Search

The current research on the deformation of buried pipeline under rockfall impact load is generally based on the analysis of the pipeline cross-sectional deformation, and the deformation caused by lateral deflection of pipeline is less considered. The two-stage method is introduced to analyze the deformation of the adjacent buried pipeline by rockfall impact. The first stage solves for the additional stress caused by rockfall impact in the pipeline, and the second stage solves for the pipeline deformation caused by the additional stress. The validity and accuracy of the method in this paper are verified by comparing with the solutions in the existing literature. In addition, the influence law of pipe diameter, wall thickness, burial depth, rockfall action position and rockfall impact velocity on the deformation of buried pipes is analyzed. The research results show that for certain working conditions and soil parameters, there will be an optimal pipeline diameter D, which minimizes the deformation of the buried pipeline under the rockfall impact; based on Pasternak foundation model and Winker foundation model to calculate the rockfall impact load on buried pipe deformation respectively, it is found that the difference between these two foundation models on pipe deformation is small.

The trajectory of a rolling stone begins and is characteristically accompanied by a certain initial rotation. Considering the influence of the initial rotation, the four basic motion forms of a rolling rock movement are analyzed, based on contact mechanics and kinematics principles. The speed calculationF formulas for a rolling rock mass were obtained. Besides, taking the dangerous rock slope of Changheba Hydropower Station in Sichuan Province as an example, the entire moving process of a rolling stone was simulated using “Rocfall software”, and the influence of an initial rotation on total kinetic energy, bounce height, and trajectory of the rolling stone during the movement was analyzed. According to the results, the determination of the most dangerous position during the movement of the rolling stone is not be affected by the initial rotation angular velocity. However, the maximum bounce height of the rolling stone at the most dangerous position increases with the increase of the initial rotation; the initial rotation of a rolling stone affects the longest distance and total horizontal distance. The probability density distribution of total kinetic energy and horizontal distance followed the Gaussian distribution; the influence of initial rotation on the central value can not be ignored. In this case, if the rotation was ignored, the rockfall disaster range would be underestimated, the rate can reach up to 94% when $$\omega =200\hbox {rad/s}$$ . The initial rotation of a rolling stone has a different sensitivity to the slope characteristics. The smooth and hard surface was the most sensitive. The larger the angular velocity, the more sensitive the slope. Therefore, the influence of a rocking stone rotating velocity and slope surface material must be considered in investigating the trajectory of the rockfalls and the provision of protective measures.

The assessment of rock fall hazard of a natural rock slope surface with ancient rock cave monuments of historic importance at World-Heritage site of Ajanta in the state of Maharashtra in India, embedded in basaltic rock formation is carried out and presented. In past the site has witnessed many small and large scale rock falls in the form of boulders which could cause the loss to the ancient rock caves of historic importance as well as en-dangering the visitor’s safety. The main cause of the rock fall is dislocation of the boulders from the natural rock surface slopes due to heavy rainfall as well as due to erosion, rock weathering, trees roots widening etc. In the present study, the rock slope surface and dislocated boulders vulnerability to failure risk is carried out with the Rockfall Hazard Rating System (RHRS) in tandem with other empirical approaches available for rock mass classification. The study using rockfall hazard rating system requires tedious field-work due to the involvement of a large number of parameters and long-stretch of the site under question. The detailed field study is carried out for the evaluation of various parameters involved in the RHRS as well as that of various empirical approaches applied. In the case of the cumulative RHRS score is more than 500 which implies that the slope surface or critical boulder site is unstable, prone to failure and need immediate attention for remedial measures. Accordingly, stabilization measures are planned on the priority basis.

Ankara Citadel which is one of the important cultural heritages in Turkey settles in the oldest part of Ankara. Rockfall event has occurred around the Citadel located on a steep hill where andesite is exposed. The rockfall problem causes a great risk to the surrounding area where road, school, floral shops, car parking. Therefore, the major aim of this research is to reveal the rockfall risk around the castle. The rockfall problems around the Ankara Citadel may be linked with weathering, freezing–thawing, earthquake, and cooling joints, and effects or combination of these in the rock units. The rockfall-related hazard at the Citadel is assessed by 2-D rockfall analyses along several profiles in this investigation. Field observations and stability analyses (kinematic and limit equilibrium) of the slopes reveal that there exist many blocks ready to fall down. Four different andesite block sizes measured in the field are separately analyzed on the basis of bounce height, fall-out distance, velocity and kinetic energy of the blocks. The obtained data are evaluated to define the possible rockfall-based hazard zones. Based on the danger zones acquired from the rockfall analyses, the removal of the fallen and loosen andesite blocks and the installation of catch barriers with suggested properties are recommended. Besides, the risk integrated into rockfall hazard rating system on the basis of structural and morphological criteria of the rock mass reveals that medium risk category to be mitigated by light remedial measures for the indicative protection exists in the study area.

Moziyan is an area containing unstable rock masses located in Hechuan District, Chongqing, China and has constantly seen group-occurring rockfalls since 1964. The present study aims to investigate the damage of Moziyan rock mass and protect the mining areas and residential areas from rockfall phenomenon. Mohr–Coulomb model in FLAC–3D Program was built to find out the rockfall initiation position. RocFall program has been used to calculate the distribution curves of stopping positions, bounce height, total kinetic energy, and translational velocity of the falling blocks varying with horizontal distance. According to the simulation results, the stability of Moziyan rock mass is controlled by the unloading cracks behind the slope, and the falling blocks have a maximum bounce height and maximum total kinetic energy of 0 m and 2720.9 kJ respectively at the horizontal position of 461.6 m, where proper protection measures should be adopted to minimize the risk of the damage of the Moziyan rock mass. Conclusively, the results of simulation indicate that a barrier of 3 m height and 3000 kJ absorption capacity is enough to resist the falling stones with a maximum speed of 13.2 m/s at the horizontal position of 461.6 m.

Rockfalls are one of the most dominant geological hazards in mountainous rocky regions with the potential to turn catastrophic if they occur in an anthropogenic environment. Therefore, the identification of potential rockfall locations is of high importance. Susceptibility is the magnitude that describes these locations and its qualitative and quantitative assessment is necessary for the timely treatment of potential events. Quantitative susceptibility assessment can be conducted using either data-driven methods such as bivariate and multivariate statistics as well as artificial neural networks or numerical methods such as static and dynamic models. In both approaches mathematical assumptions have to be made concerning the predisposing factors distribution and so there is an inherent need to achieve the higher possible confidence level in the input data. Such high-resolution data can be acquired using light detection and ranging (LiDAR) scanners. In the current study, LiDAR technology was implemented, and the data processing technique is analyzed step by step providing the reader with a view of the whole procedure. The results produced by the current methodology are validated and interpreted according to in situ measurements and observations based on unmanned aerial vehicle imagery. Post data processing, joint orientation, joint spacing and potential block volumes were extracted considering both persistent and non-persistent joints. The proposed methodology provides the creation of detailed high-resolution spatial distribution maps of the previously mentioned parameters, considering the variability of their values along the slope. The results can be used in a space-resolved susceptibility assessment providing higher-resolution input data for the subsequent susceptibility analysis.

Rockfall hazard is becoming increasingly fierce due to the higher intensity of human activities in recent years, but research on the impact process has almost come to a standstill, and there is no available method to solve the impact characteristic parameters of the falling rock. The free-fall drop of a spherical rockfall on three different granular layers was examined, and the acceleration value of the falling rock with time was assessed with a three degree of freedom linear accelerometer. Then, the velocity of the rockfall and penetration depth were successively obtained by computing the integral and double integral of the acceleration over time. The time-history curves of the acceleration and velocity of the rockfall and the curve of the acceleration with the penetration depth show that the time-history curve of the rockfall velocity can be characterized by a logistic function. The acceleration time-history curve has the characteristics of a unimodal pulse, and the acceleration curve with the penetration depth is similar in shape to an inverted “U”. The cushioning effect of the sand is the best and that of the gravel layer is the worst in these three different granular layers.

Due to limitations associated with field tests and equipment, the majority of the research conducted to evaluate the mechanical behaviour of rockfall protection barriers considers only free-falling rocks when simulating the actual situation. Based on this fact, this study introduces ψ, the ratio of the rotational kinetic energy to the kinetic energy of a rockfall, to study the rotational effect and to achieve an optimal design. LS-DYNA is used to analyse the dynamic response of the system under the impact of a rolling rock. The results indicate that a rolling rock is an adverse condition. As ψ increases, the rock displacement decreases with a clear outward rolling, which causes greater deformation of the energy dissipater of the upper support rope and greater displacement of the free end of the steel post. As ψ approaches 0.2, the tensile forces of the upper support rope and the anchor rope reach their peak values, which are 39% higher than the corresponding values when ψ is 0. Additionally, the maximum forces of the steel post and net increase by 29 and 20%, respectively. The energy consumption of the break rings and wire ring net decrease linearly. However, the slide energy and friction energy increase linearly. To facilitate further research, correction coefficients that incorporate the effect of a rotational impact and formulas that include a relation between ψ and the force of each component are obtained through curve fitting.

Wangxia rock mass was situated in Three Gorges around Yangtze River and considered to be one of largest unstable rock mass in China. The present study aims to investigate the damage of Wangxia rock mass and protect the lives of people and shipping from rockfall phenomenon. Mohr–Coulomb model in Universal Distinct Element Code was built to find out the rockfall initiation position. RocFall 4.0 program has been used to calculate horizontal location of rock end-points, maximum bounce heights, total kinetic energy, and translational velocities of the falling blocks of different weights and the input parameters were obtained by back analysis. The results show that the maximum value of bounce height and total kinetic energy is 3.63 m and 2819 kJ respectively at the horizontal location of 152.4 m, where proper protection measures should be adopted to minimize the risk of the damage of the Wangxia rock mass. Finally, the results of simulation indicate that a barrier of 5 m height and 3000 kJ absorption capacity is enough to resist the falling stones.

Rockfall is a frequent engineering disaster confronted in the capital construction engineering. The key for preventing rock fall is the evaluation of the rockfall trajectory. After extensive analysis, an innovative calculation method of rockfall trajectory, called segmented cycling algorithm, has been proposed in the paper. According to the contact relationship between the rolling stones and the slope surface, the movement divided into three sections which include the bouncing phase, the rolling (sliding) phase and collision phase, the formulae to calculate the velocity of different phases of motion are proposed respectively by segmented cycling algorithm. A similar model, based on a rock slope in Chongqing–Wanzhou highway, is established to verify the capability and validity of the presented algorithm. Compared with existing algorithm, the new algorithm is simple and clear, easy to use and so on. The algorithm meets the law of the movement of rockfall and can be used to forecast the kinetic feature of rockfall. It is also used as the basis for rockfall disaster prevention.

Transportation corridors that pass through mountainous or hilly areas are prone to rockfall hazard. Rockfall incidents in such areas can cause human fatalities and damage to properties in addition to transportation interruptions. In Malaysia, the North–South Expressway is the most significant expressway that operates as the backbone of the peninsula. A portion of this expressway in Jelapang was chosen as the site of rockfall hazard assessment in multiple scenarios. Light detection and ranging techniques are indispensable in capturing high-resolution digital elevation models related to geohazard studies. An airborne laser scanner was used to create a high-density point cloud of the study area. The use of 3D rockfall process modeling in combination with geographic information system (GIS) is a beneficial tool in rockfall hazard studies. In this study, a 3D rockfall model integrated into GIS was used to derive rockfall trajectories and velocity associated with them in multiple scenarios based on a range of mechanical parameter values (coefficients of restitution and friction angle). Rockfall characteristics in terms of frequency, height, and energy were determined through raster modeling. Analytic hierarchy process (AHP) was used to compute the weight of each rockfall characteristic raster that affects rockfall hazard. A spatial model that considers rockfall characteristics was conducted to produce a rockfall hazard map. Moreover, a barrier location was proposed to eliminate rockfall hazard. As a result, rockfall trajectories and their characteristics were derived. The result of AHP shows that rockfall hazard was significantly influenced by rockfall energy and then by frequency and height. The areas at risk were delineated and the hazard percentage along the expressway was observed and demonstrated. The result also shows that with increasing mechanical parameter values, the rockfall trajectories and their characteristics, and consequently rockfall hazard, were increased. In addition, the suggested barrier effectively restrained most of the rockfall trajectories and eliminated the hazard along the expressway. This study can serve not only as a guide for a comprehensive investigation of rockfall hazard but also as a reference that decision makers can use in designing a risk mitigation method. Furthermore, this study is applicable in any rockfall study, especially in situations where mechanical parameters have no specific values.

Rockfall is one of the common geological disasters in China, which causes huge losses to the country and the people. Based on the impulse and impulse moment theorems, and considering the stochastic factors in the process of rolling stone collision, a stochastic collision model of the rockfall-wall is established, and the analytical solution for the velocity of the rolling stone after collision is obtained. When considering the initial rotation of the rolling stone, the predicted result from the model agrees with the experimental result, and when the initial rotation is ignored, the result obtained from the model will underestimate/overestimate the rebound velocity, and the maximum reaches 20%. Furthermore, the probability distribution and the fit curve for the velocity and trajectory of the rolling stone depends on the project. The result shows that the rebound velocity and angle of the rolling stone follow a typical Gaussian distribution, and the horizontal distance and bounce height follow the Gaussian and exponential distribution, respectively. The prediction of the velocity and trajectory of the rolling stone provides a theoretical basis for the optimal design of engineering structures.

Rockfall hazard is a very common phenomenon mainly occurring in mountainous slopes, coastal cliffs, volcanoes, riverside, and trenches. In the present research, a model is developed for hazard analysis of seismic rockfalls on a regional scale. For this purpose, three models including Adaptive Neuro-Fuzzy Inference System (ANFIS), multilayer perceptron artificial neural network (MLP), and radial basis function artificial neural network (RBF) were utilized. Firooz Abad-Kojour earthquake of 2004 was used as the benchmark and the model base. The rockfall-susceptible zones predicted by ANFIS, MLP, and RBF methods were compared with the database (distribution map) of seismic rockfalls. The results showed a good overlap between MLP-predicted rockfall hazard zones and database (distribution map) of seismic rockfalls. To evaluate the statistical results of ANFIS, MLP, and RBF models, the verification parameters with high accuracy such as density ratio, quality sum (Qs), and Receiver Operating Characteristic Curve were employed. By analyzing the hazard maps and considering the Qs index obtained by ANFIS (26.76) and MLP (49.19), and RBF (13.84), it could be observed that the calculated Qs of MLP were higher than those of ANFIS and RBF. Moreover, based on the obtained value of the area under the curve from ANFIS (0.984), MLP (0.986), and RBF methods (0.884), it is seen that the MLP network, compared to ANFIS and RBF models, provided a higher accuracy in hazard analysis of rockfalls caused by the earthquake of Firooz Abad-Kojour of 2004.

The stability of a granitic rock cut located within a densely populated residential area in Madinah, Saudi Arabia, was investigated to avoid rock failure consequences. Based on the field inspection, this cut is characterized by a very irregular face leading to the occurrence of rock sliding and rockfall events in the area. Moreover, this cut lacks any type of stabilization or protection measurements. Kinematic analysis was used to analyze rock sliding events while RocFall software was used to analyze the mechanism of rockfall incidents. The results indicated to the high probability of wedge failures to take place (≈ 67%) as well as the toppling failures but with lower probability (

The main objective of this study was to evaluate the influence of the degree of weathering on the strength properties and parameters of a kinzigite gneiss. Kinzigites are important to study do to their common occurrence in southeastern Brazil, as in the city of Rio de Janeiro, where many rock slope stability problems—such as rock falls, rockslides and debris flows—are related to the occurrence of such rocks. This manuscript presents results on the influence of weathering on the parameters of the Hoek–Brown strength criterion, which is not commonly discussed in the technical literature. Specimens of this rock type were collected from a typical weathering profile developed under a tropical climate, exhibiting four classes of alteration: sound rock (I), slightly weathered rock (II), moderately weathered rock (III) and highly weathered rock (IV). Tests were performed in accordance with methods suggested by the ISRM (The complete ISRM suggested methods for rocks characterization, testing and monitoring. ISRM Turkish National Group Ankara, Turkey, 2007). The results showed that the mi parameter of the Hoek–Brown strength criterion was clearly affected by weathering; mi was 21.31 ± 8.24 for Class I materials, 13.17 ± 2.53 for Class II materials, and 11.12 ± 7.29 for Class III materials.

Cut slopes are very sensitive to weathering because of disturbed rock mass and topographical condition by excavation. During and right after an excavation process of a cut slope, weathering and erosion may act on this newly exposed rock material and mass. These acting on the rock may degrade and change its engineering properties and the stability of the cut slope in its engineering lifetime. In this study, weathering and excavation effects on stability of sixteen cut slopes in flysch-like deposits at North West Black Sea region of Turkey were investigated. The properties of the weathered and fresh rock materials including unit weight, uniaxial compressive strength, direct shear, slake durability and methylene blue tests were determined in the laboratory. Kinematic, limit equilibrium and rockfall analyses were performed for each stop. It was found that two testing cycles are insufficient to assess the degradation of the rocks based on the slake durability test results. Based on the limit equilibrium analyses, plane failure is expected with low factor of safety in one of the cut slopes. Factor of safeties of the cut slopes for mass failure are generally high except two slopes also evidenced with the field observations. No significant rockfall problems are expected according to the analyses. The effects of weathering and excavation were found to be changing between 10 and 50 cm in average within 5 years lifespan of the cut slopes. According to the results these disturbed zones would only create surficial degradation for the current thicknesses.

The coefficients of restitution are among the most important parameters in rockfall trajectory modelling. However, they are difficult to obtain, they depend on many parameters and they present a significant variation even for similar geotechnical and kinematic conditions. Many definitions for the coefficients of restitution exist, but there is no agreement on which describes better the response of a block to an impact. In this paper, an extensive experimental investigation is presented, consisting of 600 oblique impact tests and the various coefficient of restitution definitions are assessed, with an emphasis on the effects of impact angle and angular velocity. These tests follow on the research presented in Asteriou and Tsiambaos (Int J Rock Mech Min Sci 106:41–50, 2018), where free-fall tests were performed to address the effects of impact velocity, block mass and material type. It was found that all those parameters affect significantly the coefficients of restitution. Moreover, an empirical model was proposed to estimate the coefficient of restitution for central impacts. The applicability of this model is extended for oblique impacts based on the results of the tests presented in this paper.

Many sources of data (remote sensing and meteorological data, soils and groundwater samples) were used to estimate the magnitude of geological hazards, which are confirmed with field and laboratory investigation in Najran area, Kingdom Saudi Arabia. Najran area is one of these locations. It is subjected to a range of geo-hazards due to its intrinsic physiographic and geologic nature. Najran area is a growing urban and agricultural development region; however, some infrastructures have been constructed in vulnerable locations to geo-environmental hazards. The potential geo-hazards that may occur under desert conditions include sand accumulations, dune movement, mass westing and rock fall hazards, flash floods, sand stroom and problematic soils. The current study throws more light on all these geo-hazards in Najran area. Also, remediation methods for geo-hazard should be proposed to avoid these natural hazards. The present study is a trail to calculate and evaluate the drainage basins properties and potentiality using remote sensing and (GIS) tools. Twenty morphometric parameters were measured, in order to identify and evaluate flash flood hazards. Flash flood hazards in the Wadi Najran watershed is classified into three groups based on their morphometric parameters results; namely, highly, moderately and low slightly hazard degree. Our findings indicate that Najran area needs more attention and care. The Saudi Government has to join together with other people to reduce the resulting geological hazards.

The purpose of this experimental investigation is to obtain strain measurements via optical fibre sensors in the drum geotechnical centrifuge of ETH Zurich. It is part of a test series with main goal to study the behaviour of reinforced slopes subjected to self weight loading and subsequently to an impact from a rockfall event. In total 13 scaled reinforced slope models were built with a height of 180 mm and a slope inclination of 2V:1H, optimising the materials used and the different ways of model making. The maximum g-levels were 50 and 100 g and the impact loading was applied at 50 g. The optical fibre sensors were placed on various layers of the reinforcement and at different positions. Strain measurements that were recorded during different tests are logical and expected, demonstrating that optical fibre sensors can successfully be used for measuring linear strain on reinforcement layers that are tested under enhanced gravity in the geotechnical centrifuge. The experimental set up as well as the opportunities and challenges of these measurements are presented and discussed. Finally, correspondent prototype numerical models were created and analysed and the results of this analysis are compared to the corresponding experimental ones.

Land sliding is a geotechnical event that includes a wide range of ground movements such as rockfalls, deep failure of slopes and shallow debris flows, and it can cause various problems in varied civil fields such as roads and dams. Since most conventional methods are neither inexpensive nor applicable everywhere, attention has nowadays been drawn to soil bioengineering using vegetation as the environment-friendly method for slope stabilization. Soil bioengineering or using vegetation in civil engineering design is mostly applicable to shallow slope stabilization projects characterized by unstable slopes with surface movement. Vegetation has both a silent effect on soil improvement to predict the landslide and a mechanical role to increase shear and pulling-out stress on the soil. During the last decade, many researches have been carried out to clarify the effect of vegetation on slope stability, but many questions still remain to be answered.

Statistical analyses of landslide deposits from similar areas provide information on dynamics and rheology, and are the basis for empirical relationships for the prediction of future events. In Central America landslides represent an important threat in both volcanic and non-volcanic areas. Data, mainly from 348 landslides in Nicaragua, and 19 in other Central American countries have been analyzed to describe landslide characteristics and to search for possible correlations and empirical relationships. The mobility of a landslide, expressed as the ratio between height of fall (H) and run-out distance (L) as a function of the volume and height of fall; and the relationship between the height of fall and run-out distance were studied for rock falls, slides, debris flows and debris avalanches. The data show differences in run-out distance and landslide mobility among different types of landslides and between debris flows in volcanic and non-volcanic areas. The new Central American data add to and seem consistent with data published from other regions. Studies combining field observations and empirical relationships with laboratory studies and numerical simulations will help in the development of more reliable empirical equations for the prediction of landslide run-out, with applications to hazard zonation and design of optimal risk mitigation measures.

Unusual circumstances may require that a longwall retreat into or through a previously driven room. The operation can be completed successfully, but there have been a number of spectacular failures. To help determine what factors contribute to such failures, a comprehensive international database of 131 case histories has been compiled. The cases include six failures where major rock falls occurred in front of the shields, and seven even more serious failures involving major overburden weighting. The case studies suggest two types of room failure mechanism. The first is a roof fall type failure caused by loading of the immediate roof at the face as the fender or remnant longwall panel narrows. The second is an overburden weighting type failure caused by the inability of the roof to bridge the recovery room and face area, and affecting rock well above the immediate roof. The data indicate that the roof fall type of failure is less likely when intensive roof reinforcement (bolts, cables and trusses) is employed together with higher-capacity shields. The overburden weighting failures, in contrast, occurred when the roof was weak and little standing support was used. Weighting failures were not greatly affected by the density of roof reinforcement. In one of the overburden weighting cases, in a Pittsburgh coalbed mine, stress cell, convergence, bolt load and extensometer data have been used to analyze the failure in detail.