama pada tanah lunak. Penurunan konsolidasi disebabkan oleh keluarnya air pori dari dalam tanah yang disebabkan oleh peningkatan tegangan pada massa tanah. Untuk memprediksi besar penurunan serta lama waktu konsolidasi umumnya digunakan teori konsolidasi satu dimensi Terzaghi. Prediksi penurunan konsolidasi dengan teori ini, pada banyak kasus, memberikan hasil yang lebih besar dari penurunan aktual. Hal ini, salah satunya, disebabkan adanya pengabaian fenomena perkuatan tanah yang mungkin terjadi akibat proses penimbunan secara bertahap. Selain teori tersebut terdapat pula prediksi penurunan tanah dengan metode elemen hingga yang sudah menganalisis penurunan secara dua dimensi bahkan tiga dimensi. Namun untuk metode ini prediksi penurunan terhadap waktu, terutama untuk kasus perbaikan tanah dengan drainase vertikal, metode ini tidak memberikan hasil yang baik. Observasi Asaoka. Melalui prosedur ini, besarnya penurunan akhir dapat diprediksi dengan menggunakan data observasi penurunan akibat timbunan dengan menggunakan metoda curve fitting. Studi ini juga membahas perbandingan metode perhitungan penurunan dengan menggunakan teori konsolidasi Terzaghi, metode elemen hingga dan metode observasi Asaoka.Abstract. Consolidation settlement is a general geotechnical problem found embankment, particularly those founded on soft soil. Consolidation settlement is caused by the discharge of soil pore water induced by the increas of stress in soil mass. Terzaghi one dimensional theory was used to predict the settlement and time rate of consolidation. In many cases, the settlement prediction from this theory provides results much greater than the observed value due to many factors including the neglection of soil strength gain that may occur during consolidation process. In addition, there is also settlement prediction by using observed settlement data from the site using curve fitting method. This study presents settlement prediction method using Terzaghi consolidation theory, finite element method and Asaoka observational method.
Compaction Control Using Degree of Saturation and Plasticity Index on Tropical Soil Hasbullah Nawir; Laras Dipa Pramudita; Tita Kartika Dewi; Dayu Apoji; Sugeng Krisnanto
Journal of Engineering and Technological Sciences Vol. 55 No. 3 (2023)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2023.55.3.5

Abstract

Soil compaction in the field is conventionally controlled using maximum dry density, (ρd)max, and optimum moisture content, (w)opt, as the target properties. However, achieving accurate control of these target properties can be difficult due to variation of compaction energy level (CEL) and soil type. Recently, a novel soil compaction control approach using optimum degree of saturation, (Sr)opt, as the target properties has been proposed. It was argued that (Sr)opt can be a better compaction control property as the value is less sensitive to the variation of CEL and soil type. This paper presents an investigation of the compaction characteristics of tropical soils from several locations in Indonesia based on both primary and secondary data. This study was performed by exploring the relationships between (i) dry density (ρd) and Sr, (ii) (ρd) and plasticity index (PI), (iii) (ρd) and CBR, as well as (iv) (ρd) and permeability. This study showed that the (Sr)opt of the soils was 91.2%, with variation between 81.2% and 96.5%. This study also showed that (ρd)max can be related to PI at a given CEL. It is expected that the proposed relationships can be better references for field compaction control practices in Indonesia.
Co-Authors Andhika Sahadewa Apoji, Dayu Dayu Apoji Dayu Apoji Dayu Apoji, Dayu Edwin Laurencis Hendrikus, Edwin Laurencis Ekawita, Riska Khairurrijal Khairurrijal Laras Dipa Pramudita M. Dwi Pamudji M. Dwi Pamudji, M. Dwi Prasetyo, Bagus Eko Rahmatyar Fatimatuzahro Rahmatyar Fatimatuzahro, Rahmatyar Riska Ekawita Sugeng Krisnanto Tita Kartika Dewi