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Climate change brings with it phenomena such as large amounts of rainfall in short periods. Infiltration of rainwater into clayey soils is a common trigger for shallow landslides on slopes. In this way, numerous shallow landslides occur in the area of northern Croatia, and a characteristic example is the landslide “Orehovčak”. To stop the sliding of the destabilized slope, it was necessary to solve the drainage of water that infiltrates the landslide body. For this purpose, detailed geotechnical investigations and monitoring were conducted. Many data were collected at the investigation site, especially soil characteristics and groundwater fluctuations. The surface soil on the slope consists of highly plastic clay, and the sliding surface was created in contact with the solid subsoil of marl, the depth of which varies positionally. The analyses confirmed that water is a slip trigger. To solve the problem, excavations and installation of deep drains were performed. The slope safety factor confirms landslide stabilization, whose calculated value after rehabilitation was Fs = 1.645. Inclinometer readings carried out after remediation show that slope slippage stopped. This confirms that the presented remediation method is very applicable to shallow landslides in northern Croatia and similar landslides around the world.

Climate change brings with it phenomena such as large amounts of rainfall in short periods. Infiltration of rainwater into clayey soils is a common trigger for shallow landslides on slopes. In this way, numerous shallow landslides occur in the area of northern Croatia, and a characteristic example is the landslide "Orehovčak". To stop the sliding of the destabilized slope, it was necessary to solve the drainage of water that infiltrates the landslide body. For this purpose, detailed geotechnical investigations and monitoring were conducted. Many data were collected at the investigation site, especially soil characteristics and groundwater fluctuations. The surface soil on the slope consists of highly plastic clay, and the sliding surface was created in contact with the solid subsoil of marl, the depth of which varies positionally. The analyses confirmed that water is a slip trigger. To solve the problem, excavations and installation of deep drains were performed. The slope safety factor confirms landslide stabilization, whose calculated value after rehabilitation was Fs = 1.645. Inclinometer readings carried out after remediation show that slope slippage stopped. This confirms that the presented remediation method is very applicable to shallow landslides in northern Croatia and similar landslides around the world. [ABSTRACT FROM AUTHOR]

As a common geohazard, landslides may cause enormous losses of human lives and properties. It is necessary to prevent landslides by effective technical measures. The grouted micro-steel-pipe pile group is a typical composite anti-sliding structure applied in landslide-stabilization engineering, where the micropiles and the surrounding geomaterials interact to resist the landslide thrust. In this study, laboratory experiments were carried out to investigate the anti-sliding performance of a kind of 3 × 3 grouted micro-pipe pile group anchored in bedrock at different row spacing of micropiles. The results indicate that the grouted micro-pipe pile group shows a relatively large anti-sliding capacity at row spacing of 4–8 times the micropile diameter. The active earth pressure on micropiles induced by soil movement shows an approximately triangular distribution. More of the thrust load transfers from the rear pile row to the middle and front pile rows gradually as the thrust load increases, where the ratios of earth thrust among the rear, middle and front pile rows can reach up to 1:0.60:0.44. The maximum bending moment occurs at the anchoring segment close to the bedrock surface. As the thrust loading increases, the maximum bending moment of the rear pile row will first increase to a peak value and then rapidly decrease, implying the micropile group is about to lose its anti-sliding ability. The development of deformation can be characterized as three stages including the slow deformation stage, accelerating deformation stage and unstable deformation stage. It is recommended that the horizontal displacement of pile head should be less than 1% of the loading depth for actual engineering design. [ABSTRACT FROM AUTHOR]

In this study, a large-scale model test was performed to investigate the effect of the single-row and double-row micropiles on the landside stabilization. For two different testing configuration settings, the bending moment along the micropiles, failure mode, and force condition were captured and compared. It is found that the landslide thrust on piles was distributed in a triangular shape. The piles in the front row carried greater pressure than the piles in the rear row. The resistance of the sliding body behind the pile was distributed in a parabolic shape, and mainly concentrated on the middle of the pile. The piles were destroyed due to the combined shearing and bending impact applied near the slipping surface. The boundary of the failure zone was from the position of two times the pile diameter under the slipping surface to the position of two and a half times the pile diameter above the slipping surface. Under the action of the landslide, each row of piles deformed at the same time. The capability of landslide stabilization for double-row piles was better than that of a single-row pile. The sections of the pile above slide surface were mainly subjected to negative bending moments and were distributed mainly within the pile length range of one-third of the anti-sliding section above the sliding surface. The pile body of the embedded section located in the range of ten times the pile diameter below the sliding surface was subjected to a positive bending moment.

A large number of landslides occur in North-Eastern Italy during every rainy period due to the particular hydrogeological conditions of this area. Even if there are no casualties, the economic losses are often significant, and municipalities frequently do not have sufficient financial resources to repair the damage and stabilize all the unstable slopes. In this regard, the research for more economically sustainable solutions is a crucial challenge. Floating composite anchors are an innovative and low-cost technique set up for slope stabilization: it consists in the use of passive sub-horizontal reinforcements, obtained by coupling a traditional self-drilling bar with some tendons cemented inside it. This work concerns the application of this technique according to the observational method described within the Italian and European technical codes and mainly recommended for the design of geotechnical works, especially when performed in highly uncertain site conditions. The observational method prescribes designing an intervention and, at the same time, using a monitoring system in order to correct and adapt the project during realization of the works on the basis of new data acquired while on site. The case study is the landslide of Cischele, a medium landslide which occurred in 2010 after an exceptional heavy rainy period. In 2015, some floating composite anchors were installed to slow down the movement, even if, due to a limited budget, they were not enough to ensure the complete stabilization of the slope. Thanks to a monitoring system installed in the meantime, it is now possible to have a comparison between the site conditions before and after the intervention. This allows the evaluation of benefits achieved with the reinforcements and, at the same time, the assessment of additional improvements. Two stabilization scenarios are studied through an FE model: the first includes the stabilization system built in 2015, while the second evaluates a new solution proposed to further increase the slope stability. [ABSTRACT FROM AUTHOR]

Loess landslides have complicated deformation mechanisms. Accurately describing the internal failure deformation of loess landslides and establishing a theoretical method of landslide instability evaluation for the prevention of subsequent landslides have become important topics in western development project construction in China. This paper presents a case study of the Zhonglou Mountain landslide in Shaanxi Province, China. Based on field investigation results, a two-dimensional stability analysis model was constructed using the finite element method. Taking the deformation characteristics of the landslide as the research basis, the distribution laws of the displacement, stress, and shear strain of this landslide were identified with the strength reduction finite element numerical simulation method. Additionally, the safety factor was evaluated under normal and storm conditions. The numerical simulation results show that the horizontal tensile stress of the landslide was mainly distributed in the middle and upper parts of the landslide under normal conditions, while the vertical tensile stress was distributed near the sliding surface. Under heavy rainfall, the sliding force increased, and the anti-sliding force and anti-sliding section decreased; the location of the maximum shear strain shifted down from the middle and upper parts of the landslide body to the area with a shear crack, and the plastic shear strain area expanded along nearly the entire the sliding surface, leading to the occurrence of a landslide. Thus, the use of anti-slide piles to stabilize the landslide was proposed and tested. Monitoring points were arranged along the sliding surface to evaluate the displacement, stress, and strain responses. The on-site observation results agreed with the modeling results. The use of anti-slide piles was demonstrated to be an effective stabilization method for the Zhonglou Mountain landslide. [ABSTRACT FROM AUTHOR]

• A rotational landslide in a waste dump threatened services of a natural park. • Pioneer application of geomorphic reclamation to landslide stabilization. • Landslide and geomorphic reclamation were monitored by TLS and SfM-UAV. • SfM-UAV photogrammetry arises as a valid method to obtain HRTs in mining areas. Two abandoned kaolin mines, surrounding one of the most outstanding natural parks of Spain, the Alto Tajo, have caused frequent environmental impacts. Within these are unstable areas prone to extensive mass movements that influence off-site sediment dynamics over the fluvial system. A waste dump in the Nuria mine obstructing a stream in the center of a valley experienced a rotational landslide. Mass movement between 2012 and 2014 was 0.025–0.026 m day−1. To mitigate the high risk of an earthflow, a novel stabilizing surface drainage technique was implemented. Two remedial valleys designed with fluvial channels were constructed surrounding the landslide main body using natural landform design and regrading, with no need for artificial materials such as concrete or piles. This novel remediation process is generically termed geomorphic reclamation. The specific method applied to this site was GeoFluv with Natural Regrade software. Before (2014) and after geomorphic stabilization (2015–2017), the landslide was monitored using Digital Elevation Models (DEMs) of Difference (DODs) obtained by a Geomorphic Change Detection (GCD) tool. Two modern techniques, Terrestrial Laser Scanning (TLS), and, Structure from Motion photogrammetry combined with an Unmanned Aerial Vehicle (SfM-UAV), were used to acquire High-Resolution Topographies (HRTs) from which DEMs were derived. Data analysis and field monitoring results demonstrate that: i) the Nuria mine transformed almost 50% of the upper part of a natural catchment; ii) a waste dump active landslide with a surface rupture <15m posed a high-risk hazard due to its continuous advance; iii) geomorphic reclamation succeeded in stabilizing the landslide during the monitoring period; iv) SfM-UAV-based topographies offer better accuracy and higher resolution, are cheaper and are obtained faster than TLS for mine areas. [ABSTRACT FROM AUTHOR]