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1.
The Hope Slide, which occurred on January 9, 1965, involved an estimated 47-Mm3 of meta-volcanics and intrusive rocks. Previous workers reported the presence of tectonic structures (faults and shear zones) along the failure surface at the Hope Slide. These tectonic features were investigated in detail to assess their effects on rock-mass quality and the related implications for slope stability. This paper integrates basic field and laboratory concepts from structural and engineering geology. Subdividing the failure area into structural domains allowed distinct discontinuity sets to be associated with specific tectonic structures. The Geological Strength Index (GSI) was used to estimate the rock-mass damage related to the tectonic structures. Low GSI values were seen to outline tectonic damage zones. Point-load tests were used to characterise the compressive strength of rocks adjacent to the tectonic structures. Strength anisotropy, tentatively attributed to damage caused by a large shear zone, was observed in greenstone samples. Seepage zones along the failure surface were observed preferentially along shallow discontinuities that dipped downslope and in rock masses of good quality (GSI > 40). An alternative morphology of the slope failure is proposed by distinguishing between the extent of the surficial damage due to the rock-slope failure and the zone of failed material (depletion zone). For the first time, a kinematic mechanism for the Hope Slide is proposed, based on a preliminary 3-dimensional block model. A pre-1965 DEM was produced from estimates of material lost and gained as reported by previous workers. The pre-1965 DEM revealed that the tectonic structures recognised during fieldwork bounded the material that failed in the 1965 event. 相似文献
2.
Andrea Wolter Doug Stead Brent C. Ward John J. Clague Monica Ghirotti 《Landslides》2016,13(5):1067-1081
Although the 1963 Vajont Slide in Italy has been extensively studied for over 50 years, its regional geological and geomorphological context has been neglected. In this paper, we use field observations and remote sensing data to elucidate the interaction between endogenic and exogenic processes that brought the north slope of Monte Toc to failure. We present the first detailed pre- and post-failure engineering geomorphology maps of the slide area. The maps delineate two main landslide blocks, several sub-blocks, compressional and extensional zones, and secondary failures in the deposit. The maps provide new insights into the kinematics, dynamics and evolution of the slide. Finally, we discuss the origin of Vajont Gorge and a prehistoric failure that occurred at the same location as the 1963 slide. We propose, as part of a newly developed multi-stage landscape evolution sequence, that the prehistoric failure was a deep-seated gravitational slope deformation (sackung) that initiated during deglaciation and continued to slowly move until the catastrophic failure in 1963. We argue that the gorge was created by these deep-seated slow movements. 相似文献
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4.
Numerical Analysis of Block Caving-Induced Instability in Large Open Pit Slopes: A Finite Element/Discrete Element Approach 总被引：3，自引：2，他引：1
This paper addresses one of the most challenging problems in mining rock engineering—the interaction between block cave mining
and a large overlying open pit. The finite element modeling/discrete element modeling (FEM/DEM) approach was utilized in the
analysis of block caving-induced step-path failure development in a large open pit slope. The analysis indicated that there
is a threshold percentage of critical intact rock bridges along a step-path failure plane that may ensure the stability of
an open pit throughout caving operations. Transition from open pit to underground mining at Palabora mine presents an important
example of a pit wall instability triggered by caving. Using combined FEM/DEM-DFN (discrete fracture network) modeling, it
was possible to investigate the formation of a basal failure surface within an open pit slope as a direct result of cave mining.
The modeling of Palabora highlighted the importance of rock mass tensile strength and its influence on caving-induced slope
response. 相似文献
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6.
Stability analysis of the 2007 Chehalis lake landslide based on long-range terrestrial photogrammetry and airborne LiDAR data 总被引：1，自引：1，他引：0
Marc-André Brideau Matthieu Sturzenegger Doug Stead Michel Jaboyedoff Martin Lawrence Nicholas J. Roberts Brent C. Ward Thomas H. Millard John J. Clague 《Landslides》2012,9(1):75-91
On December 4th 2007, a 3-Mm3 landslide occurred along the northwestern shore of Chehalis Lake. The initiation zone is located at the intersection of the
main valley slope and the northern sidewall of a prominent gully. The slope failure caused a displacement wave that ran up
to 38 m on the opposite shore of the lake. The landslide is temporally associated with a rain-on-snow meteorological event
which is thought to have triggered it. This paper describes the Chehalis Lake landslide and presents a comparison of discontinuity
orientation datasets obtained using three techniques: field measurements, terrestrial photogrammetric 3D models and an airborne
LiDAR digital elevation model to describe the orientation and characteristics of the five discontinuity sets present. The
discontinuity orientation data are used to perform kinematic, surface wedge limit equilibrium and three-dimensional distinct
element analyses. The kinematic and surface wedge analyses suggest that the location of the slope failure (intersection of
the valley slope and a gully wall) has facilitated the development of the unstable rock mass which initiated as a planar sliding
failure. Results from the three-dimensional distinct element analyses suggest that the presence, orientation and high persistence
of a discontinuity set dipping obliquely to the slope were critical to the development of the landslide and led to a failure
mechanism dominated by planar sliding. The three-dimensional distinct element modelling also suggests that the presence of
a steeply dipping discontinuity set striking perpendicular to the slope and associated with a fault exerted a significant
control on the volume and extent of the failed rock mass but not on the overall stability of the slope. 相似文献
7.
Summary This paper investigates the processes of joint surface damage and near-surface intact rock tensile failure using a hybrid
FEM/DEM code. Selected Barton and Choubey JRC profiles were simulated in direct shear tests and the surface damage mechanisms
investigated in terms of joint surface wear or tensile fracturing of intact rock along the joint plane. Shear strength and
displacement profiles for each joint profile are numerically simulated. Numerical results agree closely with published experimental
observations. Furthermore, results show that dilation along the joint is controlled dominantly by the joint surface geometry
and the applied normal stress. Significant dilation is expected to occur where there is a large asperity provided the applied
normal stress is low. In this case, joint surface damage is limited to surface wear. In contrast, when the applied normal
stress is high, dilation will be low and damage is composed of both surface wear and asperity breakage through near-joint-surface
intact rock tensile failure. Local joint dilation angles vary in proportion to the magnitude of the dilation. Several joint
profiles with different geometrical configurations were simulated within a slope and the possible modes of joint surface damage
were investigated. It was found that due to low normal stresses acting on the joint surfaces within a slope the dominant mode
of joint surface damage is by yielding and surface wear of asperities.
Authors’ address: Amir Karami, Golder Associates Ltd., 4260 Still Creek Drive, Suite 500, Burnaby, Vancouver, British Columbia,
BC V5C 6C6 Canada 相似文献
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This paper tests the hypothesis that Integrated Coastal Zone Management (ICZM) is the best strategy for achieving good coastal governance on the North East coast of England using two geographically adjacent case studies: the East Riding coast, which has an ICZM framework in place and the Northumberland coast, which does not. Semi-structured questionnaires were used for face-to-face interviews with local representatives at each study site to underpin a common context and understanding between the interviewer and interviewee. Postal surveys were used to solicit responses from non-governmental organisations (NGOs) and governmental representatives. 相似文献
10.
On Conditions of Phytoplankton Blooms in the Coastal Waters of the North-Western East/Japan Sea 总被引：1，自引：0，他引：1
Seasonal changes of abundance of the main phytoplankton groups of species (diatoms, dinoflagellates, chrysophytes, small flagellates
and cryptophytes) and a set of environmental parameters were investigated in coastal and preestuarine waters of Peter the
Great Bay (East/Japan Sea) in May-October of 1998 and 1999. Three periods of mass development were revealed: spring, summer
and autumn blooms, with successive change of species. The conditions favourable for each group of species were determined.
Driving mechanisms of the succession include nutrients transport through seasonal pycnocline by turbulent mixing, terrestrial
nutrients supply by monsoon floods, nutrients supply by upwellings, and light control by the thickness of upper mixed layer.
Summer succession could be explained by a simple SST-MLD diagram similar to Pingree S-kh diagram with sea surface temperature
as indicator of stratification (S) and mixed layer depth as indicator of light availability (kh). 相似文献