Liquefaction potential for the Kathmandu Valley, Nepal: a sensitivity study

AbstractAn assessment of liquefaction potential for the Kathmandu Valley considering seasonal variability of the groundwater table has been conducted. To gain deeper understanding seven historical liquefaction records located adjacent to borehole datapoints (published in SAFER/GEO-591) were used to compare two methods for the estimation of liquefaction potential. Standard Penetration Test (SPT) blowcount data from 75 boreholes inform the new liquefaction potential maps. Various scenarios were modelled, i.e., seasonal variation of the groundwater table and peak ground acceleration. Ordinary kriging, implemented in ArcGIS, was used to prepare maps at urban scale. Liquefaction potential calculations using the methodology from (Sonmez, Environ Geol 44:862–871, 2003) provided a good match to the historical liquefaction records in the region. Seasonal variation of the groundwater table is shown to have a significant effect on the spatial distribution of calculated liquefaction potential across the valley. The less than anticipated liquefaction manifestations due to the Gorkha earthquake are possibly due to the seasonal water table level.

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Analisis Potensi Likuifaksi Akibat Gempa Bumi Menggunakan Metode SPT (Standar Penetration Test) Dan Cpt (Cone Penetration Test) Di Kabupaten Bantul, Yogyakarta

Wahana Fisika ◽

10.17509/wafi.v2i1.7022 ◽

2017 ◽

Vol 2 (1) ◽

pp. 8 ◽

Cited By ~ 1

Author(s):

Tini Tini ◽

Adrin Tohari ◽

Mimin Iryanti

Keyword(s):

Soil Layer ◽

Cone Penetration Test ◽

Standard Penetration Test ◽

Silty Sand ◽

Penetration Test ◽

Cone Penetration ◽

Ground Acceleration ◽

Liquefaction Potential ◽

Liquefaction Hazard ◽

Better Than

Gempa bumi yang terjadi di daerah Bantul, Yogyakarta pada 27 Mei 2006 dengan magnitudo gempa bumi sebesar 6.3 SR dapat menyebabkan terjadinya bahaya likuifaksi yang dapat merusak bangunan khususnya di wilayah Bantul Yogyakarta. Investigasi geoteknik yang telah dilakukan di Bantul, Yogyakarta dapat memberikan gambaran lapisan tanah yang berpotensi terjadinya likuifaksi. Analisis potensi likuifaksi dilakukan berdasarkan data SPT (Standard Penetration Test) dan CPT (Cone Penetration Test) dengan percepatan maksimum tanah menurut Gutenberg Richter di daerah penelitian rata-rata bernilai sebesar 2.93 m/s2 dan menurut Donovan sebesar 2.88 m/s2. Hasil analisis penelitian menunjukan bahwa lapisan tanah yang berpotensi likuifaksi didominasi oleh jenis tanah pasir lanauan da lanau pasiran yang berada pada kedalaman 0.2 – 3 m, 0.4 m, 2.4 m, 3.6 m, 7.6 – 7.8 m dan 8.2 m. Pengaruh percepatan maksimum tanah menurut Gutenberg Richter lebih besar terhadap terjadinya likuifaksi daripada menurut Donovan. Perbandingan hasil analisis potensi likuifaksi antara data SPT (Standard Penetration Test ) dan CPT (Cone Penetration Test) pada daerah penelitian menunjukan adanya kesamaan potensi likuifaksi pada lapisan tanah dengan kedalaman yang sama diantaranya pada kedalaman 0.2 m-4 m, dengan nilai Cyclic Strees Ratio (CSR) rata-rata sebesar 0.2, sedangkan berdasarkan nilai Cyclic Resistance Ratio (CRR) terdapat perbedaan nlai. Analisis berdasarkan data CPT lebih baik daripada data SPT karena data CPT lebih rapat daripada data SPT.The earthquake that occurred in Bantul, Yogyakarta on May 27, 2006 with the magnitudo of the earthquake of 6.3 SR can caused liquefaction hazard which could damage to teh building in the municipals of Bantul, Yogyakarta. Geotechnical investigation was carried in Bantul Yogyakarta, can give information about liquefaction hazard in soil layer. The liquefaction potential lanalysis was conducted using SPT and CPT methods, with Gutenberg-Richter’s maximum ground acceleration is 2.93 m/s2 and Donovan’s maximum ground acceleration is 2.88 m/s2. Result of liquefaction analysis indicate that the soil layer domination of silty sand dan sandy silt at the depth of 0.2 – 3 m, 3.6 m, 4 m 7.6 – 7.8 m and 8.2 m. Gutenberg-Richter’s maximum ground acceleration having influential for liquefaction potential better than Donovan’s maximum ground acceleration. Ratio result of liquefaction was conducted using SPT same as soil layer with CPT in resech location at the depth 0.2 m-4 m, with value Cyclic Strees Ratio (CSR) is 0.2. Even value Cyclic Resistances Ratio (CSR) have different value. The liquefaction potential lanalysis was conducted using CPT method better than SPT methods.

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Liquefaction hazard assessment and ground failure probability analysis in the Kathmandu Valley of Nepal

Geoenvironmental Disasters ◽

10.1186/s40677-021-00203-0 ◽

2022 ◽

Vol 9 (1) ◽

Author(s):

Mandip Subedi ◽

Indra Prasad Acharya

Keyword(s):

Soil Liquefaction ◽

Kathmandu Valley ◽

Borehole Data ◽

Gorkha Earthquake ◽

Engineering Structures ◽

Liquefaction Potential ◽

Ground Failure ◽

2015 Gorkha Earthquake ◽

Scenario Earthquakes ◽

Liquefaction Hazard

AbstractDuring the 2015 Gorkha Earthquake (Mw7.8), extensive soil liquefaction was observed across the Kathmandu Valley. As a densely populated urban settlement, the assessment of liquefaction potential of the valley is crucial especially for ensuring the safety of engineering structures. In this study, we use borehole data including SPT-N values of 410 locations in the valley to assess the susceptibility, hazard, and risk of liquefaction of the valley soil considering three likely-to-recur scenario earthquakes. Some of the existing and frequently used analysis and computation methods are employed for the assessments, and the obtained results are presented in the form of liquefaction hazard maps indicating factor of safety, liquefaction potential index, and probability of ground failure (PG). The assessment results reveal that most of the areas have medium to very high liquefaction susceptibility, and that the central and southern parts of the valley are more susceptible to liquefaction and are at greater risk of liquefaction damage than the northern parts. The assessment outcomes are validated with the field manifestations during the 2015 Gorkha Earthquake. The target SPT-N values (Nimproved) at potentially liquefiable areas are determined using back analysis to ascertain no liquefaction during the aforesaid three scenario earthquakes.

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The 2015 Gorkha Earthquake and response of the Kathmandu Valley sediments

Journal of Nepal Geological Society ◽

10.3126/jngs.v49i1.23136 ◽

2015 ◽

Vol 49 (1) ◽

pp. 1-5

Author(s):

Sudhir Rajaure ◽

Megh Raj Dhital ◽

Lalu Prasad Paudel

Keyword(s):

Source Zone ◽

Great Earthquake ◽

Kathmandu Valley ◽

Main Central Thrust ◽

Gorkha Earthquake ◽

Ground Acceleration ◽

Low Frequencies ◽

High Frequencies ◽

Nepal Earthquake ◽

2015 Gorkha Earthquake

The Gorkha Earthquake occurred on the gently dipping part of the Main Himalayan Thrust (MHT), close to the Main Central Thrust (MCT). This earthquake possibly occurred in the source zone of the 1833 Nepal Earthquake (Mw 7.6), which occurred after 182 years. The region between the 1905 Kangra Earthquake and 1934 Bihar-Nepal Earthquake has not produced any great earthquake since the last 500 years and still remains a potential site for great earthquake(s) in future. The Kathmandu Valley witnessed moderate ground acceleration and comparatively large velocity as recorded at Kantipath during the Mw 7.8, Gorkha Earthquake. The analysis of the records show that high frequencies were damped and low frequencies were dominant over the sedimentary basin, which can be attributed to the response of the sediments underneath. Because of damping of high frequencies, the engineered, low storey buildings were less damaged and resisted the ground shaking comparatively well. However, on the other hand, the historical monument 'Dharahara' collapsed completely and the high rise apartment buildings suffered more because of the dominance of low frequencies.

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Evaluation of Liquefaction Potential of Soil at a Power Plant Site in Chittagong, Bangladesh

International Journal of Geotechnical Earthquake Engineering ◽

10.4018/ijgee.2020010101 ◽

2020 ◽

Vol 11 (1) ◽

pp. 1-16

Author(s):

Soumyadeep Sengupta ◽

Sreevalsa Kolathayar

Keyword(s):

Power Plant ◽

Response Spectrum ◽

Ground Level ◽

Standard Penetration Test ◽

Combined Cycle ◽

Point Of View ◽

Soil Conditions ◽

Ground Acceleration ◽

Liquefaction Potential ◽

Plant Site

This study presents an evaluation of liquefaction potential for combined cycle power plant site located in the Chittagong district, Bangladesh, using standard penetration test blow counts (SPT-N values). The peak ground acceleration (PGA) values at a bedrock level were estimated deterministically using both linear and point source models as well as different ground motion prediction equations (GMPEs). The surface level hazard was estimated using amplification factors for the soil conditions present and the response spectrum at the center of the plant site was plotted. The liquefaction potential for the site was arrived at by using the SPT-N values of 33 boreholes in the site and at every 3-meter interval from the ground level to a depth of 30 meters. The results from the LPI contours at successive depths indicate that in the majority of the borehole locations, the soil up to 15 meters depth had a significant hazard of liquefaction. These findings from the present study can prove to be crucial from the structural point of view, for any future construction activities in the area.

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Closure to “Standard Penetration Test-Based Probabilistic and Deterministic Assessment of Seismic Soil Liquefaction Potential” by K. Onder Cetin, Raymond B. Seed, Armen Der Kiureghian, Kohji Tokimatsu, Leslie F. Harder Jr., Robert E. Kayen, and Robert E. S. Moss

Journal of Geotechnical and Geoenvironmental Engineering ◽

10.1061/(asce)1090-0241(2006)132:5(667.2) ◽

2006 ◽

Vol 132 (5) ◽

pp. 667-669

Author(s):

K. Onder Cetin ◽

Raymond B. Seed ◽

Armen Der Kiureghian ◽

Kohji Tokimatsu ◽

Leslie F. Harder ◽

...

Keyword(s):

Standard Penetration Test ◽

Soil Liquefaction ◽

Penetration Test ◽

Liquefaction Potential

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Experimental Research on the Liquefaction Potential of Tailings Silt in Zhuziqing Tailings Dam

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.708 ◽

2012 ◽

Vol 204-208 ◽

pp. 708-713

Author(s):

Jing You Hu ◽

Jian Bin Xie ◽

Wei Li ◽

Cheng Hui Li

Keyword(s):

Mechanical Properties ◽

Experimental Research ◽

Field Survey ◽

Physical And Mechanical Properties ◽

Field Performance ◽

Standard Penetration Test ◽

Tailings Dam ◽

Penetration Test ◽

Liquefaction Potential ◽

Lab Test

The particle composition, physical and mechanical properties of tailings silt in Zhuziqing tailings dam were tested by means of field survey and lab test. And the liquefaction potential of tailings silt in Zhuziqing tailings dam were investigated based on field-performance data using standard penetration test (SPT) and wave velocity test (WVT) methods. Results show that the liquefaction potential of tailings silt in Zhuziqing tailings dam can be evaluated by means of SPT and WVT. Results also show that there is almost non liquefaction at the places in Zhuziqing tailings dam where are under the seventh sub-dam, and there is serious liquefaction in the new sub-dam and deposited beach, which locate at the places above the eleventh sub-dam.

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