{"title":"泥炭地取样扰动机理及其对力学性能的影响","authors":"Nobutaka Yamazoe , Hiroyuki Tanaka , Toshihiro Ogino , Satoshi Nishimura","doi":"10.1016/j.sandf.2023.101361","DOIUrl":null,"url":null,"abstract":"<div><p>A soil investigation was conducted in peatlands in Japan, using two types of tube sampling methods, and the quality of the samples was evaluated. Unlike clays, peats easily lose water by compressive actions involved in sampler intrusion and core extrusion, leading to a significant loss of pore water. It was shown that this effect could be minimized by careful thin-wall sampling with a stationary piston, whereas open-drive sampling without a piston led to the significant compression of the sample core. The consequence of this disturbance on the in-situ behavior was interpreted through an examination of the mechanical properties of peat samples subjected to the “strain paths” expected during sampling in laboratory tests. By observing the deformation characteristics through a series of constant-rate-of-strain consolidation, unconfined compression, triaxial compression, and bender element tests, it was demonstrated that, contrary to soft clays, fibrous peats with high initial permeability potentially lead to the underestimation of the settlement during construction and the overestimation of strength due to inappropriate sampling. These results can be explained by the dominance of densification by disturbance over soil structure degradation. It was also noted that the sample quality varied considerably within the sampling tube.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":null,"pages":null},"PeriodicalIF":3.3000,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Mechanism of sampling disturbance for peat ground and its influence on mechanical properties\",\"authors\":\"Nobutaka Yamazoe , Hiroyuki Tanaka , Toshihiro Ogino , Satoshi Nishimura\",\"doi\":\"10.1016/j.sandf.2023.101361\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>A soil investigation was conducted in peatlands in Japan, using two types of tube sampling methods, and the quality of the samples was evaluated. Unlike clays, peats easily lose water by compressive actions involved in sampler intrusion and core extrusion, leading to a significant loss of pore water. It was shown that this effect could be minimized by careful thin-wall sampling with a stationary piston, whereas open-drive sampling without a piston led to the significant compression of the sample core. The consequence of this disturbance on the in-situ behavior was interpreted through an examination of the mechanical properties of peat samples subjected to the “strain paths” expected during sampling in laboratory tests. By observing the deformation characteristics through a series of constant-rate-of-strain consolidation, unconfined compression, triaxial compression, and bender element tests, it was demonstrated that, contrary to soft clays, fibrous peats with high initial permeability potentially lead to the underestimation of the settlement during construction and the overestimation of strength due to inappropriate sampling. These results can be explained by the dominance of densification by disturbance over soil structure degradation. It was also noted that the sample quality varied considerably within the sampling tube.</p></div>\",\"PeriodicalId\":21857,\"journal\":{\"name\":\"Soils and Foundations\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":3.3000,\"publicationDate\":\"2023-10-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Soils and Foundations\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0038080623000902\",\"RegionNum\":2,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENGINEERING, GEOLOGICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Soils and Foundations","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0038080623000902","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, GEOLOGICAL","Score":null,"Total":0}
Mechanism of sampling disturbance for peat ground and its influence on mechanical properties
A soil investigation was conducted in peatlands in Japan, using two types of tube sampling methods, and the quality of the samples was evaluated. Unlike clays, peats easily lose water by compressive actions involved in sampler intrusion and core extrusion, leading to a significant loss of pore water. It was shown that this effect could be minimized by careful thin-wall sampling with a stationary piston, whereas open-drive sampling without a piston led to the significant compression of the sample core. The consequence of this disturbance on the in-situ behavior was interpreted through an examination of the mechanical properties of peat samples subjected to the “strain paths” expected during sampling in laboratory tests. By observing the deformation characteristics through a series of constant-rate-of-strain consolidation, unconfined compression, triaxial compression, and bender element tests, it was demonstrated that, contrary to soft clays, fibrous peats with high initial permeability potentially lead to the underestimation of the settlement during construction and the overestimation of strength due to inappropriate sampling. These results can be explained by the dominance of densification by disturbance over soil structure degradation. It was also noted that the sample quality varied considerably within the sampling tube.
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.