scholarly journals STABILITAS TIANG PANCANG AKIBAT LIKUIFAKSI PADA PROYEK GEDUNG SANGGALA JAKARTA

2021 ◽  
Vol 14 (2) ◽  
pp. 1
Author(s):  
Sinta Delia ◽  
Putera Agung Maha Agung
Keyword(s):  
Pile Foundation ◽  
Cyclic Stress ◽  
Cone Penetration ◽  
Liquefaction Potential ◽  
Cyclic Stress Ratio ◽  
Cyclic Resistance ◽  
Cyclic Resistance Ratio ◽  
Group Piles ◽  
Short Time ◽  
Building Project

Liquefaction is an incident where the soil losses its shear strength due to increased porewater stress due to the incident of very fast cyclic loading in a short time. Liquefaction event due to earthquakes can cause structural failure of the building. In this case, the Sanggala Building Project in Jakarta exists at location of liquefaction potential susceptible area, and design analysis only uses the data of Cone Penetration Test (CPT). Stability analysis of pile due to liquefaction potential is aimed to determine the value of the factor of safety (FS) in the area, which is analyzed by comparing the value of Cyclic Stress Ratio (CSR) due to the earthquake and Cyclic Resistance Ratio (CRR) as the soil resistance to resist liquefaction potential. Based on the analysis and calculations performed, was obtained the value of FS > 1, which means actually the soil does not have the liquefaction potential. However, this study still takes into consideration the liquefaction potential as one of requirements of local regulation when the analysis of bearing capacity of pile foundation analyzed by the method of Schmertmann (1978) in a depth of 25 m and the results was indicated by 1660,27 kN for single pile and 12081,63 kN for the group piles. Furthermore, all these results from several stability calculations, the pile foundation system stable from liquefaction potential.

scholarly journals ANALISIS POTENSI CYCLIC MOBILITY PADA TANAH KOHESIF

2019 ◽  
Vol 2 (3) ◽  
pp. 77
Author(s):  
Nicky Fernando ◽  
Aniek Prihatiningsih
Keyword(s):  
Axial Strain ◽  
Cyclic Strain ◽  
Standard Penetration Test ◽  
Cyclic Stress ◽  
Penetration Test ◽  
Cone Penetration ◽  
Cyclic Stress Ratio ◽  
Cyclic Mobility ◽  
Cyclic Resistance ◽  
Cyclic Resistance Ratio

Likuifaksi merupakan fenomena dimana kekuatan tahanan tanah berkurang karena meningkatnya tegangan air pori saat gempa bumi berlangsung. Likuifaksi dibagi menjadi dua tipe berdasarkan proses kejadiannya yaitu flow liquefaction dan cyclic mobility. Hal pertama dalam analisis potensi likuifaksi adalah pemeriksaan kerentanan likuifaksi dari karakteristik tanah. Pemeriksaan kerentanan menggunakan empat metode yaitu Chinese criteria, metode Seed et al. dan metode Bray dan Sancio. Jika tanah menunjukan rentan terhadap likuifaksi, perhitungan evaluasi dapat dilanjutkan jika tidak maka perhitungan tidak dilanjutkan. Setelah menentukan kerentanan, tanah yang rentan likuifaksi akan ditentukan tipe likuifaksi menggunakan state criteria. Penentuan tipe likuifaksi dapat dilihat dari grafik hubungan deviatoric stress (q), mean effective stress (p’) dan axial strain (εa). Evaluasi potensi likuifaksi menggunakan metode cyclic strain approach. Metode ini menggunakan dua variabel yaitu cyclic stress ratio (CSR) dan cyclic resistance ratio (CRR) yang dapat ditentukan dari data tes lapangan untuk menentukan potensi likuifaksi setiap lapisan tanah. Tes lapangan yang digunakan adalah standard penetration test (SPT) dan cone penetration test (CPT). Penelitian ini menganalisa potensi cyclic mobility pada tanah kohesif serta faktor keamanan. Hasil dari penelitian ini menunjukan bahwa tipe likuifaksi yang terjadi adalah cyclic mobility dan adanya potensi likuifaksi pada tanah kohesif.

Analisis Tingkat Potensi Likuifaksi Di Kawasan Underpass Yogyakarta International Airpor

2020 ◽  
Vol 16 (2) ◽  
pp. 91
Author(s):  
Muhamad Agung Rahman ◽  
Teuku Faisal Fathani ◽  
Ahmad Rifa'i ◽  
Mochammad Syidik Hidayat
Keyword(s):  
Safety Factor ◽  
Stress Ratio ◽  
Cyclic Stress ◽  
Resistance Ratio ◽  
Liquefaction Potential ◽  
Cyclic Stress Ratio ◽  
International Airport ◽  
Cyclic Resistance ◽  
Potential Index ◽  
Cyclic Resistance Ratio

Fenomena likuifaksi akibat gempa merupakan berkurangnya daya dukung tanah karena hilangnya inter-granular stress antar butir-butir tanah untuk menahan beban getaran gempa akibat naiknya tegangan air pori. Dampak likuifaksi dapat menimbulkan kerugian dan kerusakan yang besar pada infrastruktur. Analisis potensi likuifaksi dilakukan di kawasan Underpass Yogyakarta International Airport (YIA) yang termasuk kedalam  formasi endapan alluvial dengan menggunakan data N-SPT pada lima data bor. Analisis potensi likuifaksi bertujuan untuk mengetahui nilai safety factor (SF) yaitu perbandingan nilai Cyclic Resistance Ratio (CRR) yang merupakan tahanan tanah terhadap likuifaksi dan Cyclic Stress Ratio (CSR)  yang merupakan tegangan geser yang timbul akibat gempa di kawasan tersebut. Peristiwa likuifaksi akan terjadi jika nilai SF kurang dari satu. Analisis tingkat potensi likuifaksi menggunakan metode Liquefaction Potential Index (LPI). Hasil analisis potensi likuifaksi di kawasan Underpass YIA menunjukan bahwa lapisan tanah pasir berpotensi mengalami likuifaksi pada kedalaman 1 m hingga 6 m dari permukaan tanah pada sisi timur (titik bor BH01, BH02) dan mulut underpass sisi barat (BH05). Pada sisi barat (titik bor BH03 dan BH04), lapisan tanah pasir di lokasi Underpass YIA tidak berpotensi likuifaksi. Berdasarkan analisis LPI menunjukkan seluruh kawasan Underpass YIA rentan terhadap ancaman likuifaksi (LPI > 5) jika terjadi gempa bumi dengan nilai percepatan muka tanah maksimum (amax) lebih dari 0,44g.

A laboratory investigation of the dynamic properties of tailings

2011 ◽  
Vol 48 (11) ◽  
pp. 1587-1600 ◽  
Author(s):  
Michael James ◽  
Michel Aubertin ◽  
Dharma Wijewickreme ◽  
G. Ward Wilson
Keyword(s):  
Dynamic Properties ◽  
Cyclic Stress ◽  
Test Results ◽  
Liquefaction Resistance ◽  
Cyclic Stress Ratio ◽  
Cyclic Resistance ◽  
Direct Simple Shear ◽  
Cyclic Resistance Ratio ◽  
Modulus Reduction

The dynamic response of tailings from a gold mine located in western Quebec was evaluated using cyclic laboratory testing. These tailings are classified as nonplastic silt and sand. Specimens of the tailings were prepared as slurries, consolidated to vertical effective stresses of 100–400 kPa, and subjected to cyclic direct simple shear testing with cyclic stress ratio, CSR, values between 0.075 and 0.15. The shear modulus reduction of the tailings under cyclic loading was found to be fairly similar to that described for clean sands in the literature. The cyclic resistance ratio, CRR (which reflects the liquefaction resistance), of the samples was not significantly affected by the effective consolidation stress (in the range considered here). Analysis of test results with the simplified method of liquefaction evaluation indicates that this method may be applicable to these tailings. However, other factors, such as the possible effects of layering and ageing of the tailings in situ, should also be considered in such an assessment.

Analisis Potensi Likuifaksi Di Kawasan Underpass Yogyakarta International Airport (YIA)

2020 ◽  
Vol 5 (1) ◽  
pp. 47
Author(s):  
Muhamad Agung Rahman ◽  
Mochammad Syidik Hidayat ◽  
Teuku Faisal Fathani ◽  
Ahmad Rifa’i
Keyword(s):  
Safety Factor ◽  
Stress Ratio ◽  
Cyclic Stress ◽  
Resistance Ratio ◽  
Cyclic Stress Ratio ◽  
International Airport ◽  
Cyclic Resistance ◽  
Cyclic Resistance Ratio

Fenomena likuifaksi akibat gempa merupakan hilang/berkurangnya daya dukung tanah karena hilangnya inter-granular stress antar butir-butir tanah untuk menahan beban getaran gempa akibat naiknya tegangan air pori. Dampak likuifaksi dapat menimbulkan kerugian dan kerusakan yang besar pada infrastruktur. Evaluasi potensi likuifaksi dilakukan di kawasan Underpass Yogyakarta International Airport  (YIA) dengan menggunakan data N-SPT sebanyak lima data bor. Analisis potensi likuifaksi bertujuan untuk mengetahui nilai safety factor (SF) di kawasan tersebut. Peristiwa likuifaksi akan terjadi jika nilai SF lebih kecil dari satu. Nilai safety factor (SF) adalah perbandingan nilai Cyclic Resistance Ratio (CRR) yang merupakan tahanan tanah terhadap likuifaksi dan Cyclic Stress Ratio (CSR)  yang merupakan tegangan geser yang timbul akibat gempa. Hasil analisis potensi likuifaksi di kawasan Underpass YIA menunjukan bahwa lapisan tanah pasir di Underpass YIA berpotensi mengalami likuifaksi pada kedalaman 4-6 m dari permukaan tanah pada titik bor BH01 dan BH05. Sedangkan pada titik bor BH02, BH03, dan BH04, lapisan tanah pasir di lokasi Underpass YIA tidak berpotensi terjadi likuifaksi. Untuk menghilangkan potensi terjadinya likuifaksi pada struktur underpass dilakukan penggalian di kedalaman 4-5 m serta dilakukan penggantian material (replacement) tanah asli dengan material sirtu setebal 50 cm.

scholarly journals Analisis Potensi Likuefaksi pada Tanah Pasir Akibat Gempa (Studi Kasus Mataram, Nusa Tenggara Barat)

2021 ◽  
Vol 6 (3) ◽  
pp. 166
Author(s):  
Gea Nurbani ◽  
Yuki Achmad Yakin
Keyword(s):  
Stress Ratio ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Standard Penetration Test ◽  
Cyclic Stress ◽  
Resistance Ratio ◽  
Penetration Test ◽  
Cyclic Stress Ratio ◽  
Cyclic Resistance ◽  
Cyclic Resistance Ratio

ABSTRAKPada hari Minggu, 5 Agustus 2018 pukul 19:46 WITA, gempa bumi mengguncang wilayah Labuan, Lombok, Nusa Tenggara Barat dengan skala magnitudo M7,0. Akibat guncangan tersebut, terjadi peristiwa likuefaksi di sebagian wilayah Provinsi Nusa Tenggara Barat dan menimbulkan kerusakan yang signifikan. Peristiwa likuefaksi dapat terjadi apabila mengalami peningkatan tekanan air pori yang dipicu oleh gempa bumi sehingga mengakibatkan tanah kehilangan kekakuan dan kuat geser tanah. Likuefaksi pada umumnya terjadi pada tanah pasir lepas dengan kondisi jenuh air. Dalam menganalisis potensi terjadinya likuefaksi di lokasi penelitian, digunakan nilai percepatan puncak di batuan dasar (PGA) sebesar 4,13 m/s2dan menggunakan data tanah hasil pengujian Standard Penetration Test (SPT). Hasil perbandingan antara ketahanan tanah atau Cyclic Resistance Ratio (CRR) dengan kemampuan tanah terlikuefaksi atau Cyclic Stress Ratio (CSR) menunjukkan bahwa likuefaksi terjadi pada rata-rata kedalaman 5,5 m – 19.5 m.Kata kunci: likuefaksi, cyclic stress ratio (CSR), cyclic resistance ratio (CRR), faktor keamanan (FK) ABSTRACTOn Sunday, August 5 2018 at 19:46 WITA, an earthquake has shook Labuan, Lombok, West Nusa Tenggara with magnitude 7.0 scale. As a result of the earthquake, liquefaction occurred in several regions of West Nusa Tenggara and caused severe damage. Liquefaction can occure when an increase in pore water pressure is triggered by an earthquake, which causes the soil losing its shear strength and stiffness. Liquefaction mostly occured in sand loose and saturated condition. Analysis of liquefaction based on Peak Ground Acceleration (PGA) at the research site 4.13 m/s2 were done according to the data of SPT (Standard Penetration Test). By comparing the value of soil resistance to liquefaction or Cyclic Resistance Ratio (CRR) and the ability of soil to be liquefied or Cyclic Stress Ratio (CSR), the analysis shows the soil in that area are liquefied at depth of 5.5 m – 19.5 m.Keywords: liquefaction, cyclic stress ratio (CSR), cyclic resistance ratio (CRR), safety of factor (SF)

scholarly journals PERANCANGAN FONDASI TIANG PANCANG PADA TANAH BERPOTENSI LIKUIFAKSI DI SULAWESI

2020 ◽  
Vol 3 (3) ◽  
pp. 865
Author(s):  
Markus Jusuf ◽  
Aksan Kawanda
Keyword(s):  
Soil Layer ◽  
Cyclic Stress ◽  
Lateral Spreading ◽  
Soil Pressure ◽  
Spreading Effect ◽  
Cyclic Resistance ◽  
Cyclic Resistance Ratio ◽  
Liquefied Soils ◽  
Moment Effect ◽  
The Moment

ABSTRACTIndonesia is a country located in the most active earthquake paths in the world. This makes Indonesia prone to earthquakes and has the potential to experience liquefaction. Liquefaction can cause pile failure, so several things need to be considered in designing piles on potentially liquefied soils. One project in Sulawesi has a profile of uniform grained saturated soil that is susceptible to liquefaction. Two things that need to be considered in the design of piles on potentially liquefied soils is to ignore the capacity of pile friction and calculate the moment due to lateral spreading effects. Calculation of liquefaction potential is done by comparing the ratio of the cyclic stress and the cyclic resistance ratio and is compared by four other methods namely: the Seed et al. (2003), Tsuchida (1970), Seed et al. (2003), and Bray & Sancio (2004). The lateral spreading effect is calculated by referring to the JRA Code where the liquefied soil layer gives pressure to the pile at 30% of the overburden stress and the soil layer above the liquefied soil gives passive soil pressure to the pole. The moment effect caused by lateral spreading results in the addition of dimensions or number of poles.Keywords: liquefaction; lateral spreading; bearing capacity; JRA Code; pile foundationABSTRAKIndonesia adalah negara yang terletak di jalur gempa teraktif di dunia. Hal ini menyebabkan Indonesia rawan gempa dan memiliki potensi untuk mengalami likuifaksi. Likuifaksi dapat menyebabkan kerusakan/kegagalan struktur yang sangat merugikan, sehingga perlu diperhatikan beberapa hal dalam merancang tiang pada tanah berpotensi likuifaksi. Salah satu proyek di Sulawesi memiliki profil tanah pasir berbutir seragam dan jenuh air yang memiliki potensi likuifaksi. Dua hal yang perlu diperhitungkan dalam perancangan tiang pada tanah berpotensi likuifaksi adalah mengabaikan daya dukung friksi tiang dan memperhitungkan momen akibat efek lateral spreading. Perhitungan potensi likuifaksi dilakukan dengan membandingkan rasio tegangan siklik (CSR) dan rasio hambatan siklik (CRR) serta dibandingkan dengan empat metode lainnya yaitu: metode Seed et al. (2003), Tsuchida (1970), Seed et al. (2003), dan Bray & Sancio (2004). Daya dukung aksial pada tiang pancang mengalami pengurangan 32% akibat lapisan tanah yang terlikuifaksi. Efek lateral spreading dihitung dengan acuan JRA Code dimana lapisan tanah terlikuifaksi memberikan tekanan ke tiang sebesar 30% dari tegangan overburden dan lapisan tanah di atas tanah terlikuifaksi memberikan tekanan tanah pasif ke tiang. Efek momen yang diakibatkan oleh lateral spreading mengakibatkan penambahan dimensi ataupun jumlah tiang.Kata kunci: likuifaksi; lateral spreading; daya dukung; JRA Code; fondasi tiang    

Regression model for evaluating liquefaction potential by discriminant analysis of the SPT N value

2005 ◽  
Vol 42 (3) ◽  
pp. 856-875 ◽  
Author(s):  
Sheng-Yao Lai ◽  
Ping-Sien Lin ◽  
Ming-Jyh Hsieh ◽  
Hoi-Fung Jim
Keyword(s):  
Discriminant Analysis ◽  
Standard Penetration Test ◽  
Cyclic Stress ◽  
Soil Liquefaction ◽  
Liquefaction Resistance ◽  
Multivariate Statistical ◽  
Liquefaction Potential ◽  
Cyclic Stress Ratio ◽  
N Value ◽  
Spt N Value

Discriminant models are developed for evaluating soil liquefaction potential, using standard penetration test (SPT) data for 592 occurrences of liquefaction and nonliquefaction. The discriminant model used is a multivariate statistical method. The square root of the SPT N value, (N1)601/2, and the logarithm of the cyclic stress ratio, ln CSR7.5, are adopted as the major parameters for analyses. Two models measuring liquefaction resistance through the SPT N value are also established in this study, which allows calculated results to be compared with the empirical curves. Key words: liquefaction, discriminant analysis, misclassified probability.

scholarly journals Analysis of potential liquefaction of sandy soils using effective confining pressure

2020 ◽  
Vol 156 ◽  
pp. 02013
Author(s):  
Siti Nur Indah Sari
Keyword(s):  
Safety Factor ◽  
Sandy Soil ◽  
Sandy Soils ◽  
Confining Pressure ◽  
Resistance Ratio ◽  
Liquefaction Potential ◽  
Cyclic Resistance ◽  
The World ◽  
Cyclic Resistance Ratio ◽  
Central Sulawesi

Earthquake disasters are some of the most frequent disasters in the world. One of the impacts of earthquakes is liquefaction. Indonesia is earthquake-prone and has been negatively impacted by liquefaction. Recently liquefaction resulting from an earthquake in Palu, Central Sulawesi caused losses in terms of material and lives motivating a more detailed study of this risk to reduce it in the future. In this study, an analysis of the liquefaction potential of sandy soil was carried out by varying the effective confining pressure to produce a graph relating fine contents (FC) to cyclic resistance ratio (CRR).The value of the cyclic resistance ratio is needed to determine the safety factor for potential liquefaction.

scholarly journals A SIMPLE SHAKING TABLE TEST TO MEASURE LIQUEFACTION POTENTIAL OF PRAMBANAN AREA, YOGYAKARTA, INDONESIA

2021 ◽  
Vol 11 (3) ◽  
pp. 89-108
Author(s):  
Lindung Zalbuin Mase ◽  
Teuku Faisal Fathani ◽  
Agus Darmawan Adi
Keyword(s):  
Dynamic Load ◽  
Stress Ratio ◽  
Shaking Table Test ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Pressure Ratio ◽  
Cyclic Stress ◽  
Shaking Table ◽  
Liquefaction Potential ◽  
Cyclic Stress Ratio

This paper presents the experimental study of liquefaction potential for sandy soil in Prambanan Area, Yogyakarta, Indonesia, which underwent liquefaction due to the Mw 6.3 Jogja Earthquake on May 27, 2006. Shaking table tests considering the variation of acceleration and shaking duration were performed to investigate the liquefaction potential of sand. The liquefaction time stages including time to start liquefaction, time to start pore pressure dissipation, and liquefaction duration were observed. The percentage of liquefaction duration increase, the excess pore water pressure ratio and the required time to generate liquefaction, and the effect of applied acceleration to cyclic stress ratio, were also presented. The results showed that the sand could undergo liquefaction under the variation of dynamic load. The variation of dynamic load significantly influenced the time stages of liquefaction, the increase of liquefaction duration percentage and cyclic stress ratio. The results also exhibited that the larger applied acceleration and the longer shaking duration means the longer liquefaction duration and the larger liquefaction potential. In general, the result could bring the recommendation to the liquefaction countermeasure for Prambanan Area.

The use of critical state soil mechanics to characterise Christchurch soil in relation to liquefaction susceptibility

2016 ◽  
Vol 49 (4) ◽  
pp. 319-333
Author(s):  
Jeremy Tan ◽  
Rolando P. Orense ◽  
Andy O’Sullivan
Keyword(s):  
Critical State ◽  
Soil Mechanics ◽  
State Parameter ◽  
Cyclic Stress ◽  
Empirical Methods ◽  
Liquefaction Potential ◽  
Liquefaction Susceptibility ◽  
Cyclic Resistance ◽  
Stress Ratios ◽  
Parameter Values

The majority of current procedures used to deduce liquefaction potential of soils rely on empirical methods. These methods have been proven to work in the past, but these methods are known to overestimate the liquefaction potential in certain regions of Christchurch due to a whole range of factors, and the theoretical basis behind these methods cannot be explained scientifically. Critical state soil mechanics theory was chosen to provide an explanation for the soil’s behaviour during the undrained shearing. Soils from two sites in Christchurch were characterised at regular intervals for the critical layers and tested for the critical state lines (CSL). Various models and relationships were then used to predict the CSL and compared with the actual CSL. However none of the methods used managed to predict the CSL accurately, and a separate Christchurch exclusive relationship was proposed. The resultant state parameter values could be obtained from shear-wave velocity plots and were then developed into cyclic resistance ratios (CRR). These were subsequently compared with cyclic stress ratios (CSR) from recent Christchurch earthquakes to obtain the factor of safety. This CSL-based approach was compared with other empirical methods and was shown to yield a favourable relationship with visual observations at the sites’ locations following the earthquake.

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