Liquefaction Analysis Research Articles

GIS based geotechnical and geological information for liquefaction analysis of Chiang Mai basin

GIS based geotechnical and geological information for liquefaction analysis of Chiang Mai basin

Stochastic analysis of the seismic performance of sheet-pile walls supporting heterogeneous liquefiable ground

This paper presents the findings of a stochastic analysis conducted to evaluate the effects of the spatial soil variability and temporal base motion variability on the seismic response of sheet pile walls supporting liquefiable ground. A random finite element analysis is used to model the centrifuge experiment performed during the 2020 phase of the Liquefaction Experiments and Analysis Project (LEAP). The relative density of the main soil deposit in the LEAP-2020 experiments ranged from 50 to 75 %. In this study the spatial variability of each centrifuge model was determined from the inflight cone penetration tests (CPT) performed before the shaking phase in each experiment. The vertical spatial correlation length was directly determined from the CPT measurements, while the mean and coefficient of variation of the soil relative density were obtained from an empirical relationship correlating the cone tip resistance with the relative density. The variability observed in the achieved base motions for the LEAP-2020 centrifuge experiments was modeled by generating synthetic base motion time histories that matched the variability observed in the response spectra of the achieved base motions. The results obtained from this analysis shed light on the effects of the base motion variability and soil density on the excess pore pressure development and the triggering of soil liquefaction. It also provides an understanding on the sensitivity of the wall lateral displacement to such variabilities. The observed variability in the simulation response is compared with the variability observed in the centrifuge experiments. This comparison is used to evaluate the capability of the current numerical simulation tools in modeling the variability in the wall response.

Techno-economic analysis of hybrid liquefaction and low-temperature adsorption carbon capture based on waste heat utilization

The techno-economic analysis of CO2 capture is important to determine its economic feasibility and its application to hybrid CO2 capture systems urgently needs more attention. This research conducts a techno-economic analysis of a hybrid CO2 system in which the waste energy and uncaptured CO2 from liquefaction are supplied to low-temperature adsorption to enhance the overall energy efficiency. Here, the process and energy models are coupled with the cost analysis model to estimate the capital cost, operational cost, and levelized cost of CO2 capture (LCOC) of the hybrid system. A series of parametric analyses are conducted to determine how the hybrid system's LCOC can be minimized. Results indicate the heat pump has the highest capital cost and is 4 times the compressor because it needs to satisfy the large cooling energy requirement. Moreover, the adsorbent mass exhibits a trade-off between a higher CO2 recovery rate and lower LCOC value due to increasing costs. Ultimately, based on 12.5 % CO2 partial pressure 1 kg/s flue gas, a liquefaction temperature of −48.15 °C, a desorption temperature of 92.5 °C, and operating pressure of 6 MPa, a comparable LCOC of 106.19 $ per tonne CO2 is yielded by the hybrid system.

Soil moisture-based global liquefaction model (SMGLM) using soil moisture active passive (SMAP) satellite data

The role of soil saturation condition on the liquefaction occurrence highlights the need for a tool to track the ground-truth soil moisture content involved in this seismic phenomenon. Soil Moisture Active Passive (SMAP) satellite estimates near-real time surface and root zone soil moisture measurements with global coverage. Typical proxies for soil saturation in liquefaction analysis include average water table depth patterns, mean annual precipitation measurements, and topographic conditions. As an alternative to these proxies, this paper incorporates satellite-based soil moisture data to enhance the understanding of the interrelation between saturation conditions and liquefaction events. Proposing a new approach for sampling non-liquefaction cases, a liquefaction/non-liquefaction database was developed in this paper based on reconnaissance reports of eleven target earthquakes. Well-known geospatial explanatory variables as well as new SMAP-based soil moisture parameters, affecting soil liquefaction, are used to develop a new soil moisture-based global liquefaction model (SMGLM), which is compared with an existing global liquefaction model. Considering the ongoing advancement of earth observing satellites, the results of this paper can build a basis for developing fully satellite-based models that could identify liquefied sites using high resolution near-real time soil moisture data.

Liquefaction of industrial zone against earthquake loading using laboratory and field measurements

Purpose. To assess the liquefaction of Kirkuk’s industrial region following a series of earthquakes that struck the city during the previous five years based on the current earthquake activity in the region. Methodology. Initially, substantial relationships for shear wave velocity in different types of soil were collected and studied, where the majority of these correlations necessitated the use of standard penetration tests in the field. Indeed, two boreholes were drilled up to a maximum depth of 10 m, and the numbers of blows for conventional penetration tests were measured at various depths in each borehole. The stated shear wave velocity values from the literature, as well as the maximum and lowest shear wave velocity constraints, were employed in a simple technique to estimate the cyclic shear stress induced by earthquake loading. Findings. Based on laboratory and field data, the safety factor against earthquake-induced liquefaction can be determined. When the worst-case scenario was examined using the suggested values of shear wave velocity, the factor of safety against earthquake was reduced by 94 % as the depth increased from 3.5 to 9 m. Originality. No previous study has tried to quantify the liquefaction impact of industrial zone of Kirkuk city as such an important rich-oil area was influenced by series of earthquakes occurrence. More importantly, for the first time field soil samples from on-site boreholes in Kirkuk city have been collected and used for liquefaction assessment since such real field data can be utilized properly in liquefaction evaluation process in the absence of any comparable quantification for the investigated area. Practical value. Precious liquefaction analysis should be performed prior to any proposed project construction in the light of increased earthquake activity in the industrial zone in Kirkuk city (Iraq).

Comparison and analysis of four advanced bounding surface models

The accuracy of the constitutive model affects the precision of the finite element analysis. Four advanced sand constitutive models—the DM04 model, the SANISAND-MS model with memory surface (MS), the SANISAND-Sf model with semi-fluidized state (Sf), and the SANISAND-MSf model with both memory surface and semi-fluidized state—are examined in this article based on a comparison of simulation and experiment results of element tests. First, four constitutive models are implemented in OpenSees, and the constitutive models are calibrated based on the cyclic loading experiments of Karlsruhe fine sand. After that, the advantages and disadvantages of four constitutive models under different test conditions are analyzed. Finally, the finite element model of the LEAP-UCD-2017 (Liquefaction Experiments and Analysis Project, University of California Davis, 2017) centrifuge test is established to evaluate the performance of the four constitutive models for solving boundary value problems. It is found that the SANISAND-MSf model can well reproduce the undrained cyclic properties.

Liquefaction analysis of sand-tire mixture with a critical state two-surface plasticity model

Liquefaction analysis of sand-tire mixture with a critical state two-surface plasticity model

Probabilistic-based seismic fragility assessment of earthquake-induced site liquefaction

As a very complex and uncertain problem, seismic liquefaction is affected by many factors, such as earthquake intensity, site conditions, soil properties, etc. During the past half a century, the state-of-the-art in analysis and evaluation of earthquake-induced soil liquefaction and its consequences as well as the state-of-the-practice in improving seismic stability to resist liquefaction have been made much progress. However, the fragility analysis and assessment for seismic liquefaction of sites have not been paid enough attention to. In this paper, the concept of seismic liquefaction fragility for building sites is proposed. The soil resistance to liquefaction and liquefaction possibility are expressed as a fragility function of ground motion intensity, which can be used to describe minor, moderate and severe liquefaction potential under different ground motion intensity. Combined with the existing research results of seismic liquefaction evaluation, the analysis method of liquefaction fragility is given. Taking a specific site as an example for liquefaction fragility analysis, it is found that taking the calculated exceedance probability of different liquefaction levels as the observation value, the liquefaction fragility function follows both lognormal distribution and log-logistic distribution. With the increase of liquefaction level, the median value of liquefaction fragility function increases, while the site liquefaction fragility curve moves to the right, which shows that the ability of the site to resist more severe liquefaction is increasing. When convolved with the analysis results of liquefaction triggering and hazard, the liquefaction fragility function can be a much efficient tool for seismic liquefaction risk analysis of specific sites.

Liquefaction susceptibility using machine learning based on SPT data

Assessing the potential for liquefaction using traditional experimental or empirical analysis procedures is both time-consuming and arduous. Employing a machine learning model that can accurately predict liquefaction potential for a specific site can reduce the time, effort, and associated costs. This study proposes several empirical machine learning models, including deep neural network (DNN), convolutional neural network (CNN), recurrent neural network (RNN), long short-term memory (LSTM), and bi-directional long short-term memory (BILSTM), to assess the liquefaction potential of soil deposits based on SPT-based post liquefaction datasets. To train the proposed models, a dataset comprising 834 liquefied and non-liquefied cases was collected to perform the liquefaction analysis. A Pearson correlation matrix was also conducted to examine the correlation between soil and seismic parameters and the probability of liquefaction. Furthermore, a sensitivity analysis was adopted to assess the impact of soil and seismic parameters on the probability of liquefaction. The proposed model's prediction capability was assessed using several performance indices, including rank analysis, accuracy matrix, and AIC criteria. The comparative analysis of the proposed models' predictive ability to determine liquefaction probability revealed that the RNN model outperformed the others, displaying the highest accuracy and lowest error index values. Subsequently, the RNN model achieved the first rank with a total score value of 70, followed by the CNN (55), DNN (52), BILSTM (47), and LSTM (16) models. The parametric analysis, rank analysis, accuracy matrix, and AIC criteria collectively demonstrate the proposed models' ability to predict liquefaction probability. Furthermore, the robustness of these models was assessed through external validation and comparative analysis.

Techno-economic analysis and optimization of green hydrogen production and liquefaction with metal hydride storage

A techno-economic analysis and three-objective optimization are reported for a system that uses a renewable energy source (RES) for hydrogen production and liquefaction in which all the produced hydrogen enters the liquefaction cycle. The system works in three phases; hydrogen liquefaction, hydrogen storage and fuel cell power generation. Every second, the mass of produced hydrogen from the electrolyzer is calculated and immediately injected into the liquefaction cycle. This happens for 3600 s during each hour and for 12 h during the day. To reduce the execution time and increase the accuracy, six different artificial neural network (ANN) models have been used, which are optimized using genetic algorithm (GA). Decision variables for optimization include solar irradiation intensity, ambient temperature, heat exchanger efficiency, and isothermal compressor output pressure. The objective functions are chosen to be total exergy efficiency, liquefaction efficiency, and total cost rate, and the optimal values of the objective functions are found to be 19.3%, 19.8%, and 10.6 $/hr, respectively. The objective functions are illustrated in terms of daily time, as well as decision variables. Also, the effect of liquefaction efficiency and specific work consumption on liquefaction cycle parameters and electrolyzer temperature have been investigated. The results show that in the range of compressor output pressure between 5 and 15 MPa, for every n % increase in heat exchanger efficiency, the liquefaction efficiency increases by (n/2) % and the amount of liquid hydrogen production at steady-state becomes 0.162 kg/h. It is also found that if the storage system is turned off and all the produced power is given to the liquefaction system, the mass of liquefied hydrogen will increase by 17% at the end of the day.

Assessment of Liquefaction Hazard for Sites in Romania Using Empirical Models

This paper is focused on the evaluation of the liquefaction hazard for different sites in Romania. To this aim, a database of 139 ground motions recorded during Vrancea intermediate-depth earthquakes having moment magnitudes MW ≥ 6.0 is employed for the evaluation of the equivalent number of cycles for this seismic source. Several functional forms for the empirical evaluation of the equivalent number of cycles considering various seismological or engineering parameters are tested and evaluated. The regression analysis shows smaller uncertainties for the empirical models based on ground motion engineering parameters. Considering the lack of information in terms of engineering parameters, a simpler empirical model which accounts for the earthquake magnitude, source–site distance and soil conditions is selected for the liquefaction hazard analysis. Based on the proposed empirical model, specific magnitude scaling factors for Vrancea intermediate-depth earthquakes are proposed for the first time as well. The liquefaction hazard analysis is performed for sites whose seismic hazard is generated by either the Vrancea intermediate-depth seismic source or by local shallow crustal seismic sources. In the case of some of the selected sites, liquefaction phenomena were observed during past large-magnitude earthquakes. Unlike previous studies dealing with liquefaction analyses for sites in Romania, in this research, the hazard assessment is performed for various ground motion levels evaluated based on probabilistic seismic hazard assessment. Liquefaction hazard curves are constructed for each analyzed site. The results of the liquefaction hazard analysis show that this phenomenon is more likely to occur in the areas exposed to Vrancea intermediate-depth earthquakes, compared to the areas affected by local shallow earthquakes. In the case of the analyzed soil profiles from Bucharest, Craiova and Ianca, the minimum liquefaction safety factors less than one even for seismic hazard levels having mean return periods of 100 years and less.

Comparison Between Liquefaction Potential Index And Liquefaction Risk Index In Solo – Yogyakarta – YIA Kulon Progo Toll Road (STA. 07+500 – STA. 16+700)

The construction of Solo – Yogyakarta – YIA Kulon Progo Toll Road aims to facilitate community economic connectivity from various sectors and increase the accessibility of tourism around southern Java. This research area has geological conditions consisting of tuff (volcanic ash sand) and shallow groundwater, which can trigger liquefaction. Historical earthquake data from The IRIS Earthquake Browser showed that an earthquake with Mw 5.2 occurred in Klaten Regency. This study investigated the index of potential liquefaction and the risk of ground failure potential due to liquefaction. The potential liquefaction analysis uses 10 SPT points at STA. 07+500 – STA. 16+700. The calculation safety factor of liquefaction analysis uses the method of Idriss-Boulanger. The index of liquefaction potential uses the LPI method, and the risk of ground failure potential due to liquefaction uses the LRI method. The result of this study shows the index of potential liquefaction and risk of ground failure potential due to liquefaction from low to very high. The correlation between the index of liquefaction potential and the risk of ground failure due to liquefaction is linear. Based on this study, further research is needed regarding liquefaction mitigation to be carried out in this study area.

Analytical Study on Ground Behavior During the 2018 Sulawesi Earthquake, Indonesia

The 2018 Sulawesi earthquake, Indonesia, caused long-distance ground flow in several areas in Palu city, about 80 km south of the epicenter, with the largest area reaching about 3.5 km × 1.5 km. The common feature of the long-distance ground flow area is that the slope of the ground surface is gentle. In this study, we aim to clarify the mechanism of the long-distance ground flow by using seismic response analysis and simplified liquefaction analysis. Three sites with different damage conditions will be targeted. Then, a one-dimensional soil column model is created from the boring log, and the response characteristics are analyzed by seismic response analysis. Also, a geological survey of the site confirmed that there are mountains of 2000 m in height around the site, thus water easily accumulates in the alluvial fan under the mountains. It is also assumed that pressurized groundwater exists. There are some possible causes of the flow: one is the formation of an aquifer beneath the surface layer, which may have initiated the flow; the other is the liquefaction from the surface layer to the cap layer, which may have caused the cap to come off and pressurized groundwater to be ejected, leading to long-distance ground flow. In this study, we consider the liquefaction of the surface layer, and the large relative displacement between the cap layer and the layer below it created water paths, and the pressurized groundwater is supplied continuously to the upper layer through the water paths. As a result, in terms of ground seismic response analysis results, shear strain and relative displacement were larger at the damaged point, but no remarkable results were obtained. However, in the simple liquefaction analysis, it was suggested that the liquefaction layer increased when the pressure is taken into account, leading to long-distance ground flow.

The Analysis of Liquefaction Potential and Post-Liquefaction Deformations at a Highway Bridge Crossing

The primary goal of this study is to geotechnically analyze the soil strength and liquefaction potential of the soil where the Seyrek highway junction and the bridge are built under earthquake-related dynamic stress. The analyses include comparisons of liquefaction potential using various empirical approaches, studies of post-liquefaction vertical deformation, and investigations into the influence of fill soil on liquefaction-induced surface deformation. Since the analyses of liquefaction potential in soils are made based on the "Simplified Method" approach, this method was also used in this study. This study also used the "Simplified Method" approach, which is the basis for studies of soil liquefaction potential. Four standard penetration tests (SPT) on the bridge piers were used to collect field data, and experiments in the lab were used to establish the requisite soil parameters. When the results of the Simplified Method analysis were performed according to the soil properties of the SK-1, SK-2, SK-3, and SK-4 drillings and the liquefaction analysis results were determined according to the required safety factor (Fs), liquefaction potential up to 18.5 meters was determined in all four SPT locations. Moreover, the results of surface damage effect analyses of the non-liquefied cover/fill layer on the Seyrek crossing bridge soil for all four SPP fields were found to be 'visible" and the liquefiable layer thickness (H2) was found to be 10.5 m. The calculated liquefaction severity index (LS) value was found to be up to 52, which means the liquefaction effect was found to be 'Possible liquefaction damage'.

Probabilistic Liquefaction Assessment Based on an In-situ State Parameter Considering Soil Spatial Variability and Various Uncertainties

The state parameter (ψ) is based on a framework of critical state soil mechanics, which reflects the influences of soil compactness and stress level and has significant advantages for liquefaction analysis. In engineering practice, a simplified procedure based on the cone penetration test (CPT) to assess the liquefaction potential in the field involves model and parameter uncertainties. Furthermore, the use of limited CPT measurements involves project-specific test uncertainties, and the spatial variability of soil properties has a remarkable effect on soil liquefaction. To tackle these challenges, this study develops a ψ-based liquefaction probability framework to integrate the prior information of project-specific CPT, and uses limited tests to characterize the 2D spatial distribution of liquefaction potential with proper consideration of various uncertainties and soil spatial variability. The framework is developed based on simulation of Gaussian stationary random fields and Markov Chain Monte Carlo simulation. The proposed method is demonstrated using real CPT data from the 2011 Tohoku-Oki earthquake in Japan. The results indicate that the ψ-based evaluation performs well and can reasonably assess the liquefaction phenomenon of heterogeneous soils. This study incorporating the spatial variability of ψ into the liquefaction probability framework provides valuable information for geotechnical engineering design.

Process analysis and optimization of high-N2 natural gas liquefaction

The demand for natural gas (NG) is increasing rapidly due to the world energy crisis. Liquefied Natural Gas (LNG) technology is one of the most flexible and reliable supply solutions, which has already been a major research hotpot in energy use. However, NG with high-N2 content lowers the gas calorific value and value of the gas and increases the energy consumption for production and transport. To address this issue, this study established nitrogen removal from the NG process using a single-column cryogenic distillation process based on Aspen HYSYS® in this study. An expanding refrigeration process using N2-CH4 was selected to provide the required cold energy for this plant, and the process power consumption and LNG specific power consumption was used as evaluation indicators. Results from sensitivity analysis showed that by the increase of natural gas feed temperature T1, the distillation column operation pressure Pc, and refrigerant high pressure P3, the LNG specific power consumption also demonstrated an increasing trend. The variables of natural gas inlet pressure P1, the outlet temperature of natural gas from pre-cooler T2, the ratio of return RR, the methane content ZCH4, the temperature of refrigerant after pre-cooler T4 and refrigerant low pressure P5 had a negative impact on the LNG specific power consumption. After conducting an optimization algorithm, the minimum LNG specific power consumption was determined to be 56.17 kJ/mol. Exergy analysis demonstrated that the total exergy destruction was 2076.13 kW. The compressor and expander components accounted for 31.57% and 26.29% of the total exergy losses respectively. This research provides valuable insights into optimizing LNG production processes by mitigating the impact of high nitrogen content, and it contributes to the advancement of LNG technology and energy efficiency in the industry.

Liquefaction analysis of soil plugs within large diameter monopiles using numerical modelling

AbstractSoil plug formation in open-ended piles due to pile driving is a widely studied phenomenon in onshore applications. The narrow diameters of traditional onshore piles ranging from 0.5 to 1.5 m facilitate plug generation during installation and transfer of enhanced confining stresses across the whole body of the soil plug. Offshore wind monopiles with larger diameters and smaller aspect ratios may not enhance confining stress within the soil plug as effectively as their onshore counterparts. Monopiles are currently the most widespread foundation in the offshore wind sector including in seismic areas. Earthquake shaking can lead to accumulation of excess pore pressure and subsequent liquefaction of the soil retained inside the plug. This research investigates the influence of monopile diameter and confining stress on the development of earthquake-induced excess pore pressure within the soil plug using fully coupled time domain Finite Element Analysis. The results presented in this paper reveal lower accumulation of earthquake-induced excess pore pressure in soil plugs subjected to confining stress. However, the influence of additional horizontal stress caused by monopile driving on the generation of excess pore pressure within the soil plug diminishes as the monopile diameter is progressively increased.

A novel peridynamic solution for modelling saturated soil-pore fluid interaction in liquefaction analysis

Saturated soil-pore fluid interaction under earthquake shaking can cause extensive damages to critical infrastructure systems. As such, accurate modeling of saturated soil-pore fluid interaction and its consequences (e.g., seismically-induced large deformation) are of particular importance for liquefaction analysis. Peridynamics (PD) has emerged as an effective method for solving large deformation problems by overcoming the disadvantage of finite element method caused by mesh dependency. However, the PD has not been extended to model soil-pore fluid interaction, limiting its application in liquefaction analysis. To bridge this gap, a novel solution strategy is presented for modeling soil-pore fluid interaction (i.e., the u-p equations herein) in liquefaction analysis of saturated granular soils, based on a hybrid PD (HPD) method recently proposed by the authors and co-workers. An explicit-explicit method is used to solve the coupled u-p equations. Liquefiable soil on level and sloped ground are analyzed and compared with experimental data and finite element simulations to validate availability and efficiency of the method, demonstrating the method to be effective in solving the soil-pore fluid equations and applicable to a broad range of geotechnical earthquake engineering problems associated with liquefaction.

Study on the dynamic pore water pressure model of centerline tailings sand based on dynamic triaxial tests

The increase of pore water pressure under a dynamic load is an important reason for the vibration liquefaction of saturated sand. Therefore, studying the dynamic pore water pressure model of tailings sand plays an important role in the seismic liquefaction analysis of tailings ponds. In this paper, the dynamic pore water pressure development characteristics of tailings fine sand and tailings silt in a tailings pond with the centerline method are studied by dynamic triaxial tests. The research results show that the liquefaction dynamic pore pressure ratio of tailings fine sand shows a trend of "rising–smooth–rising" with increasing vibration frequency ratio, and the liquefaction dynamic pore-pressure ratio of tailings silt shows an approximate linear and stable increasing trend. According to the development law of dynamic pore pressure, a new tailings sand pore pressure stress model is proposed in this paper, and the fitting effect is compared with four different pore pressure models, which verifies the applicability of the new model to predict the growth of dynamic pore pressure in tailings and silt.

Estimating of Post-liquefaction Settlement Based on SPT Data in Klaten Regency, Central Java

A strong earthquake with Mw 6.3 occurred in Yogyakarta on May 27, 2006, causes of damage to DI Yogyakarta Province and Central Java Province, including Klaten Regency. The geological stratigraphy consists of volcanic breccias, lava and tuff in this area and generally shallow groundwater levels, which can trigger liquefaction. The potential liquefaction analysis in this study uses Standard Penetration Test (SPT) data carried out in 3 districts, namely Delanggu, Polanharjo, and Karanganom District uses Idriss-Boulanger method. The peak ground acceleration was calculated by Next Generation Attenuation (NGA) method using data obtained from the Pacific Earthquake Engineering Research (PEER) Center database. The peak ground acceleration that causes liquefaction in this study is at least 0.29 g in bedrock. All areas indicated potential liquefaction with varying depths. Polanharjo District is the most susceptible to potential liquefaction. The method proposed by Zhang estimates post-liquefaction settlement in this study from 3.3 – 42.4 cm (light to extensive damage) in Klaten Regency. Based on the results, further mitigation studies are needed in Klaten Regency to minimize settlement that will occur due to liquefaction. This study is required in planning the construction of toll road in Klaten Regency.