scholarly journals A Large Old Landslide in Sichuan Province, China: Surface Displacement Monitoring and Potential Instability Assessment

2021 ◽  
Vol 13 (13) ◽  
pp. 2552
Author(s):  
Siyuan Ma ◽  
Chong Xu ◽  
Xiaoyi Shao ◽  
Xiwei Xu ◽  
Aichun Liu
Keyword(s):  
Rock Mass ◽  
Deformation Rate ◽  
Early Recognition ◽  
Surface Displacement ◽  
Sichuan Province ◽  
Middle Part ◽  
Deformation Monitoring ◽  
Disaster Mitigation ◽  
Landslide Body ◽  
Unstable Rock

Using advanced Differential Interferometric Synthetic Aperture Radar (InSAR) with small baseline subsets (SBAS) and Permanent Scatter Interferometry (PSI) techniques and C-band Sentinel-1A data, this research monitored the surface displacement of a large old landslide at Xuecheng town, Lixian County, Sichuan Province, China. Based on the MassMov2D model, the effect of the dynamic process and deposit thickness of the potentially unstable rock mass (deformation rate < −70 mm/year) on this landslide body were numerically simulated. Combined with terrain data and images generated by an Unmanned Aerial Vehicle (UAV), the driving factors of this old landslide were analyzed. The InSAR results show that the motion rate in the middle part of the landslide body is the largest, with a range of −55 to −80 mm/year on average, whereas those of the upper part and toe area were small, with a range of −5 to −20 mm/year. Our research suggests that there is a correlation between the LOS (line of sight) deformation rate and rainfall. In rainy seasons, particularly from May to July, the deformation rate is relatively high. In addition, the analysis suggests that SBAS can provide smoother displacement time series, even in areas with vegetation and the steepest sectors of the landslide. The simulation results show that the unstable rock mass may collapse and form a barrier dam with a maximum thickness of about 16 m at the Zagunao river in the future. This study demonstrates that combining temporal UAV measurements and InSAR techniques from Sentinel-1A SAR data allows early recognition and deformation monitoring of old landslide reactivation in complex mountainous areas. In addition, the information provided by InSAR can increase understanding of the deformation process of old landslides in this area, which would enhance urban safety and assist in disaster mitigation.

Analysis of Unstable Rock-Mass Stability Based on Limit Equilibrium Method and Strength Reduction Method

2016 ◽  
Vol 858 ◽  
pp. 73-80
Author(s):  
Ying Kong ◽  
Hua Peng Shi ◽  
Hong Ming Yu
Keyword(s):  
Rock Mass ◽  
Failure Mode ◽  
Posterior Margin ◽  
Reduction Method ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Strength Reduction ◽  
Strength Reduction Method ◽  
Rock Masses ◽  
Unstable Rock

With the slope unstable rock masses of a stope in Longsi mine, Jiaozuo City, China as the target, we computed and analyzed the stability of unstable rock masses using a limit equilibrium method (LEM) and a discrete element strength reduction method (SRM). Results show that the unstable rock masses are currently stable. Under the external actions of natural weathering, rainfall and earthquake, unstable rock mass 1 was manifested as a shear slip failure mode, and its stability was controlled jointly by bedding-plane and posterior-margin steep inclined joints. In comparison, unstable rock mass 2 was manifested as a tensile-crack toppling failure mode, and its stability was controlled by the perforation of posterior-margin joints. From the results of the 2 methods we find the safety factor determined from SRM is larger, but not significantly, than that from LEM, and SRM can simulate the progressive failure process of unstable rock masses. SRM also provides information about forces and deformation (e.g. stress-strain, and displacement) and more efficiently visualizes the parts at the slope that are susceptible to instability, suggesting SRM can be used as a supplementation of LEM.

scholarly journals Study on the Deformation Mechanism of Soft Rock Roadway under Blasting Disturbance in Baoguo Iron Mine

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Hong-di Jing ◽  
Yuan-hui Li ◽  
Kun-meng Li
Keyword(s):  
Rock Mass ◽  
Deformation Mechanism ◽  
Soft Rock ◽  
Deformation Monitoring ◽  
Underground Mines ◽  
Blasting Vibration ◽  
Iron Mine ◽  
The Stability ◽  
Soft Rock Roadway ◽  
Rock Roadway

In order to study the deformation mechanism of soft rock roadway in underground mines, it is necessary not only to study the influence of the dynamic disturbance caused by the cyclic mining blasting vibration on the stability of the soft rock roadway but also to study the degradation of the roadway surrounding rock itself and other factors. The paper presented a synthetic research system to investigate the factors that influence roadway rock structure deterioration in Baoguo Iron Mine. Firstly, the stability of rock mass was analyzed from the perspective of the physical and structural characteristics of the rock mass. Afterwards, according to monitoring data of mining blasting vibration, a suitable safety blasting prediction model for Baoguo Iron Mine was determined. And then, combining the results of mining blasting vibration monitoring and deformation monitoring, the effect of cyclic mining blasting on the stability of the soft rock roadway was obtained. By systematically studying the intrinsic factors of rock quality degradation and external environmental disturbances and their interactions, this paper comprehensively explores the deformation mechanism of soft rock roadway and provides the support for fundamentally solving the large deformation problems of soft rock roadway in underground mines.

scholarly journals Sentinel-1 SAR Interferometry for Surface Deformation Monitoring in Low-Land Permafrost Areas

2018 ◽  
Vol 10 (9) ◽  
pp. 1360 ◽  
Author(s):  
Tazio Strozzi ◽  
Sofia Antonova ◽  
Frank Günther ◽  
Eva Mätzler ◽  
Gonçalo Vieira ◽  
...  
Keyword(s):  
Time Series ◽  
Surface Displacement ◽  
Deformation Monitoring ◽  
In Situ Measurements ◽  
River Delta ◽  
Sar Interferometry ◽  
The Arctic ◽  
Lena River ◽  
Lena River Delta

Low-land permafrost areas are subject to intense freeze-thaw cycles and characterized by remarkable surface displacement. We used Sentinel-1 SAR interferometry (InSAR) in order to analyse the summer surface displacement over four spots in the Arctic and Antarctica since 2015. Choosing floodplain or outcrop areas as the reference for the InSAR relative deformation measurements, we found maximum subsidence of about 3 to 10 cm during the thawing season with generally high spatial variability. Sentinel-1 time-series of interferograms with 6–12 day time intervals highlight that subsidence is often occurring rather quickly within roughly one month in early summer. Intercomparison of summer subsidence from Sentinel-1 in 2017 with TerraSAR-X in 2013 over part of the Lena River Delta (Russia) shows a high spatial agreement between both SAR systems. A comparison with in-situ measurements for the summer of 2014 over the Lena River Delta indicates a pronounced downward movement of several centimetres in both cases but does not reveal a spatial correspondence between InSAR and local in-situ measurements. For the reconstruction of longer time-series of deformation, yearly Sentinel-1 interferograms from the end of the summer were considered. However, in order to infer an effective subsidence of the surface through melting of excess ice layers over multi-annual scales with Sentinel-1, a longer observation time period is necessary.

scholarly journals Research on Deformation Mechanisms of a High Geostress Soft Rock Roadway and Double-Shell Grouting Technology

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Fengnian Wang ◽  
Shizhuang Chen ◽  
Pan Gao ◽  
Zhibiao Guo ◽  
Zhigang Tao
Keyword(s):  
Mechanical Properties ◽  
Rock Mass ◽  
Large Deformation ◽  
Coal Mine ◽  
Soft Rock ◽  
In Situ Stress ◽  
Deformation Monitoring ◽  
Deformation And Failure ◽  
Working Face ◽  
High Geostress

In this study, the deformation characteristics and mechanical properties of coal and rock mass in the S2N5 working face of the Xiaokang coal mine are analyzed to address the problem of large deformation of soft rocks with high in situ stress surrounding roadways. Through a newly developed grouting pipe, a double-shell grouting technology, consisting of low-pressure grouting and high-pressure split grouting, is proposed for the Xiaokang coal mine. In addition, the effect of grouting is evaluated by borehole peeping and deformation monitoring. The results show that the double-shell grouting technology can effectively improve the overall mechanical properties of the surrounding coal and rock mass, preventing the large deformation and failure of the roadway. This technology can be useful when analyzing and preventing large deformation of soft rock roadways.

scholarly journals Chasing a hidden fracture using seismic refraction tomography: case study Preonzo, Switzerland

2020 ◽  
Author(s):  
Mauro Häusler ◽  
Franziska Glüer ◽  
Jan Burjánek ◽  
Donat Fäh
Keyword(s):  
Rock Mass ◽  
Seismic Refraction ◽  
Slope Instability ◽  
Mode Analysis ◽  
Mode Shapes ◽  
Small Aperture ◽  
Higher Modes ◽  
Refraction Tomography ◽  
Tension Cracks ◽  
Unstable Rock

&lt;p&gt;The Preonzo rock slope instability in southern Switzerland partly collapsed in 2012, releasing a volume of ~210&amp;#8217;000 m3 and leaving behind an unstable rock mass of about 140&amp;#8217;000 m3. Shortly after the collapse, a small-aperture seismic array measurement was performed on the remaining unstable volume. The analysis of these data showed a fundamental resonance frequency of about 3.5 Hz and strong wavefield amplifications with factors of more than 30 in direction perpendicular to open tension cracks. Normal mode analysis by frequency domain decomposition using the fundamental and several higher modes allowed for mapping the fracture network of the instability.&lt;br&gt;However, the observed amplification factors and mode shapes could not be explained solely by the open tension cracks visible at the surface. Strong amplifications, especially at frequencies of higher modes, were observed on the uphill part of the rear fracture, which was supposed to be outside the presumed unstable area. The zone where amplifications rapidly decreased in the uphill direction coincides roughly with a geomorphological lineament in the field, interpreted as an additional, but hidden, rear fracture.&amp;#160;&lt;br&gt;We performed active seismic refraction tomography across this lineament and discovered distinct low velocity anomalies in the transition zone from high to low amplifications, supporting the interpretation of an additional fracture. Considering this new finding, the volume of the unstable rock mass increases by about 40 %.&amp;#160;&lt;/p&gt;

scholarly journals Spatial and Temporal Evolution of the Infiltration Characteristics of a Loess Landslide

2020 ◽  
Vol 9 (1) ◽  
pp. 26 ◽  
Author(s):  
Dongdong Yang ◽  
Haijun Qiu ◽  
Yanqian Pei ◽  
Sheng Hu ◽  
Shuyue Ma ◽  
...  
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Temporal Evolution ◽  
Infiltration Rate ◽  
Middle Part ◽  
Loess Landslide ◽  
Infiltration Rates ◽  
Disturbed Soil ◽  
Landslide Body ◽  
Over Time

Infiltration plays an important role in influencing slope stability. However, the influences of slope failure on infiltration and the evolution of infiltration over time and space remain unclear. We studied and compared the infiltration rates in undisturbed loess and disturbed loess in different years and at different sites on loess landslide bodies. The results showed that the average initial infiltration rate in a new landslide body (triggered on 11 October 2017) were dramatically higher than those in a previous landslide body (triggered on 17 September 2011) and that the infiltration rates of both landslide types were higher than the rate of undisturbed loess. The initial infiltration rate in the new landslide body sharply decreased over the 4–5 months following the landslide because of the appearance of physical crusts. Our observations indicated that the infiltration rate of the disturbed soil in a landslide evolved over time and that the infiltration rate gradually approached that of undisturbed loess. Furthermore, in the undisturbed loess, both the initial and quasi-steady infiltration rates were slightly higher in the loess than in the paleosol, and in the previous landslide body, the infiltration rate was highest in the upper part, intermediate in the middle part, and lowest in the lower part. This study can help us to better understand the evolution process of infiltration in undisturbed loess, previous landslides, and new landslides.

scholarly journals Application of FBG Sensing Technology to Internal Deformation Monitoring of Landslide

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Haiyou Peng ◽  
Bolin Chen ◽  
Ping Dong ◽  
Si chen ◽  
Yunping Liao ◽  
...  
Keyword(s):  
Slip Surface ◽  
Survey Methods ◽  
Surface Displacement ◽  
Deformation Monitoring ◽  
In Situ Monitoring ◽  
Fiber Grating ◽  
Monitoring Point ◽  
Sensing Technology ◽  
Internal Deformation

Limited by geological survey methods, processes, and cost, it has long been a difficult thing to accurately detect the position of landslide slip surface and monitor the landslide internal deformation. Fiber Bragg grating (FBG) sensing technology has been widely used in geological engineering and geotechnical engineering due to its high-precision property. In this research, FBG sensing technology was applied to the monitoring of landslide internal deformation in Toudu, Chongqing, China. The in situ monitoring by FBG accurately determined the position of the landslide slip surface. Based on the relationship between fiber grating strain and deflection, the formula between landslide internal deformation and fiber grating strain was obtained, and the rationality of the formula was verified by the monitoring data of surface displacement. Finally, the internal deformation at the monitoring point of the Toudu landslide was calculated and the mechanism of the landslide was analyzed.

Engineering-geological characterisation and activity analysis of a deep-seated rockslide near Laatsch (South Tyrol)

2020 ◽  
Author(s):  
Klaus Voit ◽  
Christina Rechberger ◽  
Christine Fey ◽  
Volkmar Mair ◽  
Christian Zangerl
Keyword(s):  
Rock Mass ◽  
Laser Scanning ◽  
Failure Process ◽  
Deformation Monitoring ◽  
Permafrost Degradation ◽  
Large Area ◽  
Mountain Ridge ◽  
Worst Case ◽  
Deformation And Failure ◽  
South Tyrol

&lt;p&gt;Deep-seated rockslides in Alpine areas are common phenomena, especially if geological and tectonic conditions enable a disintegration of the rock mass extending deep into the ground. Furthermore, the failure process usually is controlled by groundwater flow, permafrost degradation and rock weathering mostly by input of surface water along geological discontinuities as well as by temperature fluctuations. Thereby, extensive slope areas can become unstable and &amp;#8211; in the worst case &amp;#8211; can endanger population and infrastructure.&lt;/p&gt;&lt;p&gt;At the valley entrance of the M&amp;#252;nstertal at the stream Rambach (South Tyrol, Italy), close to the national road SS41 ca. road kilometres 6.5, a deep-seated rockslide was formed at a south-facing mountain slope with a gradient of ca. 30 - 50&amp;#176;. The U-shaped valley was formed by glaciers, whereby the valley floor is filled with alluvial sediments. The rockslide is approx. 400 m wide, measures approx. &amp;#160;700 m in height at its longest extension and comprise a total rock volume of approx. &amp;#160;500,000 m&amp;#179;. The geological bedrock consists of foliated metamorphic rocks (mainly orthogneisses) which partially is covered by talus and glacial sediments. In the past and still continuing, the area was exposed to major tectonic stress due to its close range to the Vinschgau and Schlinig fault zones generating a dense fracture system in the rock mass.&lt;/p&gt;&lt;p&gt;Since several years, the highly active rockslide shows displacements of several metres per year. In 2014, the road SS41 was relocated over a length of ca. 800&amp;#160;m to the other side of the Rambach due to ongoing rock fall events. Field surveys conducted at that time already showed clear geomorphological indications for the destabilization of a large area at the mountain ridge by the presence of primary and secondary scarps, tension cracks, and up-hill facing scarps in the slope area ranging up to the mountain ridge.&lt;/p&gt;&lt;p&gt;Geological field studies in 2018 and 2019 were carried out to investigate the rockslide geometry and kinematics as well as deformation and failure processes. Quantification of the deformation rates was carried out by multi-temporal terrestrial laser scanning (TLS). From a kinematic point of view, the rockslide can be divided into different slabs of varying activity showing actual deformation rates between approx. 0.3 to 3.6 m per year. The individual slabs show a translational movement behaviour with minor internal deformation. However, also a rotational kinematics along polygonal slip surfaces was observed. Disintegration and formation of slabs mostly takes place along pre-existing steeply dipping joint surfaces.&lt;/p&gt;&lt;p&gt;In this contribution, a preliminary geological, geometrical and kinematical model of the current rockslide is presented by the detailed analyses of field mapping and deformation monitoring data.&lt;/p&gt;

Numerical Investigation of the Minimum Roof Thickness of Mining Stope in Bailing Copper-Zinc Mine

2014 ◽  
Vol 670-671 ◽  
pp. 668-673
Author(s):  
Jiang Feng Ma ◽  
Xiu Li Zhang ◽  
Yu Yong Jiao ◽  
Hu Nan Tian
Keyword(s):  
Rock Mass ◽  
Numerical Model ◽  
Stress Distribution ◽  
Numerical Investigation ◽  
Damage Zone ◽  
Three Dimensional ◽  
Surface Displacement ◽  
Ore Body ◽  
Zinc Mine ◽  
Copper Zinc

A three-dimensional numerical model of the rock mass including ore body is established by FLAC3D software, and then the surface subsidence caused by backfilling under different roof thicknesses of mining stope (the vertical distance between upper mining limit and surface) are calculated and analyzed. By comparing the surface displacement, the stress distribution, and the damage zone under different conditions, the minimum roof thickness is determined.

Sign in / Sign up

Export Citation Format

Share Document