Key Laboratory of Earthquake Engineering and Engineering Vibration, Institute of Engineering Mechanics, China Earthquake Administration, Haerbin, 150081, Heilongjiang, China.
Institute of Engineering Mechanics, China Earthquake Administration, Haerbin, 150081, Heilongjiang, China.
Sci Rep. 2022 Jun 10;12(1):9588. doi: 10.1038/s41598-022-13549-8.
A large-scale sand liquefaction producing typical and novel surface phenomena was found at the epicenter of Songyuan M5.7 earthquake occurring on May 28, 2018. Field survey and experimental test encompassing boring sampling, standard penetration test (SPT), cone penetration test (CPT), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF) were performed to ascertain the liquefaction damage and site characteristic. Cone penetration test is an excellent assay for the identification of liquefied sand layer and acquisition of physio-mechanical parameter. Moreover, the assay is applicable for in-situ post-earthquake investigation. Factors promoting the formation and controlling the distribution of the sand liquefaction were analyzed. The liquefaction impacted an 80 km2 area, and was primarily embodied as sand boil and water sprout on rice field, despite producing no significant structural damage. Due to the simple profile of local soil layer, ground motion, geomorphic condition, and groundwater level were the main factors governing the distribution of the liquefaction. Majority of the liquefied sand layer was discovered at the depth less than 10 m. However, deep layer liquefaction at the depth greater than 18 m was also discovered, which was demonstrated by the upward movement of liquefied sand towards the upper silty clay layer at the depth of 17 m. Most importantly, we have identified loess liquefaction, a phenomenon which had not been reported previously in Northeast China. Lastly, it is important to highlight the risk of significant liquefaction damage at Songyuan. Hence, investigating the liquefaction risk is potentially beneficial for augmenting planning on earthquake mitigation, engineering reconnaissance, and design project.
2018 年 5 月 28 日松原 5.7 级地震震中发现大规模砂土液化，产生典型和新颖的地表现象。通过现场调查和试验测试，包括钻孔取样、标准贯入试验（SPT）、圆锥贯入试验（CPT）、扫描电子显微镜（SEM）、X 射线衍射（XRD）和 X 射线荧光（XRF），确定了液化损伤和场地特征。圆锥贯入试验是识别液化砂层和获取物理力学参数的极好方法。此外，该方法适用于地震后的现场调查。分析了促进砂土液化形成和控制其分布的因素。液化影响了 80 平方公里的区域，主要表现为稻田中的砂沸和水喷，但没有造成重大结构损坏。由于局部土层、地震动、地貌条件和地下水位的简单剖面，是控制液化分布的主要因素。大部分液化砂层发现于 10 米以下的深度。然而，也发现了深度大于 18 米的深层液化，这是由液化砂向上移动到 17 米深处的粉质粘土层所证明的。最重要的是，我们已经确定了黄土液化，这是在中国东北地区以前没有报道过的现象。最后，需要强调松原地区存在重大液化风险。因此，调查液化风险对于加强地震减灾规划、工程勘察和设计项目是有益的。
