Multiple-block plane shear slope failure

1987 ◽  
Vol 24 (4) ◽  
pp. 479-489
Author(s):  
B. Stimpson ◽  
K. Barron ◽  
K. Kosar
Keyword(s):  
Failure Mode ◽  
Slope Failure ◽  
Shear Failure ◽  
Effective Means ◽  
Bentonite Clay ◽  
Equilibrium Analysis ◽  
Slope Failures ◽  
Plane Shear ◽  
Strip Mine ◽  
Highwall Slope

Field examination of highwall slope failures occurring in some coal strip mines in Alberta in association with bentonite has led to the concept of a multiple-block plane shear failure mode in which a series of individual block failures regresses back into the slope for distances up to five times the slope height. These failures cause a rapid deterioration of the bench from which the dragline operates, reduce productivity, and necessitate bench maintenance to provide a safe, stable bench prior to the next pass of the dragline.A probabilistic limiting equilibrium analysis was developed to predict the positions of successive failure blocks and its predictions were compared with slope geometry and laboratory strength data from a producing coal strip mine in which a failure was active.Two slope failures reported in the literature (Folkestone Warren landslips and an Oxford Clay brick pit, both in England) were reanalysed using the multiple-block plane shear failure mode, and it is suggested that this mode of failure offers an alternative explanation for the slope kinematics observed.Finally, the most effective means of reducing the probability of failure or controlling the extent of slope failure retrogression is by dewatering. Key words: slopes, failure, coal mining, bentonite, clay bands, plane shear, case history, probabilistic analysis.

scholarly journals An Experimental Study on Mechanical Behavior of Parallel Joint Specimens under Compression Shear

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Fei Wang ◽  
Ping Cao ◽  
Yu Chen ◽  
Qing-peng Gao ◽  
Zhu Wang
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Failure Mode ◽  
Shear Failure ◽  
Strain Curve ◽  
Shear Loading ◽  
Plane Shear ◽  
Joint Spacing ◽  
Dip Angle ◽  
Joint Inclination

In order to investigate the influence of the joint on the failure mode, peak shear strength, and shear stress-strain curve of rock mass, the compression shear test loading on the parallel jointed specimens was carried out, and the acoustic emission system was used to monitor the loading process. The joint spacing and joint overlap were varied to alter the relative positions of parallel joints in geometry. Under compression-shear loading, the failure mode of the joint specimen can be classified into four types: coplanar shear failure, shear failure along the joint plane, shear failure along the shear stress plane, and similar integrity shear failure. The joint dip angle has a decisive effect on the failure mode of the specimen. The joint overlap affects the crack development of the specimen but does not change the failure mode of the specimen. The joint spacing can change the failure mode of the specimen. The shear strength of the specimen firstly increases and then decreases with the increase of the dip angle and reaches the maximum at 45°. The shear strength decreases with the increase of the joint overlap and increases with the increase of the joint spacing. The shear stress-displacement curves of different joint inclination samples have differences which mainly reflect in the postrupture stage. From monitoring results of the AE system, the variation regular of the AE count corresponds to the failure mode, and the peak value of the AE count decreases with the increase of joint overlap and increases with the increase of joint spacing.

scholarly journals Mechanical Respond and Failure Mode of Large Size Honeycomb Sandwiched Composites under In-Plane Shear Load

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4248 ◽  
Author(s):  
Wang ◽  
Wang ◽  
Liu ◽  
Zhang ◽  
Wan ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Shear Strain ◽  
Failure Mode ◽  
Field Distribution ◽  
Shear Failure ◽  
Buckling Load ◽  
Analysis Method ◽  
Plane Shear ◽  
Large Size ◽  
Honeycomb Sandwich

The present work focuses on the in-plane shear respond and failure mode of large size honeycomb sandwich composites which consist of plain weave carbon fabric laminate skins and aramid paper core. A special size specimen based on a typical element of aircraft fuselage was designed and manufactured. A modified in-plane shear test method and the corresponding fixture was developed. Three large size specimens were tested. The distributed strain gauges were used to monitor the mechanical response and ultimate bearing capacity. The results show that a linear respond of displacement and strain appears with the increase of the load. The average shear failure load reaches 205.68 kN with the shear failure occurring on the face sheet, and the maximum shear strain monitored on the composite plate is up to 16,115 με. A combination of theoretical analysis and finite element method (FEM) was conducted to predict the shear field distribution and the overall buckling load. The out-of-plane displacement field distribution and in-plane shear strain field distribution under the pure shear loading were revealed. The theoretical analysis method was deduced to obtain the variation rule of the shear buckling load. A good agreement was achieved among the experiment, theoretical analysis, and FEM results. It can be concluded that the theoretical analysis method is relatively conservative, and the FEM is more accurate in case of deformation and strain. The results predicted by h element and p element methods are very close. The results of the study could provide data support for the comprehensive promotion of the design and application of honeycomb sandwich composites.

Analysis on Progressive Slipping-Shear Failure Mode of Bedding Slope of Hard Rock with Medium or Large Dip Angle

2013 ◽  
Vol 438-439 ◽  
pp. 1232-1237
Author(s):  
Yu Feng Wei ◽  
De Xin Nei
Keyword(s):  
Failure Mode ◽  
Slope Failure ◽  
Failure Modes ◽  
Shear Failure ◽  
Hard Rock ◽  
Concrete Gravity Dam ◽  
Geologic History ◽  
Deformation And Failure ◽  
The Right ◽  
Bedding Slope

Kala Hydropower Station is located in the midstream of Yalong River in Sichuan Province of China, and the type of dam is concrete gravity dam, with a largest dam height of 129 m, an installed capacity of 1000 MW and a storage capacity of 255.8 million cubic meters. The slope on the right bank of the dam site is mainly composed of hard metasandstone and marbles interbedded with carbonaceous slates and the dip of rock formation is the same as the aspect of slope, so that it is a typical bedding slope. The field survey indicates that the failure of bedding slope of hard rock is not on a common mode of slipping-bending or buckling, but on an uncommon failure mode. The paper introduces a research method that starts with geologic history, analyzes current state and predicts the future failure mode, analyzes the characteristics and phenomenon of slope failure, and adopts the finite element calculation method to analyze the plastic zone resulting from slope deformation. According to the deformation evidence and calculation results, the engineering geologic mechanical theory is used to analyze the deformation and failure mode of slope, and it is indicated that the current and future failure modes of hard rock slope with large thickness are all slipping-shear failure.

scholarly journals The evolution of slope failures: mechanisms of rupture propagation

2004 ◽  
Vol 4 (1) ◽  
pp. 147-152 ◽  
Author(s):  
D. N. Petley
Keyword(s):  
Slope Failure ◽  
Complex Stress ◽  
Basal Region ◽  
Rupture Propagation ◽  
Slope Failures ◽  
Stress Regime ◽  
Detailed Surface ◽  
Landslide Mass ◽  
Region Data ◽  
Detailed Assessment

Abstract. Forecasting the occurrence of large, catastrophic slope failures remains very problematic. It is clear that in order advance this field a greater understanding is needed of the processes through which failure occurs. In particular, there is a need to comprehend the processes through which a rupture develops and propagates through the slope, and the nature of the inter-relationship between the stress and strain states of the landslide mass. To this end, a detailed analysis has been undertaken of the movement records for the Selborme Cutting slope failure, in which failure was deliberately triggered through pore pressure elevation. The data demonstrate that it is possible to determine the processes occurring in the basal region of the landslide, and thus controlling the movement of the mass, from the surface movement patterns. In particular, it is clear that the process of rupture development and propagation has a unique signature, allowing the development of the rupture to be traced from detailed surface monitoring. For landslides undergoing first time failure through rupture propagation, this allows the prediction of the time of failure as per the "Saito" approach. It is shown that for such predictions to be reliable, data from a number of points across the landslide mass are needed. Interestingly, due to the complex stress regime in that region, data from the crown may not be appropriate for failure prediction. Based upon these results, the application of new techniques for the detailed assessment of spatial patterns of the development of strain may potentially allow a new insight into the development of rupture surfaces and may ultimately permit forecasting of the temporal occurrence of failure.

Machine learning-based failure mode identification of RCSPSW

2021 ◽  
Author(s):  
Dongqi Jiang ◽  
Shanquan Liu ◽  
Tao Chen ◽  
Gang Bi
Keyword(s):  
Machine Learning ◽  
Failure Mode ◽  
Failure Modes ◽  
Shear Failure ◽  
Tall Buildings ◽  
Shear Walls ◽  
Superior Performance ◽  
Ann Model ◽  
Mode Recognition ◽  
Wide Range

<p>Reinforced concrete – steel plate composite shear walls (RCSPSW) have attracted great interests in the construction of tall buildings. From the perspective of life-cycle maintenance, the failure mode recognition is critical in determining the post-earthquake recovery strategies. This paper presents a comprehensive study on a wide range of existing experimental tests and develops a unique library of 17 parameters that affects RCSPSW’s failure modes. A total of 127 specimens are compiled and three types of failure modes are considered: flexure, shear and flexure-shear failure modes. Various machine learning (ML) techniques such as decision trees, random forests (RF), <i>K</i>-nearest neighbours and artificial neural network (ANN) are adopted to identify the failure mode of RCSPSW. RF and ANN algorithm show superior performance as compared to other ML approaches. In Particular, ANN model with one hidden layer and 10 neurons is sufficient for failure mode recognition of RCSPSW.</p>

Recurrent rock avalanches progressively dismantle mountain ridges in the Longmen Shan, China, most recently in the 2008 Wenchuan earthquake

2021 ◽  
Author(s):  
Janusz Wasowski ◽  
Maurice McSaveney ◽  
Luca Pisanu ◽  
Vincenzo Del Gaudio ◽  
Yan Li ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Ambient Noise ◽  
Slope Failure ◽  
Mass Movement ◽  
Rock Avalanche ◽  
Ground Vibration ◽  
Source Area ◽  
Slope Failures ◽  
Rock Avalanches ◽  
Beichuan County

&lt;p&gt;Large earthquake-triggered landslides, in particular rock avalanches, can have catastrophic consequences. However, the recognition of slopes prone to such failures remains difficult, because slope-specific seismic response depends on many factors including local topography, landforms, structure and internal geology. We address these issues by exploring the case of a rock avalanche of &gt;3 million m&lt;sup&gt;3&lt;/sup&gt; triggered by the 2008 Mw7.9 Wenchuan earthquake in the Longmen Shan range, China. The failure, denominated Yangjia gully rock avalanche, occurred in Beichuan County (Sichuan Province), one of the areas that suffered the highest shaking intensity and death toll caused by co-seismic landsliding. Even though the Wenchuan earthquake produced tens of large (volume &gt;1 million m&lt;sup&gt;3&lt;/sup&gt;) rock avalanches, few studies so far have examined the pre-2008 history of the failed slope or reported on the stratigraphic record of mass-movement deposits exposed along local river courses. The presented case of the Yangjia gully rock avalanche shows the importance of such attempts as they provide information on the recurrence of large slope failures and their associated hazards. Our effort stems from recognition, on 2005 satellite imagery, of topography and morphology indicative of a large, apparently pre-historic slope failure and the associated breached landslide dam, both features closely resembling the forms generated in the catastrophic 2008 earthquake. The follow-up reconstruction recognizes an earlier landslide deposit exhumed from beneath the 2008 Yangjia gully rock avalanche by fluvial erosion since May 2008. We infer a seismic trigger also for the pre-2008 rock avalanche based on the following circumstantial evidence: i) the same source area (valley-facing, terminal portion of a flat-topped, elongated mountain ridge) located within one and a half kilometer of the seismically active Beichuan fault; ii) significant directional amplification of ground vibration, sub-parallel to the failed slope direction, detected via ambient noise measurements on the ridge adjacent to the source area of the 2008 rock avalanche and iii) common depositional and textural features of the two landslide deposits. Then, we show how, through consideration of the broader geomorphic and seismo-tectonic contexts, one can gain insight into the spatial and temporal recurrence of catastrophic slope failures&amp;#160; in Beichuan County and elsewhere in the Longmen Shan. This insight, combined with local-scale geologic and geomorphologic knowledge, may guide selection of suspect slopes for reconnaissance, wide-area ambient noise investigation aimed at discriminating their relative susceptibility to co-seismic catastrophic failures. We indicate the feasibility of such investigations through the example of this study, which uses 3-component velocimeters designed to register low amplitude ground vibration.&lt;/p&gt;

scholarly journals Experimental Study on the Shear Performance of Shallow Hinge Joints for Prefabricated Hollow Slab Bridges

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Hanbin Yi ◽  
Chuanxi Li ◽  
Li Dai
Keyword(s):  
Shear Stress ◽  
Failure Mode ◽  
Shear Failure ◽  
Internal Force ◽  
Force Transmission ◽  
Transmission Performance ◽  
Joint Stress ◽  
Hinge Joint ◽  
Vehicle Load ◽  
Joint Fracture

To investigate whether shallow hinge joint fracture was caused by shear stress or flexural stress, during the demolition and reconstruction of Xiaojiang River bridge, two original girders were collected and shipped to the lab, and the shallow hinge joint between the two girders was rebuilt. Tests were performed to investigate the cracking load, failure mode, and force transmission performance of the hollow slab girder and shallow hinge joint under vehicle load. The test result shows that under eccentric load, when the load increases to 365 kN, the midspan bottom slab of the testing girder starts to fracture; as the load increases to 560 kN, the roof slab of the testing girder starts to fracture; the hinge joint has a maximum horizontal opening of 0.153 mm and vertical relative displacement of 0.201 mm; during the entire test loading process, the shallow hinge joint structure does not develop fracture and shear failure; and the shallow hinge structure demonstrates excellent shear stress transmission performance. In addition, based on hinge slab theory, the hinge joint internal force under vehicle load was calculated. Based on ACI 318-05 specification, CAN/CSA-S6-00, and JTG D61-2005, the hinge joint shear bearing capacity was calculated. Hinge joint stress resistances calculated from the three specifications all exceed the internal force. Among them, the calculation results from ACI 318-05 and CAN/CSA-S6-00 are similar, while the result from JTG D61-2005 specification significantly exceeds the internal force, which is mainly because the designed concrete direct shear strength fvd in the Chinese specification does not consider factors such as bonding surface coarseness, concrete pouring sequence, and material properties. Theoretical calculations and tests show that the actual failure mode of the shallow hinge joint in prefabricated hollow slab girder bridges is not caused by shear stress.

Investigating the controls of submarine landslides and associated hazards in Pangnirtung Fiord, Eastern Baffin Island (Nunavut)

2021 ◽  
Author(s):  
Philip Sedore ◽  
Alexandre Normandeau ◽  
Vittorio Maselli
Keyword(s):  
High Latitude ◽  
Debris Flows ◽  
Slope Failure ◽  
Recurrence Time ◽  
High Recurrence Rate ◽  
Baffin Island ◽  
Submarine Landslides ◽  
Slope Failures ◽  
Near Surface ◽  
Submarine Slope

&lt;p&gt;High-latitude fiords are susceptible to hazardous subaerial and submarine slope failures. Recent investigations have shown that past slope failures in fiords of Greenland and Alaska have generated devastating landslide induced tsunamis. Since coastal communities inhabit these high-latitude fiords, it is critical to understand the slope failure recurrence time, their distribution, potential triggers, and ability to generate tsunamis. In this study, we identified &gt; 50 near-surface submarine landslides in Pangnirtung Fiord, eastern Baffin Island, Nunavut, using multibeam bathymetric and sub-bottom profiler data, along with sediment gravity-cores collected in 2019. Morphometric and morphological analyses, along with sedimentological analyses, were carried out on submarine landslide deposits to quantify their spatial and temporal distribution throughout the fiord and to evaluate the factors that may have triggered the slope failures.&lt;/p&gt;&lt;p&gt;Combining bathymetric with topographic data from unmanned aerial vehicle imagery, we found that most of these landslide deposits are relatively small (~ 0.08 km&lt;sup&gt;2&lt;/sup&gt;) and are associated with outwash fans and steep fiord sidewalls. However, since most slope failure head scarps lie between the intertidal zone and ~30 m water depth, they could not be mapped, which makes it challenging to determine the triggers of the submarine slope failures. Radiocarbon dating reveals that most of these surficial landslide deposits are younger than 500 years old and that they were most likely triggered at different times. This finding highlights a high recurrence rate of slope failures within the fiord, suggesting that localised triggers are responsible for slope failures within the fiord, as opposed to widespread, seismically induced triggers which do not occur as frequently in the study area. In addition, the elongated morphology of the landslide deposits and the varying degrees of landslide deposit surface roughness supports localised point-source triggers. Since most landslides are associated with subaerial outwash fans and deltas, we suggest that triggers of these relatively frequent submarine landslides within Pangnirtung Fiord include rapid floodwater input, subaerial debris flows, and sea-ice loading during low tide.&lt;/p&gt;&lt;p&gt;This research shows that slope failures in a high-latitude fiord are affected by the interaction of numerous subaerial and submarine processes, leading us to speculate that a potential increase in the frequency of subaerial debris flows and river floods due to climate change may increase the recurrence of submarine landslides.&lt;strong&gt; &lt;/strong&gt;&lt;/p&gt;

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