Analysis of instability conditions and failure mode of a special type of translational landslide using a long-period monitoring data: a case study of the Wobaoshi landslide (Bazhong city, China)

Abstract. A translational landslide comprising nearly horizontal sand and mud interbed was widely developed in the Ba river basin of the Qinba–Longnan mountain area. Scholars have conducted theoretical research on this rainfall-induced landslide; however, owing to the lack of landslide monitoring engineering and data, demonstrating and validating the theoretical research wasdifficult. This study considered a translational landslide with an unusual morphology: the Wobaoshi landslide, which is located in Bazhong city, China. First, the formation conditions of this landslide were ascertained through field exploration, and the deformation and failure characteristics of the plate-shaped sliding body were analyzed. Then, long-period monitoring engineering was conducted to obtain multi-parameter monitoring data, such as crack width, rainfall intensity, and pore-water pressure. Finally, through the mechanical model analysis of the multi-stage sliding bodies, the calculating formula of the maximum height of the multi-stage plate girders, hcr, was derived，and the long-period monitoring data were used to verify its accuracy. Combined with numerical simulation and calculations, the deformation and failure modes of the plate-shaped sliding bodies were analyzed and explored. In this paper, the multi-parameter monitoring data proved that the stability of the sliding body is affected greatly by the rainfall intensity and pore-water pressure and the pore-water pressure in the crack is positive for the beginning of the plate-shaped sliding bodies, and an optimization monitoring method for this type of landslide was proposed. Therefore, this paper has theoretical and practical significance for the intensive study of translational landslides in this area.

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Monitoring of Inland Tide Embankment of Binzhou Port

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1065-1069.499 ◽

2014 ◽

Vol 1065-1069 ◽

pp. 499-502 ◽

Cited By ~ 1

Author(s):

Jian Shan Gao

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Soil Mass ◽

Monitoring Data ◽

Structure Stability ◽

Integrated Monitoring ◽

Initial Stage ◽

Hyperbolic Curve ◽

Settlement Monitoring

For the purpose of foundation and structure stability during the construction of tide embankment, three monitoring projects including embankment settlement monitoring, berm platform settlement monitoring and pore water pressure monitoring are installed. Integrated monitoring data shows that foundation appears oversize instantaneous settlement on account of high construction speed, short loading interval at initial stage. Following with the shaping of embankment, stable monitoring data range, slow change rate and high dissipation speed of pore water pressure come along. Based on actual embankment settlement data, consolidation degree of soil mass is high and foundation stability becomes strong by means of hyperbolic curve.

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Analysis of the instability conditions and failure mode of a special type of translational landslide using long-term monitoring data: a case study of the Wobaoshi landslide (in Bazhong, China)

Natural Hazards and Earth System Science ◽

10.5194/nhess-20-1305-2020 ◽

2020 ◽

Vol 20 (5) ◽

pp. 1305-1319

Author(s):

Yimin Liu ◽

Chenghu Wang ◽

Guiyun Gao ◽

Pu Wang ◽

Zhengyang Hou ◽

...

Keyword(s):

Failure Mode ◽

Water Pressure ◽

Monitoring Data ◽

Geomechanical Model ◽

Deformation And Failure ◽

Translational Landslide ◽

Geological Conditions ◽

Long Term Monitoring ◽

Term Monitoring

Abstract. A translational landslide comprised of nearly horizontal sandstone and mudstone interbeds occurred in the Ba River basin of the Qinba–Longnan mountainous area. Previous studies have succeeded to some extent in investigating the formation mechanism and failure mode of this type of rainfall-induced landslide. However, it is very difficult to demonstrate and validate the previously established geomechanical model, owing to lack of landslide monitoring data. In this study, we considered a translational landslide exhibiting an unusual morphology, i.e., the Wobaoshi landslide, which occurred in Bazhong, China. First, geological conditions of this landslide were determined through field surveys, and the deformation and failure mode of the plate-shaped main bodies were analyzed. Second, long-term monitoring was performed to obtain multiparameter monitoring data (width of the crown crack, rainfall, and accumulated water pressure in cracks). Finally, an equation was developed to evaluate the critical water height of the multistage bodies, i.e., hcr, based on the geomechanical model analysis of the multistage main sliding bodies, and the reliability of this equation was verified using long-term relevant monitoring data. Subsequently, the deformation and failure mode of the plate-shaped bodies were analyzed and investigated based on numerical simulations and calculations. Thus, the monitoring data and geomechanical model proved that the accumulated water pressure in cracks makes cracks open much wider and causes the plate-shaped bodies to creep. Simultaneously, an optimized monitoring methodology was proposed for this type of landslide. Therefore, these research findings are of reference significance for the rainfall-induced translational landslides in this area.

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AN ESTIMATION METHOD OF PORE WATER PRESSURE USING FIELD MONITORING DATA AND TANK MODEL REGARDING SURFACE FAILURE

Journal of Japan Society of Civil Engineers Ser C (Geosphere Engineering) ◽

10.2208/jscejge.73.141 ◽

2017 ◽

Vol 73 (2) ◽

pp. 141-156

Author(s):

Mitsuru YABE ◽

Yusuke TERADA ◽

Satoshi NONAMI ◽

Kenji TOBITA ◽

Shoji UENO ◽

...

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Estimation Method ◽

Field Monitoring ◽

Monitoring Data ◽

Tank Model ◽

Surface Failure

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Mechanical Properties of Sandstone Roof and Surrounding-Rock Control of Mining Roadways Subject to Reservoir Water Disturbance

Advances in Civil Engineering ◽

10.1155/2021/6656812 ◽

2021 ◽

Vol 2021 ◽

pp. 1-16

Author(s):

Bin Ma ◽

Zaiqiang Hu ◽

Xingzhou Chen ◽

Lili Chen ◽

Wei Du

Keyword(s):

Crack Initiation ◽

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Surrounding Rock ◽

Water Inflow ◽

Reservoir Water ◽

Deformation And Failure ◽

Joint Dislocations ◽

Rock Structure

Sandstone-roofed roadways are susceptible to deformation and failure caused by reservoir-water-induced disturbances, thereby compromising human safety. Using rock-mechanics testing techniques, numerical simulations, and engineering principles, this study investigates the strength, deformation, and pore-structure characteristics of sandstone roofs as well as means to support the surrounding rock structure. The results obtained in this study reveal that the residual strain is proportional to the pore-water pressure, which, in turn, causes a significant reduction in the elastic modulus during the unloading phase. Furthermore, an increase in the pore-water pressure causes the shear failure of specimens in compression. The delay between crack initiation and specimen-volume expansion decreases. Moreover, the specimen demonstrates increased deformation and failure responses to changes in the confining pressure, thereby resulting in accelerated conversion. Changes in water inflow can be correlated to crack initiation, propagation, and fracture. This water inflow gradually increases with an increase in the osmotic pressure. Correspondingly, the volumetric strain required for maximum water inflow undergoes a gradual decrease. The increased water inflow can be considered a precursor to specimen failure. In addition, fractures in the surrounding rock structures are mainly caused by joint dislocations. The increase in pore pressure promotes the development of dislocation fractures in the deep surrounding rocks. Subsequently, these fractures overlap with their open counterparts to form large fractures; this increases the roadway-roof subsidence and layer separation of the shallow surrounding rocks, thereby further increasing the fracture count. Lastly, the use of high-performance rock bolts, cable-bolt reinforcements, and W-shaped steel bands is expected to ensure the stability of rocks surrounding sandstone-roofed roadways subject to water-pressure disturbances.

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Drained deformation and failure due to cyclic pore pressures in soft natural clay at low stresses

Canadian Geotechnical Journal ◽

10.1139/t87-026 ◽

1987 ◽

Vol 24 (2) ◽

pp. 208-215 ◽

Cited By ~ 4

Author(s):

K. D. Eigenbrod ◽

J.-P. Burak ◽

J. Graham

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Shear Stresses ◽

Alternative Mechanism ◽

Natural Clay ◽

Deformation And Failure ◽

First Approximation ◽

Pore Water Pressures ◽

Normal And Shear Stresses

Slow, recurring downslope movements in northern climates are frequently referred to as "creep movements," and are usually related to outwards freezing followed by vertical thawing movements. An alternative mechanism is examined in the reported test data.Undisturbed block samples of proglacial clay from a slope near yellowknife, N.W.T., have been tested by cyclically varying the pore-water pressure in triaxial specimens by an amount Δu, and measuring the resulting strains per cycle. The specimens were initially anisotropically consolidated with normal and shear stresses corresponding to those in the moving mantle. Drainage was permitted throughout the testing. This procedure represents changes that can occur in a natural slope from (a) seasonal groundwater level changes and (b) elevated pore-water pressures that accompany thawing. After 60–100 cycles, the pore-water pressure was systematically increased to the value Δuf at which the samples failed. This occurred on a steep, low-stress envelope, approximately c′ = 4 KPa, [Formula: see text]. The envelope is probably controlled by the nuggety macrostructure of the clay and appears to be slightly to the left of the [Formula: see text] locus.The strains per cycle were approximately linear in the range 30–100 cycles. As a first approximation they have been modelled as varying linearly with the ratio Δu/Δuf almost up to failure at Δu/Δuf = 1.0. Key words: downslope creep, solifluction, slope stability, clay, pore-water pressure, cyclic loading, low-stress failure.

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TIME TO THE END OF PRIMARY CONSOLIDATION (EOP) OF SOFT CLAYEY SOILS: CONCERNING THE EFFECT OF ATTERBERG’S LIMIT AND CYCLIC LOADING HISTORY

HUE UNIVERSITY JOURNAL OF SCIENCE TECHNIQUES AND TECHNOLOGY ◽

10.26459/hueuni-jtt.v128i2b.5424 ◽

2019 ◽

Vol 128 (2B) ◽

pp. 29-41

Author(s):

Trần Thanh Nhàn

Keyword(s):

Cyclic Loading ◽

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Clayey Soils ◽

Loading History ◽

Cyclic Shear ◽

Wide Range ◽

Primary Consolidation ◽

Time Required

In order to observe the end of primary consolidation (EOP) of cohesive soils with and without subjecting to cyclic loading, reconstituted specimens of clayey soils at various Atterberg’s limits were used for oedometer test at different loading increments and undrained cyclic shear test followed by drainage with various cyclic shear directions and a wide range of shear strain amplitudes. The pore water pressure and settlement of the soils were measured with time and the time to EOP was then determined by different methods. It is shown from observed results that the time to EOP determined by 3-t method agrees well with the time required for full dissipation of the pore water pressure and being considerably larger than those determined by Log Time method. These observations were then further evaluated in connection with effects of the Atterberg’s limit and the cyclic loading history.

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Conjectures, Hypotheses, and Theories of Drumlin Formation (In memory of Stanislaw Baranowski)

Journal of Glaciology ◽

10.3189/s0022143000011552 ◽

1981 ◽

Vol 27 (97) ◽

pp. 503-505 ◽

Cited By ~ 1

Author(s):

Ian J. Smalley

Keyword(s):

Shear Strength ◽

Pore Water ◽

Stress Level ◽

Critical Stress ◽

Pore Water Pressure ◽

Water Pressure ◽

Glacial Till ◽

Forming Process ◽

Stress Levels

AbstractRecent investigations have shown that various factors may affect the shear strength of glacial till and that these factors may be involved in the drumlin-forming process. The presence of frozen till in the deforming zone, variation in pore-water pressure in the till, and the occurrence of random patches of dense stony-till texture have been considered. The occurrence of dense stony till may relate to the dilatancy hypothesis and can be considered a likely drumlin-forming factor within the region of critical stress levels. The up-glacier stress level now appears to be the more important, and to provide a sharper division between drumlin-forming and non-drumlin-forming conditions.

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