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Geologic section map of the secondary faults on the hanging wall of the West Qinling fault. a The landslide is located on the hanging wall of the Tianshui–Fenghuang fault; b secondary faults with the same southward trend developed here, dislocating the Neogene mudstone; and c secondary faults as well as joints developed within the fault zone cutting the mudstone into a fragmented texture
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A landslide occurred on the morning of December 16, 2013, in Liujiabao village, Tianshui City, Gansu Province, China. The 260,000 m3 of landslide material traveled a distance of 190 m downslope and damaged a village road and several farmhouses before it stopped on the middle of the slope. These landslide materials are still threatening the lives an...
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Citations
... The plasticity and deformability of Neogene mudstones generally play a crucial role in geological disasters such as landslides, accompanying disintegration and weakening the strength of mudstone [4][5][6][7]. In addition, the burial depth also affects the disintegration of Neogene mudstone and the progression of landslides [8,9], with varying stress states, rock transformations, and geological effects at distinct levels [10,11]. Thus, a thorough investigation on the disintegration characteristics of Neogene mudstones at various burial depths is essential to better our comprehension of mudstone landslide mechanisms and the recognition of potential landslide hazards [12][13][14][15]. ...
The complex structure of Neogene mudstone plays an important role in geological disasters. A close relationship exists between the mechanisms of mudstone landslides and the disintegration characteristics of rocks. Therefore, understanding the disintegration characteristics of Neogene mudstone at different depths is crucial for enhancing engineering safety and assessing landslide stability. This study employed Neogene mudstone from different depths to perform disintegration and plastic limit experiments and revealed the sliding mechanisms of landslides involving Neogene mudstone, providing theoretical support for mitigating mudstone geological disasters. Our results demonstrate that Neogene mudstone from different depths experiences varied stress conditions and pore water pressure due to geological actions, significantly affecting the disintegration characteristics. By ignoring the factors of the slip surface, the slake durability index of mudstone decreases with increasing burial depth, while the plasticity limit index tends to rise. The influence of groundwater, geo-stress, and pore structure on Neogene mudstones at different depths results in overall weak stability and disintegration. Landslide occurrences are likely connected to the mechanical properties of mudstones at the slip surface, where a low slake durability index and higher plasticity index make the mudstones prone to fracturing, breaking, and disintegrating once in contact with water.
... According to historical records, this area has experienced many large earthquakes in the past, such as the Ms 7.0 Gangu West earthquake in 143 A.D, the Ms 7.0 Tianshui earthquake in 734 A.D, and the Ms 6( 1 / 2 ) Wushan earthquake in 1765 A.D, which induced tens of thousands of loess landslides (Zhang et al. 2020a, b;Wang et al. 2020b;Xin et al. 2017). Historical earthquake-induced landslides are generally large scale, which are prone to be reactivated by rainfall, river erosion, and engineering activities (Peng et al. 2015(Peng et al. , 2016Sun et al. 2017;Wang et al. 2020a;Bhambri et al. 2017). ...
On April 30, 2022, the old Wangqi landslide was reactivated in Weinan Town, Tianshui City, Gansu Province, China. The landslide with a volume of approximately 547,500 m 3 destroyed 30,000 m 2 of farmland and 100 m of the rural road. Based on field investigation, unmanned sub-aerial photography, and numerical calculation, the reactivation mechanism, run-out processes, and failure mode of the landslide were analyzed. The results indicate that the new Wangqi landslide is a typical reactivated thrust-load-caused loess landslide affected by the leakage of water storage wells, and two water storage wells mainly control its boundary. The new Wangqi landslide has apparent characteristics of deformation transferring from the trailing edge to the leading edge, and its failure pattern is creep-cracking type. The duration of the landslide movement is approximately 25 s, the maximum velocity of the sliding mass is about 2.5 m/s, and about 9% of the potential energy is converted into kinetic energy during the landslide movement. The landslide undergoes four stages from deformation to failure: deep creep, tension cracking, penetration of sliding zone, and sliding stages. Our results may be used as a reference for the risk management of landslides induced by human engineering activities in rural areas.
... Landslides are one of the major and most frequently occurring natural hazards. The stability analysis and sliding evolution simulation of single landslides and the distribution characteristics and susceptibility evaluation of regional landslides have always been research hotspots [1,2]. Our work focuses on the study of regional landslides. ...
Landslides are a typical geological hazard that endangers people’s lives and property in the Loess Plateau. The destructiveness of large-scale landslides, in particular, is incalculable. For example, traffic disruptions, river blockages, and house collapses may all result from landslides. Thus, it is urgent to compile a complete inventory of landslides in a specific region. The investigation object of this study is Baoji City, Shaanxi Province, China. Using the multi-temporal high-resolution remote sensing images from Google Earth, we preliminarily completed the cataloging of large-scale (area > 5000 m2) landslides in the study area through visual interpretation. The inventory was subsequently compared with the existing literature and hazard records for improvement and supplement. We decoded 3422 landslides with a total area of 360.7 km2 and an average area of 105,400 m2 for each individual landslide. The largest landslide had an area of 1.71 km2, while the smallest one was 6042 m2. In previous studies, we analyzed these data without describing the data sources in detail. We now provide a shared dataset of each landslide in shp format, containing geographic location, boundary information, etc. The dataset is significantly useful for understanding the distribution characteristics of large-scale landslides in this region. Moreover, it can serve as basic data for the study of paleolandslide resurrection.
... Other characteristics include strong hydrophilicity and poor water permeability (Li (2017)) [31]. The presence of red beds allowed the overlying slope to slide along a gently inclined layer during the rainy season [32]. Under specific physical and chemical conditions, the low-strength plastic soil, soft plastic soil, flowing plastic rock, and soil mass that are created in the sliding zone are a key part of landslides. ...
The survey area is located in the planning area of Longquan national urban park, with frequent human activities, numerous water conservancy, transportation projects, and frequent geological disasters such as landslides. The Red Mudstone has low strength and easy to soften in the case of water, and it is very prone to landslide in rainy season. At present, there are many studies on Red Mudstone Landslides, but most of them are analyzed by geological means, and the monitoring process is also dominated by surface deformation and settlement; there is less analysis with hydrogeological that is caused by rainfall and human activities. For Red Mudstone Landslides, to effectively reveal and analyze the process of the Slip Mechanism, we need to carry out the characteristics of hydrogeological structure and underground physical structure, and compare with surface monitoring and point geological structure. In this study, a one-year field survey and hydrogeophysical survey were carried out. Combined with the characteristics of environmental geology, the geophysical forward modeling problem based on finite element method was used to verify the influence of rainfall on the electrical characteristics of underground media. The smoothness constrained least square method and three-dimensional unstructured grid method are used to interpret the ERT data, analyze the abnormal patterns of electrical structure of landslide in different seasons, and correspond well with the GPR data. According to the characteristics of surface vegetation and weathering, as well as the displacement and settlement monitoring after landslide, the spatial characteristics of red bed landslide are revealed, and the relationship between landslide, rainfall, and human activities is clarified.
... Landslides often occur on fault zones when triggered by earthquakes or concentrated rainfall and cause considerable fatalities and economic losses (Guo et al. 2015;Kojima et al. 2015;Peng et al. 2016). Relatively fragmentized geological structure formed by fault activities in history is prone to landslides. ...
The geological structures of fault zones control the occurrence of landslides and determine their characteristics and motion styles, especially in igneous rock areas with high rock strength. On 20 May 2021, a fault-controlled landslide occurred during heavy rainfall near Chengtian village in Zhejiang Province, China. The landslide abruptly destroyed a provincial highway in front of the slope and rushed into a river resulting in a barrier lake, which blocked local traffic for 17 days. The pseudotachylites, scratches and striations observed on the exposed impermeable breccia bedrock confirmed the sliding surface as part of the Cretaceous fault plane. The original rhyolite slope located on the fault zone had been subjected to weathering, creating favourable geological and hydrogeological structures for a landslide. Due to the low fluidity of the sliding materials, the sliding mass decelerated quickly and blocked the river, resulting in a geo-disaster chain. This paper presents a typical instance of landslides controlled by geological structures on a fault zone.
... Loess-mudstone landslides are one of the most catastrophic slope instability phenomena that has distributed widely and occurred frequently in the Loess plateau (Wen et al. 2005;Wen and He 2012), posing a serious risk to construction infrastructures and human lives. Thus, there has been many researchers paid attention to the mechanical behavior of loess-mudstone landslides soils (Kimura et al. 2015;Mu et al. 2019;Peng et al. 2015;Peng et al. 2016). ...
... Chen et al. (2014) pointed out that the slip zone soils of loess-mudstone landslides exhibit strainsoftening behavior, which may be caused by the existing of fine soil particles such as expanded clay particles in the slip zone soils. Peng et al. (2016) conducted a field survey on the Liujiabu loessmudstone landslide and concluded that the evolution process of landslides is controlled by the fault fracture. Li et al. (2016) carried out a semi-similar material physical model test to investigate the initiating conditions of precipitation-induced loess-mudstone landslides and proposed that the initiation of landslides are related to factors such as precipitation intensity, duration and thickness of overlying loess soils. ...
Whereas loess-mudstone landslides are widely distributed and frequently occurred at the loess Plateau, this type of landslides is hard to detect due to its particularity, and easily generates serious losses. To clarify the shear characteristics and formation mechanism of loess-mudstone landslides, field investigations, ring shear tests and numerical simulation analyses were performed on the loess specimens collected from the Dingjiagou landslide in Yan’an city, China. The test results showed that both the peak strength and residual strength of slip zone soils have a decreasing tendency with moisture content, while the increasing of normal stress caused an increase in the shear strength. These phenomena indicate that the rise in the moisture content induced by precipitation or the decreasing of normal stress due to excavation activities would result in the weakening of slip zone soils. Numerical simulations of the evolution process of slope failure using the finite element method were conducted based on the Mohr-Coulomb criterion. It was found that the heavy precipitation played a more important role in the slope instability compared with the excavation. In addition, the field investigation showed that loess soils with well-developed cracks and underlying mudstone soils provide material base for the formation of loess-mudstone landslides. Finally, the formation mechanism of this type of landslides was divided into three stages, namely, the local deformation stage, the penetration stage, the creeping — sliding stage. This study may provide a basis for understanding the sliding process of loess-mudstone landslides, as well as guidelines for the prevention and mitigation of loess-mudstone landslides.
... Likewise, the study by Irsyam et al. (1999) reported that the progression of rock disintegration was responsible for numerous instabilities during the construction of the Tulis hydroelectric power. Moreover, previous researchers also made similar observations that the instability of carbonaceous mudstone embankments is closely related to the weathering and disintegration of mudstone (Waroszewski et al. 2015;Peng et al. 2016). Zeng et al. (2019a, b) by crack experiments. ...
Carbonaceous mudstone is a common embankment material with the characteristics of water softening and water disintegration, which often causes the instability of embankments. This paper presents an experimental work on the disintegration characteristics and mechanisms of carbonaceous mudstone under the combined action of load and cyclic drying-wetting. Disintegration tests were conducted by a novel instrument. Afterward, the evolution of disintegration parameters [i.e., coefficient of uniformity (Cu), coefficient of curvature (Cc), disintegration rate (DRE), disintegration ratio (Dr), and fractal dimension (D)] during the disintegration process was studied. Finally, the gray relational theory was used to evaluate the impact of disintegration characteristics on the degree of stability of carbonaceous mudstone. The results show that the large particles decrease in number and the small particles increase in number with increasing drying-wetting cycles. Moreover, the DREs of carbonaceous mudstone are very high with final values larger than 10% in all cases. Generally, the larger the load is, the higher the DRE is, while the lower the Dr is. The D increases with the increase of load and number of cycles. The results of gray relation analysis show that the variation in the Dr is the best parameter for characterizing the disintegration of carbonaceous mudstone. The Dr of carbonaceous mudstone decreases with increasing number of drying-wetting cycles under different loads, which can provide a useful reference for the stability analysis and engineering practice of carbonaceous mudstone embankments.
... Loess forms through the deposition of aeolian sediments [1] in arid or semi-arid environments, so it normally has unique structural properties [2] and water sensitivity [3,4]. In many cases, such properties can result in negative effects, including extensive surface erosion [5,6] and catastrophic geological hazards [7][8][9]. Covering an estimated total area of 6.4 × 10 5 km 2 , the Loess Plateau has the most complex loess topography in China and, therefore, exhibits great environmental vulnerability to human activities [10,11]. Especially in recent years, frequent and intense disturbance by external factors, including human engineering activities [12,13] and extreme climate change [14,15], have exacerbated this vulnerability. ...
The structural index is an important quantitative parameter for revealing the structural properties of loess. However, there is no a widely accepted measurement method for structural index at present. This study aims at presenting a novel method for obtaining the loess structural index (LSI), based on the application of computed tomography (CT) scanning techniques and laboratory physico-mechanical tests. The mountainous area of Lvliang in northwest China was taken as the study area, and Late Pleistocene loess samples were taken from various sites in the region. Several physical parameters were first measured using laboratory tests, including dry density, pore ratio, and liquidity index. CT scanning was used to observe sample microstructures, and a mathematical relationship was established between CT image parameters and the physical property indices, through three dimensions (3D) reconstruction and slice porosity analysis. The results revealed that LSI can be expressed as a non-linear function related to CT image parameters, dry density, and the liquidity index of the loess. Compared with traditional calculation methods, this novel technique calculates the LSI by using an empirical formula, which is less labor-intensive. Such results indicate that the method warrants wide application in the future.
... Research into the characteristics and kinematic features of loess-mudstone landslides has attracted much attention from Chinese landslide experts. Many efforts have been made in this respect, for instance, through field surveys and remote sensing interpretation (RSI) (Wen et al. 2005;Peng et al. 2015Peng et al. , 2016Peng et al. , 2018bLi and Mo 2019), physical modelling tests (Li et al. 2016;Zhang et al. 2017a), and numerical simulations (Zhang et al. 2017b;Mu et al. 2020). Field investigations and RSI can provide evidence of the dynamic processes of landslides but cannot reveal their temporal evolution. ...
Loess-mudstone landslides are widely distributed in Northwest China. However, the deformation features and kinematic processes of these landslides are still not well understood. The Chenhecun landslide occurred on June 10, 2016, near Chenhe village, Dongxiang County, China. Based on detailed field surveys, Google Earth images, and borehole investigations, a geological profile of the landslide was constructed. Using the two-dimensional discrete element software MatDEM, this work analyses the deformation behaviours and kinetic characteristics of the landslide. In the dynamic analysis, the landslide failure process, velocity, displacement, heat generation, and energy conversion are taken into account. During the whole simulated landslide process, the sliding mass at the rear and bottom edges exhibits lower mobility than at the front and upper edges. The kinetic energy of the landslide dominates in the acceleration stage, and friction is the main source of energy dissipation during the entirety of the landslide movement. A band-like high-heat zone is formed near the sliding belt, and this zone expands forward with sliding. The gravitational potential energy is mainly converted into heat, kinetic energy, and elastic potential energy. In addition, the simulated geometry and accumulation characteristics from the MatDEM are in good agreement with the topographic features of the landslide. This work could provide an important reference for understanding the motion of similar geological hazards in the area.
... These include two mega projects for urban expansion; the Mountain Excavation and City Construction (MECC) and the Lanzhou New District (LZND) projects; and two large scale landscaping projects targeting mainly agriculture; the Gully Stabilization and Land Reclamation (GSLR) and the Gully Control and Highland Protection (GCHP). These projects are associated with the recent local Chinese Government policy for "land creation" to meet the need for the rapid economy growth in China, but there is a risk of a concomitant rise in loess-related geohazards where these projects are implemented without carefully designed engineering controls Li et al., 2014b;Peng et al., 2014Peng et al., , 2016a. To gain a better insight into the potential geohazards that might result from these ongoing large-scale engineering activities in the Loess Plateau, there is a need to build on existing research foundations and further carefully investigate: (1) how changes in loess structure (from undisturbed to reworked/remolded) influences failure behavior; (2) how interactions between water and loess in these new landscapes can give rise to excessive volume changes (piping, subsidence, collapse, hydro-consolidation) and potentially catastrophic loess landslides; (3) how future seismic activity can affect loess deformation (e.g. ...
Loess is a meta-stable, cemented assemblage of mainly silt and clay-sized particles of low plasticity. When dry it behaves like a brittle material, but when wetted up the fabric rapidly collapses. Unique geomorphological features include extensive surface erosion, soil piping (loess ‘karst’), catastrophic landslides, and widespread collapse (hydro-consolidation). The Chinese Loess Plateau is a more or less continuous drape of thick loess covering some 440,000 km². It is one of China's regions that is most prone to geohazards. This paper reviews advances in the research related to loess geohazards, drawing particular attention to the need to apply research findings to recent, very large (mega-)construction projects in loess terrain such as the Mountain Excavation and City Construction in Yan'an levelling 78 km² for urban expansion, the Lanzhou New District creating 246 km² of new level ground for construction, and large engineered interventions in the landscape for gully control and land reclamation such as those in Shaanxi and Gansu generating agricultural land covering an area of some 8000 km². These projects are in response to increasing pressures to facilitate expansion of urban centres, their interconnecting infrastructures and their agricultural support systems. It is argued that, where proper application of scientific knowledge for engineering control (e.g. densification, drainage) of these new landscapes is absent, these projects could generate a substantial, and costly geohazard legacy for future generations.
