44%of steep slope cropland in Europe vulnerable to drought

Steep-slope cropland plays a vital role in food production,economic development,ecosystem diversity,and Eu-ropean cultural heritage.However,these systems are susceptible to extreme weather events.The 2022 summer drought significantly impacted European agriculture,but the specific effects on steep-slope crops remain uncer-tain.Clarifying this is essential for comprehending similar future events and for implementing effective water management strategies to ensure the sustainability of steep-slope agriculture and associated ecosystem services.This study quantitatively analyzes the spatial distribution of twelve major European steep-slope(>12%)crops and assesses agricultural drought severity during the 2022 events using open-access spatial data.The satellite-based Vegetation Health Index(VHI)is utilized to identify critical hotspots.Results show that olive grove is the most widespread crop in steep slope agriculture(34%of total area),followed by wheat(24%),maize(16%),and vineyard(11%).Almost half of the steep-slope agriculture in Europe suffered drought during summer 2022.Vineyards were hardest affected at 79%,primarily in northern Portugal,northern Spain,southern France,and central Italy.Sunflowers followed at 62%,mainly in Spain,central Italy,southern France,and northern Roma-nia.Olive groves ranked third at 59%,with the most impact in northern Portugal,southern and central Spain,and southern Italy.Maize was also significantly affected at 54%.In this paper,we therefore highlight the need to increase steep-slope agriculture resilience by improving water management and promoting sustainable land practices.

Exploring mechanism of hidden,steep obliquely inclined bedding landslides using a 3DEC model:A case study of the Shanyang landslide in Shaanxi Province,China

Catastrophic geological disasters frequently occur on slopes with obliquely inclined bedding structures(also referred to as obliquely inclined bedding slopes),where the apparent dip sliding is not readily visible.This phenomenon has become a focal point in landslide research.Yet,there is a lack of studies on the failure modes and mechanisms of hidden,steep obliquely inclined bedding slopes.This study investigated the Shanyang landslide in Shaanxi Province,China.Using field investigations,laboratory tests of geotechnical parameters,and the 3DEC software,this study developed a numerical model of the landslide to analyze the failure process of such slopes.The findings indicate that the Shanyang landslide primarily crept along a weak interlayer under the action of gravity.The landslide,initially following a dip angle with the support of a stable inclined rock mass,shifted direction under the influence of argillization in the weak interlayer,moving towards the apparent dip angle.The slide resistance effect of the karstic dissolution zone was increasingly significant during this process,with lateral friction being the primary resistance force.A reduction in the lateral friction due to karstic dissolution made the apparent dip sliding characteristics of the Shanyang landslide more pronounced.Notably,deformations such as bending and uplift at the slope’s foot suggest that the main slide resistance shifts from lateral friction within the karstic dissolution zone to the slope foot’s resistance force,leading to the eventual buckling failure of the landslide.This study unveils a novel failure mode of apparent dip creep-buckling in the Shanyang landslide,highlighting the critical role of lateral friction from the karstic dissolution zone in its failure mechanism.These insights offer a valuable reference for mitigating risks and preventing disasters related to obliquely inclined bedding landslides.

Kinematic analysis of geosynthetics-reinforced steep slopes with curved sloping surfaces and under earthquake regions

A procedure of kinematic analysis is presented in this study to assess the reinforcement force of geosynthetics required under seismic loadings, particularly for steep slopes which are hardly able to maintain its stability. Note that curved sloping surfaces widely exist in natural slopes, but existing literatures were mainly focusing on a planar surface in theoretical derivation, due to complicated calculations. Moreover, the non-uniform soil properties cannot be accounted for in conventional upper bound analysis. Pseudo-dynamic approach is used to represent horizontal and vertical accelerations which vary with time and space. In an effort to resolve the above problems, the discretization technique is developed to generate a discretized failure mechanism, decomposing the whole failure block into various components. An elementary analysis permits calculations of rates of work done by external and internal forces. Finally, the upper bound solution of the required reinforcement force is formulated based on the work rate-based balance equation. A parametric study is carried out to give insights on the implication of influential factors on the performance of geosynthetic-reinforced steep slopes.

Assessment of soil erosion in the Irga watershed on the eastern edge of the Chota Nagpur Plateau,India

Human activities to improve the quality of life have accelerated the natural rate of soil erosion.In turn,these natural disasters have taken a great impact on humans.Human activities,particularly the conversion of vegetated land into agricultural land and built-up area,stand out as primary contributors to soil erosion.The present study investigated the risk of soil erosion in the Irga watershed located on the eastern fringe of the Chota Nagpur Plateau in Jharkhand,India,which is dominated by sandy loam and sandy clay loam soil with low soil organic carbon(SOC)content.The study used the Revised Universal Soil Loss Equation(RUSLE)and Geographical Information System(GIS)technique to determine the rate of soil erosion.The five parameters(rainfall-runoff erosivity(R)factor,soil erodibility(K)factor,slope length and steepness(LS)factor,cover-management(C)factor,and support practice(P)factor)of the RUSLE were applied to present a more accurate distribution characteristic of soil erosion in the Irga watershed.The result shows that the R factor is positively correlated with rainfall and follows the same distribution pattern as the rainfall.The K factor values in the northern part of the study area are relatively low,while they are relatively high in the southern part.The mean value of the LS factor is 2.74,which is low due to the flat terrain of the Irga watershed.There is a negative linear correlation between Normalized Difference Vegetation Index(NDVI)and the C factor,and the high values of the C factor are observed in places with low NDVI.The mean value of the P factor is 0.210,with a range from 0.000 to 1.000.After calculating all parameters,we obtained the average soil erosion rate of 1.43 t/(hm^(2)•a),with the highest rate reaching as high as 32.71 t/(hm^(2)•a).Therefore,the study area faces a low risk of soil erosion.However,preventative measures are essential to avoid future damage to productive and constructive activities caused by soil erosion.This study also identifies the spatial distribution of soil erosion rate,which will help policy-makers to implement targeted soil erosion control measures.

Extensive identification of landslide boundaries using remote sensing images and deep learning method

The frequent occurrence of extreme weather events has rendered numerous landslides to a global natural disaster issue.It is crucial to rapidly and accurately determine the boundaries of landslides for geohazards evaluation and emergency response.Therefore,the Skip Connection DeepLab neural network(SCDnn),a deep learning model based on 770 optical remote sensing images of landslide,is proposed to improve the accuracy of landslide boundary detection.The SCDnn model is optimized for the over-segmentation issue which occurs in conventional deep learning models when there is a significant degree of similarity between topographical geomorphic features.SCDnn exhibits notable improvements in landslide feature extraction and semantic segmentation by combining an enhanced Atrous Spatial Pyramid Convolutional Block(ASPC)with a coding structure that reduces model complexity.The experimental results demonstrate that SCDnn can identify landslide boundaries in 119 images with MIoU values between 0.8and 0.9;while 52 images with MIoU values exceeding 0.9,which exceeds the identification accuracy of existing techniques.This work can offer a novel technique for the automatic extensive identification of landslide boundaries in remote sensing images in addition to establishing the groundwork for future inve stigations and applications in related domains.

Deformation and failure of a high-steep slope induced by multi-layer coal mining

During underground mining,accurate revelation on the deformation and failure mechanisms of a high-steep slope under multi-layer mining conditions facilitates the prevention and control of geological disasters in mines.Numerical simulation based on discrete element theory can be used to explore the characteristics and mechanism of action of deformation and failure of a slope under complex geological and multi-layer mining conditions.By utilising PFC2 D(particle flow code) software,the deformation and failure characteristics of a high-steep slope in Faer Coal Mine in Guizhou Province,China were investigated.Additionally,the mechanism of influence of different numbers of mining layers on the deformation and failure of the high and steep slope was elucidated.The result showed that after the goaf passed by the slope toe,multi-layer mining aggravated the subsidence and deformation of the slope toe:the slope toppled forward as it sank.The toppling of the slope changed the slope structures:the strata in the front of the slope were transformed from anti-dip to down-dip features.Extruded by collapsedtoppled rock mass,the slope toe and the rock mass located in the lower part of the slope toe generally exhibited a locking effect on the slope.Multi-layer mining degraded the overall stability of the slope,in that the total displacement of the slope was much greater than the total mining thickness of the coal seams.Based on the aforementioned research,ideas for preventing and controlling geological disasters during mining operations under a high-steep slope were proposed.

Sensitivity analysis for parameters of a monitoring system for steep slopes of open-pit mines

Monitoring the stability of steep slopes of open-pit mines is a major issue relating to production safety in mines.In order to determine the technical parameters of a new type of supervising system applied in monitoring steep slopes of open-pit mines,the MSARMA method was used to establish analytical models for the monitoring system,given various parameter settings based on the description of mechanical monitoring principles.We used this sensitivity analysis to conclude that the setting of the most sensitive location of a mechanical monitoring system should be within a range of 1/5～1/2 of the lower part in a vertical direction of steep slopes,with a rational and feasible range of the dip angle setting between 0°～20°.Given the analytical results of our on-site experiments,we have shown that the parameters determined reflect the stability of steep slopes accurately and effectively.These conclusions provide a basis for the application of a new type of steep slope stability monitoring technology in open-pit mines.

Quantitative analysis of biotechnical reinforcement for a steep slope consisting of composite coal-gangue-soil medium adjacent to a mined-out area

The engineering and geological characteristics of a steep slope consisting of coal gangue, rock and soil medium in Huating coal mine have been comprehensively investigated. Owing to humid weather, heavy rainfall, vegetation and porous characteristics of the soil and rock mass, the steep slope will be destabilized and induce mud-rock flow or derive hazard easily. Firstly, based on the classical slope reinforcement theory, some regularity between the shear and displacement in the destabilized zone of the slope with or without root strength contribution is presented. Then, based on the experimental and statistical analysis of root strength, hydrological characteristics and stability status, etc., some possible biotechnical techniques for reinforcement of the steep slope have been suggested. These methods are important for quantitative analysis of destabilization of the slope and design of the biotechnical reinforcement.

Finite element analysis of steep excavation slope failure by CFS theory

The distribution of Coulomb failure stress （CFS） change in the steep excavation slope is calculated by finite element method in this paper, and the failure mechanics under different conditions have been investigated. Comparing the CFSs before and after the slope excavation （stress loading and unloading processes）, the dangerous internal zone and the most likely failure external area are attained. Given the shear cracks on the top surface while tensile stress or cracks along the toe of the slope, we analyze the high cutting-angle steep slope in Kaixian county of the Three Gorges Reservoir region. We bring forward that the peak value of CFS after excavation can reach to the order of 0.1 MPa, which is greatly higher than that of before. Our preliminary results are useful for optimizing the reinforcement structure during the steep slope stabilization engineering.

Study on high and steep slope stability of surface mine based on RFPA-SRM

The instability and failure mechanism of high and steep slopes in surface mines, and the basis for some reasonable landslide prevention measures were provided using the RFPA-SRM. Based on the actual progress of the Pingzhuang Western Surface Mine and based on strength reduction method, the dynamic instability processes of the top high and steep slope was simulated. Also, the landslide mode was determined, the characteristics of the displacement distribution, the deformation, failure, and the stress distribution in the slope were demonstrated, and the stability was calculated. Conclusions can be drawn as follows： the landslide or failure of high and steep slopes on a surface mine is a gradual process, in which the slope undergoes the generation, expansion, and connection of the fractures and the displacement increases until landslide occurs; a small portion of the upper rocks fail due to the tension and the lower rocks fail due to the shear; the potential sliding surface is combined and the essential cause of the landslide is the shear stress concentration.

Finite element analysis of displacements of double pile-column bridge piers at steep slope

In order to study bearing characteristics of bridge pile at steep slope under complex loads in mountians, according to double pile-column bridge piers engineering at steep slope and test models in laboratory, finite element analysis of pile-column bridge piers was carried out using software ADINA under different loadings, such as horizontal loading in the longitudinal direction along bridge, vertical loadings, slope top loadings and complex loadings. The numerical simulation results show that displacements of front pile pier top and back pile pier top are different under horizontal loadings in the longitudinal direction along bridge or vertical loadings, the displacements of front pile pier top are higher than those of back pile pier top, and its difference increases with the increase of loadings. Vertical displacements will also appear under slope top loadings, and displacements of front pier top are higher than those of back pier top too, while its difference reduces with the increase of loadings. Displacements of both front pile pier top and back pile pier top under comlex loading are larger than those under single loading.

Research on Deformation and Force of Bridge Pile Foundation on High and Steep Slope in Mountainous Area

With the rapid development of my country’s economy, the demand for infrastructure construction is also increasing. However, in most areas of China, the terrains are mountainous and hilly. Some projects have to be built on steep slopes. Choosing viaducts or half-bridges on high-steep slopes is not only conducive to the protection of the surrounding environment, but also conducive to the stability of the slope. Bridges usually choose the form of pile foundation-high pier bridge. This paper uses numerical simulation to study and analyze the bridge pile foundation of the slope section. Relying on actual engineering, use the finite element software ABAQUS6.14 to establish a three-dimensional finite element model to study the bearing mechanism and mechanical characteristics of the pile foundation under vertical load, horizontal load and inclined load, discuss the influence of the nature of the soil around the pile and the stiffness of the pile body on the deformation and internal force of the bridge pile foundation in the slope section. The analysis results show that the horizontal load has a great influence on the horizontal displacement of the pile, but has a small influence on the vertical displacement, and the vertical load is just the opposite. Inclined load has obvious “p-Δ” effect. The increase in soil elastic modulus and pile stiffness will reduce the displacement of the pile foundation, but after reaching a certain range, the displacement of the pile foundation will tend to be stable. Therefore, in actual engineering, if the displacement of the pile foundation fails to meet the requirements, the hardness of the soil and the stiffness of the pile can be appropriately increased, but not blindly.

Stability analysis of new safety cleaning bank in steep slope mining

Based on the study of the slope with gently granular structure in Xingqiao open mine, a new safety cleaning bank mode for steep slope mining was developed, including setting up dint cut, and forming natural retaining wall based on the character of gentle incline slope. It can effectively eliminate the impact of sliding body on the bottom working place and slope body, reduce the dilution of ore, keep rainwater from upper steps away, decrease influence of the weak intermediate layer, and cut cost of disposal waste rock. The safety and reliability of the mode were analyzed and verified from 3 aspects: static load calculation, ANSYS simulation of dynamic loading and spot experiment. The result of static loading calculation shows that the retaining wall can support accumulation and extrusion of granular body, and the glide or overturn disaster will not take place. The simulations of dynamic loading show that the retaining wall remains stable until sliding body collapses from 360 m (10 sublevels). Only one new safety cleaning bank in each 15 sublevels can fully meet the need of engineering. The new mode sustains steep slope (mining,) increases the angle of ultimate slope, and reduces invalid overburden amount of rock by 3%5%. The result of spot experiment has verified the exactness of the above calculations and simulations.

A gravity similitude model for studying steep rock slopes

A method of a large experimental model coupled with a smaller one and an equivalent replacement method are adopted to study the deformation and the failure mechanism of a steep rock slope, in order to solve the difficult problems in space gravity similitude of the experimental model on steep rock slope with weak layers. The experimental results on the Lianziya Precipice of the Yangtze Three Gorges are in general agreement with the field observations. The experimental method adopted is proved to be successful in molding the complex geological condition especially with the weak layers.

Sustainable water resource management in steep-slope agriculture

Steep-slope agricultural landscapes are under threat due to climate change.On the one hand,the growing fre-quency of extreme high-intensity rainfall events concentrated in both temporal and spatial scales are causing flash floods or slope failure risk scenarios.On the other hand,future climate projections indicate a significant expansion of arid zones in the steep slope agricultural system.There is evidence that these landscapes face a high risk of growing water scarcity.Considering their unique role in crop production,ecosystem diversity,and crop production,ecosystem diversity,and cultural heritage,understanding sustainable water resource manage-ment for mitigating climate change-induced drought has never been more urgent than today.In these landscapes,unique indigenous knowledge of water conservation is adopted to manage water resources improving their re-silience optimally.It is,therefore,necessary to promote water storage to mitigate floods or increase the resilience to prolonged drought(creating at the same time favourable conditions for biodiversity).Modern technological advances(e.g.,high-resolution remote sensing and GIS-based modelling)are crucial in supporting these activities and understanding earth’s surface processes.

Research on Effect of Heap Loading on Deformation and Mechanical Properties of Bridge Double Pile Foundation on Steep Slope

In order to analyze the deformation and stress characteristics of the pile foundation on the slope, this paper uses the finite element software Abaqus for numerical simulation. The displacement and stress data of pile under different working conditions (the combination of heap load and vertical load and horizontal load and inclined load) were collected;the distribution of pile displacement, axial force and bending moment were analyzed. Simulation results show that: slope top loading has little effect on vertical displacement; when the heap load exceeds 200 kPa, the horizontal displacement is greatly affected. Pile axial force decreases with pile burial depth;pile lateral resistance plays a more adequate role in the rock and soil layer. The bending moment of double pile foundation is positive at the top and negative at the bottom. Applied oblique load has obvious p-Δ effect.

Characteristics, Fertility Status and Fertility Capability Classification of Steep Slope Soils of the Dschang Cliff (Cameroon Western Highlands)

Mountainous ecosystem soils are subject to colonization nowadays for agricultural purposes due to an increasing population in towns making the detailed characterization of such soils indispensable. This work aims to characterize the steep slopes soils of the Dschang hills and to evaluate their fertility level for agricultural valorization. Thus, four soil profiles were dug at various topographic positions (summit (SP), shoulder (MP), backslope (BP) and footslope (PP)) following a toposequence. Samples of disturbed and undisturbed soils were taken and analyzed in the laboratory according to standard methods. The Fertility Capability Classification (FCC) and simple limitation methods were used to identify major agricultural constraints. The main results show that profiles thickness is moderate, between 0 and 120 cm, with a high sand content (at least 50%) over the entire toposequence, especially at the surface. The study site has four types of soils, namely Eutric Cambisols (ochric) in SP and Leptic Eutric Cambisols (Humic) in MP, Eutric Cambisols (Humic) in BP and Stagnic Oxygleyic Dystric Gleysols (Humic) in pp. The soils are very acidic at PP, moderately acidic at BP and SP and slightly acidic at MP. Organic matter is higher at the surface than at depth at the topographic segments of MP, BP and PP and low to SP. The C/N ratio is high (>17) in all profiles except P4 (<10). In addition, the cation exchange capacity (CEC), the sum of exchangeable bases, total nitrogen and available phosphorus is low in all profiles. The Ca/ Mg/K balance in all the profiles shows a cation imbalance and a relatively high concentration of exchangeable potassium compared to the ideal situation (76% Ca, 18% Mg and 6% K). The major constraints to crop production are: aluminum toxicity (a) and nutrients leaching (e), textural discontinuity (LS), flooding (g), low nutrient reserve (k), sand (S), clay (C) and slope (t). Hence the fertility capacity classes of these soils are CCaegk (PP), SSek (BP), SSte (MP) and LSaek (SP). To improve the yield, it will require off-season crop cultivation, fertilization and liming, and earthworks.

Buckling failure analysis and numerical manifold method simulation forhigh and steep slope: A case study

Buckling failure of layered rock slopes due to self-weight is common in mountain areas, especially for high andsteep slope, and it frequently results in serious disasters. Previous research has focused on qualitatively evaluatingslope buckling stability and rarely studied the whole process from bending deformation to forming landslide. Inthis work, considering the tensile and compressive characteristics of rock, the simulation of high and steep slopebucking failure evolved in Bawang Mountain, was conducted by numerical manifold method. The bucklingdeformation mechanism and progressive failure process of Bawang Mountain high steep slope were studied. Thereliability of the numerical method was verified by the comparison of theoretical calculation and field measurement data. The results show that numerical manifold method can accurately simulate high and steep slopebuckling failure process by preforming interlayer and cross joints. The process of slope buckling deformation andinstability failure can be divided into minor sliding-creep deformation, interlayer dislocation-slight bending,traction by slope toe-sharp uplift, accelerated sliding-landslide formation. Under the long-term action of selfweight, the evolution of slope buckling from formation to landslide is a progressive failure process, whichmainly contains three stages: slight bending deformation, intense uplift deformation and landslide formation.

Application of Three-Dimensional Laser Scanning and Surveying in Geological Investigation of High Rock Slope

The appearance of 3D laser scanning technology is one of the most important technology revolutions in surveying and mapping field. It can be widely used in many interrelated fields, such as engineering constructions and 3D measurements, owing to its prominent characteristics of the high efficiency and high precision. At present its application is still in the initial state, and it is quite rarely used in China, especially in geotechnical engineering and geological engineering fields. Starting with a general introduction of 3D laser scanning technology, this article studies how to apply the technology to high rock slope investigations. By way of a case study, principles and methods of quick slope documentation and occurrence measurement of discontinuities are discussed and analyzed. Analysis results show that the application of 3D laser scanning technology to geotechnical and geological engineering has a great prospect and value.

Study of the seismic performance of hybrid A-frame micropile/MSE (mechanically stabilized earth) wall

The Hybrid A-Frame Micropile/MSE （mechanically stabilized earth） Wall suitable for mountain roadways is put forward in this study： a pair of vertical and inclined micropiles goes through the backfill region of a highway MSE Wall from the road surface and are then anchored into the foundation. The pile cap and grade beam are placed on the pile tops, and then a road barrier is connected to the grade beam by connecting pieces. The MSE wall＇s global stability, local stability and impact resistance of the road barrier can be enhanced simultaneously by this design. In order to validate the serviceability of the hybrid A-frame micropile/MSE wall and the reliability of the numerical method, scale model tests and a corresponding numerical simulation were conducted. Then, the seismic performance of the MSE walls before and after reinforcement with micropiles was studied comparatively through numerical methods. The results indicate that the hybrid A-frame micropile/ MSE wall can effectively control earthquake-induced deformation, differential settlement at the road surface, bearing pressure on the bottom and acceleration by means of a rigid-soft combination of micropiles and MSE. The accumulated displacement under earthquakes with amplitude of 0.1-0.5 g is reduced by 36.3%-46.5%, and the acceleration amplification factor on the top of the wall is reduced by 13.4%, 15.7% and 19.3% based on 0.1, 0.3 and 0.5 g input earthquake loading, respectively, In addition, the earthquake-induced failure mode of the MSE wall in steep terrain is the sliding of the MSE region along the backslope, while the micropiles effectively control the sliding trend. The maximum earthquake-induced pile bending moment is in the interface between MSE and slope foundation, so it is necessary to strengthen the reinforcement of the pile body in the interface. Hence, it is proven that the hybrid A-frame micropile/MSE wall system has good seismic performance.