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61.
Despite the gently dipping slopes (ca 1°), large-scale submarine slope failures have occurred on the mid-Norwegian continental
margin (Storegga, Sklinnadjupet, Traenadjupet), suggesting the presence of special conditions predisposing to failure in this
formerly glaciated margin. With a volume estimated between 2,400 and 3,200 km3 and an affected area of approximately 95,000 km2, the Storegga slide represents one of the largest and best-studied submarine slides of Holocene age known worldwide. Finite
element modeling of slope failure indicates that a large (6.5 < Ms < 7.0) seismic triggering mechanism would not be sufficient
to cause failure at more than 110 m below the seabed as observed for the slip planes at Storegga (northern sidewall). This
implies that other factors (e.g., liquefaction, strain softening, gas charging, rapid burial) are needed to explain the occurrence
of the Storegga slide with a deep surface of failure. In this paper, we discuss the importance of the compaction effect of
rapidly accumulated sediments in the slide area. During compaction, sediment grains reorganize themselves, thereby, expelling
pore water. Consequently, depending on sedimentation rate and permeability, excess pore pressures might result beneath less
permeable sediments. Our modeling and cross-checking illustrate how excess pore pressure generation due to high sedimentation
rate could explain the development of layers of weakness, and thus, how such a large slide might have been initiated in deep
sediments. Using the highest sedimentation rate estimated in the area (36 and 27 m/kyr between 16.2 and 15 kyr BP), 1D modeling
shows excess pore pressure values of around 200 kPa at a depth of 100 m below the seafloor 15 kyr BP and 60 kPa at a depth
of 100 m at the time of the slide (8 kyr BP). Excess pore pressure apparently drastically reduced the resistance of the sediment
(incomplete consolidation). In addition, 2D modeling shows that permeability anisotropies can significantly affect the lateral
extent of excess pore pressure dissipation, affecting, that way, normally consolidated sediments far from the excess pore
pressure initiation area. 相似文献
62.
钢筋混凝土带暗支撑双功能剪力墙的力学计算模型 总被引:3,自引:0,他引:3
提出了钢筋混凝土带暗支撑双功能剪力墙结构。在试验研究基础上,建立了该体系的力学计算模型,计算结果与实测结果符合较好。 相似文献
63.
64.
65.
The sliding block theory was proposed by Newmark for determining the permanent displacement of embankments and dams under earthquake loading. This paper highlights recent applications of sliding block theory to different geotechnical structures. The equations to determine seismic factor of safety, yield acceleration and permanent displacement are given for rock block, soil slope, landfill cover, geosynthetic-reinforced soil retaining wall, and composite breakwater. The presented equations for seismic stability degenerate to that of static stability in the absence of earthquake. The permanent displacement for various structures can be obtained from that of a horizontal sliding block through a correction factor. A simplified procedure is included for the permanent displacement under vertical acceleration. The sliding block approach is rational for design under high seismic load. 相似文献
66.
O. Slaymaker 《International Journal of Earth Sciences》1999,88(2):317-324
Although British Columbia experiences many natural hazards, there is as yet no unified policy to promote natural hazard management
in the province. The problem is not in the quantity and quality of geoscience assessment of natural hazards, but instead,
it is suggested, in the isolation of that work from broader risk perspectives and in the lack of clarity of division of responsibilities
between various levels of government. The example of recent changes in perception of the terrain stability problem illustrates
how natural hazard problems are driven by social and political priorities rather than by geoscience priorities.
Received: 22 November 1998 / Accepted: 22 November 1998 相似文献
67.
Influence of rainfall on the deformation and stability of a slope in overconsolidated clays: a case study 总被引:2,自引:0,他引:2
The behaviour of an instrumented unstable slope in a profile of weathered overconsolidated clay has been analysed. Available
field investigation data and laboratory tests were integrated in a coupled hydromechanical model of the slope. Particular
attention was given to the unsaturated soil conditions above the water table and to the influence of the rainfall record.
Recorded pore-water pressures helped to identify the hydrogeological conditions of the slope. The coupled model was used to
compute slope deformations and the variation of safety with time. Actual rainfall records were also integrated into the analysis.
Comparison of measurements and calculations illustrate the nature of the slope instability and the complex relationships between
mechanical and hydraulic factors.
Electronic Publication 相似文献
68.
Influence of earthquakes on the stability of slopes 总被引:2,自引:0,他引:2
Robert Hack Dinand Alkema Gerard A.M. Kruse Noud Leenders Lucia Luzi 《Engineering Geology》2007,91(1):4-15
Earthquakes are a major trigger for instability of natural and man-made slopes. Often the instability of slopes due to an earthquake causes more destruction and kills more people than the actual earthquake itself. A comparison is made between different methodologies to analyze the potential stability of slopes during earthquakes. Theoretically, it seems simple to calculate the stability of a slope during an earthquake. In reality, however, the stability is influenced by so many parameters that are either not known or which influence is so poorly known that a decent estimation of stability cannot be made. Offshore the situation is worse because proper data required for stability calculations are even less available than onshore. On- and offshore, erosion and weathering create continuously slopes that may become unstable during a future earthquake, offshore also sedimentation creates continuously new slopes. Another fundamental problem in stability analysis is the complicated and largely unknown behavior of seismic waves in three-dimensions in natural materials. The lack of accurate data and the unknown behavior of seismic waves in three-dimensions make estimations of slope stability during an earthquake unreliable. 相似文献
69.
镇江市是江苏省滑坡地质灾害较为严重的城市,其地质灾害防治工作开展较早,积累了一定的防治管理经验。而焦山索道上站滑坡治理工程是多种滑坡治理技术方法和措施的综合应用,通过混凝土抗滑桩、锚索、锚杆、排水以及挂网喷播复绿等技术方式和措施的应用,成功地完成了焦山索道上站的滑坡治理工程,为镇江市其他滑坡地质灾害的治理提供了一定的参考借鉴作用。 相似文献
70.
A large number of studies have documented the structural and sedimentary architecture of the Corinth Gulf, especially the major E–W trending normal faults important in accommodating the main extensional strain and associated growth of the Gilbert fan deltas. However, the role of several N–S oriented structures that crop out at the surface and are detectable at depth by seismic reflection and gravity surveys are not clearly understood. Based on new geological data, collected near Xylokastro, we describe the N–S oriented tectonic activity of this area. The mapped inland faults correspond to off-shore structures identified in re-interpreted seismic lines and appear to have acted as a major transfer zone during the opening of the Corinth Gulf. Reconstruction of the paleo-topography based on sedimentary facies and the environment of clay mineral formation suggest these transfer zones played an important role in controlling both local structural relief and depositional conditions of the Gilbert fan deltas. 相似文献