Journal of Jilin University(Earth Science Edition) ›› 2018, Vol. 48 ›› Issue (4): 1165-1173.doi: 10.13278/j.cnki.jjuese.20170075

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Shear Strength and Failure Characteristics of Marine Soft Soil in Lianyungang

Gou Fugang1,2, Gong Xulong1,2, Wang Guangya1,2   

  1. 1. Geological Survey of Jiangsu Province, Nanjing 210049, China;
    2. Key Laboratory of Earth Fissures Geological Disaster Ministry of Land and Resources, Nanjing 210049, China
  • Received:2017-12-03 Online:2018-07-26 Published:2018-07-26
  • Supported by:
    Supported by Project of China Geological Survey (1212011220005), Comprehensive Geological Survey Project in Jiangsu Coastal Area (20120223) and Lianyungang Urban Geological Survey Project(20170821)

Abstract: The soft soil in Lianyungang is a heterogeneous marine soft soil deposited in an alkaline environment, its shear strength is inherently anisotropic. We studied the unconsolidated undrained shear strength of soft soil by tri-axial UU test, UTC test, Fast shear test, and FVT test. The results indicate that the horizontal plane shear strength is the lowest; while the vertical plane shear strength is the highest. Using the cohesion and friction angle obtained by the three axis UU test, we restored the stress of soil shear failure state based on the soil unit limit equilibrium theory, and calculated the actual shear strength of soil. The average shear soil strength of the tri-axial UU test is 13.13 kPa. The angle between the sample fracture surface and the horizontal plane is most concentrated in the range of 45.1°-45.7°. The average strength of the UTC test approximately equates that of the three axis UU test. The average soft soil strength by the conventional FVT test is 19.72 kPa, nearly 6.60 kPa higher than that by the other two tests. This phenomenon is related to the mechanical disturbance of the lab test samples, the change of the stress state of the soil, and the characteristics of shear plane.

Key words: shear strength, tri-axial unconsolidation and undrained test, unconfined compression test, field vane shear test, correlation

CLC Number: 

  • P642
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