Liquefaction-induced Ground Failure Research Articles

Developing region-specific fragility function for predicting probability of liquefaction induced ground failure

The liquefaction potential index (LPI) has been widely used to develop fragility function for predicting the liquefaction-induced ground failure. As the fragility function tends to vary from one region to another, it is best developed based on region-specific data. When the amount of region-specific data is limited, how to develop the region-specific fragility curve is a challenging problem. In this study, a hierarchical Bayesian model (HBM) is suggested for developing region-specific fragility functions based on LPI, which can systematically consider the effects of the amount and characteristics of the local data as well as the data from other regions. The suggested method is illustrated with an example. It is shown that the HBM outperforms the lumped parameter model (LPM) which does not consider the inter-region variability of the fragility curves. When the amount of region-specific data is large, the fragility function developed based on the HBM is very close to that developed based on the independent parameter model (IPM), which constructs a region-specific fragility function utilizing only the region-specific data. When the region-specific data is not enough, the HBM also outperforms the IPM through borrowing information from other regions.

Site response and liquefaction hazard analysis of Hawassa town, Main Ethiopian Rift

The study area is located in one of the most earthquake prone regions in southern Ethiopia, which is characterized by small-to-intermediate earthquake occurrences causing damage to buildings. Predicting liquefaction hazard potential and local site effects are imperative to manage earthquake hazard and reduce the damage to buildings and loss of lives. The objectives of this work were to perform the equivalent linear response analysis (ELA) and shear wave velocity (Vs.)-based liquefaction hazard analysis and classify the site into different seismic site classes based on the European and American codes. The SPT-N and Vs.30 values showed the site falls in the C and D classes based on the NEHRP (2015) code but falls in the B and C classes based on the EC8 (2003) code. The susceptibility of liquefaction was evaluated using grain size analysis curves. Moreover, peak ground acceleration (PGA), spectral acceleration (SA), and maximum strain (%), which are very critical to understanding the local site effects, were estimated by the DeepsoilV.7 program. The cyclic stress ratio and cyclic resistance ratio were used to calculate the factor of safety (FS). A liquefaction potential index (LPI), probability of liquefaction (PL), and probability of liquefaction induced ground failure (PG) were used to assess the probability of liquefaction. The peak ground acceleration (g) values ranged from 0.166 to 0.281 g, whereas spectral acceleration (g) was found to be high at 0.1–1s. The liquefaction susceptibility screening criteria revealed that the study area is highly susceptible to liquefaction. FS is < 1 for a liquefied site, but FS is > 1 for non-liquefied sites. In comparison to non-liquefied sites, the liquefaction forecast site has a liquefaction potential index value of 0–54.16, very likely high PL, and high PG. The findings will be helpful in the design of structures and in solving practical challenges in earthquake engineering.

Assessment of liquefaction potential in the central Po plain from integrated geomorphological, stratigraphic and geotechnical analysis

Large portions of the highly populated central Po Plain in northern Italy are susceptible to major liquefaction–induced ground failure and resulting damage, as illustrated by the 2012 Mw 5.6–5.8 earthquake sequence. Our work presents a comprehensive geomorphological, stratigraphic and geotechnical dataset from a 1012 km2 study area in the alluvial plain, analysed through the integration of different methodologies. For hazard reduction planning, we qualitatively and quantitatively assess liquefaction potential by the identification of three discrete geomorphological domains. Each geomorphological domain has variable Late Pleistocene to Holocene geological evolution, geotechnical characteristics and thus liquefaction susceptibility, as deduced from interpretation of three 25–m deep continuous cores and calculation of liquefaction potential based on the geotechnical analysis of 239 cone penetration tests (CPTs). For land use planning, we present this information at various map scales consistent with inherent uncertainties of data availability. The investigation procedures and geological–geotechnical interpretations may be applicable to similar liquefaction–prone areas elsewhere.

Fragility Functions for Liquefaction-Induced Ground Failure

AbstractThe predicted severity of liquefaction manifested at the ground surface is a popular and pragmatic proxy of damage potential for infrastructure. Toward this end, the liquefaction potential ...

Probability of Liquefaction induced Ground Failure under the Earthquake Scenario in Kathmandu Valley

Kathmandu valley is highly susceptible to liquefaction hazard due to the presence of liquefiable soil up to considerable depth, the presence of shallow ground water table and occurrence of earthquakes at regular intervals. Past studies have also shown the occurrence of liquefaction with examples of observed ejection of sand boil and formation of cracks throughout the valley during 1934 Nepal-Bihar earthquake. Events similar to these were also observed during recent 2015 Gorkha Nepal earthquake in twelve different locations within the valley. In this study, standard penetration test (SPT) based probabilistic model has been used taking 113 borehole logs data collected from within the valley to determine liquefaction-induced probability of ground failure under 2015 earthquake scenario with moment magnitude M w of 7.8 and peak ground acceleration of 0.16g.Calculations were done in MS Excel 2013 and results were plotted in ArcGIS 10.2 to produce liquefaction induced potential ground failure map.The result shows that 20.13%, 35.13%, 15.46%, 13.67% and 15.43% of the study area lie in very high, high, medium, low and very low risk of liquefaction hazard, respectively. About 83% of the observed liquefied locations after the earthquake were found in very high and high risk while the rests were found in medium risk of liquefaction hazard.

Modification of the liquefaction potential index to consider the topography in Christchurch, New Zealand

Abstract In recent years, many have mapped the liquefaction potential index (LPI) to describe the liquefaction hazard at regional scale. Several investigators have calibrated the LPI to field observations of liquefaction-induced ground failure after a number of major earthquakes; the significance of LPI values and their correlation with the severity of liquefaction-induced ground failure can vary greatly depending on the calibration. In this study, the LPI was computed at more than 1200 cone penetration test soundings across the Christchurch area, New Zealand, using peak ground accelerations from the 2011 Christchurch Earthquake. Based on detailed field observations of liquefaction-induced ground failure after the earthquake, it was shown that the LPI has potential for discriminating between areas with no liquefaction-induced ground failure hazard and areas that may experience liquefaction-induced ground oscillations and settlement; however, the LPI performed poorly at sites where severe ground failures occurred, especially at sites that experienced lateral spreading. As many researchers have found a positive correlation between lateral spreading and the proximity and depth of a nearby free-face (i.e., a steep topographic depression, river channel, etc.), a new LPI framework was proposed that includes a parameter named the free-face ratio (FFR). FFR was shown to have a significant correlation with field observations of lateral spreading in Christchurch. It was shown that by incorporating FFR into the LPI framework, modified LPI values are positively correlated with the severity of field observations of liquefaction-induced ground failure in Christchurch. It was also shown that maps can be produced based on LPI and FFR, and such maps rarely underpredict the liquefaction-induced ground failure hazard, unlike maps based on the unmodified LPI.

Assessment of earthquake-induced liquefaction hazard in urban areas of Hanoi city using LPI-based method

Assessment of earthquake-induced liquefaction hazard in urban areas of Hanoi city using LPI-based method

Earthquake induced liquefaction hazard, probability and risk assessment in the city of Kolkata, India: its historical perspective and deterministic scenario

Liquefaction-induced ground failure is one amongst the leading causes of infrastructure damage due to the impact of large earthquakes in unconsolidated, non-cohesive, water saturated alluvial terrains. The city of Kolkata is located on the potentially liquefiable alluvial fan deposits of Ganga-Bramhaputra-Meghna Delta system with subsurface litho-stratigraphic sequence comprising of varying percentages of clay, cohesionless silt, sand, and gravel interbedded with decomposed wood and peat. Additionally, the region has moderately shallow groundwater condition especially in the post-monsoon seasons. In view of burgeoning population, there had been unplanned expansion of settlements in the hazardous geological, geomorphological, and hydrological conditions exposing the city to severe liquefaction hazard. The 1897 Shillong and 1934 Bihar-Nepal earthquakes both of M w 8.1 reportedly induced Modified Mercalli Intensity of IV–V and VI–VII respectively in the city reportedly triggering widespread to sporadic liquefaction condition with surface manifestation of sand boils, lateral spreading, ground subsidence, etc., thus posing a strong case for liquefaction potential analysis in the terrain. With the motivation of assessing seismic hazard, vulnerability, and risk of the city of Kolkata through a consorted federal funding stipulated for all the metros and upstart urban centers in India located in BIS seismic zones III, IV, and V with population more than one million, an attempt has been made here to understand the liquefaction susceptibility condition of Kolkata under the impact of earthquake loading employing modern multivariate techniques and also to predict deterministic liquefaction scenario of the city in the event of a probabilistic seismic hazard condition with 10% probability of exceedance in 50 years and a return period of 475 years. We conducted in-depth geophysical and geotechnical investigations in the city encompassing 435 km2 area. The stochastically synthesized bedrock ground motion for both the 1897 and 1934 earthquakes on non-linear analysis of local site conditions through DEEPSOIL Geotechnical analysis package present surface level peak ground acceleration of the order of 0.05–0.14 g for the 1934 Bihar-Nepal earthquake while for the 1897 Shillong earthquake it is found to be in the range of 0.03–0.11 g. The factor of safety (FOS) against liquefaction, the probability of liquefaction (P L), the liquefaction potential index (LPI), and the liquefaction risk index are estimated under the influence of these two earthquakes wherein the city is classified into severe (LPI > 15), high (5 < LPI ≤ 15), moderate (0 < LPI ≤ 5), and non-liquefiable (LPI = 0) susceptibility zones. While the 1934 Bihar-Nepal earthquake induced moderate to severe liquefaction hazard condition in the city in mostly the deltaic plain and interdistributary marsh geomorphologic units with 13.5% sites exhibiting moderate hazard with a median LPI of 1.8, 8.5% sites depicting high with a median LPI of 9.1 and 4% sites with a median LPI of 18.9 exhibiting severe hazard condition, 1897 Shillong earthquake induced mostly non-liquefaction condition with very few sites depicting moderate and high liquefaction hazard. A conservative liquefaction hazard scenario of the city on the other hand estimated through deterministic approach for 10% probability of exceedance in 50 years predicts a high hazard zone in the 3.5–19 m depth region with FOS < 1 and P L > 65% comprising of coarse-grained sediments of sand, silty sand, and clayey silty sand in mostly the deltaic plain geomorphologic unit with 39.1% sites depicting severe liquefaction hazard with a median LPI of 28.3. A non-linear regression analysis on both the historical and deterministic liquefaction scenarios in P L versus LPI domain with ± 1 standard deviation confidence bound generated a cubic polynomial relationship between the two liquefaction hazard proxies. This study considered a bench mark for other cities in the country and elsewhere forms an integral part of the mega-seismic microzonation endeavors undertaken in all the earthquake-prone counties in the world.

Dynamic Analyses of Two Buildings Founded on Liquefiable Soils during the Canterbury Earthquake Sequence

AbstractA series of major earthquakes near Christchurch, New Zealand, produced different levels of liquefaction-induced ground failure and damage to multistory buildings in the city’s central busin...

Assessment of earthquake-induced ground liquefaction susceptibility for Hanoi city using geological and geomorphologic characteristics

Assessment of earthquake-induced ground liquefaction susceptibility for Hanoi city using geological and geomorphologic characteristics

Numerical investigation of the effects of geometric and seismic parameters on liquefaction-induced lateral spreading

Abstract The lateral movement of a liquefiable soil layer on gentle slopes is the most visible and devastating type of liquefaction-induced ground failure. Recent earthquakes have shown that this phenomenon causes severe damages to coastal structures, pier of the bridges and life-lines by exerting large lateral forces on the structures. In this paper coupled dynamic field equations of extended Biot's theory with u-p formulation are used for simulating the phenomenon and the soil behavior is modeled by a critical state two-surface plasticity model for sands. Furthermore, in this study variation of permeability coefficient during liquefaction is taken into account. The permeability coefficient is related to variation of the excess pore water pressure ratio. At first, two centrifuge tests on liquefiable sand which have gently inclined ground surfaces with different conditions are simulated and numerical results are compared with experimental observations. These comparisons showed that numerical simulations have very good consistency with experimental observations in modeling of excess pore pressures, lateral displacements, and surface settlements. After validation, the effects of different factors such as ground slope, thickness of the liquefiable layer, soil relative density, maximum acceleration of dynamic loading, frequency of input motion and number of load cycles are investigated on the amount of lateral displacement. At the end, by using the results of the conducted extensive parametric study, a new relation is proposed for estimating the magnitude of maximum lateral displacement. Comparison of the results of this equation with experimental records, field observations and other empirical relations shows the advantage of this equation over other previously proposed relations.

Effects of Ground Failure on Buildings, Ports, and Industrial Facilities

Soil liquefaction occurred at many sites during the 2010 Maule, Chile, earthquake, often leading to ground failure and lateral spreading. Of particular interest are the effects of liquefaction on built infrastructure. Several buildings were damaged significantly due to foundation movements resulting from liquefaction. Liquefaction-induced ground failure also displaced and distorted waterfront structures, which adversely impacted the operation of some of Chile's key port facilities. Important case histories that document the effects of ground failure on buildings, ports, and industrial facilities are presented in this paper.

Effect of Earthquake Induced Lateral Soil Movement On Pile Behavior

One of the most common causes of ground failure during earthquakes is the liquefaction phenomenon, which produces severe damage to property. Although methods are available for seismic analysis of pile foundations, most of them consider soil to be an elastic material. Collapse of piled foundations in liquefiable areas has been observed in most recent strong earthquakes despite the fact that a large margin of safety is employed in their design. Lateral spreading of gently-sloping deposits of liquefiable sand is a cause of much damage in earthquakes, reportedly more than any other form of liquefaction-induced ground failure. The present investigation finds the effect of earthquake induced lateral soil movement on lateral pile capacity. Parametric study is carried out on the same model by changing the ground surface to different slopes on the top of the non liquefiable layer and by changing the length of the pile in the bottom layer of the non liquefiable layer. The paper focuses on the behaviour of pile under lateral soil movement due to earthquake. The bending moment and displacement behaviour of pile is studied in detail for different slope conditions.

Assessment of liquefaction hazards in Charleston quadrangle, South Carolina

Abstract In this paper an improved method for evaluation of liquefaction hazard is presented. The liquefaction potential index developed by Iwasaki and his co-workers is modified using the concept of probability. The modified liquefaction potential index is then calibrated with field observation data, which yields an empirical equation for the probability of liquefaction-induced ground failure. The method and procedure is then employed to study the ground shaking level of the 1886 Charleston, South Carolina earthquake based on an analysis of liquefaction hazard in the Charleston peninsula. The results show that the ground shaking level of the 1886 event may be represented with moment magnitude Mw = 6.9 and peak ground surface acceleration amax = 0.2 g. Finally, the liquefaction hazard in the Charleston quadrangle is evaluated and mapped using the ground motion that corresponds to the 475-year return period. Details of this assessment, including limitation of the results, are presented.

Liquefaction potential index: A critical assessment using probability concept

Liquefaction potential index (IL) was developed by Iwasaki et al. in 1978 to predict the potential of liquefaction to cause foundation damage at a site. The index attempted to provide a measure of the severity of liquefaction, and according to its developer, liquefaction risk is very high if IL > 15, and liquefaction risk is low if IL ≤ 5. Whereas the simplified procedure originated by Seed and Idriss in 1971 predicts what will happen to a soil element, the IL predicts the performance of the whole soil column and the consequence of liquefaction at the ground surface. Several applications of the IL have been reported by engineers in Japan, Taiwan, and the United States, although the index has not been evaluated extensively. In this paper, the IL is critically assessed for its use in conjunction with a cone penetration test (CPT)-based simplified method for liquefaction evaluation. Emphasis of the paper is placed on the appropriateness of the formulation of the index IL and the calibration of this index with a database of case histories. To this end, the framework of IL by Iwasaki et al. is maintained but the effect of using different models of a key component in the formulation is explored. The results of the calibration of IL are presented. Moreover, use of IL is extended by introducing an empirical formula for assessing the probability of liquefaction-induced ground failure.

Estimating severity of liquefaction-induced damage near foundation

Abstract An empirical procedure for estimating the severity of liquefaction-induced ground damage at or near foundations of existing buildings is established. The procedure is based on an examination of 30 case histories from recent earthquakes. The data for these case histories consist of observations of the damage that resulted from liquefaction, and the subsurface soil conditions as revealed by cone penetration tests. These field observations are used to classify these cases into one of three damaging effect categories, ‘no damage’, ‘minor to moderate damage’, and ‘major damage’. The potential for liquefaction-induced ground failure at each site is calculated and expressed as the probability of ground failure. The relationship between the probability of ground failure and the damage class is established, which allows for the evaluation of the severity of liquefaction-induced ground damage at or near foundations. The procedure presented herein represents a significant attempt to address the issue of liquefaction effect. Caution must be exercised, however, when using the proposed model and procedure for estimating liquefaction damage severity, because they are developed based on limited number of case histories.

Liquefaction-induced ground failure: a study of the Chi-Chi earthquake cases

The 1999 Chi-Chi, Taiwan earthquake caused great destruction to buildings, bridges, and other facilities, and a death toll of more than 2400. Lessons should be learned from this event, which, albeit disastrous, represents a rare full-scale experimentation in geotechnical engineering and related fields. Of particular interest to geotechnical engineers is the phenomenon of soil liquefaction that caused significant damage to buildings, lifelines and harbor facilities. These liquefaction phenomena, in the forms of sand boils, lateral spreads, tilting and settlement of buildings, and ground settlement, were observed in the Chi-Chi event. Shortly after the earthquake, an extensive field investigation in the Yuanlin area, including in situ tests and laboratory tests, was conducted by Moh and Associates and other parties. These in situ and laboratory tests along with ground performance observations form the basis for the present study. In this paper, 24 cases of ground performance in the areas that suffered the most from liquefaction are studied. The ground performance in selected cases of the 24 cases is accounted for through a series of liquefaction analyses. The analysis of the potential of liquefaction and ground failure is performed using Cone Penetration Test (CPT) data. The results of the analyses show that the field observations of ground performance in the Yuanlin area in the Chi-Chi event can be accounted for satisfactorily using the evaluation procedure by Ishihara (Ishihara, K., 1985. Stability of natural deposits during earthquakes. Proc., 11th Int. Conf. on Soil Mechanics and Foundation Engineering, San Francisco, CA, vol. 1, pp. 321–376.).

The earthquake threat in southwestern British Columbia: A geologic perspective

Ten moderate to large (magnitude 6–7) earthquakes have occurred in southwestern British Columbia and northwestern Washington in the last 130 years. A future large earthquake close to Vancouver, Victoria, or Seattle would cause tens of billions of dollars damage and would seriously impact the economies of Canada and the United States. An improved understanding of seismic hazards and risk in the region has been gained in recent years by using geologic data to extend the short period of instrumented seismicity. Geologic studies have demonstrated that historically unprecedented, magnitude 8 to 9 earthquakes have struck the coastal Pacific Northwest on average once every 500 years over the last several thousand years; another earthquake of this size can be expected in the future. Geologic data also provide insights into the likely damaging effects of future large earthquakes in the region. Much of the earthquake damage will result directly from ground shaking, but damage can also be expected from secondary phenomena, including liquefaction, landslides, and tsunamis. Vancouver is at great risk from earthquakes because important infrastructure, including energy and transportation lifelines, probably would be damaged or destroyed by landslides and liquefaction-induced ground failure.

Liquefaction Analysis of the 1971 Ground Failure at the San Fernando Valley Juvenile Hall, California

A lateral spread seriously damaged the San Fernando Valley Juvenile Hall during the 1971 San Fernando earthquake. A subsurface investigation in 1981 was conducted using cone penetration and standard penetration tests to define the stratigraphy and to obtain samples and penetration data for a liquefaction analysis. The investigation showed that a loose layer of sandy silt and silty sand at a depth of approximately 4.5–5.5 m (14.8–18.0 ft) liquefied during the earthquake. The liquefaction zone is located in a layer of sediment estimated to be younger than 10,000 yrs. Sediment underlying the failure zone, which is estimated to be older than 35,000 yrs, is marginally to highly resistant to liquefaction-induced ground failure.

Mapping liquefaction-induced ground failure potential : Youd, T L; Perkins, D M J Geotech Engng Div ASCE, V104, NGT4, April 1978, p433–446

Mapping liquefaction-induced ground failure potential : Youd, T L; Perkins, D M J Geotech Engng Div ASCE, V104, NGT4, April 1978, p433–446