Shear strength (fall cone) from IODP Hole 386-M0085B

Undrained shear strength data from fall cone testing of the above given hole of International Ocean Discovery Program (IODP) Expedition 386 (Japan Trench Paleoseismology). This dataset was obtained at the end of the core processing workflow during the third phase (Personal Sampling Party, PSP) of expedition 386, which took place between 2022-11-15 – 2022-11-30 onboard D/V Chikyu. Measurements were performed on the work halves of core sections at an interval of approx. 1 meter using an ELE International fall cone penetrometer (STANDARD BS1377) with the following cone specifications: 35 mm cone, 30 degrees angle, around 30 g, stainless steel, 3.25 (+/-0.05) mm rod diameter. The fall cone penetrometer measures the penetration of a cone as it free falls and embeds itself in the sediment. During testing, the cone (pointing downward) was lowered, so that it just touched the surface of the split core before it was locked in place with the dial gauge reading noted. Undrained shear strength was determined using the empirical formula determined by Hansbo (1957, http://urn.kb.se/resolve?urn=urn:nbn:se:swedgeo:diva-356). The formula of Hansbo (1957) may be inadequate for silty sediment (present in some Expedition 386 cores); therefore, fall cone measurements were obtained preferably in clay-dominated intervals. In three cases (386-M0081B-1H-21,25.5; 386-M0088D-1H-7,25.5; 386-M0091B-1H-10,25.5), data collection was not successful for different reasons (IT problems, human failure). For the sake of completeness, however, the "Sample labels" were nevertheless noted and results left empty.For further methodological information see methods chapter in Strasser, M. et al., 2023 https://doi.org/10.14379/iodp.proc.386.102.2023

本数据集为国际大洋发现计划（International Ocean Discovery Program, IODP）386航次（日本海沟古地震学研究）指定钻孔的锥贯试验不排水抗剪强度数据。该数据集采集于386航次第三阶段——个人采样队（Personal Sampling Party, PSP）的岩心处理流程末期，此阶段航次于2022年11月15日至2022年11月30日期间在“Chikyu”号科考船上开展。测量采用ELE International锥贯仪（符合BS1377标准），在岩心劈开面的工作半段以约1米的间隔进行测试，该锥贯仪的参数如下：锥头直径35 mm，锥角30°，质量约30 g，材质为不锈钢，杆径3.25（±0.05）mm。锥贯仪通过让锥头自由下落并嵌入沉积物中，测量其贯入深度以获取数据。测试时，尖端朝下的锥头被降下至恰好接触劈开岩心表面，随后固定位置并记录百分表读数。不排水抗剪强度通过Hansbo（1957）提出的经验公式计算（http://urn.kb.se/resolve?urn=urn:nbn:se:swedgeo:diva-356）。需注意，Hansbo（1957）公式对于粉砂质沉积物（386航次部分岩心中存在该类沉积物）可能并不适用，因此测试优先选择以黏土为主的层位。共有3组测量（386-M0081B-1H-21,25.5；386-M0088D-1H-7,25.5；386-M0091B-1H-10,25.5）因各类原因（信息技术故障、人为失误）未能成功获取数据。但为保证数据集完整性，仍记录了对应的“样品标签”，并将结果留空。更多方法学细节可参见Strasser M.等人2023年发表的研究论文（https://doi.org/10.14379/iodp.proc.386.102.2023），具体内容见该文献的方法学章节。