SPT-based Liquefaction Triggering Research Articles

Study of soil liquefaction potential at Anutapura General Hospital, Palu City, Central Sulawesi Province

On September 28, 2018, at 18:02 local time, a strong tectonic earthquake with a moment magnitude of 7.5 struck Central Sulawesi Province, Indonesia, triggering liquefaction disasters in Palu city and Sigi district. The project of the Anutapura Medical Centre (AMC) building at the Anutapura General Hospital in Palu city is one of the Indonesian government programs to support the rehabilitation and reconstruction of infrastructure after the earthquake. This hospital is located close to the liquefaction-affected area in Balaroa. Geologically, the hospital area is also located in the formation of Holocene deposits that have not been fully lithified. This study aims to analyze the liquefaction potential, which focuses on the construction area of the AMC building. The soil grain size distribution was used for the preliminary analysis of potentially liquified soils. The SPT-based liquefaction triggering procedure was used to calculate the safety factor (SF) against liquefaction. Subsequently, the SF value was further analyzed using the liquefaction severity index (LSI) to determine the severity level. The results show that soils in the study area have the potential to liquefy with a low to moderate severity level. The results are expected to be used as consideration to mitigate the possible liquefaction.

Design of Stone Column to Mitigate Soil Liquefaction: Cases Study of Yogyakarta International Airport

A low-to-medium cohesionless soil with low fines content was predominantly observed at the surfaces of Yogyakarta International Airport (YIA). The condition exposed subsoil of YIA to Liquefaction in addition to its location on a high seismic zone which has increased the likelihood of massive ground shaking. This means it is necessary to improve soil condition and vibro-replacement using stone column was selected as the appropriate method due to its recent popularity for the enhancement of sandy ground. Stone column has the ability to reduce the Cyclic Stress Ratio (CSR) of liquefiable soil and can be reliably evaluated. Therefore, this study was conducted to evaluate the risk of Liquefaction at YIA by adopting the SPT-based Liquefaction triggering procedure and presuming its manifestation using Liquefaction Severity Index (LSI). It is pertinent to state that the theoretical approach introduced by Priebe was used to design the geometry and center-to-center distance of stone column. The results were presented in the form of maps with a 50 m × 50 m grid size which include the cut and fill, LSI before and after improvement, stone column spacing, as well as stone column depth. It was discovered that the triangular spacing required for stone column ranged from 1.25 m to 2.5 m while the maximum depth was found to be 6 m. Moreover, stone column inclusion efficiently reduced the severity of Liquefaction from medium to very low for the areas studied. However, stone column has several limitations and this means a combination of soil improvement methods needs to be applied to areas with moderate LSI.

Liquefaction potential hazard study at UIN Datokarama, Palu City, Central Sulawesi

In June 2019, the Asian Development Bank approved emergency rehabilitation and reconstruction assistance (EARR) to help Indonesia rebuild better critical infrastructure damaged by the 2018 Palu-Donggala earthquake. One of the EARR sub-projects is the reconstruction of Universitas Islam Negeri (UIN) Datokarama that suffered significant damage from the combined effects of the tsunami and earthquake. The design for the building's reconstruction incorporated better principles of deconstruction, including pile foundations to ensure the facilities are earthquake, tsunami, and liquefaction resistant. This study purpose is to evaluate liquefaction potential and estimate its severity or damage potential to structures in the reconstruction site. Liquefaction potential will be assessed in two ways, first by using soil deposits grain sizes distribution method from Japan technical standards for port and harbour facilities and second by safety factor against liquefaction (FOS) method using the SPT-based liquefaction triggering analysis with the revised magnitude scaling factor (MSF) relationship by Idriss and Boulanger. Liquefaction Potential Index (LPI) from Iwasaki will be used for estimating liquefaction severity. The analysis is performed on dataset taken from 6 boreholes in location dominated by saturated sandy soil and shallow ground water. Based on the result, liquefaction potentially triggered at various depth with consistent LPI index at > 15, The reconstruction site has a very high liquefaction risk.

SPT-based probabilistic evaluation of soil liquefaction potential considering design life of civil infrastructures

The standard penetration test (SPT) is commonly used in the simplified liquefaction triggering procedure for assessing soil liquefaction potential. However, liquefaction assessment results evaluated from limited SPTs contain significant uncertainties. Moreover, the design levels of seismic ground motion, a key input to the SPT-based liquefaction triggering procedure, depend on the design life of a given structure. Thus, disregarding the above-mentioned uncertainties and the design life of a structure can lead to biased liquefaction assessment results and pose a significant risk to civil structures. To tackle this challenge, this study proposes a fully probabilistic framework for delineating the spatial distribution of soil liquefaction potential in a vertical cross-section of a specific site over the target structure design life (e.g., 50 years). The method is used to analyze real data from the Wildlife Liquefaction Array, USA, and demonstrates its ability to capture the spatial distribution of liquefaction potential and quantify the liquefaction probability at each point of a cross section. A sensitivity study is also performed and shows that the liquefaction probability of the cross-section increases with the target design life of the structure. These results provide practitioners with valuable information for accurate assessment and effective mitigation of liquefaction risk.

SPT-based probabilistic and deterministic assessment of seismic soil liquefaction triggering hazard

This study serves as an update to the Cetin et al. (2000, 2004) [1,2] databases and presents new liquefaction triggering curves. Compared with these studies from over a decade ago, the resulting new Standard Penetration Test (SPT)-based triggering curves have shifted to slightly higher CSR-levels for a given N1,60,CS for values of N1,60,CS greater than 15 blows/ft, but the correlation curves remain essentially unchanged at N1,60,CS values less than 15 blows/ft. This paper addresses the improved database and the methodologies used for the development of the updated triggering relationships. A companion paper addresses the principal issues that cause differences among three widely used SPT-based liquefaction triggering relationships.

Application of deterministic and probabilistic ‐ SPT based liquefaction assessment triggering models

AbstractThis paper presents an application of the SPT based liquefaction triggering models (both deterministic and probabilistic) proposed by Boulanger and Idriss (2010). Several authors consider deterministic approaches to be beneficial in areas of high seismicity. The procedure for predicting probability of liquefaction however can be alternative tool of analysis that could complement the deterministic procedures by providing information on the relative risk of liquefaction between design alternatives. It is used to estimate the probability of liquefaction for a given design earthquake magnitude and acceleration. Both deterministic and probabilistic approaches were used for a liquefaction susceptible soil profile for different percentage of fines. The location is in Ohrid, as a specific area with high groundwater tables, complex geological conditions and medium level seismicity. The potential of liquefaction is determined for all layers of the soil. The results show that the probabilistic approaches shouldn't be excluded in this assessment and can be more favourable for areas of intermediate seismicity.

Liquefaction potential assessment of Guwahati city using first-order second-moment method

Soil liquefaction is the failure of the soil due to the sudden increase in a pore water pressure causing the effective stress to reduce significantly thus losing shear strength, with the resulting effect causing the fluid type behavior of the soil. Guwahati city, the capital of Assam, lies in the northeastern region of India and this whole region is considered seismically very active (seismically sixth position globally). The whole region is categorized in Zone-V according to the seismic zoning map of India as per IS 1893:2002 (Part 1). This region witnessed/experienced several major and great earthquakes in the past such as 1897 Shillong and 1950 Assam earthquakes. The soil deposits of the city mainly consist of an alluvial type of Holocene age and the presence of shallow groundwater table makes it vulnerable to soil liquefaction. In this study, an assessment of soil liquefaction potential of Guwahati city is performed based on the methods proposed by Youd and Idriss (J Geotech Geoenviron Eng 127:297, 2001) and Idriss and Boulanger (2010; CPT- and SPT-based liquefaction triggering procedures, 2014) using standard penetration test data. The evaluation of liquefaction potential is carried out for 82 borehole sites considering the Great 1897 Shillong earthquake of Mw 8.1 with a peak ground acceleration of 0.36 g. In the deterministic approach, the various parameters are involved in the evaluation of liquefaction potential, and the uncertainties of the input parameters as well as model cause the dissimilarity of the result. For instance, the same input parameters for both the models show different factor of safety. Hence, a comprehensive probability approach considering the uncertainty of parameters is essential for the evaluation of liquefaction susceptibility. In this study, reliability analysis for both the models based on first- order second-moment method has been used. The Reliability Index based on input parameters such as cyclic resistance ratio and cyclic stress ratio computed for both the models and subsequent liquefaction probability are established. The result shows the city is in most vulnerable condition even up to 15 m depth considering both the methods proposed by Youd and Idriss (J Geotech Geoenviron Eng 127:297, 2001) and Idriss and Boulanger (2010; CPT- and SPT-based liquefaction triggering procedures, 2014). Therefore, extra measure should be taken while constructing structure in and around the study area.

Magnitude scaling factors in liquefaction triggering procedures

A revised magnitude scaling factor (MSF) relationship for CPT-based and SPT-based liquefaction triggering analyses is presented in this paper. The revised MSF relationship incorporates functional dependency on the soil characteristics [represented by clean sand equivalent penetration resistances in the present form] as well as on earthquake magnitude. The revisions in MSF are based on the examination of cyclic testing results for a broad range of soil types and densities, analyses of strong ground motion records to develop relationships for the equivalent number of loading cycles for different soil properties, and the synthesis of those results into an MSF relationship suitable for implementation in practice. A separate study [2] showed that use of the revised MSF relationship in CPT-based and SPT-based liquefaction triggering procedures is well-supported by the case history databases. Other factors known to fundamentally influence the MSF are discussed.

Examination of the Kσ Overburden Correction Factor on Liquefaction Resistance

AbstractThe overburden correction factor (Kσ) is used to account for the curvature of the cyclic strength envelope with increasing consolidation stress, and it provides part of the basis for extrapolation of liquefaction-triggering correlations based on standard penetration test (SPT) and cone penetration test (CPT) to larger depths than covered by current databases of liquefaction case histories. This paper presents an updated database of laboratory test results defining Kσ effects. Laboratory test results included in previous databases are reexamined in light of current understanding of factors that can affect laboratory measurements of cyclic strengths, including the effects of increasing density with increasing consolidation stress, variable overconsolidation ratios, and other factors. The updated database is used to examine potential biases in the Kσ relationships used in two SPT-based liquefaction triggering procedures. The first relationship was found to be conservative with respect to the data for...

Discussion of “Examination and Reevaluation of SPT-Based Liquefaction Triggering Case Histories” by Ross W. Boulanger, Daniel W. Wilson, and I. M. Idriss

Discussion of “Examination and Reevaluation of SPT-Based Liquefaction Triggering Case Histories” by Ross W. Boulanger, Daniel W. Wilson, and I. M. Idriss

Closure to “Examination and Reevaluation of SPT-Based Liquefaction Triggering Case Histories” by Ross W. Boulanger, Daniel W. Wilson, and I. M. Idriss

Closure to “Examination and Reevaluation of SPT-Based Liquefaction Triggering Case Histories” by Ross W. Boulanger, Daniel W. Wilson, and I. M. Idriss

Examination of SPT-Based Liquefaction Triggering Correlations

The differences between the liquefaction triggering correlations published by Seed et al. (1984) and those published more recently by Cetin et al. (2004) and those by Idriss and Boulanger (2004 , 2008) are examined in this paper. The case histories, which cause the Cetin et al. correlation of the cyclic resistance ratio, adjusted for M = 7.5 and σ v′ = 1 atm, to plot significantly lower than those by Seed et al. and Idriss and Boulanger, are examined in detail. The lower position of the Cetin et al. liquefaction triggering correlation is found to be primarily caused by their interpretations and usage for 8 of the 11 key case histories that had controlled the position of their liquefaction triggering correlation. When properly interpreted, these eight case histories no longer support the position of the published Cetin et al. liquefaction triggering curve.

Effective Stress Soil Model Calibration Based on In Situ Measured Soil Properties

AbstractNumerical analyses for soil structures under monotonic and cyclic loading using nonlinear models have developed rapidly in recent years. Effective stress-based soil models are incorporated in the analyses to predict soil deformation and/or liquefaction. However, in applications to engineering projects, model parameter calibration often becomes an obstacle to the practical use of the model because of the uncertainties and lack of appropriate laboratory test results. This article proposes a procedure to calibrate a soil model for simulating liquefaction and ultimate failure under monotonic and/or cyclic loading, using data based on in situ measurements in the standard penetration test (SPT). The ultimate failure state that limits soil dilation is based on the correlation of residual strength to void ratio, and the state-dependent dilatancy concept. A relationship between soil liquefaction resistance and equivalent number of cycles is developed based on published SPT-based liquefaction triggering cha...

Subsurface Characterization at Ground Failure Sites in Adapazari, Turkey

Ground failure in Adapazari, Turkey during the 1999 Kocaeli earthquake was severe. Hundreds of structures settled, slid, tilted, and collapsed due in part to liquefaction and ground softening. Ground failure was more severe adjacent to and under buildings. The soils that led to severe building damage were generally low plasticity silts. In this paper, the results of a comprehensive investigation of the soils of Adapazari, which included cone penetration test (CPT) profiles followed by borings with standard penetration tests (SPTs) and soil index tests, are presented. The effects of subsurface conditions on the occurrence of ground failure and its resulting effect on building performance are explored through representative case histories. CPT- and SPT-based liquefaction triggering procedures adequately identified soils that liquefied if the clay-size criterion of the Chinese criteria was disregarded. The CPT was able to identify thin seams of loose liquefiable silt, and the SPT (with retrieved samples) allowed for reliable evaluation of the liquefaction susceptibility of fine-grained soils. A well-documented database of in situ and index testing is now available for incorporating in future CPT- and SPT-based liquefaction triggering correlations.