Papers by Keyword: Soil Liquefaction

Abstract: Pacitan City, the capital of Pacitan Regency is located at the southern part of East Java Province. This area is facing directly to the earthquake source due to plates subduction between Indo-Australia and Eurasia plates. Southern part of this City is coastal resort area which is geologicaly consists of alluvial deposits that is still under compaction and some of the upper layers are consist of loose material. According to the condition, this area is vulnerable to the earthquake induced soil liquefaction. Five soil borings and 30 cone penetration tests were conducted in this study area to investigate soil properties for evaluating soil liquefaction. Severity of the potential surface damages due to liquefaction were identified by calculating Liquefaction Potential Index (LPI). The results show that study area is vulnerable to soil liquefaction, with potential damage severity vary from very low to very high. Medium to high severity of potential damage are distributed in almost area of the city, and only in the southern part close to the coast line have very high severity level.

Abstract: On the basis of Virtual Work, in this paper, the formulae are deduced for the floatation response of buried pipeline duo to the soil liquefaction. A beam model based on the theory of beam on elastic foundation is used for the pipeline buried in non-liquefied and liquefied area, considering the effects of nonlinear soil constraint and the initial deformation, the length of liquefied area, and the axial force acting on the pipeline. The study of floatation response of buried pipeline are conducted using the nonlinear increment element method, some results are given.

Abstract: In this paper, the formulae are deduced for the floatation response of pipeline buried in liquefied soil. The beam model based on the theory of beam on elastic foundation is used for the pipeline buried in non-liquefied and liquefied soil. The soil property is nonlinear, the floating force induced by the soil liquefaction is related to the position of pipeline, is nonlinear also. For the convenience and simplification of analysis, the nonlinear increment element method was used and lots of numerical analysis was conducted, including: the floatation response of pipeline buried in homogeneous soil, the floatation response of pipeline buried in non-homogeneous soil, and the floatation response of pipeline buried in discontinuous liquefied area. The influential factors on the floatation response of buried pipeline buried in liquefied soil including spring stiff of liquefied soil, the initial deformation, the length of liquefied area, the axial force acting on the pipeline, the material of pipeline, and the diameter of pipeline. The calculation results of discontinuous liquefied area draw a significant conclusion that for a long liquefied area, to make the soil non-liquefied in the middle of liquefied area may decrease the length of liquefied area and reduce the flotation displacement of pipeline greatly.

Abstract: By collecting the China mainland liquefied survey record, analyzed the constitution of the SPT data. Have an in-depth understanding of the SPT liquefaction discrimination model in the Code of Seismic Design of Building in China. Reviews the development and evolution of the discrimination formula in the seismic code, and analyzed the results of the methods adopted in seismic codes of different versions by liquefaction survey data in mainland China, then discuss the reliability and feasibility of the current code. Eventually provide support for the amendments to the specification liquefaction method of our country.

Abstract: On the basis of fluid-structure-interaction of the liquefaction soil, pipeline and the conveying fluid, in this paper, the differential vibration equations of the buried pipeline are deduced. The differential quadrature method (DQM) was tried to use to analyze the natural frequency of buried pipeline in liquefaction soil under the effect of flow velocity, fluid density, pressure in pipe, viscosity of pipe, axial force, elastic coefficient of the soil. Some preliminary conclusions concerning with the natural frequency of buried pipeline are also obtained. The theoretical research of the seismic effect on the pipeline in the liquefaction soil is presented.

Abstract: A discrimination model for soil liquefaction is established by analyzing the liquefied and non-liquefied sites in the Bachu Xinjiang earthquake, based on 44 shear wave velocity data. One of them is based on the Code for seismic design of buildings, which is a linear model. The model is brief and convenient, while the evaluation success rate is 80%. But compared with the nonlinear model, the linear model is not advanced enough. The other model is based on probability analysis, and the evaluation success rate can reach up to 93%. And the discrimination results are high in reliability rely on real data analysis.

Abstract: Based on survey of the Bachu-Jiashi earthquake liquefaction sites, much new basic liquefaction information were obtained and China’s liquefaction database was enriched. A detailed investigation of the Bachu earthquake liquefaction site was conducted, in which three kinds of in situ test measures were used to obtain the site information, and given China mainland SPT data of liquefaction site increase by 40%. By site investigation, international standard liquefaction site CPT data were obtained, and also, the first measurement of liquefaction site data by SPT and CPT index was conducted. With the new data, the feasibility of liquefaction discrimination methods of China was inspected.

Abstract: The Taipei Basin in Taiwan is an extremely special case under the constraints of environmental conditions. Pumping of groundwater in the basin was banned in 1968 due to the land subsidence. Since then, groundwater level in the Taipei basin has risen over the years and the land subsidence has also stopped. However, due to the continuous rise of groundwater level, the soil liquefaction potential of saturated sand soil strata has increased. Thus, the groundwater in Taipei basin should be controlled based on the suitable groundwater level to reduce the possibility of land subsidence or soil liquefaction. This study proposes a novel performance of groundwater management model, which considers the three aspects of safe yield, soil liquefaction, and land subsidence. In this process, a three-dimensional groundwater numerical model is primarily established with MODFLOW, and the safe yield and groundwater level are deduced through the Hill method. The second part requires an estimation of the soil liquefaction potential by applying the Seed97 method. The third part of the process includes an estimation of the subsidence of sand by adopting the Ishihara method and the subsidence of clay blanket through the Terazaghi method. Finally, combine the limited groundwater level through the application of the said methods, the proper scope for the level of groundwater in the Taipei Basin is then estimated. Hence, the maximum amount of groundwater that can be pumped could be estimated based on the suitable lower limit of groundwater level, and the minimum amount of groundwater that can be pumped could be estimated based on the suitable upper limit of groundwater level. The study result indicates the central region in the basin has a high potential of soil liquefaction, while the periphery of the basin has a high potential for land subsidence. In consideration of three environmental limited constraints, namely, safe yield of groundwater, soil liquefaction, and land subsidence, could estimate the maximum groundwater amount that can be generated per annum is about 0.77x109m3 to 1.03x109m3, while the minimum groundwater amount per annum is about 0.53x 109m3 to 0.71x109m3.

Abstract: The serious soil liquefaction phenomenon in Bachu-Jiashi earthquake on 24th February, 2003, which is the most prominent phenomena of sand liquefaction since the Tangshan Great Earthquake in 1976. Based on the earthquake liquefied investigation, inspect SPT and CPT applicability in situ tests. The results show that our country SPT specification and CPT specification of non-liquefied sites evaluation rate is higher than liquefied sites evaluation success rate, the liquefied sites evaluation rate are 88% and 88% respectively, but for liquefied sites evaluation rate are 38% and 55%. The result is tends to danger and the reason need further investigation, so establish a suitable liquefied prediction method should be to the future work in the local area.

Abstract: Soil liquefaction is extremely detrimental to the Central Henan transit railway line project. The present study proposes a preliminary design to evaluate the effects of liquefaction and to determine the parameters and protective measures that need to be implemented. The geological properties, clay content, groundwater level, and the thickness of the overlying non-liquefied soil were initially determined. Then, a standard penetration test was employed to analyse the soil liquefaction potential in an iron mine in the Central Henan rail transport project. The evaluation of similar engineering project sites with middle-class areas vulnerable to liquefaction is important to determine the necessary anti-liquefaction measures.