1Yantai Center of Coastal Geological Survey, China Geological Survey, China
2Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, China
Received:August 13, 2021 Published: August 24, 2021
Corresponding author:Hongxian Chu, Yantai Center of Coastal Geological Survey, China geological survey, Yantai 264000, China,
Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
Based on geophysical survey and Marine geological data, the characteristics of seabed topography, stratum structure and geological
structure in the Caofeidian deep trough area are studied, and the formation reasons and influencing factors of topography and
geomorphology in the caofeidian deep trough area are analyzed. Based on H6 borehole data, it is determined that the regional
stratigraphic age is from Holocene to Late Pleistocene, and three transgressions occurred. Geo-slope analysis software is used
to calculate the stability of submarine SLOPE quantitatively, and the stability of SLOPE under extreme conditions such as large
wind wave and earthquake is simulated and analyzed. It is concluded that if the intensity of the tangshan earthquake occurs, the
seabed slope will have a large deformation and the overall instability may occur. Engineering measures can be used to restrain the
deformation of the seabed slope and structures and prevent the seabed geological disasters caused by the earthquake. The results
of the project can be applied to other areas of the ocean and coastal zone.
The Caofeidian sea area is located in the north of Bohai Bay in
China, and the shore is the Caofeidian Port area. Chu Hongxian et al.
studied the seabed topography and geomorphology characteristics
of the Caofeidian deep trough area by using the multi-stage
bathymetric topography, side scan sonar, Marine geophysics and
Marine geology data obtained. The detailed interpretation of
shallow seismic profile, single-channel seismic profile and multichannel
seismic profile with high resolution and high signalto-
noise ratio is carried out, and some new understandings are
a) The development of topography and geomorphology in the
Caofeidian deep trough is controlled by geological structure,
paleo-Luanhe river delta evolution, Marine hydrodynamic
force and human activities. The subsidence of the deep
submarine structure is the basis of the formation of the
topography and landform of the Caofeidian deep trough
area, and the evolution of the abandoned delta of the ancient
Luanhe River formed the landform of the Caofeidian headland
under the action of Marine hydrodynamic force. The caofeidian
project had obvious siltation effect on the tidal flat and made
the deep trough area in the scouring environment.
b) By testing and analyzing the grain size, carbon-14, palynology,
geochemistry, clay minerals and heavy minerals content
characteristics of H6 borehole cores in the depth range of
120 meters, the strata, sedimentary facies and sedimentary
environment of H6 borehole can be divided into six alternating
layers from top to bottom: shallow sea facies-continental
facies-shallow sea facies-continental facies-coastal facies
- continental facies. The regional stratigraphic age is from
Holocene to Late Pleistocene, when the climatic environment
was in a warmer period and three transgressions occurred.
c) Taking the typical sea area of Caofeidian deep trough as the
research target, the calculation model  of typical SLOPE
of Caofeidian deep trough was established, and the seabed
topographic parameters, stratigraphic structure parameters,
soil physical and mechanical parameters and other indicators
calculated by the model were determined. Geo-slope SLOPE
analysis software was used to perform quantitative calculation
of the stability of seabed SLOPE. The stability of submarine
slope under natural condition before construction and after
large-scale construction is analyzed, and the stability of
slope under extreme conditions such as large wind wave and
earthquake is simulated.
d) According to the research results of Newmark dynamic
analysis method [2-4], if the intensity of tangshan earthquake
occurs, the seabed slope deformation is large, the slope cannot
remain stable, and the overall instability may occur .
Therefore, engineering measures should be taken to restrain
the deformation of submarine slopes and structures, which
is conducive to the prevention of seabed geological disasters
caused by earthquakes.
e) The project team has carried out the research and development
of sounding data processing methods (surge filter application
and correction method) and the application practice of technical
methods. The results of this project provide the benchmark
data for the follow-up evaluation of Marine environment in the
later stage of engineering and can be applied to other areas of
ocean and coastal zone.
Chu HX, Fang ZH, Shi HJ, Gao XH (2016) Analysis and evaluation on the slope stability of Caofeidian deep trough. The Ocean Engineering 34(3): 114-122.
Abramson LW, Lee T S, Sharma S, Boyce G M (2001) Slope Stability and Stabilization Methods, 2nd edition, John Wiley & Sons Inc, New York, USA.
Anderson D G, Martin G R, John D Bowe, Larry L Brown, Deborah H Butler, et al (2008) Seismic Analysis and Design of Retaining Walls, Buried Structures, Slopes, and Embankments (NCHRP REPORT 611), Transportation Research Board p. 1-148.
Shi HJ, Chu HX, Gao XH (2013) The discussion of submarine slope stability analysis. Marine Geology Frontiers 29 (3): 44-45.