Md Abdul Lahil Baki , Misko Cubrinovski , Mark Edward Stringer , Sjoerd van Ballegooy , Nikolaos Ntritsos
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The Skempton’s <em>B</em>-value and P-wave velocity were comparatively used as measures for partial saturation in the laboratory. <em>B</em>-value - <em>V</em><sub>p</sub> relationships from the test results indicate that <em>V</em><sub>p</sub> steadily increases with the <em>B</em>-value until a threshold <em>B</em>-value is reached beyond which <em>V</em><sub>p</sub> remains unchanged at values indicating full saturation, i.e. <em>V</em><sub>p</sub> ;≥ ;1600 ;m/s. In general, the liquefaction resistance of tested sand and silty sand increases with a decrease in the <em>B</em>-value or <em>V</em><sub>p</sub>, i.e. with a reduction in the degree of saturation. Furthermore, test results suggest existence of threshold <em>B</em>-values and <em>V</em><sub>p</sub> for tested soils beyond which no significant increase in the liquefaction resistance was observed. This threshold B-values and <em>V</em><sub>p</sub> were found to be dependent on soil type and applied confining stress. The effects of partial saturation on liquefaction strength are different for the sand and silty sand when using <em>V</em><sub>p</sub> as a measure for the degree of saturation. While a gradual rate of increase in liquefaction strength with decreasing <em>V</em><sub>p</sub> is observed for the tested sand, the liquefaction strength of silty sand shows similar gradual increase with a decrease in <em>V</em><sub>p</sub> up to about 800 ;m/s, which is then followed by an abrupt increase in the liquefaction strength for <em>V</em><sub>p</sub> ;< ;800 ;m/s. Generally good agreement between liquefaction strength of tested soils and published data was observed, with a clear distinctive feature in the behaviour of the silty sand as compared to clean sands.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.3000,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0038080623001294/pdfft?md5=b059019dbce97716f05cff9874f7134a&pid=1-s2.0-S0038080623001294-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Effects of partial saturation on the liquefaction resistance of sand and silty sand from Christchurch\",\"authors\":\"Md Abdul Lahil Baki , Misko Cubrinovski , Mark Edward Stringer , Sjoerd van Ballegooy , Nikolaos Ntritsos\",\"doi\":\"10.1016/j.sandf.2023.101400\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The liquefaction resistance of partially saturated soil was experimentally investigated for one clean sand and one silty sand collected from a site in Christchurch, in an area severely affected by liquefaction in the 2010–2011 Canterbury earthquakes. A series of cyclic undrained tests were performed on fully and partially saturated sand and silty sand specimens, in conjunction with evaluation of saturation conditions in situ based on comprehensive field measurements of P-wave velocity (<em>V<sub>p</sub></em>) in Christchurch deposits. The Skempton’s <em>B</em>-value and P-wave velocity were comparatively used as measures for partial saturation in the laboratory. <em>B</em>-value - <em>V</em><sub>p</sub> relationships from the test results indicate that <em>V</em><sub>p</sub> steadily increases with the <em>B</em>-value until a threshold <em>B</em>-value is reached beyond which <em>V</em><sub>p</sub> remains unchanged at values indicating full saturation, i.e. <em>V</em><sub>p</sub> ;≥ ;1600 ;m/s. In general, the liquefaction resistance of tested sand and silty sand increases with a decrease in the <em>B</em>-value or <em>V</em><sub>p</sub>, i.e. with a reduction in the degree of saturation. 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引用次数: 0
摘要
在2010-2011年坎特伯雷地震液化严重影响地区的基督城,对一种洁净砂和一种粉质砂进行了部分饱和土的抗液化实验研究。在Christchurch沉积物中,对完全饱和和部分饱和的砂和粉质砂进行了一系列循环不排水试验,并基于p波速度(Vp)的综合现场测量对原位饱和条件进行了评估。用Skempton的b值和纵波速度作为部分饱和度的测量方法,在实验室进行了比较。试验结果的b值- Vp关系表明,Vp随着b值的增加而稳步增加,直到达到一个阈值b值,超过该阈值,Vp保持不变,即Vp;≥;1600;m/s。总的来说,被试砂和粉砂的抗液化能力随着b值或Vp的降低而增加,即随着饱和度的降低而增加。此外,试验结果表明,测试土壤存在阈值b和Vp,超过阈值后,液化阻力没有显著增加。阈值b值和Vp值与土壤类型和外加围应力有关。以Vp作为饱和度指标时,部分饱和对砂土和粉砂液化强度的影响是不同的。试验砂的液化强度随Vp的降低呈逐渐增加的趋势,粉砂的液化强度随Vp的降低呈逐渐增加的趋势,最高可达800 m/s左右,随后随Vp的降低液化强度突然增加;; 800 m / s。总的来说,测试土壤的液化强度与公布的数据之间的一致性很好,与清洁砂相比,粉质砂的行为具有明显的独特特征。
Effects of partial saturation on the liquefaction resistance of sand and silty sand from Christchurch
The liquefaction resistance of partially saturated soil was experimentally investigated for one clean sand and one silty sand collected from a site in Christchurch, in an area severely affected by liquefaction in the 2010–2011 Canterbury earthquakes. A series of cyclic undrained tests were performed on fully and partially saturated sand and silty sand specimens, in conjunction with evaluation of saturation conditions in situ based on comprehensive field measurements of P-wave velocity (Vp) in Christchurch deposits. The Skempton’s B-value and P-wave velocity were comparatively used as measures for partial saturation in the laboratory. B-value - Vp relationships from the test results indicate that Vp steadily increases with the B-value until a threshold B-value is reached beyond which Vp remains unchanged at values indicating full saturation, i.e. Vp ;≥ ;1600 ;m/s. In general, the liquefaction resistance of tested sand and silty sand increases with a decrease in the B-value or Vp, i.e. with a reduction in the degree of saturation. Furthermore, test results suggest existence of threshold B-values and Vp for tested soils beyond which no significant increase in the liquefaction resistance was observed. This threshold B-values and Vp were found to be dependent on soil type and applied confining stress. The effects of partial saturation on liquefaction strength are different for the sand and silty sand when using Vp as a measure for the degree of saturation. While a gradual rate of increase in liquefaction strength with decreasing Vp is observed for the tested sand, the liquefaction strength of silty sand shows similar gradual increase with a decrease in Vp up to about 800 ;m/s, which is then followed by an abrupt increase in the liquefaction strength for Vp ;< ;800 ;m/s. Generally good agreement between liquefaction strength of tested soils and published data was observed, with a clear distinctive feature in the behaviour of the silty sand as compared to clean sands.
期刊介绍:
Soils and Foundations is one of the leading journals in the field of soil mechanics and geotechnical engineering. It is the official journal of the Japanese Geotechnical Society (JGS)., The journal publishes a variety of original research paper, technical reports, technical notes, as well as the state-of-the-art reports upon invitation by the Editor, in the fields of soil and rock mechanics, geotechnical engineering, and environmental geotechnics. Since the publication of Volume 1, No.1 issue in June 1960, Soils and Foundations will celebrate the 60th anniversary in the year of 2020.
Soils and Foundations welcomes theoretical as well as practical work associated with the aforementioned field(s). Case studies that describe the original and interdisciplinary work applicable to geotechnical engineering are particularly encouraged. Discussions to each of the published articles are also welcomed in order to provide an avenue in which opinions of peers may be fed back or exchanged. In providing latest expertise on a specific topic, one issue out of six per year on average was allocated to include selected papers from the International Symposia which were held in Japan as well as overseas.